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• How to design a data model that deals with (real) contracts?

  - by Geoffrey

  I was looking for some advice on designing a data model for contract administration. The general life cycle of a contract is thus: Contract is created and in a "draft" state. It is viewable internally and changes may be made. Contract goes out to vendor, status is set to "pending" Contract is rejected by vendor. At this state, nothing can be done to the contract. No statuses may be added to the collection. Contract is accepted by vendor. At this state, nothing can be done to the contract. No statuses may be added to the collection. I obviously want to avoid a situation where the contract is accepted and, say, the amount is changed. Here are my classes: [EnforceNoChangesAfterDraftState] public class VendorContract { public virtual Vendor Vendor { get; set; } public virtual decimal Amount { get; set; } public virtual VendorContact VendorContact { get; set; } public virtual string CreatedBy { get; set; } public virtual DateTime CreatedOn { get; set; } public virtual FileStore Contract { get; set; } public virtual IList<VendorContractStatus> ContractStatus { get; set; } } [EnforceCorrectWorkflow] public class VendorContractStatus { public virtual VendorContract VendorContract { get; set; } public virtual FileStore ExecutedDocument { get; set; } public virtual string Status { get; set; } public virtual string Reason { get; set; } public virtual string CreatedBy { get; set; } public virtual DateTime CreatedOn { get; set; } } I've omitted the filestore class, which is basically a key/value lookup to find the document based on its guid. The VendorContractStatus is mapped as a many-to-one in Nhibernate. I then use a custom validator as described here. If anything but draft is returned in the VendorContractStatus collection, no changes are allowed. Furthermore the VendorContractStatus must follow the correct workflow (you can add a rejected after a pending, but you can't add anything else to the collection if a reject or accepted exists, etc.). All sounds alright? Well a colleague has argued that we should simply add an "IsDraft" bool property to VendorContract and not accept updates if IsDraft is false. Then we should setup a method inside of VendorContractStatus for updating the status, if something gets added after a draft, it sets the IsDraft property of VendorContract to false. I do not like this as it feels like I'm dirtying up the POCOs and adding logic that should persist in the validation area, that no rules should really exist in these classes and they shouldn't be aware of their states. Any thoughts on this and what is the better practice from a DDD perspective? From my view, if in the future we want more complex rules, my way will be more maintainable over the long run. Say we have contracts over a certain amount to be approved by a manager. I would think it would be better to have a one-to-one mapping with a VendorContractApproval class, rather than adding IsApproved properties, but that's just speculation. This might be splitting hairs, but this is the first real gritty enterprise software project we've done. Any advice would be appreciated!

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• How to best propagate changes upwards a hierarchical structure for binding?

  - by H.B.

  If i have a folder-like structure that uses the composite design pattern and i bind the root folder to a TreeView. It would be quite useful if i can display certain properties that are being accumulated from the folder's contents. The question is, how do i best inform the folder that changes occurred in a child-element so that the accumulative properties get updated? The context in which i need this is a small RSS-FeedReader i am trying to make. This are the most important objects and aspects of my model: Composite interface: public interface IFeedComposite : INotifyPropertyChanged { string Title { get; set; } int UnreadFeedItemsCount { get; } ObservableCollection<FeedItem> FeedItems { get; } } FeedComposite (aka Folder) public class FeedComposite : BindableObject, IFeedComposite { private string title = ""; public string Title { get { return title; } set { title = value; NotifyPropertyChanged("Title"); } } private ObservableCollection<IFeedComposite> children = new ObservableCollection<IFeedComposite>(); public ObservableCollection<IFeedComposite> Children { get { return children; } set { children.Clear(); foreach (IFeedComposite item in value) { children.Add(item); } NotifyPropertyChanged("Children"); } } public FeedComposite() { } public FeedComposite(string title) { Title = title; } public ObservableCollection<FeedItem> FeedItems { get { ObservableCollection<FeedItem> feedItems = new ObservableCollection<FeedItem>(); foreach (IFeedComposite child in Children) { foreach (FeedItem item in child.FeedItems) { feedItems.Add(item); } } return feedItems; } } public int UnreadFeedItemsCount { get { return (from i in FeedItems where i.IsUnread select i).Count(); } } Feed: public class Feed : BindableObject, IFeedComposite { private string url = ""; public string Url { get { return url; } set { url = value; NotifyPropertyChanged("Url"); } } ... private ObservableCollection<FeedItem> feedItems = new ObservableCollection<FeedItem>(); public ObservableCollection<FeedItem> FeedItems { get { return feedItems; } set { feedItems.Clear(); foreach (FeedItem item in value) { AddFeedItem(item); } NotifyPropertyChanged("Items"); } } public int UnreadFeedItemsCount { get { return (from i in FeedItems where i.IsUnread select i).Count(); } } public Feed() { } public Feed(string url) { Url = url; } Ok, so here's the thing, if i bind a TextBlock.Text to the UnreadFeedItemsCount there won't be simple notifications when an item is marked unread, so one of my approaches has been to handle the PropertyChanged event of every FeedItem and if the IsUnread-Property is changed i have my Feed make a notification that the property UnreadFeedItemsCount has been changed. With this approach i also need to handle all PropertyChanged events of all Feeds and FeedComposites in Children of FeedComposite, from the sound of it, it should be obvious that this is not such a very good idea, you need to be very careful that items never get added or removed to any collection without having attached the PropertyChanged event handler first and things like that. Also: What do i do with the CollectionChanged-Events which necessarily also cause a change in the sum of the unread items count? Sounds like more event handling fun. It is such a mess, it would be great if anyone has an elegant solution to this since i don't want the feed-reader to end up as awful as my first attempt years ago when i didn't even know about DataBinding...

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• Const-correctness semantics in C++

  - by thirtythreeforty

  For fun and profit™, I'm writing a trie class in C++ (using the C++11 standard.) My trie<T> has an iterator, trie<T>::iterator. (They're all actually functionally const_iterators, because you cannot modify a trie's value_type.) The iterator's class declaration looks partially like this: template<typename T> class trie<T>::iterator : public std::iterator<std::bidirectional_iterator_tag, T> { friend class trie<T>; struct state { state(const trie<T>* const node, const typename std::vector<std::pair<typename T::value_type, std::unique_ptr<trie<T>>>>::const_iterator& node_map_it ) : node{node}, node_map_it{node_map_it} {} // This pointer is to const data: const trie<T>* node; typename std::vector<std::pair<typename T::value_type, std::unique_ptr<trie<T>>>>::const_iterator node_map_it; }; public: typedef const T value_type; iterator() =default; iterator(const trie<T>* node) { parents.emplace(node, node->children.cbegin()); // ... } // ... private: std::stack<state> parents; // ... }; Notice that the node pointer is declared const. This is because (in my mind) the iterator should not be modifying the node that it points to; it is just an iterator. Now, elsewhere in my main trie<T> class, I have an erase function that has a common STL signature--it takes an iterator to data to erase (and returns an iterator to the next object). template<typename T> typename trie<T>::iterator trie<T>::erase(const_iterator it) { // ... // Cannot modify a const object! it.parents.top().node->is_leaf = false; // ... } The compiler complains because the node pointer is read-only! The erase function definitely should modify the trie that the iterator points to, even though the iterator shouldn't. So, I have two questions: Should iterator's constructors be public? trie<T> has the necessary begin() and end() members, and of course trie<T>::iterator and trie<T> are mutual friends, but I don't know what the convention is. Making them private would solve a lot of the angst I'm having about removing the const "promise" from the iterator's constructor. What are the correct const semantics/conventions regarding the iterator and its node pointer here? Nobody has ever explained this to me, and I can't find any tutorials or articles on the Web. This is probably the more important question, but it does require a good deal of planning and proper implementation. I suppose it could be circumvented by just implementing 1, but it's the principle of the thing!

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• Data Warehouse ETL slow - change primary key in dimension?

  - by Jubbles

  I have a working MySQL data warehouse that is organized as a star schema and I am using Talend Open Studio for Data Integration 5.1 to create the ETL process. I would like this process to run once per day. I have estimated that one of the dimension tables (dimUser) will have approximately 2 million records and 23 columns. I created a small test ETL process in Talend that worked, but given the amount of data that may need to be updated daily, the current performance will not cut it. It takes the ETL process four minutes to UPDATE or INSERT 100 records to dimUser. If I assumed a linear relationship between the count of records and the amount of time to UPDATE or INSERT, then there is no way the ETL can finish in 3-4 hours (my hope), let alone one day. Since I'm unfamiliar with Java, I wrote the ETL as a Python script and ran into the same problem. Although, I did discover that if I did only INSERT, the process went much faster. I am pretty sure that the bottleneck is caused by the UPDATE statements. The primary key in dimUser is an auto-increment integer. My friend suggested that I scrap this primary key and replace it with a multi-field primary key (in my case, 2-3 fields). Before I rip the test data out of my warehouse and change the schema, can anyone provide suggestions or guidelines related to the design of the data warehouse the ETL process how realistic it is to have an ETL process INSERT or UPDATE a few million records each day will my friend's suggestion significantly help If you need any further information, just let me know and I'll post it. UPDATE - additional information: mysql> describe dimUser; Field Type Null Key Default Extra user_key int(10) unsigned NO PRI NULL auto_increment id_A int(10) unsigned NO NULL id_B int(10) unsigned NO NULL field_4 tinyint(4) unsigned NO 0 field_5 varchar(50) YES NULL city varchar(50) YES NULL state varchar(2) YES NULL country varchar(50) YES NULL zip_code varchar(10) NO 99999 field_10 tinyint(1) NO 0 field_11 tinyint(1) NO 0 field_12 tinyint(1) NO 0 field_13 tinyint(1) NO 1 field_14 tinyint(1) NO 0 field_15 tinyint(1) NO 0 field_16 tinyint(1) NO 0 field_17 tinyint(1) NO 1 field_18 tinyint(1) NO 0 field_19 tinyint(1) NO 0 field_20 tinyint(1) NO 0 create_date datetime NO 2012-01-01 00:00:00 last_update datetime NO 2012-01-01 00:00:00 run_id int(10) unsigned NO 999 I used a surrogate key because I had read that it was good practice. Since, from a business perspective, I want to keep aware of potential fraudulent activity (say for 200 days a user is associated with state X and then the next day they are associated with state Y - they could have moved or their account could have been compromised), so that is why geographic data is kept. The field id_B may have a few distinct values of id_A associated with it, but I am interested in knowing distinct (id_A, id_B) tuples. In the context of this information, my friend suggested that something like (id_A, id_B, zip_code) be the primary key. For the large majority of daily ETL processes (80%), I only expect the following fields to be updated for existing records: field_10 - field_14, last_update, and run_id (this field is a foreign key to my etlLog table and is used for ETL auditing purposes).

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• Normalizing a table

  - by Alex

  I have a legacy table, which I can't change. The values in it can be modified from legacy application (application also can't be changed). Due to a lot of access to the table from new application (new requirement), I'd like to create a temporary table, which would hopefully speed up the queries. The actual requirement, is to calculate number of business days from X to Y. For example, give me all business days from Jan 1'st 2001 until Dec 24'th 2004. The table is used to mark which days are off, as different companies may have different days off - it isn't just Saturday + Sunday) The temporary table would be created from a .NET program, each time user enters the screen for this query (user may run query multiple times, with different values, table is created once), so I'd like it to be as fast as possible. Approach below runs in under a second, but I only tested it with a small dataset, and still it takes probably close to half a second, which isn't great for UI - even though it's just the overhead for first query. The legacy table looks like this: CREATE TABLE [business_days]( [country_code] [char](3) , [state_code] [varchar](4) , [calendar_year] [int] , [calendar_month] [varchar](31) , [calendar_month2] [varchar](31) , [calendar_month3] [varchar](31) , [calendar_month4] [varchar](31) , [calendar_month5] [varchar](31) , [calendar_month6] [varchar](31) , [calendar_month7] [varchar](31) , [calendar_month8] [varchar](31) , [calendar_month9] [varchar](31) , [calendar_month10] [varchar](31) , [calendar_month11] [varchar](31) , [calendar_month12] [varchar](31) , misc. ) Each month has 31 characters, and any day off (Saturday + Sunday + holiday) is marked with X. Each half day is marked with an 'H'. For example, if a month starts on a Thursday, than it will look like (Thursday+Friday workdays, Saturday+Sunday marked with X): ' XX XX ..' I'd like the new table to look like so: create table #Temp (country varchar(3), state varchar(4), date datetime, hours int) And I'd like to only have rows for days which are off (marked with X or H from previous query) What I ended up doing, so far is this: Create a temporary-intermediate table, that looks like this: create table #Temp_2 (country_code varchar(3), state_code varchar(4), calendar_year int, calendar_month varchar(31), month_code int) To populate it, I have a union which basically unions calendar_month, calendar_month2, calendar_month3, etc. Than I have a loop which loops through all the rows in #Temp_2, after each row is processed, it is removed from #Temp_2. To process the row there is a loop from 1 to 31, and substring(calendar_month, counter, 1) is checked for either X or H, in which case there is an insert into #Temp table. [edit added code] Declare @country_code char(3) Declare @state_code varchar(4) Declare @calendar_year int Declare @calendar_month varchar(31) Declare @month_code int Declare @calendar_date datetime Declare @day_code int WHILE EXISTS(SELECT * From #Temp_2) -- where processed = 0) BEGIN Select Top 1 @country_code = t2.country_code, @state_code = t2.state_code, @calendar_year = t2.calendar_year, @calendar_month = t2.calendar_month, @month_code = t2.month_code From #Temp_2 t2 -- where processed = 0 set @day_code = 1 while @day_code <= 31 begin if substring(@calendar_month, @day_code, 1) = 'X' begin set @calendar_date = convert(datetime, (cast(@month_code as varchar) + '/' + cast(@day_code as varchar) + '/' + cast(@calendar_year as varchar))) insert into #Temp (country, state, date, hours) values (@country_code, @state_code, @calendar_date, 8) end if substring(@calendar_month, @day_code, 1) = 'H' begin set @calendar_date = convert(datetime, (cast(@month_code as varchar) + '/' + cast(@day_code as varchar) + '/' + cast(@calendar_year as varchar))) insert into #Temp (country, state, date, hours) values (@country_code, @state_code, @calendar_date, 4) end set @day_code = @day_code + 1 end delete from #Temp_2 where @country_code = country_code AND @state_code = state_code AND @calendar_year = calendar_year AND @calendar_month = calendar_month AND @month_code = month_code --update #Temp_2 set processed = 1 where @country_code = country_code AND @state_code = state_code AND @calendar_year = calendar_year AND @calendar_month = calendar_month AND @month_code = month_code END I am not an expert in SQL, so I'd like to get some input on my approach, and maybe even a much better approach suggestion. After having the temp table, I'm planning to do (dates would be coming from a table): select cast(convert(datetime, ('01/31/2012'), 101) -convert(datetime, ('01/17/2012'), 101) as int) - ((select sum(hours) from #Temp where date between convert(datetime, ('01/17/2012'), 101) and convert(datetime, ('01/31/2012'), 101)) / 8) Besides the solution of normalizing the table, the other solution I implemented for now, is a function which does all this logic of getting the business days by scanning the current table. It runs pretty fast, but I'm hesitant to call a function, if I can instead add a simpler query to get result. (I'm currently trying this on MSSQL, but I would need to do same for Sybase ASE and Oracle)

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• Get item from spinner into url

  - by ShadowCrowe

  I searched for an answer but couldn't find it. The problem: Depending on the selected spinner-item the application should show a different image. At this moment I can't get it to work. The Url works like this: "my.site.com/images/" imc_met ".png" were imc_met is the filename. I can't get it to work. Btw the app isn't finished yet package example.myapplication; import java.io.IOException; import java.net.MalformedURLException; import java.net.URI; import java.net.URISyntaxException; import java.net.URL; import java.util.ArrayList; import java.util.List; import android.app.Activity; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.view.Menu; import android.view.View; import android.view.View.OnClickListener; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.ImageView; import android.widget.Spinner; public class itemsActivity extends Activity { private Spinner spinner1, spinner2; private Button btnSubmit; private Bitmap image; private ImageView imageView; private String imc_met, imc; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.items); addItemsOnSpinner2(); addListenerOnButton(); addListenerOnSpinnerItemSelection(); } // add items into spinner dynamically public void addItemsOnSpinner2() { spinner2 = (Spinner) findViewById(R.id.spinner2); List<String> list = new ArrayList<String>(); list.add("list 1"); list.add("list 2"); list.add("list 3"); ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, list); dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); spinner2.setAdapter(dataAdapter); } public void addListenerOnSpinnerItemSelection() { spinner1 = (Spinner) findViewById(R.id.spinner1); spinner1.setOnItemSelectedListener(new CustomOnItemSelectedListener()); } // get the selected dropdown list value public void addListenerOnButton() { spinner1 = (Spinner) findViewById(R.id.spinner1); spinner2 = (Spinner) findViewById(R.id.spinner2); btnSubmit = (Button) findViewById(R.id.btnSubmit); spinner1.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) { if(spinner1.getSelectedItem()!=null){ imc_met = spinner1.getSelectedItem().toString(); } } @Override public void onNothingSelected(AdapterView<?> arg0) { // TODO Auto-generated method stub } }); imageView = (ImageView)findViewById(R.id.ImageView01); btnSubmit.setOnClickListener(new OnClickListener() { public void onClick(View v) { URL url = null; try { url = new URL("my.site.com"); //here should the right link appear. } catch (MalformedURLException e) { e.printStackTrace(); } try { if (url != null) { image = BitmapFactory.decodeStream(url.openStream()); } } catch (IOException e) { e.printStackTrace(); } imageView.setImageBitmap(image); } }); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } }

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• Async networking + threading problem

  - by randallmeadows

  I kick off a network request, assuming no login credentials are required to talk to the destination server. If they are required, then I get an authentication challenge, at which point I display a view requesting said credentials from the user. When they are supplied, I restart the network request, using those credentials. That's all fine and dandy, as long as I only do one request at a time. But I'm not, typically. When both requests are kicked off, I get the first challenge, and present the prompt (using -presentModalViewController:). Then the 2nd challenge comes in. And I crash when it tries to display the 2nd prompt. I have the bulk of this wrapped in an @synchronized() block, but this has no effect because these delegate methods are all being called on the same (main) thread. The docs say the delegate methods are called on the same thread in which the connection was started. OK, no problem; I'll just write a method that I run on a background thread using -performSelectorInBackground: NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO]; [connections addObject:connection]; [self performSelectorInBackground:@selector(startConnection:) withObject:connection]; [connection release]; - (void)startConnection:(NSURLConnection *)connection { NSAutoreleasePool *pool = [NSAutoreleasePool new]; [connection scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; [connection start]; [pool drain]; } which should put every network request, and its callbacks, on its own thread, and then my @synchronized() blocks will take effect. The docs for -initWithRequest:... state "Messages to the delegate will be sent on the thread that calls this method. By default, for the connection to work correctly the calling thread’s run loop must be operating in the default run loop mode." Ok, I'm doing that. They also state "If you pass NO [for startImmediately], you must schedule the connection in a run loop before starting it." OK, I'm doing that, too. Furthermore, the docs for NSRunLoop state "Each NSThread object, including the application’s main thread, has an NSRunLoop object automatically created for it as needed. If you need to access the current thread’s run loop, you do so with the class method currentRunLoop." I'm assuming this applies to the background thread created by the call -performSelectorInBackground... (which does appear to be the case, when I execute 'po [NSClassFromString(@"NSRunLoop") currentRunLoop]' in the -startConnection: method). The -startConnection: method is indeed being called. But after kicking off the connection, I now never get any callbacks on it. None of the -connectionDid… delegate methods. (I even tried explicitly starting the thread's run loop, but that made no difference; I've used threads like this before, and I've never had to start the run loop manually before--but I'm now grasping at straws...) I think I've come up with a workaround such that I only handle one request at a time, but it's kludgy and I'd like to do this the Right Way. But, what am I missing here? Thanks! randy

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• AJAX Generated Select Won't Redirect

  - by James

  So, basically I have this select / drop down menu that I use AJAX to retrieve and create, though when an option is selected (so onChange) I want it to redirect! Though, this still isn't working, I don't get any errors thrown when trying, and tried to do alert() debug methods yet the alerts don't get called. jquery $("#schoolMenu").change(function() { option = $("#schoolMenu option:selected").text(); alert(option); if(option != "- Please Select -") { window.location = "http://www.itmustbecollege.com/pics/pics-from-"+$("#schoolMenu option:selected").val(); } }); This is what is used to call the AJAX // // Populate Schools // $("#state").change(function() { option = $("#state option:selected").text(); if($(this).attr("class") == "menu") { if(option != "- Please Select -") { $.ajax({ type: "GET", url: "/includes/functions.php", data: "f=school&p="+option+"&m=yes", success: function(msg) { $("#fSchool").html("<p style=\"margin-left: 20px;\">Select School:</p>"+ msg); $("#fSchool").show(); $("#school").focus(); } }); } else { $("#fSchool").html(""); $("#fSchool").hide(); } } else { if(option != "- Please Select -") { $.ajax({ type: "GET", url: "/includes/functions.php", data: "f=school&p="+option, success: function(msg) { $("#fSchool").html(msg); $("#fSchool").show(); $("#school").focus(); } }); } else { $("#fSchool").html(""); $("#fSchool").hide(); } } }); It loads perfectly, if you look at http://www.itmustbecollege.com/quotes/ on that bar where you can do "sort by" of Popular | Newest | Category | School if you hover over school a dropdown comes up, select any country and another one appears, though when that is changed nothing happens. here is the PHP for that second drop down // Get College List function getCollege($state, $m = "no", $l = "no") { // Displays Schools if($m == "yes") { $options = '<select id="schoolMenu" name="school"><option value="select" selected="selected">- Please Select -</option>'; } else if($l == "yes" || $l == "yes2") { $options = ''; } else { $options = '<select name="school"><option value="select" selected="selected">- Please Select -</option>'; } $listArray = split("\|\\\\", $list); for($i=0; $i < count($listArray); $i++) { if($m == "yes") { $options .= '<option value="'. trim(titleReplace($listArray[$i])) .'">'. trim($listArray[$i]) .'</option>'; } else if($l == "yes") { $options .= '<li><a href="/quotes/quotes-from-'. titleReplace($listArray[$i]) .'" title="'. trim($listArray[$i]) .' Quotes">'. trim($listArray[$i]) .'</a></li>'; } else if($l == "yes2") { $options .= '<li><a href="/pics/pics-from-'. titleReplace($listArray[$i]) .'" title="'. trim($listArray[$i]) .' Pictures">'. trim($listArray[$i]) .'</a></li>'; } else { $options .= '<option value="'. trim($listArray[$i]) .'">'. trim($listArray[$i]) .'</option>'; } } echo $options .='</select>'; return false; } any help would be great! EDIT: Also, the way I have those drop downs coming for the menus is a bit weird and when you hover over any other "sort by" link they disappear, this is a problem with the "sort by school" because the first select box shows the list up, and if you go and select a school then somehow float over another link it disappears, any help on how to delay that or fix that minor problem?

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• Table Name is null in the sqlite database in android device

  - by Mahe

  I am building a simple app which stores some contacts and retrieves contacts in android phone device. I have created my own database and a table and inserting the values to the table in phone. My phone is not rooted. So I cannot access the files, but I see that values are stored in the table. And tested on a emulator also. Till here it is fine. Display all the contacts in a list by fetching data from table. This is also fine. But the problem is When I am trying to delete the record, it shows the table name is null in the logcat(not an exception), and the data is not deleted. But in emulator the data is getting deleted from table. I am not able to achieve this through phone. This is my code for deleting, public boolean onContextItemSelected(MenuItem item) { super.onContextItemSelected(item); AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item .getMenuInfo(); int menuItemIndex = item.getItemId(); String[] menuItems = getResources().getStringArray(R.array.menu); String menuItemName = menuItems[menuItemIndex]; String listItemName = Customers[info.position]; if (item.getTitle().toString().equalsIgnoreCase("Delete")) { Toast.makeText( context, "Selected List item is: " + listItemName + "MenuItem is: " + menuItemName, Toast.LENGTH_LONG).show(); DB = context.openOrCreateDatabase("CustomerDetails.db", MODE_PRIVATE, null); try { int pos = info.position; pos = pos + 1; Log.d("", "customers[pos]: " + Customers[info.position]); Cursor c = DB .rawQuery( "Select customer_id,first_name,last_name from CustomerInfo", null); int rowCount = c.getCount(); DB.delete(Table_name, "customer_id" + "=" + String.valueOf(pos), null); DB.close(); Log.d("", "" + String.valueOf(pos)); Toast.makeText(context, "Deleted Customer", Toast.LENGTH_LONG) .show(); // Customers[info.position]=null; getCustomers(); } catch (Exception e) { Toast.makeText(context, "Delete unsuccessfull", Toast.LENGTH_LONG).show(); } } this is my logcat, 07-02 10:12:42.976: D/Cursor(1560): Database path: CustomerDetails.db 07-02 10:12:42.976: D/Cursor(1560): Table name : null 07-02 10:12:42.984: D/Cursor(1560): Database path: CustomerDetails.db 07-02 10:12:42.984: D/Cursor(1560): Table name : null Don't know the reason why data is not being deleted. Data exists in the table. This is the specification I have given for creating the table public static String customer_id="customer_id"; public static String site_id="site_id"; public static String last_name="last_name"; public static String first_name="first_name"; public static String phone_number="phone_number"; public static String address="address"; public static String city="city"; public static String state="state"; public static String zip="zip"; public static String email_address="email_address"; public static String custlat="custlat"; public static String custlng="custlng"; public static String Table_name="CustomerInfo"; final SQLiteDatabase DB = context.openOrCreateDatabase( "CustomerDetails.db", MODE_PRIVATE, null); final String CREATE_TABLE = "create table if not exists " + Table_name + " (" + customer_id + " integer primary key autoincrement, " + first_name + " text not null, " + last_name + " text not null, " + phone_number+ " integer not null, " + address+ " text not null, " + city+ " text not null, " + state+ " text not null, " + zip+ " integer not null, " + email_address+ " text not null, " + custlat+ " double, " + custlng+ " double " +" );"; DB.execSQL(CREATE_TABLE); DB.close(); Please correct my code. I am struggling from two days. Any help is appreciated!!

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• Can someone help me compare using F# over C# in this specific example (IP Address expressions)?

  - by Phobis

  So, I am writing code to parse and IP Address expression and turn it into a regular expression that could be run against and IP Address string and return a boolean response. I wrote the code in C# (OO) and it was 110 lines of code. I am trying to compare the amount of code and the expressiveness of C# to F# (I am a C# programmer and a noob at F#). I don't want to post both the C# and F#, just because I don't want to clutter the post. If needed, I will do so. Anyway, I will give an example. Here is an expression: 192.168.0.250,244-248,108,51,7;127.0.0.1 I would like to take that and turn it into this regular expression: ((192.168.0.(250|244|245|246|247|248|108|51|7))|(127.0.0.1)) Here are some steps I am following: Operations: Break by ";" 192.168.0.250,244-248,108,51,7 127.0.0.1 Break by "." 192 168 0 250,244-248,108,51,7 Break by "," 250 244-248 108 51 7 Break by "-" 244 248 I came up with F# that produces the output. I am trying to forward-pipe through my operations listed above, as I think that would be more expressive. Can anyone make this code better? Teach me something :) open System let createItemArray (group:bool) (y:char) (items:string[]) = [| let indexes = items.Length - 1 let group = indexes > 0 && group if group then yield "(" for i in 0 .. indexes do yield items.[i].ToString() if i < indexes then yield y.ToString() if group then yield ")" |] let breakBy (group:bool) (x:string) (y:char): string[] = x.Split(y) |> createItemArray group y let breakItem (x:string) (y:char): string[] = breakBy false x y let breakGroup (x:string) (y:char): string[] = breakBy true x y let AddressExpression address:string = let builder = new System.Text.StringBuilder "(" breakGroup address ';' |> Array.collect (fun octet -> breakItem octet '.') |> Array.collect (fun options -> breakGroup options ',') |> Array.collect (fun (ranges : string) -> match (breakGroup ranges '-') with | x when x.Length > 3 -> match (Int32.TryParse(x.[1]), Int32.TryParse(x.[3])) with | ((true, a) ,(true, b)) -> [|a .. b|] |> Array.map (int >> string) |> createItemArray false '-' | _ -> [|ranges|] | _ -> [|ranges|] ) |> Array.iter (fun item -> match item with | ";" -> builder.Append ")|(" | "." -> builder.Append "\." | "," | "-" -> builder.Append "|" | _ -> builder.Append item |> ignore ) builder.Append(")").ToString() let address = "192.168.0.250,244-248,108,51,7;127.0.0.1" AddressExpression address

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• Dependency Injection in ASP.NET MVC NerdDinner App using Unity 2.0

  - by shiju

  In my previous post Dependency Injection in ASP.NET MVC NerdDinner App using Ninject, we did dependency injection in NerdDinner application using Ninject. In this post, I demonstrate how to apply Dependency Injection in ASP.NET MVC NerdDinner App using Microsoft Unity Application Block (Unity) v 2.0.Unity 2.0Unity 2.0 is available on Codeplex at http://unity.codeplex.com . In earlier versions of Unity, the ObjectBuilder generic dependency injection mechanism, was distributed as a separate assembly, is now integrated with Unity core assembly. So you no longer need to reference the ObjectBuilder assembly in your applications. Two additional Built-In Lifetime Managers - HierarchicalifetimeManager and PerResolveLifetimeManager have been added to Unity 2.0.Dependency Injection in NerdDinner using UnityIn my Ninject post on NerdDinner, we have discussed the interfaces and concrete types of NerdDinner application and how to inject dependencies controller constructors. The following steps will configure Unity 2.0 to apply controller injection in NerdDinner application. Step 1 – Add reference for Unity Application BlockOpen the NerdDinner solution and add  reference to Microsoft.Practices.Unity.dll and Microsoft.Practices.Unity.Configuration.dllYou can download Unity from at http://unity.codeplex.com .Step 2 – Controller Factory for Unity The controller factory is responsible for creating controller instances.We extend the built in default controller factory with our own factory for working Unity with ASP.NET MVC. public class UnityControllerFactory : DefaultControllerFactory {     protected override IController GetControllerInstance(RequestContext reqContext, Type controllerType)     {         IController controller;         if (controllerType == null)             throw new HttpException(                     404, String.Format(                         "The controller for path '{0}' could not be found" +         "or it does not implement IController.",                     reqContext.HttpContext.Request.Path));           if (!typeof(IController).IsAssignableFrom(controllerType))             throw new ArgumentException(                     string.Format(                         "Type requested is not a controller: {0}",                         controllerType.Name),                         "controllerType");         try         {             controller = MvcUnityContainer.Container.Resolve(controllerType)                             as IController;         }         catch (Exception ex)         {             throw new InvalidOperationException(String.Format(                                     "Error resolving controller {0}",                                     controllerType.Name), ex);         }         return controller;     }   }   public static class MvcUnityContainer {     public static IUnityContainer Container { get; set; } }  Step 3 – Register Types and Set Controller Factory private void ConfigureUnity() {     //Create UnityContainer               IUnityContainer container = new UnityContainer()     .RegisterType<IFormsAuthentication, FormsAuthenticationService>()     .RegisterType<IMembershipService, AccountMembershipService>()     .RegisterInstance<MembershipProvider>(Membership.Provider)     .RegisterType<IDinnerRepository, DinnerRepository>();     //Set container for Controller Factory     MvcUnityContainer.Container = container;     //Set Controller Factory as UnityControllerFactory     ControllerBuilder.Current.SetControllerFactory(                         typeof(UnityControllerFactory));            } Unity 2.0 provides a fluent interface for type configuration. Now you can call all the methods in a single statement.The above Unity configuration specified in the ConfigureUnity method tells that, to inject instance of DinnerRepositiry when there is a request for IDinnerRepositiry and  inject instance of FormsAuthenticationService when there is a request for IFormsAuthentication and inject instance of AccountMembershipService when there is a request for IMembershipService. The AccountMembershipService class has a dependency with ASP.NET Membership provider. So we configure that inject the instance of Membership Provider.After the registering the types, we set UnityControllerFactory as the current controller factory. //Set container for Controller Factory MvcUnityContainer.Container = container; //Set Controller Factory as UnityControllerFactory ControllerBuilder.Current.SetControllerFactory(                     typeof(UnityControllerFactory)); When you register a type  by using the RegisterType method, the default behavior is for the container to use a transient lifetime manager. It creates a new instance of the registered, mapped, or requested type each time you call the Resolve or ResolveAll method or when the dependency mechanism injects instances into other classes. The following are the LifetimeManagers provided by Unity 2.0ContainerControlledLifetimeManager - Implements a singleton behavior for objects. The object is disposed of when you dispose of the container.ExternallyControlledLifetimeManager - Implements a singleton behavior but the container doesn't hold a reference to object which will be disposed of when out of scope.HierarchicalifetimeManager - Implements a singleton behavior for objects. However, child containers don't share instances with parents.PerResolveLifetimeManager - Implements a behavior similar to the transient lifetime manager except that instances are reused across build-ups of the object graph.PerThreadLifetimeManager - Implements a singleton behavior for objects but limited to the current thread.TransientLifetimeManager - Returns a new instance of the requested type for each call. (default behavior)We can also create custome lifetime manager for Unity container. The following code creating a custom lifetime manager to store container in the current HttpContext. public class HttpContextLifetimeManager<T> : LifetimeManager, IDisposable {     public override object GetValue()     {         return HttpContext.Current.Items[typeof(T).AssemblyQualifiedName];     }     public override void RemoveValue()     {         HttpContext.Current.Items.Remove(typeof(T).AssemblyQualifiedName);     }     public override void SetValue(object newValue)     {         HttpContext.Current.Items[typeof(T).AssemblyQualifiedName]             = newValue;     }     public void Dispose()     {         RemoveValue();     } }  Step 4 – Modify Global.asax.cs for configure Unity container In the Application_Start event, we call the ConfigureUnity method for configuring the Unity container and set controller factory as UnityControllerFactory void Application_Start() {     RegisterRoutes(RouteTable.Routes);       ViewEngines.Engines.Clear();     ViewEngines.Engines.Add(new MobileCapableWebFormViewEngine());     ConfigureUnity(); }Download CodeYou can download the modified NerdDinner code from http://nerddinneraddons.codeplex.com

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• The How-To Geek Holiday Gift Guide (Geeky Stuff We Like)

  - by The Geek

  Welcome to the very first How-To Geek Holiday Gift Guide, where we’ve put together a list of our absolute favorites to help you weed through all of the junk out there to pick the perfect gift for anybody. Though really, it’s just a list of the geeky stuff we want. We’ve got a whole range of items on the list, from cheaper gifts that most anybody can afford, to the really expensive stuff that we’re pretty sure nobody is giving us. Stocking Stuffers Here’s a couple of ideas for items that won’t break the bank. LED Keychain Micro-Light   Magcraft 1/8-Inch Rare Earth Cube Magnets Best little LED keychain light around. If they don’t need the penknife of the above item this is the perfect gift. I give them out by the handfuls and nobody ever says anything but good things about them. I’ve got ones that are years old and still running on the same battery.  Price: $8   Geeks cannot resist magnets. Jason bought this pack for his fridge because he was sick of big clunky magnets… these things are amazing. One tiny magnet, smaller than an Altoid mint, can practically hold a clipboard right to the fridge. Amazing. I spend more time playing with them on the counter than I do actually hanging stuff.  Price: $10 Lots of Geeky Mugs   Astronomy Powerful Green Laser Pointer There’s loads of fun, geeky mugs you can find on Amazon or anywhere else—and they are great choices for the geek who loves their coffee. You can get the Caffeine mug pictured here, or go with an Atari one, Canon Lens, or the Aperture mug based on Portal. Your choice. Price: $7   No, it’s not a light saber, but it’s nearly bright enough to be one—you can illuminate low flying clouds at night or just blind some aliens on your day off. All that for an extremely low price. Loads of fun. Price: $15       Geeky TV Shows and Books Sometimes you just want to relax and enjoy a some TV or a good book. Here’s a few choices. The IT Crowd Fourth Season   Doctor Who, Complete Fifth Series Ridiculous, funny show about nerds in the IT department, loved by almost all the geeks here at HTG. Justin even makes this required watching for new hires in his office so they’ll get his jokes. You can pre-order the fourth season, or pick up seasons one, two, or three for even cheaper. Price: $13   It doesn’t get any more nerdy than Eric’s pick, the fifth all-new series of Doctor Who, where the Daleks are hatching a new master plan from the heart of war-torn London. There’s also alien vampires, humanoid reptiles, and a lot more. Price: $52 Battlestar Galactica Complete Series   MAKE: Electronics: Learning Through Discovery Watch the epic fight to save the human race by finding the fabled planet Earth while being hunted by the robotic Cylons. You can grab the entire series on DVD or Blu-ray, or get the seasons individually. This isn’t your average sci-fi TV show. Price: $150 for Blu-ray.   Want to learn the fundamentals of electronics in a fun, hands-on way? The Make:Electronics book helps you build the circuits and learn how it all works—as if you had any more time between all that registry hacking and loading software on your new PC. Price: $21       Geeky Gadgets for the Gadget-Loving Geek Here’s a few of the items on our gadget list, though lets be honest: geeks are going to love almost any gadget, especially shiny new ones. Klipsch Image S4i Premium Noise-Isolating Headset with 3-Button Apple Control   GP2X Caanoo MAME/Console Emulator If you’re a real music geek looking for some serious quality in the headset for your iPhone or iPod, this is the pair that Alex recommends. They aren’t terribly cheap, but you can get the less expensive S3 earphones instead if you prefer. Price: $50-100   Eric says: “As an owner of an older version, I can say the GP2X is one of my favorite gadgets ever. Touted a “Retro Emulation Juggernaut,” GP2X runs Linux and may be the only open source software console available. Sounds too good to be true, but isn’t.” Price: $150 Roku XDS Streaming Player 1080p   Western Digital WD TV Live Plus HD Media Player If you do a lot of streaming over Netflix, Hulu Plus, Amazon’s Video on Demand, Pandora, and others, the Roku box is a great choice to get your content on your TV without paying a lot of money.  It’s also got Wireless-N built in, and it supports full 1080P HD. Price: $99   If you’ve got a home media collection sitting on a hard drive or a network server, the Western Digital box is probably the cheapest way to get that content on your TV, and it even supports Netflix streaming too. It’ll play loads of formats in full HD quality. Price: $99 Fujitsu ScanSnap S300 Color Mobile Scanner   Doxie, the amazing scanner for documents Trevor said: “This wonderful little scanner has become absolutely essential to me. My desk used to just be a gigantic pile of papers that I didn’t need at the moment, but couldn’t throw away ‘just in case.’ Now, every few weeks, I’ll run that paper pile through this and then happily shred the originals!” Price: $300   If you don’t scan quite as often and are looking for a budget scanner you can throw into your bag, or toss into a drawer in your desk, the Doxie scanner is a great alternative that I’ve been using for a while. It’s half the price, and while it’s not as full-featured as the Fujitsu, it might be a better choice for the very casual user. Price: $150       (Expensive) Gadgets Almost Anybody Will Love If you’re not sure that one of the more geeky presents is gonna work, here’s some gadgets that just about anybody is going to love, especially if they don’t have one already. Of course, some of these are a bit on the expensive side—but it’s a wish list, right? Amazon Kindle       The Kindle weighs less than a paperback book, the screen is amazing and easy on the eyes, and get ready for the kicker: the battery lasts at least a month. We aren’t kidding, either—it really lasts that long. If you don’t feel like spending money for books, you can use it to read PDFs, and if you want to get really geeky, you can hack it for custom screensavers. Price: $139 iPod Touch or iPad       You can’t go wrong with either of these presents—the iPod Touch can do almost everything the iPhone can do, including games, apps, and music, and it has the same Retina display as the iPhone, HD video recording, and a front-facing camera so you can use FaceTime. Price: $229+, depending on model. The iPad is a great tablet for playing games, browsing the web, or just using on your coffee table for guests. It’s well worth buying one—but if you’re buying for yourself, keep in mind that the iPad 2 is probably coming out in 3 months. Price: $500+ MacBook Air  The MacBook Air comes in 11” or 13” versions, and it’s an amazing little machine. It’s lightweight, the battery lasts nearly forever, and it resumes from sleep almost instantly. Since it uses an SSD drive instead of a hard drive, you’re barely going to notice any speed problems for general use. So if you’ve got a lot of money to blow, this is a killer gift. Price: $999 and up. Stuck with No Idea for a Present? Gift Cards! Yeah, you’re not going to win any “thoughtful present” awards with these, but you might just give somebody what they really want—the new Angry Birds HD for their iPad, Cut the Rope, or anything else they want. ITunes Gift Card   Amazon.com Gift Card Somebody in your circle getting a new iPod, iPhone, or iPad? You can get them an iTunes gift card, which they can use to buy music, games or apps. Yep, this way you can gift them a copy of Angry Birds if they don’t already have it. Or even Cut the Rope.   No clue what to get somebody on your list? Amazon gift cards let them buy pretty much anything they want, from organic weirdberries to big screen TVs. Yeah, it’s not as thoughtful as getting them a nice present, but look at the bright side: maybe they’ll get you an Amazon gift card and it’ll balance out. That’s the highlights from our lists—got anything else to add? Share your geeky gift ideas in the comments. Latest Features How-To Geek ETC The How-To Geek Holiday Gift Guide (Geeky Stuff We Like) LCD? LED? Plasma? 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• Gone With the Wind?

  - by antony.reynolds

  Where Have All the Composites Gone? I was just asked to help out with an interesting problem at a customer.  All their composites had disappeared from the EM console, none of them showed as loading in the log files and there was an ominous error message in the logs. Symptoms After a server restart the customer noticed that none of his composites were available, they didn’t show in the EM console and in the log files they saw this error message: SEVERE: WLSFabricKernelInitializer.getCompositeList Error during parsing and processing of deployed-composites.xml file This indicates some sort of problem when parsing the deployed-composites.xml file.  This is very bad because the deployed-composites.xml file is basically the table of contents that tells SOA Infrastructure what composites to load and where to find them in MDS.  If you can’t read this file you can’t load any composites and your SOA Server now has all the utility of a chocolate teapot. Verification We can look at the deployed-composites.xml file from MDS either by connecting JDeveloper to MDS, exporting the file using WLST or exporting the whole soa-infra MDS partition by using EM->SOA->soa-infra->Administration->MDS Configuration.  Exporting via EM is probably the easiest because it then prepares you to fix the problem later.  After exporting the partition to local storage on the SOA Server I then ran an XSLT transform across the file deployed-composites/deployed-composites.xml. <?xml version="1.0" encoding="utf-8"?> <xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="http://www.w3.org/1999/xhtml">     <xsl:output indent="yes"/>     <xsl:template match="/">         <testResult>             <composite-series>                 <xsl:attribute name="elementCount"><xsl:value-of select="count(deployed-composites/composite-series)"/></xsl:attribute>                 <xsl:attribute name="nameAttributeCount"><xsl:value-of select="count(deployed-composites/composite-series[@name])"/></xsl:attribute>                 <xsl:attribute name="defaultAttributeCount"><xsl:value-of select="count(deployed-composites/composite-series[@default])"/></xsl:attribute>                 <composite-revision>                     <xsl:attribute name="elementCount"><xsl:value-of select="count(deployed-composites/composite-series/composite-revision)"/></xsl:attribute>                     <xsl:attribute name="dnAttributeCount"><xsl:value-of select="count(deployed-composites/composite-series/composite-revision[@dn])"/></xsl:attribute>                     <xsl:attribute name="stateAttributeCount"><xsl:value-of select="count(deployed-composites/composite-series/composite-revision[@state])"/></xsl:attribute>                     <xsl:attribute name="modeAttributeCount"><xsl:value-of select="count(deployed-composites/composite-series/composite-revision[@mode])"/></xsl:attribute>                     <xsl:attribute name="locationAttributeCount"><xsl:value-of select="count(deployed-composites/composite-series/composite-revision[@location])"/></xsl:attribute>                     <composite>                         <xsl:attribute name="elementCount"><xsl:value-of select="count(deployed-composites/composite-series/composite-revision/composite)"/></xsl:attribute>                         <xsl:attribute name="dnAttributeCount"><xsl:value-of select="count(deployed-composites/composite-series/composite-revision/composite[@dn])"/></xsl:attribute>                         <xsl:attribute name="deployedTimeAttributeCount"><xsl:value-of select="count(deployed-composites/composite-series/composite-revision/composite[@deployedTime])"/></xsl:attribute>                     </composite>                 </composite-revision>                 <xsl:apply-templates select="deployed-composites/composite-series"/>             </composite-series>         </testResult>     </xsl:template>     <xsl:template match="composite-series">             <xsl:if test="not(@name) or not(@default) or composite-revision[not(@dn) or not(@state) or not(@mode) or not(@location)]">                 <ErrorNode>                     <xsl:attribute name="elementPos"><xsl:value-of select="position()"/></xsl:attribute>                     <xsl:copy-of select="."/>                 </ErrorNode>             </xsl:if>     </xsl:template> </xsl:stylesheet> The output from this is not pretty but it shows any <composite-series> tags that are missing expected attributes (name and default).  It also shows how many composites are in the file (111) and how many revisions of those composites (115). <?xml version="1.0" encoding="UTF-8"?> <testResult xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="http://www.w3.org/1999/xhtml">    <composite-series elementCount="111" nameAttributeCount="110" defaultAttributeCount="110">       <composite-revision elementCount="115" dnAttributeCount="114" stateAttributeCount="115"                           modeAttributeCount="115"                           locationAttributeCount="114">          <composite elementCount="115" dnAttributeCount="114" deployedTimeAttributeCount="115"/>       </composite-revision>       <ErrorNode elementPos="82">          <composite-series xmlns="">             <composite-revision state="on" mode="active">                <composite deployedTime="2010-12-15T11:50:16.067+01:00"/>             </composite-revision>          </composite-series>       </ErrorNode>    </composite-series> </testResult> From this I could see that one of the <composite-series> elements (number 82 of 111) seemed to be corrupt. Having found the problem I now needed to fix it. Fixing the Problem The solution was really quite easy.  First for safeties sake I took a backup of the exported MDS partition.  I then edited the deployed-composites/deployed-composites.xml file to remove the offending <composite-series> tag. Finally I restarted the SOA domain and was rewarded by seeing that the deployed composites were now visible. Summary One possible cause of not being able to see deployed composites after a SOA 11g system restart is a corrupt deployed-composites.xml file.  Retrieving this file from MDS, repairing it, and replacing it back into MDS can solve the problem.  This still leaves the problem of how did this file become corrupt!

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• Day 2 - Game Design Documentation

  - by dapostolov

  So yesterday I didn't cut any code for my game but I was able to do a tiny bit of research on the XNA Game Development Technology and the communities out there and do you know what? I feel I'm a bit closer to my goal. The bad news is today I didn't cut code either. However, not all is lost because I wanted to get my ideas on paper and today I just did that.  Today, I began to jot down notes about the game and how I felt the visual elements would interact with each other. Unlike my workplace, my personal level of documentation is nothing more than a task list or a mind map of my ideas; it helps me streamline my solutions quiet effectively and circumvent the long process of articulating each thought to the n-th degree. I truly dislike documentation (because I have an extremely hard time articulating my thought and solutions); however, because I tend to do a really good job with documentation I tend to get stuck writing the buggers. But as a generalist remark: 'No Developer likes documentation.' For now let's stick with my basic notes and call this post a living document. Here are my notes, fresh, from after watching the new first episode of Merlin second season! Actually, a quick recommendation to anyone who is reading this (if anyone is): I truly recommend you envelope yourself in the medium or task you're trying to tackle. Be one with moment and feel it! For instance: Are you writing a fantasy script / game? What would the music of the genre sound like? For me the Conan the Barbarian soundtrack by Basil Poledouris is frackin awesome. There are many other good CD's out there, which I listen to (some who even use medival instruments, but Conan I keep returning to. It's a creative trigger for me. Ask yourself what would the imagery look like? Time to surf google for artist renditions of fantasy! What would the game feel like? Start playing some of your favorite games that inspire you, be wary though, have some self control and don't let it absorb your time. Anyhow, onto the documentation... Screens, Scenes, and Sprites. Oh My! (groan...) The first thing that came to mind were the screens, I thought the following would suffice: Menu Screen Character Customisation Screen Loading Screen? Battle Ground The Menu Screen Ok. So, the thought here is when the game loads a huge title is displayed: Wizard Wars. The player is prompted with 3 menu items: 1 Player Game, 2 Player Game, and Exit. Since I'm targetting the PC platform, as a non-networked game to start, I picture myself running my mouse over each menu option and the visual element of the menu item changes, along with a sound to indicate that I am over a curent menu item. And as I move my mouse away, it changes back, and possibly an exit mouse sound. Maybe on the screen somewhere is a brazier alit with a magical tome open right beside it, OR, maybe the tome is the menu! I hear the menu music as mellow, not obtrusive or piercing. On a menu item select, a confirmation sound bellows to indicate the players selection. The Esc key will always return me to the previous screens or desktop. The menu screen must feel...dark, like a really important ritual is about to happen and thus the music should build up. 1 Player Game - > Customize Character(s) 2 Player Game - > Customize Character(s) Exit - > Back to Windows Notes: So the first thing I pick up here are a couple things: First and foremost, my artistic abilities suck crap, so I may have to hire an artist (now that i've said that, lets get techy) graphical objects will be positioned within a scene on each screen / window. Menu items will be represented grapically, possibly animated, and have sound / animation effects triggered by user input or a time line. I have an animated scene involving a brazier or fire on a stick IF I was to move this game to the xbox, I'd have to track which menu item is currently selected (unless I do a mouse pointer type thing.) WindowObject has a scene A Scene has many GameObjects GameObject has a position graphic or animation MenuObject is a GameObject which has a mouse in, mouse out, and click event which either does something graphically (animation), does something with sound, or moves to another screen.  Character Customisation Screen With either the 1 or 2 player option selected, both selections will come to this screen; a wizard requires a name, powers, and vestements of course! Player one will configure his character first and then player two. I considered a split screen for PC but to have two people fighting over a keyboard would probably suck. For XBox, a split screen could work; maybe when I get into the networking portion (phase 2 blog?) of this game I will remove the 2 player option for PC and provide only multiplayer and I will leave 2 player for xbox...hmm... Anyhow...I picture the creation process as follows: Name: (textbox / keyboard entry) - for xbox, this would have to be different. Robe Color: (color box, or something) Stats: Speed, Oomph, and Health. (as sliders) 1 as minimum and 10 as maximum. Ok, Back, and Cancel buttons / options. Each stat has a benefit which are listed below. The idea is the player decides if he wants his wizard to run fast, be a tank and ... hit with a purse.Regardless, the player will have a pool of 12 points to use. Ideally, A balanced wizard will have 5 in each attribute. Spells? The only spell of choice is a ball of fire which comes without question. The music and screen should still feel like a ritual. The Character Speed Basically, how fast your character moves and casts. Oomph (Best Monster Truck Voice): PURE POWAH!!! The damage output of your fireball. Health How much damage you can take. Notes: I realise the game dynamics may sound uninteresting at the moment; but I think after a couple releases, we could have some other grand ideas such as: saved profiles, gold to upgrade arsenal of spells, talents, etc...but for now...a vanilla fireball thrower mage will suffice for this experiment. OK. So... a MenuObject  may need to be loosely coupled to allow future items such as networking? may be a button? a CharacterObject has a name speed oomph health and a funky robe color. cap on the three stats (1-10) an arsenal of 1 spell (possibly could expand this) The Loading Screen As is. The Battleground Screen For now, I'm keeping the screen as max resolution for the PC. The screen isn't going to move or even be a split screen. I'm not aiming high here because I want to see what level of change is involved when new features / concepts are added to game content. I'm interested to find out if we could apply techniques such as MVC or MVVM to this type of development or is it too tightly coupled? This reminds me when when my best friend and I were brainstorming our game idea (this is going back a while...1994, 6?) and he cringed at the thought of bringing business technology into games, especially when I suggested a database to store character information and COM / DCOM as the medium, but it seems I wasn't far off (reflecting); just like his implementation of a xml "config file" for dynamic direct-x menus back before .net in 1999...anyhow...i digress... The Battle One screen, two characters lobing balls of fire at each other...It doesn't get better than that. Every so often a scroll appears...and the fireballs bounce off walls, or the wizard has rapid fire, or even scrolls of healing! The scroll options are endless. Two bars at the top, each the color of the wizard (with their name beside the bar) indicate how much health they have. Possibly the appearance of the scrolls means the battle is taking too long? I'm thinking 1 player controls: up, down, left, right and space to fire the button. Or even possibly, mouse click and shift - mouse button to fire a spell in the direction they are facing. Two player controls: a, s, d, f and space AND arrows (up, down, left, right) and Del key or Crtl. The game ends when a player has 0 health and a dialog box appears asking for a rematch / reconfigure / exit. Health goes down when a fireball (friendly or not), connects with a wizard. When a wizard connects with a scroll, a countdown clock / icon appears near the health bar and the wizard begins to glow. For the most part, a wizard can have only scroll 1 effect on him at a time. Notes: Ok, there's alot to cover here. a CharacterObject is a GameObject it travels at a set velocity it travels in a direction it has sounds (walking, running, casting, impact, dying, laughing, whistling, other?) it has animations (walking, running, casting, impact, dying, laughing, idle, other?) it has a lifespan (determined by health) it is alive or dead it has a position a ScrollObject is a GameObject it carries a transferance of points "damage" (or healing, bad scroll effect?) (determinde by caster) it carries a transferance of "other" it is stationary it has a sound on impact it has a stationary animation it has an impact animation / or transfers an impact animation it has a fade animation? it has a lifespan (determined by game) it is alive or dead it has a position a WallObject is a GameObject it has a sound on fireball impact? it is a still image / stationary it has an impact animation / or transfers an impact animation it is dead it has a position A FireBall is a GameObject it carries a transferance of poinst "damage" (or healing, bad scroll effect?) (determinde by caster) it travels at a set velocity it travels in a direction it has a sound it has a travel animation it has an impact animation / or transfers an impact animation it has a fade animation? it has a lifespan (determined by caster) it is alive or dead it has a position As I look at this, I can see some common attributes in each object that I can carry up to the GameObject. I think I'm going to end the documentation here, it's taken me a bit of time to type this all out, tomorrow. I'll load up my IDE and my paint studio to get some good old fashioned cowboy hacking going!   D.

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• Adventures in MVVM &ndash; My ViewModel Base

  - by Brian Genisio's House Of Bilz

  More Adventures in MVVM First, I’d like to say: THIS IS NOT A NEW MVVM FRAMEWORK. I tend to believe that MVVM support code should be specific to the system you are building and the developers working on it.  I have yet to find an MVVM framework that does everything I want it to without doing too much.  Don’t get me wrong… there are some good frameworks out there.  I just like to pick and choose things that make sense for me.  I’d also like to add that some of these features only work in WPF.  As of Silveright 4, they don’t support binding to dynamic properties, so some of the capabilities are lost. That being said, I want to share my ViewModel base class with the world.  I have had several conversations with people about the problems I have solved using this ViewModel base.  A while back, I posted an article about some experiments with a “Rails Inspired ViewModel”.  What followed from those ideas was a ViewModel base class that I take with me and use in my projects.  It has a lot of features, all designed to reduce the friction in writing view models. I have put the code out on Codeplex under the project: ViewModelSupport. Finally, this article focuses on the ViewModel and only glosses over the View and the Model.  Without all three, you don’t have MVVM.  But this base class is for the ViewModel, so that is what I am focusing on. Features: Automatic Command Plumbing Property Change Notification Strongly Typed Property Getter/Setters Dynamic Properties Default Property values Derived Properties Automatic Method Execution Command CanExecute Change Notification Design-Time Detection What about Silverlight? Automatic Command Plumbing This feature takes the plumbing out of creating commands.  The common pattern for commands in a ViewModel is to have an Execute method as well as an optional CanExecute method.  To plumb that together, you create an ICommand Property, and set it in the constructor like so: Before public class AutomaticCommandViewModel { public AutomaticCommandViewModel() { MyCommand = new DelegateCommand(Execute_MyCommand, CanExecute_MyCommand); } public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } public DelegateCommand MyCommand { get; private set; } } With the base class, this plumbing is automatic and the property (MyCommand of type ICommand) is created for you.  The base class uses the convention that methods be prefixed with Execute_ and CanExecute_ in order to be plumbed into commands with the property name after the prefix.  You are left to be expressive with your behavior without the plumbing.  If you are wondering how CanExecuteChanged is raised, see the later section “Command CanExecute Change Notification”. After public class AutomaticCommandViewModel : ViewModelBase { public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } }   Property Change Notification One thing that always kills me when implementing ViewModels is how to make properties that notify when they change (via the INotifyPropertyChanged interface).  There have been many attempts to make this more automatic.  My base class includes one option.  There are others, but I feel like this works best for me. The common pattern (without my base class) is to create a private backing store for the variable and specify a getter that returns the private field.  The setter will set the private field and fire an event that notifies the change, only if the value has changed. Before public class PropertyHelpersViewModel : INotifyPropertyChanged { private string text; public string Text { get { return text; } set { if(text != value) { text = value; RaisePropertyChanged("Text"); } } } protected void RaisePropertyChanged(string propertyName) { var handlers = PropertyChanged; if(handlers != null) handlers(this, new PropertyChangedEventArgs(propertyName)); } public event PropertyChangedEventHandler PropertyChanged; } This way of defining properties is error-prone and tedious.  Too much plumbing.  My base class eliminates much of that plumbing with the same functionality: After public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get<string>("Text"); } set { Set("Text", value);} } }   Strongly Typed Property Getters/Setters It turns out that we can do better than that.  We are using a strongly typed language where the use of “Magic Strings” is often frowned upon.  Lets make the names in the getters and setters strongly typed: A refinement public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get(() => Text); } set { Set(() => Text, value); } } }   Dynamic Properties In C# 4.0, we have the ability to program statically OR dynamically.  This base class lets us leverage the powerful dynamic capabilities in our ecosystem. (This is how the automatic commands are implemented, BTW)  By calling Set(“Foo”, 1), you have now created a dynamic property called Foo.  It can be bound against like any static property.  The opportunities are endless.  One great way to exploit this behavior is if you have a customizable view engine with templates that bind to properties defined by the user.  The base class just needs to create the dynamic properties at runtime from information in the model, and the custom template can bind even though the static properties do not exist. All dynamic properties still benefit from the notifiable capabilities that static properties do. For any nay-sayers out there that don’t like using the dynamic features of C#, just remember this: the act of binding the View to a ViewModel is dynamic already.  Why not exploit it?  Get over it :) Just declare the property dynamically public class DynamicPropertyViewModel : ViewModelBase { public DynamicPropertyViewModel() { Set("Foo", "Bar"); } } Then reference it normally <TextBlock Text="{Binding Foo}" />   Default Property Values The Get() method also allows for default properties to be set.  Don’t set them in the constructor.  Set them in the property and keep the related code together: public string Text { get { return Get(() => Text, "This is the default value"); } set { Set(() => Text, value);} }   Derived Properties This is something I blogged about a while back in more detail.  This feature came from the chaining of property notifications when one property affects the results of another, like this: Before public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); RaisePropertyChanged("Percentage"); RaisePropertyChanged("Output"); } } public int Percentage { get { return (int)(100 * Score); } } public string Output { get { return "You scored " + Percentage + "%."; } } } The problem is: The setter for Score has to be responsible for notifying the world that Percentage and Output have also changed.  This, to me, is backwards.    It certainly violates the “Single Responsibility Principle.” I have been bitten in the rear more than once by problems created from code like this.  What we really want to do is invert the dependency.  Let the Percentage property declare that it changes when the Score Property changes. After public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public int Percentage { get { return (int)(100 * Score); } } [DependsUpon("Percentage")] public string Output { get { return "You scored " + Percentage + "%."; } } }   Automatic Method Execution This one is extremely similar to the previous, but it deals with method execution as opposed to property.  When you want to execute a method triggered by property changes, let the method declare the dependency instead of the other way around. Before public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); WhenScoreChanges(); } } public void WhenScoreChanges() { // Handle this case } } After public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public void WhenScoreChanges() { // Handle this case } }   Command CanExecute Change Notification Back to Commands.  One of the responsibilities of commands that implement ICommand – it must fire an event declaring that CanExecute() needs to be re-evaluated.  I wanted to wait until we got past a few concepts before explaining this behavior.  You can use the same mechanism here to fire off the change.  In the CanExecute_ method, declare the property that it depends upon.  When that property changes, the command will fire a CanExecuteChanged event, telling the View to re-evaluate the state of the command.  The View will make appropriate adjustments, like disabling the button. DependsUpon works on CanExecute methods as well public class CanExecuteViewModel : ViewModelBase { public void Execute_MakeLower() { Output = Input.ToLower(); } [DependsUpon("Input")] public bool CanExecute_MakeLower() { return !string.IsNullOrWhiteSpace(Input); } public string Input { get { return Get(() => Input); } set { Set(() => Input, value);} } public string Output { get { return Get(() => Output); } set { Set(() => Output, value); } } }   Design-Time Detection If you want to add design-time data to your ViewModel, the base class has a property that lets you ask if you are in the designer.  You can then set some default values that let your designer see what things might look like in runtime. Use the IsInDesignMode property public DependantPropertiesViewModel() { if(IsInDesignMode) { Score = .5; } }   What About Silverlight? Some of the features in this base class only work in WPF.  As of version 4, Silverlight does not support binding to dynamic properties.  This, in my opinion, is a HUGE limitation.  Not only does it keep you from using many of the features in this ViewModel, it also keeps you from binding to ViewModels designed in IronRuby.  Does this mean that the base class will not work in Silverlight?  No.  Many of the features outlined in this article WILL work.  All of the property abstractions are functional, as long as you refer to them statically in the View.  This, of course, means that the automatic command hook-up doesn’t work in Silverlight.  You need to plumb it to a static property in order for the Silverlight View to bind to it.  Can I has a dynamic property in SL5?     Good to go? So, that concludes the feature explanation of my ViewModel base class.  Feel free to take it, fork it, whatever.  It is hosted on CodePlex.  When I find other useful additions, I will add them to the public repository.  I use this base class every day.  It is mature, and well tested.  If, however, you find any problems with it, please let me know!  Also, feel free to suggest patches to me via the CodePlex site.  :)

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• SQL SERVER – Concurrency Basics – Guest Post by Vinod Kumar

  - by pinaldave

  This guest post is by Vinod Kumar. Vinod Kumar has worked with SQL Server extensively since joining the industry over a decade ago. Working on various versions from SQL Server 7.0, Oracle 7.3 and other database technologies – he now works with the Microsoft Technology Center (MTC) as a Technology Architect. Let us read the blog post in Vinod’s own voice. Learning is always fun when it comes to SQL Server and learning the basics again can be more fun. I did write about Transaction Logs and recovery over my blogs and the concept of simplifying the basics is a challenge. In the real world we always see checks and queues for a process – say railway reservation, banks, customer supports etc there is a process of line and queue to facilitate everyone. Shorter the queue higher is the efficiency of system (a.k.a higher is the concurrency). Every database does implement this using checks like locking, blocking mechanisms and they implement the standards in a way to facilitate higher concurrency. In this post, let us talk about the topic of Concurrency and what are the various aspects that one needs to know about concurrency inside SQL Server. Let us learn the concepts as one-liners: Concurrency can be defined as the ability of multiple processes to access or change shared data at the same time. The greater the number of concurrent user processes that can be active without interfering with each other, the greater the concurrency of the database system. Concurrency is reduced when a process that is changing data prevents other processes from reading that data or when a process that is reading data prevents other processes from changing that data. Concurrency is also affected when multiple processes are attempting to change the same data simultaneously. Two approaches to managing concurrent data access: Optimistic Concurrency Model Pessimistic Concurrency Model Concurrency Models Pessimistic Concurrency Default behavior: acquire locks to block access to data that another process is using. Assumes that enough data modification operations are in the system that any given read operation is likely affected by a data modification made by another user (assumes conflicts will occur). Avoids conflicts by acquiring a lock on data being read so no other processes can modify that data. Also acquires locks on data being modified so no other processes can access the data for either reading or modifying. Readers block writer, writers block readers and writers. Optimistic Concurrency Assumes that there are sufficiently few conflicting data modification operations in the system that any single transaction is unlikely to modify data that another transaction is modifying. Default behavior of optimistic concurrency is to use row versioning to allow data readers to see the state of the data before the modification occurs. Older versions of the data are saved so a process reading data can see the data as it was when the process started reading and not affected by any changes being made to that data. Processes modifying the data is unaffected by processes reading the data because the reader is accessing a saved version of the data rows. Readers do not block writers and writers do not block readers, but, writers can and will block writers. Transaction Processing A transaction is the basic unit of work in SQL Server. Transaction consists of SQL commands that read and update the database but the update is not considered final until a COMMIT command is issued (at least for an explicit transaction: marked with a BEGIN TRAN and the end is marked by a COMMIT TRAN or ROLLBACK TRAN). Transactions must exhibit all the ACID properties of a transaction. ACID Properties Transaction processing must guarantee the consistency and recoverability of SQL Server databases. Ensures all transactions are performed as a single unit of work regardless of hardware or system failure. A – Atomicity C – Consistency I – Isolation D- Durability Atomicity: Each transaction is treated as all or nothing – it either commits or aborts. Consistency: ensures that a transaction won’t allow the system to arrive at an incorrect logical state – the data must always be logically correct.  Consistency is honored even in the event of a system failure. Isolation: separates concurrent transactions from the updates of other incomplete transactions. SQL Server accomplishes isolation among transactions by locking data or creating row versions. Durability: After a transaction commits, the durability property ensures that the effects of the transaction persist even if a system failure occurs. If a system failure occurs while a transaction is in progress, the transaction is completely undone, leaving no partial effects on data. Transaction Dependencies In addition to supporting all four ACID properties, a transaction might exhibit few other behaviors (known as dependency problems or consistency problems). Lost Updates: Occur when two processes read the same data and both manipulate the data, changing its value and then both try to update the original data to the new value. The second process might overwrite the first update completely. Dirty Reads: Occurs when a process reads uncommitted data. If one process has changed data but not yet committed the change, another process reading the data will read it in an inconsistent state. Non-repeatable Reads: A read is non-repeatable if a process might get different values when reading the same data in two reads within the same transaction. This can happen when another process changes the data in between the reads that the first process is doing. Phantoms: Occurs when membership in a set changes. It occurs if two SELECT operations using the same predicate in the same transaction return a different number of rows. Isolation Levels SQL Server supports 5 isolation levels that control the behavior of read operations. Read Uncommitted All behaviors except for lost updates are possible. Implemented by allowing the read operations to not take any locks, and because of this, it won’t be blocked by conflicting locks acquired by other processes. The process can read data that another process has modified but not yet committed. When using the read uncommitted isolation level and scanning an entire table, SQL Server can decide to do an allocation order scan (in page-number order) instead of a logical order scan (following page pointers). If another process doing concurrent operations changes data and move rows to a new location in the table, the allocation order scan can end up reading the same row twice. Also can happen if you have read a row before it is updated and then an update moves the row to a higher page number than your scan encounters later. Performing an allocation order scan under Read Uncommitted can cause you to miss a row completely – can happen when a row on a high page number that hasn’t been read yet is updated and moved to a lower page number that has already been read. Read Committed Two varieties of read committed isolation: optimistic and pessimistic (default). Ensures that a read never reads data that another application hasn’t committed. If another transaction is updating data and has exclusive locks on data, your transaction will have to wait for the locks to be released. Your transaction must put share locks on data that are visited, which means that data might be unavailable for others to use. A share lock doesn’t prevent others from reading but prevents them from updating. Read committed (snapshot) ensures that an operation never reads uncommitted data, but not by forcing other processes to wait. SQL Server generates a version of the changed row with its previous committed values. Data being changed is still locked but other processes can see the previous versions of the data as it was before the update operation began. Repeatable Read This is a Pessimistic isolation level. Ensures that if a transaction revisits data or a query is reissued the data doesn’t change. That is, issuing the same query twice within a transaction cannot pickup any changes to data values made by another user’s transaction because no changes can be made by other transactions. However, this does allow phantom rows to appear. Preventing non-repeatable read is a desirable safeguard but cost is that all shared locks in a transaction must be held until the completion of the transaction. Snapshot Snapshot Isolation (SI) is an optimistic isolation level. Allows for processes to read older versions of committed data if the current version is locked. Difference between snapshot and read committed has to do with how old the older versions have to be. It’s possible to have two transactions executing simultaneously that give us a result that is not possible in any serial execution. Serializable This is the strongest of the pessimistic isolation level. Adds to repeatable read isolation level by ensuring that if a query is reissued rows were not added in the interim, i.e, phantoms do not appear. Preventing phantoms is another desirable safeguard, but cost of this extra safeguard is similar to that of repeatable read – all shared locks in a transaction must be held until the transaction completes. In addition serializable isolation level requires that you lock data that has been read but also data that doesn’t exist. Ex: if a SELECT returned no rows, you want it to return no. rows when the query is reissued. This is implemented in SQL Server by a special kind of lock called the key-range lock. Key-range locks require that there be an index on the column that defines the range of values. If there is no index on the column, serializable isolation requires a table lock. Gets its name from the fact that running multiple serializable transactions at the same time is equivalent of running them one at a time. Now that we understand the basics of what concurrency is, the subsequent blog posts will try to bring out the basics around locking, blocking, deadlocks because they are the fundamental blocks that make concurrency possible. Now if you are with me – let us continue learning for SQL Server Locking Basics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Concurrency

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• NRF Online Merchandising Workshop: Where Online Retailers Are Focusing for Holiday and Beyond

  - by Rose Spicer-Oracle

  0 0 1 1204 6863 Oracle Corporation 57 16 8051 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} Last month we attended the NRF Online Merchandising Workshop in LA, and it was a great opportunity to catch up with our customers, meet new retailers, and hear some great presentations from VF Corporation, Zazzle, Julep Beauty, Backcountry, eBags and more. The one-on-one conversations with Merchants and the keynote presentations carry the same themes across companies of all sizes and across verticals. With only 125 days left (and counting) until Black Friday, these conversations provided some great insight in to what’s top of mind for retailers during the most stressful time of their year, and a sneak peek in to what they will deliver this holiday season.  Some of the most popular topics were: When to start promoting for holiday: seems like a funny conversation to have in July, but a number of retailers said they already had their holiday shopping gift guides live on their site, and it was attracting a significant portion of their onsite traffic. When it comes to timing, most retailers were questioning when to begin their holiday promotions -- carefully balancing when to release pricing and specials, and knowing that customers are holding out for last-minute deals and price drops. Many retailers noted the frustrations around transparent pricing by Amazon and a few other mega-retailers last year, publishing their “lowest prices of the season” as early as October – ensuring shoppers that those prices were the best they could get all season long. Many retailers felt their hands were forced to drop prices. Others kept their set pricing with negative customer reaction, causing some to miss their holiday goals. The pressure is on, and most retailers identified November 1 as their target start date for the holiday promotions blitz. Some are even waiting for the big guys to release their “lowest prices of the season” guides and will then follow suit.      Attribution is tough – and a huge focus: understanding the path to conversion is a tough nut to crack, especially in the new omnichannel world where consumers use multiple touchpoints to make a single purchase, and internal management wants to know hard data. This has lead many retailers to invest in attribution; carefully tracking their online marketing efforts to determine what gets “credit” for the sale, instead of giving credit to the “last click.” Retailers noted that it is very difficult to determine the numbers when online and offline worlds collide – like when a shopper uses digital channels for research and then makes a purchase in a store. As one of the presenters from The North Face mentioned in her keynote, a key to enabling better customer service and satisfaction when it comes to converged online and offline sales is training the in-store staff, and creating a culture where it eventually “doesn’t matter what group gets the credit” if they all add to the sale. No doubt, the area of attribution will be a big area of retail investment in the coming years.      How to plan for the converged world: planning to ensure inventory gets where it needs to be was another concern. In conversations with retailers, we advised them to analyze customer patterns: where shoppers purchase items, where the items were sourced from and even where items are returned. This analysis is very valuable in determining inventory plans. From there, retailers can more accurately plan and allocate inventory to support both the online and offline customer behavior. As we head into the holiday season, the need for accurate enterprise-wide inventory visibility, and providing that information to associates, is even more critical to the brand-wide customer experience.       Improving the search / navigation / usability of the site(s): Aside from some of the big ideas and standard holiday pricing pressure, most conversations we had centered around continuing to improve the basics of the site. Reinvesting in search and navigation came up time and time again (FitForCommerce blogged about what a big topic it was at the event as well). Obviously getting shoppers on their path quickly and allowing them to find what they need fast is critical, but it was definitely interesting to hear just how much effort is still going in to honing the search and navigation experience. Adding new elements to search and navigation like typeahed, inventive navigation refinements, and new navigation categories like gift guides, specialized boutiques and flash sales were top of mind, in addition to searchandising and making search-driven product recommendations. (Oracle can help!)       Reducing cart abandonment: always a hot topic that is top of mind for every online retailer. Getting shoppers to the cart is often less then half the battle; getting them to click “buy” and complete the transaction is much more difficult. While retailers carefully study the checkout process and where shoppers tend to bounce, they know that how they design their checkout page is critical. We’re all online shoppers in our personal lives and we know how frustrating it can be when total prices are not transparent (i.e. shipping, processing, taxes is not included until the very last possible screen before clicking that buy button). Online retailers are struggling with where in the checkout process to surface the total price to be charged to reduce cart abandonment, while not showing the total figure too early in the process that it keeps shoppers from getting to checkout altogether. Recent research shows that providing total pricing prior to the checkout process dramatically reduces cart abandonment – as it serves as a filter to those shopping within a specific price band. Much of the cart abandonment discussion leads us to…       The free shipping / free returns question: it’s no secret that because of Amazon and programs like Prime, consumers expect free shipping, much to the chagrin of the smaller retailer. The reality is that if you’re not a mega-retailer, shipping is an expensive part of doing business that doesn’t allow most retailers to keep their prices low and offer free shipping. This has many retailers venturing out on the “free returns” path, especially in apparel. A number of retailers we spoke with are testing a flat rate shipping fee with free returns to see if they can crack the price threshold where shoppers are willing to pay for shipping with an added service. But, free shipping remains king.      Social ads and retargeting: they are working, but do they turn off consumers? That’s the big question. Every retailer we spoke with during a roundtable on the topic said that social ads and retargeting (where that pair of boots you’re been eyeing on a site magically follows you around the Internet) work and are meeting campaign goals. The larger question many retailers are asking is if this type of tactic is turning off a large number of shoppers, even if these campaigns are meeting their early goals. Retailers also mentioned that Facebook ads are working very well for them, especially when it comes to new customer acquisition, serving as a complimentary a channel to SEO when it comes to engaging new customers. While there are always new things to experiment with in retail, standard challenges are top of mind as retailers scramble to get ready for holiday. It will undoubtedly be another record-breaking online shopping season, but as retailers get more and more advanced with each Black Friday, expect some exciting things. This excitement needs to be backed by sound solutions and optimized operations. Then again, consumers are expecting more than ever, so I don’t doubt that retailers are already thinking about the possibilities of holiday 2015… and beyond. Customers who read this article, also found value in the following stories: Personalization for Retail: http://blogs.oracle.com/retail/entry/personalization_for_retailShop Direct User Experience Focus Drives Sales:https://blogs.oracle.com/retail/entry/shop_direct_user_experience_focusMaking Waves: Australian Online Retailer SurfStitch: https://blogs.oracle.com/oracleretail/entry/surf_stitchWhat’s new in Oracle Commerce v11.1 for RetailWhat the Content+Commerce Equation is Missing

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• Lightning talk: Coderetreat

  - by Michael Williamson

  In the spirit of trying to encourage more deliberate practice amongst coders in Red Gate, Lauri Pesonen had the idea of running a coderetreat in Red Gate. Lauri and I ran the first one a few weeks ago: given that neither of us hadn’t even been to a coderetreat before, let alone run one, I think it turned out quite well. The participants gave positive feedback, saying that they enjoyed the day, wrote some thought-provoking code and would do it again. Sam Blackburn was one of the attendees, and gave a lightning talk to the other developers in one of our regular lightning talk sessions: In case you can’t watch the video, I’ve transcribed the talk below, although I’d recommend watching the video if you can — I didn’t have much time to do the transcribing! So, what is a coderetreat? So it’s not just something in Red Gate, there’s a website and everything, although it’s not a very big website. It calls itself a community network. The basic ideas behind coderetreat are: you’ve got one day, and you split it into one hour sections. You spend three quarters of that coding, and do a little retrospective at the end. You’re supposed to start fresh each, we were told to delete our code after every session. We were in pairs, swapping after each session, and we did the same task every time. In fact, Conway’s Game of Life is the only task mentioned anywhere that I find for coderetreat. So I don’t know what we’ll do next time, or if we’re meant to do the same thing again. There are some guiding principles which felt to us like restrictions, that you have to code in crazy ways to encourage better code. Final thing is that it’s supposed to be free for outsiders to join. It’s meant to be a kind of networking thing, where you link up with people from other companies. We had a pilot day with Michael and Lauri. Since it was basically the first time any of us had done anything like this, everybody was from Red Gate. We didn’t chat to anybody else for the initial one. The task was Conway’s Game of Life, which most of you have probably heard of it, all but one of us knew about it when did the coderetreat. I won’t got into the details of what it is, but it felt like the right size of task, basically one or two groups actually produced something working by the end of the day, and of course that doesn’t mean it’s necessarily a day’s work to produce that because we were starting again every hour. The task really drives you more than trying to create good code, I found. It was really tempting to try and get it working rather than stick to the rules. But it’s really good to stop and try again because there are so many what-ifs when you’ve finished writing something, “what if I’d done it this way?”. You can answer all those questions at a coderetreat because it’s not about getting a product out the door, it’s about learning and playing with ideas. So we had all these different practices we were trying. I’ll try and go through most of these. Single responsibility is this idea that everything should do just one thing. It was the very first session, we were still trying to figure out how do you go about the Game of Life? So by the end of forty-five minutes hadn’t produced very much for that first session. We were still thinking, “Do we start with a board, how do we represent all these squares? It can be infinitely big, help, this is getting really difficult!”. So, most of us didn’t really get anywhere on the first one. Although it was interesting that some people started with the board, one group started with the FateDecider class that decides whether things live or die. A sort of god class, but in a good way. They managed to implement all of the rules without even defining how the squares were arranged or anything like that. Another thing we tried was TDD (test-driven development). I’m sure most of you know what TDD is: Watch a test, watch it fail for the right reason Write code to pass the test, watch it pass Refactor, check the test still passes Repeat! It basically worked, we were able to produce code, but we often found the tests defined the direction that code went, which is obviously the idea of TDD. But you tend to find that by the time you’ve even written your first assertion, which is supposed to be the very first thing you write, because you write your tests backwards from the assertions back to the initial conditions, you’ve already constrained the logic of the code in some way by the time you’ve done that. You then get to this situation of, “Well, we actually want to go in a slightly different direction. Can we do this?”. Can we write tests that don’t constrain the architecture? Wrapping up all primitives: it’s kind of turtles all the way down. We had a Size, which has a Width and Height, which both derive from Dimension. You’ve got pages of code before you’ve even done anything. No getters and setters (use tell don’t ask instead): mocks and stubs for tests are required if you want to assert that your results are what you think they should be. You can’t just check the internal state of the code. And people found that really challenging and it made them think in a different way which I think is really good. Not having mutable state: that was kind of confusing because we weren’t quite sure what fitted within that rule and what didn’t, and I think we were trying too hard to follow the rule rather than the guideline. No if-statements: supposed to use polymorphism instead, but polymorphism still requires a factory with conditional behaviour. We did something really crazy to get around this: public T If(bool condition, Func<T> left, Func<T> right) { var dict = new Dictionary<bool, Func<T>> {{true, left}, {false, right}}; return dict[condition].Invoke(); } That is not really polymorphism, is it? For-loops: you can always replace a for-loop with recursion, but it doesn’t tend to make it any more readable unless it’s the kind of task that really lends itself to that. So it was interesting, it was good practice, but it wouldn’t make it easier it’s the kind of tree-structure algorithm where that would help. Having a limit on the number of levels of indentation: again, I think it does produce very nice, clean code, but it wasn’t actually a challenge because you just extract methods. That’s quite a useful thing because you can apply that to real code and say, “Okay, should this method really be going crazy like this?” No talking: we hated that. It’s like there’s two of you at a computer, and one of you is doing the typing, what does the other guy do if they’re not allowed to talk. The answer is TDD ping-pong – one person writes the tests, and then the other person writes the code to pass the test. And that creates communication without actually having to have discussion about things which is kind of cool. No code comments: just makes no difference to anything. It’s a forty-five minute exercise, so what are you going to put comments in code for? Finally, this is my fault. I discovered an entertaining way of doing the calculation that was kind of cool (using convolutions over the state of the board). Unfortunately, it turns out to be really hard to implement in C#, so didn’t even manage to work out how to do that convolution in C#. It’s trivial in some high-level languages, but you need something matrix-orientated for it to really work. That’s most of it, really. The thoughts that people went away with: we put down our answers to questions like “What have you learnt?” and “What surprised you?”, “How are you going to do things differently?”, and most people said redoing the problem is really, really good for understanding it properly. People hate having a massive legacy codebase that they can’t change, so being able to attack something three different ways in an environment where the end-product isn’t important: that’s something people really enjoyed. Pair-programming: also people said that they wanted to do more of that, especially with TDD ping-pong, where you write the test and somebody else writes the code. Various people thought different things about immutables, but most people thought they were good, they promote functional programming. And TDD people found really hard. “Tell, don’t ask” people found really, really hard and really, really, really hard to do well. And the recursion just made things trickier to debug. But most people agreed that coderetreats are really cool, and we should do more of them.

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• Clustering Basics and Challenges

  - by Karoly Vegh

  For upcoming posts it seemed to be a good idea to dedicate some time for cluster basic concepts and theory. This post misses a lot of details that would explode the articlesize, should you have questions, do not hesitate to ask them in the comments.  The goal here is to get some concepts straight. I can't promise to give you an overall complete definitions of cluster, cluster agent, quorum, voting, fencing, split brain condition, so the following is more of an explanation. Here we go. -------- Cluster, HA, failover, switchover, scalability -------- An attempted definition of a Cluster: A cluster is a set (2+) server nodes dedicated to keep application services alive, communicating through the cluster software/framework with eachother, test and probe health status of servernodes/services and with quorum based decisions and with switchover/failover techniques keep the application services running on them available. That is, should a node that runs a service unexpectedly lose functionality/connection, the other ones would take over the and run the services, so that availability is guaranteed. To provide availability while strictly sticking to a consistent clusterconfiguration is the main goal of a cluster.  At this point we have to add that this defines a HA-cluster, a High-Availability cluster, where the clusternodes are planned to run the services in an active-standby, or failover fashion. An example could be a single instance database. Some applications can be run in a distributed or scalable fashion. In the latter case instances of the application run actively on separate clusternodes serving servicerequests simultaneously. An example for this version could be a webserver that forwards connection requests to many backend servers in a round-robin way. Or a database running in active-active RAC setup.  -------- Cluster arhitecture, interconnect, topologies -------- Now, what is a cluster made of? Servers, right. These servers (the clusternodes) need to communicate. This of course happens over the network, usually over dedicated network interfaces interconnecting all the clusternodes. These connection are called interconnects.How many clusternodes are in a cluster? There are different cluster topologies. The most simple one is a clustered pair topology, involving only two clusternodes:  There are several more topologies, clicking the image above will take you to the relevant documentation. Also, to answer the question Solaris Cluster allows you to run up to 16 servers in a cluster. Where shall these clusternodes be placed? A very important question. The right answer is: It depends on what you plan to achieve with the cluster. Do you plan to avoid only a server outage? Then you can place them right next to eachother in the datacenter. Do you need to avoid DataCenter outage? In that case of course you should place them at least in different fire zones. Or in two geographically distant DataCenters to avoid disasters like floods, large-scale fires or power outages. We call this a stretched- or campus cluster, the clusternodes being several kilometers away from eachother. To cover really large distances, you probably need to move to a GeoCluster, which is a different kind of animal.  What is a geocluster? A Geographic Cluster in Solaris Cluster terms is actually a metacluster between two, separate (locally-HA) clusters.  -------- Cluster resource types, agents, resources, resource groups -------- So how does the cluster manage my applications? The cluster needs to start, stop and probe your applications. If you application runs, the cluster needs to check regularly if the application state is healthy, does it respond over the network, does it have all the processes running, etc. This is called probing. If the cluster deems the application is in a faulty state, then it can try to restart it locally or decide to switch (stop on node A, start on node B) the service. Starting, stopping and probing are the three actions that a cluster agent does. There are many different kinds of agents included in Solaris Cluster, but you can build your own too. Examples are an agent that manages (mounts, moves) ZFS filesystems, or the Oracle DB HA agent that cares about the database, or an agent that moves a floating IP address between nodes. There are lots of other agents included for Apache, Tomcat, MySQL, Oracle DB, Oracle Weblogic, Zones, LDoms, NFS, DNS, etc.We also need to clarify the difference between a cluster resource and the cluster resource group.A cluster resource is something that is managed by a cluster agent. Cluster resource types are included in Solaris cluster (see above, e.g. HAStoragePlus, HA-Oracle, LogicalHost). You can group cluster resources into cluster resourcegroups, and switch these groups together from one node to another. To stick to the example above, to move an Oracle DB service from one node to another, you have to switch the group between nodes, and the agents of the cluster resources in the group will do the following:  On node A Shut down the DB Unconfigure the LogicalHost IP the DB Listener listens on unmount the filesystem   Then, on node B: mount the FS configure the IP  startup the DB -------- Voting, Quorum, Split Brain Condition, Fencing, Amnesia -------- How do the clusternodes agree upon their action? How do they decide which node runs what services? Another important question. Running a cluster is a strictly democratic thing.Every node has votes, and you need the majority of votes to have the deciding power. Now, this is usually no problem, clusternodes think very much all alike. Still, every action needs to be governed upon in a productive system, and has to be agreed upon. Agreeing is easy as long as the clusternodes all behave and talk to eachother over the interconnect. But if the interconnect is gone/down, this all gets tricky and confusing. Clusternodes think like this: "My job is to run these services. The other node does not answer my interconnect communication, it must be down. I'd better take control and run the services!". The problem is, as I have already mentioned, clusternodes very much think alike. If the interconnect is gone, they all assume the other node is down, and they all want to mount the data backend, enable the IP and run the database. Double IPs, double mounts, double DB instances - now that is trouble. Also, in a 2-node cluster they both have only 50% of the votes, that is, they themselves alone are not allowed to run a cluster.  This is where you need a quorum device. According to Wikipedia, the "requirement for a quorum is protection against totally unrepresentative action in the name of the body by an unduly small number of persons.". They need additional votes to run the cluster. For this requirement a 2-node cluster needs a quorum device or a quorum server. If the interconnect is gone, (this is what we call a split brain condition) both nodes start to race and try to reserve the quorum device to themselves. They do this, because the quorum device bears an additional vote, that could ensure majority (50% +1). The one that manages to lock the quorum device (e.g. if it's an FC LUN, it SCSI reserves it) wins the right to build/run a cluster, the other one - realizing he was late - panics/reboots to ensure the cluster config stays consistent.  Losing the interconnect isn't only endangering the availability of services, but it also endangers the cluster configuration consistence. Just imagine node A being down and during that the cluster configuration changes. Now node B goes down, and node A comes up. It isn't uptodate about the cluster configuration's changes so it will refuse to start a cluster, since that would lead to cluster amnesia, that is the cluster had some changes, but now runs with an older cluster configuration repository state, that is it's like it forgot about the changes.  Also, to ensure application data consistence, the clusternode that wins the race makes sure that a server that isn't part of or can't currently join the cluster can access the devices. This procedure is called fencing. This usually happens to storage LUNs via SCSI reservation.  Now, another important question: Where do I place the quorum disk?  Imagine having two sites, two separate datacenters, one in the north of the city and the other one in the south part of it. You run a stretched cluster in the clustered pair topology. Where do you place the quorum disk/server? If you put it into the north DC, and that gets hit by a meteor, you lose one clusternode, which isn't a problem, but you also lose your quorum, and the south clusternode can't keep the cluster running lacking the votes. This problem can't be solved with two sites and a campus cluster. You will need a third site to either place the quorum server to, or a third clusternode. Otherwise, lacking majority, if you lose the site that had your quorum, you lose the cluster. Okay, we covered the very basics. We haven't talked about virtualization support, CCR, ClusterFilesystems, DID devices, affinities, storage-replication, management tools, upgrade procedures - should those be interesting for you, let me know in the comments, along with any other questions. Given enough demand I'd be glad to write a followup post too. Now I really want to move on to the second part in the series: ClusterInstallation.  Oh, as for additional source of information, I recommend the documentation: http://docs.oracle.com/cd/E23623_01/index.html, and the OTN Oracle Solaris Cluster site: http://www.oracle.com/technetwork/server-storage/solaris-cluster/index.html

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• Announcing ASP.NET MVC 3 (Release Candidate 2)

  - by ScottGu

  Earlier today the ASP.NET team shipped the final release candidate (RC2) for ASP.NET MVC 3.  You can download and install it here. Almost there… Today’s RC2 release is the near-final release of ASP.NET MVC 3, and is a true “release candidate” in that we are hoping to not make any more code changes with it.  We are publishing it today so that people can do final testing with it, let us know if they find any last minute “showstoppers”, and start updating their apps to use it.  We will officially ship the final ASP.NET MVC 3 “RTM” build in January. Works with both VS 2010 and VS 2010 SP1 Beta Today’s ASP.NET MVC 3 RC2 release works with both the shipping version of Visual Studio 2010 / Visual Web Developer 2010 Express, as well as the newly released VS 2010 SP1 Beta.  This means that you do not need to install VS 2010 SP1 (or the SP1 beta) in order to use ASP.NET MVC 3.  It works just fine with the shipping Visual Studio 2010.  I’ll do a blog post next week, though, about some of the nice additional feature goodies that come with VS 2010 SP1 (including IIS Express and SQL CE support within VS) which make the dev experience for both ASP.NET Web Forms and ASP.NET MVC even better. Bugs and Perf Fixes Today’s ASP.NET MVC 3 RC2 build contains many bug fixes and performance optimizations.  Our latest performance tests indicate that ASP.NET MVC 3 is now faster than ASP.NET MVC 2, and that existing ASP.NET MVC applications will experience a slight performance increase when updated to run using ASP.NET MVC 3. Final Tweaks and Fit-N-Finish In addition to bug fixes and performance optimizations, today’s RC2 build contains a number of last-minute feature tweaks and “fit-n-finish” changes for the new ASP.NET MVC 3 features.  The feedback and suggestions we’ve received during the public previews has been invaluable in guiding these final tweaks, and we really appreciate people’s support in sending this feedback our way.  Below is a short-list of some of the feature changes/tweaks made between last month’s ASP.NET MVC 3 RC release and today’s ASP.NET MVC 3 RC2 release: jQuery updates and addition of jQuery UI The default ASP.NET MVC 3 project templates have been updated to include jQuery 1.4.4 and jQuery Validation 1.7.  We are also excited to announce today that we are including jQuery UI within our default ASP.NET project templates going forward.  jQuery UI provides a powerful set of additional UI widgets and capabilities.  It will be added by default to your project’s \scripts folder when you create new ASP.NET MVC 3 projects. Improved View Scaffolding The T4 templates used for scaffolding views with the Add-View dialog now generates views that use Html.EditorFor instead of helpers such as Html.TextBoxFor. This change enables you to optionally annotate models with metadata (using data annotation attributes) to better customize the output of your UI at runtime. The Add View scaffolding also supports improved detection and usage of primary key information on models (including support for naming conventions like ID, ProductID, etc).  For example: the Add View dialog box uses this information to ensure that the primary key value is not scaffold as an editable form field, and that links between views are auto-generated correctly with primary key information. The default Edit and Create templates also now include references to the jQuery scripts needed for client validation.  Scaffold form views now support client-side validation by default (no extra steps required).  Client-side validation with ASP.NET MVC 3 is also done using an unobtrusive javascript approach – making pages fast and clean. [ControllerSessionState] –> [SessionState] ASP.NET MVC 3 adds support for session-less controllers.  With the initial RC you used a [ControllerSessionState] attribute to specify this.  We shortened this in RC2 to just be [SessionState]: Note that in addition to turning off session state, you can also set it to be read-only (which is useful for webfarm scenarios where you are reading but not updating session state on a particular request). [SkipRequestValidation] –> [AllowHtml] ASP.NET MVC includes built-in support to protect against HTML and Cross-Site Script Injection Attacks, and will throw an error by default if someone tries to post HTML content as input.  Developers need to explicitly indicate that this is allowed (and that they’ve hopefully built their app to securely support it) in order to enable it. With ASP.NET MVC 3, we are also now supporting a new attribute that you can apply to properties of models/viewmodels to indicate that HTML input is enabled, which enables much more granular protection in a DRY way.  In last month’s RC release this attribute was named [SkipRequestValidation].  With RC2 we renamed it to [AllowHtml] to make it more intuitive: Setting the above [AllowHtml] attribute on a model/viewmodel will cause ASP.NET MVC 3 to turn off HTML injection protection when model binding just that property. Html.Raw() helper method The new Razor view engine introduced with ASP.NET MVC 3 automatically HTML encodes output by default.  This helps provide an additional level of protection against HTML and Script injection attacks. With RC2 we are adding a Html.Raw() helper method that you can use to explicitly indicate that you do not want to HTML encode your output, and instead want to render the content “as-is”: ViewModel/View –> ViewBag ASP.NET MVC has (since V1) supported a ViewData[] dictionary within Controllers and Views that enables developers to pass information from a Controller to a View in a late-bound way.  This approach can be used instead of, or in combination with, a strongly-typed model class.  The below code demonstrates a common use case – where a strongly typed Product model is passed to the view in addition to two late-bound variables via the ViewData[] dictionary: With ASP.NET MVC 3 we are introducing a new API that takes advantage of the dynamic type support within .NET 4 to set/retrieve these values.  It allows you to use standard “dot” notation to specify any number of additional variables to be passed, and does not require that you create a strongly-typed class to do so.  With earlier previews of ASP.NET MVC 3 we exposed this API using a dynamic property called “ViewModel” on the Controller base class, and with a dynamic property called “View” within view templates.  A lot of people found the fact that there were two different names confusing, and several also said that using the name ViewModel was confusing in this context – since often you create strongly-typed ViewModel classes in ASP.NET MVC, and they do not use this API.  With RC2 we are exposing a dynamic property that has the same name – ViewBag – within both Controllers and Views.  It is a dynamic collection that allows you to pass additional bits of data from your controller to your view template to help generate a response.  Below is an example of how we could use it to pass a time-stamp message as well as a list of all categories to our view template: Below is an example of how our view template (which is strongly-typed to expect a Product class as its model) can use the two extra bits of information we passed in our ViewBag to generate the response.  In particular, notice how we are using the list of categories passed in the dynamic ViewBag collection to generate a dropdownlist of friendly category names to help set the CategoryID property of our Product object.  The above Controller/View combination will then generate an HTML response like below.    Output Caching Improvements ASP.NET MVC 3’s output caching system no longer requires you to specify a VaryByParam property when declaring an [OutputCache] attribute on a Controller action method.  MVC3 now automatically varies the output cached entries when you have explicit parameters on your action method – allowing you to cleanly enable output caching on actions using code like below: In addition to supporting full page output caching, ASP.NET MVC 3 also supports partial-page caching – which allows you to cache a region of output and re-use it across multiple requests or controllers.  The [OutputCache] behavior for partial-page caching was updated with RC2 so that sub-content cached entries are varied based on input parameters as opposed to the URL structure of the top-level request – which makes caching scenarios both easier and more powerful than the behavior in the previous RC. @model declaration does not add whitespace In earlier previews, the strongly-typed @model declaration at the top of a Razor view added a blank line to the rendered HTML output. This has been fixed so that the declaration does not introduce whitespace. Changed "Html.ValidationMessage" Method to Display the First Useful Error Message The behavior of the Html.ValidationMessage() helper was updated to show the first useful error message instead of simply displaying the first error. During model binding, the ModelState dictionary can be populated from multiple sources with error messages about the property, including from the model itself (if it implements IValidatableObject), from validation attributes applied to the property, and from exceptions thrown while the property is being accessed. When the Html.ValidationMessage() method displays a validation message, it now skips model-state entries that include an exception, because these are generally not intended for the end user. Instead, the method looks for the first validation message that is not associated with an exception and displays that message. If no such message is found, it defaults to a generic error message that is associated with the first exception. RemoteAttribute “Fields” -> “AdditionalFields” ASP.NET MVC 3 includes built-in remote validation support with its validation infrastructure.  This means that the client-side validation script library used by ASP.NET MVC 3 can automatically call back to controllers you expose on the server to determine whether an input element is indeed valid as the user is editing the form (allowing you to provide real-time validation updates). You can accomplish this by decorating a model/viewmodel property with a [Remote] attribute that specifies the controller/action that should be invoked to remotely validate it.  With the RC this attribute had a “Fields” property that could be used to specify additional input elements that should be sent from the client to the server to help with the validation logic.  To improve the clarity of what this property does we have renamed it to “AdditionalFields” with today’s RC2 release. ViewResult.Model and ViewResult.ViewBag Properties The ViewResult class now exposes both a “Model” and “ViewBag” property off of it.  This makes it easier to unit test Controllers that return views, and avoids you having to access the Model via the ViewResult.ViewData.Model property. Installation Notes You can download and install the ASP.NET MVC 3 RC2 build here.  It can be installed on top of the previous ASP.NET MVC 3 RC release (it should just replace the bits as part of its setup). The one component that will not be updated by the above setup (if you already have it installed) is the NuGet Package Manager.  If you already have NuGet installed, please go to the Visual Studio Extensions Manager (via the Tools –> Extensions menu option) and click on the “Updates” tab.  You should see NuGet listed there – please click the “Update” button next to it to have VS update the extension to today’s release. If you do not have NuGet installed (and did not install the ASP.NET MVC RC build), then NuGet will be installed as part of your ASP.NET MVC 3 setup, and you do not need to take any additional steps to make it work. Summary We are really close to the final ASP.NET MVC 3 release, and will deliver the final “RTM” build of it next month.  It has been only a little over 7 months since ASP.NET MVC 2 shipped, and I’m pretty amazed by the huge number of new features, improvements, and refinements that the team has been able to add with this release (Razor, Unobtrusive JavaScript, NuGet, Dependency Injection, Output Caching, and a lot, lot more).  I’ll be doing a number of blog posts over the next few weeks talking about many of them in more depth. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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• That Escalated Quickly

  - by Jesse Taber

  Originally posted on: http://geekswithblogs.net/GruffCode/archive/2014/05/17/that-escalated-quickly.aspxI have been working remotely out of my home for over 4 years now. All of my coworkers during that time have also worked remotely. Lots of folks have written about the challenges inherent in facilitating communication on remote teams and strategies for overcoming them. A popular theme around this topic is the notion of “escalating communication”. In this context “escalating” means taking a conversation from one mode of communication to a different, higher fidelity mode of communication. Here are the five modes of communication I use at work in order of increasing fidelity: Email – This is the “lowest fidelity” mode of communication that I use. I usually only check it a few times a day (and I’m trying to check it even less frequently than that) and I only keep items in my inbox if they represent an item I need to take action on that I haven’t tracked anywhere else. Forums / Message boards – Being a developer, I’ve gotten into the habit of having other people look over my code before it becomes part of the product I’m working on. These code reviews often happen in “real time” via screen sharing, but I also always have someone else give all of the changes another look using pull requests. A pull request takes my code and lets someone else see the changes I’ve made side-by-side with the existing code so they can see if I did anything dumb. Pull requests can facilitate a conversation about the code changes in an online-forum like style. Some teams I’ve worked on also liked using tools like Trello or Google Groups to have on-going conversations about a topic or task that was being worked on. Chat & Instant Messaging  - Chat and instant messaging are the real workhorses for communication on the remote teams I’ve been a part of. I know some teams that are co-located that also use it pretty extensively for quick messages that don’t warrant walking across the office to talk with someone but reqire more immediacy than an e-mail. For the purposes of this post I think it’s important to note that the terms “chat” and “instant messaging” might insinuate that the conversation is happening in real time, but that’s not always true. Modern chat and IM applications maintain a searchable history so people can easily see what might have been discussed while they were away from their computers. Voice, Video and Screen sharing – Everyone’s got a camera and microphone on their computers now, and there are an abundance of services that will let you use them to talk to other people who have cameras and microphones on their computers. I’m including screen sharing here as well because, in my experience, these discussions typically involve one or more people showing the other participants something that’s happening on their screen. Obviously, this mode of communication is much higher-fidelity than any of the ones listed above. Scheduled meetings are typically conducted using this mode of communication. In Person – No matter how great communication tools become, there’s no substitute for meeting with someone face-to-face. However, opportunities for this kind of communcation are few and far between when you work on a remote team. When a conversation gets escalated that usually means it moves up one or more positions on this list. A lot of people advocate jumping to #4 sooner than later. Like them, I used to believe that, if it was possible, organizing a call with voice and video was automatically better than any kind of text-based communication could be. Lately, however, I’m becoming less convinced that escalating is always the right move. Working Asynchronously Last year I attended a talk at our local code camp given by Drew Miller. Drew works at GitHub and was talking about how they use GitHub internally. Many of the folks at GitHub work remotely, so communication was one of the main themes in Drew’s talk. During the talk Drew used the phrase, “asynchronous communication” to describe their use of chat and pull request comments. That phrase stuck in my head because I hadn’t heard it before but I think it perfectly describes the way in which remote teams often need to communicate. You don’t always know when your co-workers are at their computers or what hours (if any) they are working that day. In order to work this way you need to assume that the person you’re talking to might not respond right away. You can’t always afford to wait until everyone required is online and available to join a voice call, so you need to use text-based, persistent forms of communication so that people can receive and respond to messages when they are available. Going back to my list from the beginning of this post for a second, I characterize items #1-3 as being “asynchronous” modes of communication while we could call items #4 and #5 “synchronous”. When communication gets escalated it’s almost always moving from an asynchronous mode of communication to a synchronous one. Now, to the point of this post: I’ve become increasingly reluctant to escalate from asynchronous to synchronous communication for two primary reasons: 1 – You can often find a higher fidelity way to convey your message without holding a synchronous conversation 2 - Asynchronous modes of communication are (usually) persistent and searchable. You Don’t Have to Broadcast Live Let’s start with the first reason I’ve listed. A lot of times you feel like you need to escalate to synchronous communication because you’re having difficulty describing something that you’re seeing in words. You want to provide the people you’re conversing with some audio-visual aids to help them understand the point that you’re trying to make and you think that getting on Skype and sharing your screen with them is the best way to do that. Firing up a screen sharing session does work well, but you can usually accomplish the same thing in an asynchronous manner. For example, you could take a screenshot and annotate it with some text and drawings to illustrate what it is you’re seeing. If a screenshot won’t work, taking a short screen recording while your narrate over it and posting the video to your forum or chat system along with a text-based description of what’s in the recording that can be searched for later can be a great way to effectively communicate with your team asynchronously. I Said What?!? Now for the second reason I listed: most asynchronous modes of communication provide a transcript of what was said and what decisions might have been made during the conversation. There have been many occasions where I’ve used the search feature of my team’s chat application to find a conversation that happened several weeks or months ago to remember what was decided. Unfortunately, I think the benefits associated with the persistence of communicating asynchronously often get overlooked when people decide to escalate to a in-person meeting or voice/video call. I’m becoming much more reluctant to suggest a voice or video call if I suspect that it might lead to codifying some kind of design decision because everyone involved is going to hang up the call and immediately forget what was decided. I recognize that you can record and archive these types of interactions, but without being able to search them the recordings aren’t terribly useful. When and How To Escalate I don’t mean to imply that communicating via voice/video or in person is never a good idea. I probably jump on a Skype call with a co-worker at least once a day to quickly hash something out or show them a bit of code that I’m working on. Also, meeting in person periodically is really important for remote teams. There’s no way around the fact that sometimes it’s easier to jump on a call and show someone my screen so they can see what I’m seeing. So when is it right to escalate? I think the simplest way to answer that is when the communication starts to feel painful. Everyone’s tolerance for that pain is different, but I think you need to let it hurt a little bit before jumping to synchronous communication. When you do escalate from asynchronous to synchronous communication, there are a couple of things you can do to maximize the effectiveness of the communication: Takes notes – This is huge and yet I’ve found that a lot of teams don’t do this. If you’re holding a meeting with  > 2 people you should have someone taking notes. Taking notes while participating in a meeting can be difficult but there are a few strategies to deal with this challenge that probably deserve a short post of their own. After the meeting, make sure the notes are posted to a place where all concerned parties (including those that might not have attended the meeting) can review and search them. Persist decisions made ASAP – If any decisions were made during the meeting, persist those decisions to a searchable medium as soon as possible following the conversation. All the teams I’ve worked on used a web-based system for tracking the on-going work and a backlog of work to be done in the future. I always try to make sure that all of the cards/stories/tasks/whatever in these systems always reflect the latest decisions that were made as the work was being planned and executed. If held a quick call with your team lead and decided that it wasn’t worth the effort to build real-time validation into that new UI you were working on, go and codify that decision in the story associated with that work immediately after you hang up. Even better, write it up in the story while you are both still on the phone. That way when the folks from your QA team pick up the story to test a few days later they’ll know why the real-time validation isn’t there without having to invoke yet another conversation about the work. Communicating Well is Hard At this point you might be thinking that communicating asynchronously is more difficult than having a live conversation. You’re right: it is more difficult. In order to communicate effectively this way you need to very carefully think about the message that you’re trying to convey and craft it in a way that’s easy for your audience to understand. This is almost always harder than just talking through a problem in real time with someone; this is why escalating communication is such a popular idea. Why wouldn’t we want to do the thing that’s easier? Easier isn’t always better. If you and your team can get in the habit of communicating effectively in an asynchronous manner you’ll find that, over time, all of your communications get less painful because you don’t need to re-iterate previously made points over and over again. If you communicate right the first time, you often don’t need to rehash old conversations because you can go back and find the decisions that were made laid out in plain language. You’ll also find that you get better at doing things like writing useful comments in your code, creating written documentation about how the feature that you just built works, or persuading your team to do things in a certain way.

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• How to mount a blu-ray drive?

  - by Stephan Schielke

  Maybe it is for the best to close this question. This has nothing to do with a bluray drive in general anymore. Probably a hardware defect. I will try to test it with a windows system and different cables again... Thx so far. I have a bluray/dvd/cdrom drive with SATA. Ubuntu wont find it under /dev/sd wodim --devices wodim: Overview of accessible drives (1 found) : ------------------------------------------------------------------------- 0 dev='/dev/sg2' rwrw-- : 'HL-DT-ST' 'BDDVDRW CH08LS10' ------------------------------------------------------------------------- cdrecord -scanbus scsibus2: 2,0,0 200) 'HL-DT-ST' 'BDDVDRW CH08LS10' '2.00' Removable CD-ROM fdisk dont even lists it. Ubuntu only automounts blank DVDs, but neither CDROM nor Blurays. I also changed the sata slot, sata cable and the power cable. The drive works with a windows system. This happens when I try to mount: sudo mount -t auto /dev/scd0 /media/bluray mount: you must specify the filesystem type I tried all filesystems there are. I also installed makemkv. It finds the drive but not the disc. Here is my /dev ls -al /dev total 12 drwxr-xr-x 17 root root 4420 2011-11-25 19:36 . drwxr-xr-x 28 root root 4096 2011-11-25 07:12 .. crw------- 1 root root 10, 235 2011-11-25 19:28 autofs -rw-r--r-- 1 root root 630 2011-11-25 19:28 .blkid.tab -rw-r--r-- 1 root root 630 2011-11-25 19:28 .blkid.tab.old drwxr-xr-x 2 root root 700 2011-11-25 19:27 block drwxr-xr-x 2 root root 100 2011-11-25 19:27 bsg crw------- 1 root root 10, 234 2011-11-25 19:28 btrfs-control drwxr-xr-x 3 root root 60 2011-11-25 19:27 bus drwxr-xr-x 2 root root 3820 2011-11-25 19:28 char crw------- 1 root root 5, 1 2011-11-25 19:28 console lrwxrwxrwx 1 root root 11 2011-11-25 19:28 core -> /proc/kcore drwxr-xr-x 2 root root 60 2011-11-25 19:28 cpu crw------- 1 root root 10, 60 2011-11-25 19:28 cpu_dma_latency drwxr-xr-x 7 root root 140 2011-11-25 19:27 disk crw------- 1 root root 10, 61 2011-11-25 19:28 ecryptfs crw-rw---- 1 root video 29, 0 2011-11-25 19:28 fb0 lrwxrwxrwx 1 root root 13 2011-11-25 19:28 fd -> /proc/self/fd crw-rw-rw- 1 root root 1, 7 2011-11-25 19:28 full crw-rw-rw- 1 root fuse 10, 229 2011-11-25 19:28 fuse crw------- 1 root root 251, 0 2011-11-25 19:28 hidraw0 crw------- 1 root root 251, 1 2011-11-25 19:28 hidraw1 crw------- 1 root root 10, 228 2011-11-25 19:28 hpet lrwxrwxrwx 1 root root 14 2011-11-25 19:27 .initramfs -> /run/initramfs drwxr-xr-x 4 root root 220 2011-11-25 19:28 input crw------- 1 root root 1, 11 2011-11-25 19:28 kmsg srw-rw-rw- 1 root root 0 2011-11-25 19:28 log brw-rw---- 1 root disk 7, 0 2011-11-25 19:28 loop0 brw-rw---- 1 root disk 7, 1 2011-11-25 19:28 loop1 brw-rw---- 1 root disk 7, 2 2011-11-25 19:28 loop2 brw-rw---- 1 root disk 7, 3 2011-11-25 19:28 loop3 brw-rw---- 1 root disk 7, 4 2011-11-25 19:28 loop4 brw-rw---- 1 root disk 7, 5 2011-11-25 19:28 loop5 brw-rw---- 1 root disk 7, 6 2011-11-25 19:28 loop6 brw-rw---- 1 root disk 7, 7 2011-11-25 19:28 loop7 drwxr-xr-x 2 root root 60 2011-11-25 19:27 mapper crw------- 1 root root 10, 227 2011-11-25 19:28 mcelog crw-r----- 1 root kmem 1, 1 2011-11-25 19:28 mem drwxr-xr-x 2 root root 60 2011-11-25 19:27 net crw------- 1 root root 10, 59 2011-11-25 19:28 network_latency crw------- 1 root root 10, 58 2011-11-25 19:28 network_throughput crw-rw-rw- 1 root root 1, 3 2011-11-25 19:28 null crw-rw-rw- 1 root root 195, 0 2011-11-25 19:28 nvidia0 crw-rw-rw- 1 root root 195, 255 2011-11-25 19:28 nvidiactl crw------- 1 root root 1, 12 2011-11-25 19:28 oldmem crw-r----- 1 root kmem 1, 4 2011-11-25 19:28 port crw------- 1 root root 108, 0 2011-11-25 19:28 ppp crw------- 1 root root 10, 1 2011-11-25 19:28 psaux crw-rw-rw- 1 root tty 5, 2 2011-11-25 20:00 ptmx drwxr-xr-x 2 root root 0 2011-11-25 19:27 pts brw-rw---- 1 root disk 1, 0 2011-11-25 19:28 ram0 brw-rw---- 1 root disk 1, 1 2011-11-25 19:28 ram1 brw-rw---- 1 root disk 1, 10 2011-11-25 19:28 ram10 brw-rw---- 1 root disk 1, 11 2011-11-25 19:28 ram11 brw-rw---- 1 root disk 1, 12 2011-11-25 19:28 ram12 brw-rw---- 1 root disk 1, 13 2011-11-25 19:28 ram13 brw-rw---- 1 root disk 1, 14 2011-11-25 19:28 ram14 brw-rw---- 1 root disk 1, 15 2011-11-25 19:28 ram15 brw-rw---- 1 root disk 1, 2 2011-11-25 19:28 ram2 brw-rw---- 1 root disk 1, 3 2011-11-25 19:28 ram3 brw-rw---- 1 root disk 1, 4 2011-11-25 19:28 ram4 brw-rw---- 1 root disk 1, 5 2011-11-25 19:28 ram5 brw-rw---- 1 root disk 1, 6 2011-11-25 19:28 ram6 brw-rw---- 1 root disk 1, 7 2011-11-25 19:28 ram7 brw-rw---- 1 root disk 1, 8 2011-11-25 19:28 ram8 brw-rw---- 1 root disk 1, 9 2011-11-25 19:28 ram9 crw-rw-rw- 1 root root 1, 8 2011-11-25 19:28 random crw-rw-r--+ 1 root root 10, 62 2011-11-25 19:28 rfkill lrwxrwxrwx 1 root root 4 2011-11-25 19:28 rtc -> rtc0 crw------- 1 root root 254, 0 2011-11-25 19:28 rtc0 lrwxrwxrwx 1 root root 3 2011-11-25 19:38 scd0 -> sr0 brw-rw---- 1 root disk 8, 0 2011-11-25 19:28 sda brw-rw---- 1 root disk 8, 1 2011-11-25 19:28 sda1 brw-rw---- 1 root disk 8, 2 2011-11-25 19:28 sda2 brw-rw---- 1 root disk 8, 3 2011-11-25 19:28 sda3 brw-rw---- 1 root disk 8, 5 2011-11-25 19:28 sda5 brw-rw---- 1 root disk 8, 6 2011-11-25 19:28 sda6 brw-rw---- 1 root disk 8, 16 2011-11-25 19:28 sdb brw-rw---- 1 root disk 8, 17 2011-11-25 19:28 sdb1 crw-rw---- 1 root disk 21, 0 2011-11-25 19:28 sg0 crw-rw---- 1 root disk 21, 1 2011-11-25 19:28 sg1 crw-rw----+ 1 root cdrom 21, 2 2011-11-25 19:28 sg2 lrwxrwxrwx 1 root root 8 2011-11-25 19:28 shm -> /run/shm crw------- 1 root root 10, 231 2011-11-25 19:28 snapshot drwxr-xr-x 4 root root 280 2011-11-25 19:28 snd brw-rw----+ 1 root cdrom 11, 0 2011-11-25 19:38 sr0 lrwxrwxrwx 1 root root 15 2011-11-25 19:28 stderr -> /proc/self/fd/2 lrwxrwxrwx 1 root root 15 2011-11-25 19:28 stdin -> /proc/self/fd/0 lrwxrwxrwx 1 root root 15 2011-11-25 19:28 stdout -> /proc/self/fd/1 crw-rw-rw- 1 root tty 5, 0 2011-11-25 19:35 tty crw--w---- 1 root tty 4, 0 2011-11-25 19:28 tty0 crw------- 1 root root 4, 1 2011-11-25 19:28 tty1 crw--w---- 1 root tty 4, 10 2011-11-25 19:28 tty10 crw--w---- 1 root tty 4, 11 2011-11-25 19:28 tty11 crw--w---- 1 root tty 4, 12 2011-11-25 19:28 tty12 crw--w---- 1 root tty 4, 13 2011-11-25 19:28 tty13 crw--w---- 1 root tty 4, 14 2011-11-25 19:28 tty14 crw--w---- 1 root tty 4, 15 2011-11-25 19:28 tty15 crw--w---- 1 root tty 4, 16 2011-11-25 19:28 tty16 crw--w---- 1 root tty 4, 17 2011-11-25 19:28 tty17 crw--w---- 1 root tty 4, 18 2011-11-25 19:28 tty18 crw--w---- 1 root tty 4, 19 2011-11-25 19:28 tty19 crw------- 1 root root 4, 2 2011-11-25 19:28 tty2 crw--w---- 1 root tty 4, 20 2011-11-25 19:28 tty20 crw--w---- 1 root tty 4, 21 2011-11-25 19:28 tty21 crw--w---- 1 root tty 4, 22 2011-11-25 19:28 tty22 crw--w---- 1 root tty 4, 23 2011-11-25 19:28 tty23 crw--w---- 1 root tty 4, 24 2011-11-25 19:28 tty24 crw--w---- 1 root tty 4, 25 2011-11-25 19:28 tty25 crw--w---- 1 root tty 4, 26 2011-11-25 19:28 tty26 crw--w---- 1 root tty 4, 27 2011-11-25 19:28 tty27 crw--w---- 1 root tty 4, 28 2011-11-25 19:28 tty28 crw--w---- 1 root tty 4, 29 2011-11-25 19:28 tty29 crw------- 1 root root 4, 3 2011-11-25 19:28 tty3 crw--w---- 1 root tty 4, 30 2011-11-25 19:28 tty30 crw--w---- 1 root tty 4, 31 2011-11-25 19:28 tty31 crw--w---- 1 root tty 4, 32 2011-11-25 19:28 tty32 crw--w---- 1 root tty 4, 33 2011-11-25 19:28 tty33 crw--w---- 1 root tty 4, 34 2011-11-25 19:28 tty34 crw--w---- 1 root tty 4, 35 2011-11-25 19:28 tty35 crw--w---- 1 root tty 4, 36 2011-11-25 19:28 tty36 crw--w---- 1 root tty 4, 37 2011-11-25 19:28 tty37 crw--w---- 1 root tty 4, 38 2011-11-25 19:28 tty38 crw--w---- 1 root tty 4, 39 2011-11-25 19:28 tty39 crw------- 1 root root 4, 4 2011-11-25 19:28 tty4 crw--w---- 1 root tty 4, 40 2011-11-25 19:28 tty40 crw--w---- 1 root tty 4, 41 2011-11-25 19:28 tty41 crw--w---- 1 root tty 4, 42 2011-11-25 19:28 tty42 crw--w---- 1 root tty 4, 43 2011-11-25 19:28 tty43 crw--w---- 1 root tty 4, 44 2011-11-25 19:28 tty44 crw--w---- 1 root tty 4, 45 2011-11-25 19:28 tty45 crw--w---- 1 root tty 4, 46 2011-11-25 19:28 tty46 crw--w---- 1 root tty 4, 47 2011-11-25 19:28 tty47 crw--w---- 1 root tty 4, 48 2011-11-25 19:28 tty48 crw--w---- 1 root tty 4, 49 2011-11-25 19:28 tty49 crw------- 1 root root 4, 5 2011-11-25 19:28 tty5 crw--w---- 1 root tty 4, 50 2011-11-25 19:28 tty50 crw--w---- 1 root tty 4, 51 2011-11-25 19:28 tty51 crw--w---- 1 root tty 4, 52 2011-11-25 19:28 tty52 crw--w---- 1 root tty 4, 53 2011-11-25 19:28 tty53 crw--w---- 1 root tty 4, 54 2011-11-25 19:28 tty54 crw--w---- 1 root tty 4, 55 2011-11-25 19:28 tty55 crw--w---- 1 root tty 4, 56 2011-11-25 19:28 tty56 crw--w---- 1 root tty 4, 57 2011-11-25 19:28 tty57 crw--w---- 1 root tty 4, 58 2011-11-25 19:28 tty58 crw--w---- 1 root tty 4, 59 2011-11-25 19:28 tty59 crw------- 1 root root 4, 6 2011-11-25 19:28 tty6 crw--w---- 1 root tty 4, 60 2011-11-25 19:28 tty60 crw--w---- 1 root tty 4, 61 2011-11-25 19:28 tty61 crw--w---- 1 root tty 4, 62 2011-11-25 19:28 tty62 crw--w---- 1 root tty 4, 63 2011-11-25 19:28 tty63 crw--w---- 1 root tty 4, 7 2011-11-25 19:28 tty7 crw--w---- 1 root tty 4, 8 2011-11-25 19:28 tty8 crw--w---- 1 root tty 4, 9 2011-11-25 19:28 tty9 crw------- 1 root root 5, 3 2011-11-25 19:28 ttyprintk crw-rw---- 1 root dialout 4, 64 2011-11-25 19:28 ttyS0 crw-rw---- 1 root dialout 4, 65 2011-11-25 19:28 ttyS1 crw-rw---- 1 root dialout 4, 74 2011-11-25 19:28 ttyS10 crw-rw---- 1 root dialout 4, 75 2011-11-25 19:28 ttyS11 crw-rw---- 1 root dialout 4, 76 2011-11-25 19:28 ttyS12 crw-rw---- 1 root dialout 4, 77 2011-11-25 19:28 ttyS13 crw-rw---- 1 root dialout 4, 78 2011-11-25 19:28 ttyS14 crw-rw---- 1 root dialout 4, 79 2011-11-25 19:28 ttyS15 crw-rw---- 1 root dialout 4, 80 2011-11-25 19:28 ttyS16 crw-rw---- 1 root dialout 4, 81 2011-11-25 19:28 ttyS17 crw-rw---- 1 root dialout 4, 82 2011-11-25 19:28 ttyS18 crw-rw---- 1 root dialout 4, 83 2011-11-25 19:28 ttyS19 crw-rw---- 1 root dialout 4, 66 2011-11-25 19:28 ttyS2 crw-rw---- 1 root dialout 4, 84 2011-11-25 19:28 ttyS20 crw-rw---- 1 root dialout 4, 85 2011-11-25 19:28 ttyS21 crw-rw---- 1 root dialout 4, 86 2011-11-25 19:28 ttyS22 crw-rw---- 1 root dialout 4, 87 2011-11-25 19:28 ttyS23 crw-rw---- 1 root dialout 4, 88 2011-11-25 19:28 ttyS24 crw-rw---- 1 root dialout 4, 89 2011-11-25 19:28 ttyS25 crw-rw---- 1 root dialout 4, 90 2011-11-25 19:28 ttyS26 crw-rw---- 1 root dialout 4, 91 2011-11-25 19:28 ttyS27 crw-rw---- 1 root dialout 4, 92 2011-11-25 19:28 ttyS28 crw-rw---- 1 root dialout 4, 93 2011-11-25 19:28 ttyS29 crw-rw---- 1 root dialout 4, 67 2011-11-25 19:28 ttyS3 crw-rw---- 1 root dialout 4, 94 2011-11-25 19:28 ttyS30 crw-rw---- 1 root dialout 4, 95 2011-11-25 19:28 ttyS31 crw-rw---- 1 root dialout 4, 68 2011-11-25 19:28 ttyS4 crw-rw---- 1 root dialout 4, 69 2011-11-25 19:28 ttyS5 crw-rw---- 1 root dialout 4, 70 2011-11-25 19:28 ttyS6 crw-rw---- 1 root dialout 4, 71 2011-11-25 19:28 ttyS7 crw-rw---- 1 root dialout 4, 72 2011-11-25 19:28 ttyS8 crw-rw---- 1 root dialout 4, 73 2011-11-25 19:28 ttyS9 d rwxr-xr-x 3 root root 60 2011-11-25 19:28 .udev crw-r----- 1 root root 10, 223 2011-11-25 19:28 uinput crw-rw-rw- 1 root root 1, 9 2011-11-25 19:28 urandom drwxr-xr-x 2 root root 60 2011-11-25 19:27 usb crw------- 1 root root 252, 0 2011-11-25 19:28 usbmon0 crw------- 1 root root 252, 1 2011-11-25 19:28 usbmon1 crw------- 1 root root 252, 2 2011-11-25 19:28 usbmon2 crw------- 1 root root 252, 3 2011-11-25 19:28 usbmon3 crw------- 1 root root 252, 4 2011-11-25 19:28 usbmon4 crw------- 1 root root 252, 5 2011-11-25 19:28 usbmon5 crw------- 1 root root 252, 6 2011-11-25 19:28 usbmon6 crw------- 1 root root 252, 7 2011-11-25 19:28 usbmon7 crw------- 1 root root 252, 8 2011-11-25 19:28 usbmon8 drwxr-xr-x 4 root root 80 2011-11-25 19:28 v4l crw------- 1 root root 10, 57 2011-11-25 19:28 vboxdrv crw------- 1 root root 10, 56 2011-11-25 19:28 vboxnetctl drwxr-x--- 4 root vboxusers 80 2011-11-25 19:28 vboxusb crw-rw---- 1 root tty 7, 0 2011-11-25 19:28 vcs crw-rw---- 1 root tty 7, 1 2011-11-25 19:28 vcs1 crw-rw---- 1 root tty 7, 2 2011-11-25 19:28 vcs2 crw-rw---- 1 root tty 7, 3 2011-11-25 19:28 vcs3 crw-rw---- 1 root tty 7, 4 2011-11-25 19:28 vcs4 crw-rw---- 1 root tty 7, 5 2011-11-25 19:28 vcs5 crw-rw---- 1 root tty 7, 6 2011-11-25 19:28 vcs6 crw-rw---- 1 root tty 7, 128 2011-11-25 19:28 vcsa crw-rw---- 1 root tty 7, 129 2011-11-25 19:28 vcsa1 crw-rw---- 1 root tty 7, 130 2011-11-25 19:28 vcsa2 crw-rw---- 1 root tty 7, 131 2011-11-25 19:28 vcsa3 crw-rw---- 1 root tty 7, 132 2011-11-25 19:28 vcsa4 crw-rw---- 1 root tty 7, 133 2011-11-25 19:28 vcsa5 crw-rw---- 1 root tty 7, 134 2011-11-25 19:28 vcsa6 crw------- 1 root root 10, 63 2011-11-25 19:28 vga_arbiter crw-rw----+ 1 root video 81, 0 2011-11-25 19:28 video0 crw-rw-rw- 1 root root 1, 5 2011-11-25 19:28 zero sg_scan -i gives me: sudo sg_scan -i /dev/sg0: scsi0 channel=0 id=0 lun=0 [em] ATA ST31000524NS SN12 [rmb=0 cmdq=0 pqual=0 pdev=0x0] /dev/sg1: scsi0 channel=0 id=1 lun=0 [em] ATA WDC WD15EADS-00S 01.0 [rmb=0 cmdq=0 pqual=0 pdev=0x0] /dev/sg2: scsi2 channel=0 id=0 lun=0 [em] HL-DT-ST BDDVDRW CH08LS10 2.00 [rmb=1 cmdq=0 pqual=0 pdev=0x5] sg_map gives me: /dev/sg0 /dev/sda /dev/sg1 /dev/sdb /dev/sg2 /dev/scd0 lsscsi -l gives me: [0:0:0:0] disk ATA ST31000524NS SN12 /dev/sda state=running queue_depth=1 scsi_level=6 type=0 device_blocked=0 timeout=30 [0:0:1:0] disk ATA WDC WD15EADS-00S 01.0 /dev/sdb state=running queue_depth=1 scsi_level=6 type=0 device_blocked=0 timeout=30 [2:0:0:0] cd/dvd HL-DT-ST BDDVDRW CH08LS10 2.00 /dev/sr0 state=running queue_depth=1 scsi_level=6 type=5 device_blocked=0 timeout=30 my udf mod is: filename: /lib/modules/3.0.0-14-generic/kernel/fs/udf/udf.ko license: GPL description: Universal Disk Format Filesystem author: Ben Fennema srcversion: 6ABDE012374D96B9685B8E5 depends: crc-itu-t vermagic: 3.0.0-14-generic SMP mod_unload modversions Do I need special drivers or mods enabled? Do I need to change some BIOS settings? edit: Somehow I am now able to fire the mount command without any filesystem errors, but now I get: mount: no medium found on /dev/sr0

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• Windows Azure Evolution &ndash; Preview Developer Portal

  - by Shaun

  With the MEET Windows Azure event on 7th June, there are many new features and updates in windows azure platform. In the coming several posts I will try to cover some of them. And in the first post here I would like to just have a quick walkthrough of the new preview developer portal.   History of the Developer Portal If you have been working with windows azure since 2009 or 2010, you should remember the first version of the developer portal. It was built in HTML with very limited features. I have the impression when I was using is old one. The layout is not that attractive and you have very limited features. On November, 2010 alone with the SDK 1.3 release, the developer portal was getting a big jump. In order to give more usability and features this it turned to be built on Silverlight. Hence it runs like a desktop application with many windows, lists, commands and context menus. From 2010 till now many features were involved into this portal, such as the remote desktop, co-admin, virtual connect, VM role, etc.. And the portal itself became more and more complicated. But it brought some problems by using the Silverlight. The first one is the browser capability. As you know in most mobile and tablet device the browser doesn’t allow the rich content plugin, such as Flash and Silverlight. This means people cannot open and configure their azure services from their iPad, iPhone and Windows Phone, etc., even though what they need may just be restart a hosted service, or view the status of their databases. Another problem is the performance. Silverlight provides rich experience to the users, but also needs more bandwidth. So in this upgrade the preview developer portal will be back to use HTML, with JavaScript, as a mobile friendly, cross browser, interactively web site.   Preview Portal vs. Silverlight Portal Before I started to talk about the new preview portal I’d better highlight that, this preview portal is a PREVIEW version, which means even though you can do almost all features that already in the old one, as long as some cool new features I will mention in the coming several posts, there are something still under developed and migrated. So sometimes you need to switch back to the old one. For example, in preview portal there is no co-admin manage function, no remote desktop function and the SQL database manage function will take you back to the old SQL Azure Manage Portal. But as Microsoft said these missing features will be moved in the preview portal in the couple of next few months. Since the public URL of the developer portal, https://windows.azure.com/, had been changed to point to this preview one, you need to click to preview button on top of the page and click the “Take me to the previous portal” link.   Overview There are four parts in the preview portal. On the top is the header which shows the account you are currently logging in. If you click on the header it will show the top menu of windows azure, where you can navigate to the windows azure home page, the price information page, community and account, etc.. The navigation bar is on the left hand side, with the categories listed below. ALL ITEMS All items in your windows azure account, includes the web sites, services, databases, etc.. WEB SITES The web sites in your windows azure account. It will only show the web sites you have. The linked resources will be shown if you drill down into a web site. VIRTUAL MACHINES The virtual machines that you had been deployed to azure. CLOUD SERVICES All windows azure hosted services in your account. SQL DATABASES All SQL databases (SQL Azure) in your account. STORAGE All windows azure storage services in your account. NETWORKS The virtual network (Windows Azure Connect) you had been created. The available items will be listed in the main part of the page based on which category your currently selected. If there’s no item it will show the link to you to quick create. At the bottom of the page there will be the command and information bar. Based on what is selected and what is performed by the user, it will show the related information and commands. For example, in the image below when I was creating a new web site, the information bar told me that my web site is being provisioned; and there are two commands in the command bar. And once it ready the command bar will show some commands that I can do to my new web site. The “Web Sites” is a new feature introduced alone with this upgrade. It gives us an easier and quicker way to establish a website from the scratch or from some existing library. I will introduce it more details in the coming next post. Also in the command bar you can create a service by clicking the NEW button. It will slide the creation panel up to you.   Where’s My Hosted Services The Windows Azure Hosted Services had been renamed to the Cloud Services. Create a new service would be very easy. Just click the NEW button at the bottom of the page, and select the CLOUD SERVICE and QIUICK CREATE. This will create a blank hosted service without deployment and certificate. It just needs you to specify the service URL and the affinity/region. Then the service will be shown in the list. If you clicked the item all information will be shown in the main part. Since there’s no package deployed to this service so currently we cannot see any information about it. But we can upload the package by using the command at the bottom. And as you can see, we could manage the configuration, instances, certificates and we can scale up and down (change the VM size), in and out (increase and decrease the instance count) to our service. Assuming I had created an ASP.NET MVC 3 web role project in Visual Studio and completed the package. Then I can click the UPLOAD button in this page to deploy my package. In the popping up window I just specify my deployment name, package file and configure file. Also I can check the box below so that it will NOT warn me if only one instance of this deployment. Once we clicked the OK button our package will be uploaded and provisioned by the platform. After a while we can see the service was ready from the information bar. We can have the basic information about this service and deployment if we to the dashboard page. For example the usage overview diagram, status, URL, public IP address, etc.. In the configure page we can view and change the CSCFG content such as the monitor setting, connection strings, OS family. In scale page we can increase and decrease the count of the instances. And in the instances page we can view all instances status. And, if your services is using some SQL databases and storages they will be shown as the linked resources under the linked resources page. And you can manage the certificates of this service as well under the certificates page.   How About My Storage Services The storage service can be managed by clicking into the STORAGES link in the navigation bar. And we can create a new storage service from the NEW button. After specify the storage name and region it will be previsioned by the platform. If you want to copy or manage the storage key you can just click the Manage Keys button at the bottom, which is very easy. What I want to highlight here is that, you can monitor your storage service by enabling the monitor configuration. Click the storage item in the list and navigate to the configure page. As you can see in the page you can enable the monitoring for blob, table and queue. And you can also enable the logging when any requests come to the storage. But as the tooltip shown in the page, enabling the monitoring and logging will increase the usage of the storage, which means increase the bill of them. So make sure you enable them properly.   And My SQL Databases (SQL Azure) The last thing I want to quick introduce is the SQL databases, which was formally named SQL Azure. You can create a new SQL Database Server and a new database by clicking the ADD button under the SQL Database navigation item. In the popping up windows just specify the database name, the edition, size, collation and the server. You can select an existing SQL Database Server if you have, or cerate a new one. If you selected to create a new server, there will be another step you need to do, which is specify the server login, password and the region. Once it ready you can mange your databases as well as the servers in the portal. In a particular server you can update the firewall settings in its Configure page. So, What Else There are some other area on the preview portal I didn’t cover, such as the virtual machines, virtual network and web sites. Regarding the virtual machines and web sites I will talk about them in the future separated post. Regarding the virtual network, it the Windows Azure Connect we are familiar with. But as I mention in the beginning of this post, the preview portal is still under developed. Some features are not available here. For example, you cannot manage the co-admin of your subscriptions, you cannot open the remote desktop on your hosted services, and you cannot navigate to the Windows Azure Service Bus, Access Control and Caching, which formally named Windows Azure AppFabric directly. In these cases you need to navigate back to the old portal. So in the coming several months we might need to use both these two sites.   Summary In this post I quick introduced the new windows azure developer portal. Since it had been rearranged and renamed I demonstrated some features that existing in the old portal, such as how to create and deploy a hosted service, how to provision a storage service and SQL database. All features in the old portal had been, is being and will be migrated into this new portal, but some of them were in a different category and page we need to figure out.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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• Routing to a Controller with no View in Angular

  - by Rick Strahl

  I've finally had some time to put Angular to use this week in a small project I'm working on for fun. Angular's routing is great and makes it real easy to map URL routes to controllers and model data into views. But what if you don't actually need a view, if you effectively need a headless controller that just runs code, but doesn't render a view?Preserve the ViewWhen Angular navigates a route and and presents a new view, it loads the controller and then renders the view from scratch. Views are not cached or stored, but displayed and then removed. So if you have routes configured like this:'use strict'; // Declare app level module which depends on filters, and services window.myApp = angular.module('myApp', ['myApp.filters', 'myApp.services', 'myApp.directives', 'myApp.controllers']). config(['$routeProvider', function($routeProvider) { $routeProvider.when('/map', { template: "partials/map.html ", controller: 'mapController', reloadOnSearch: false, animation: 'slide' }); … $routeProvider.otherwise({redirectTo: '/map'}); }]); Angular routes to the mapController and then re-renders the map.html template with the new data from the $scope filled in.But, but… I don't want a new View!Now in most cases this works just fine. If I'm rendering plain DOM content, or textboxes in a form interface that is all fine and dandy - it's perfectly fine to completely re-render the UI.But in some cases, the UI that's being managed has state and shouldn't be redrawn. In this case the main page in question has a Google Map on it. The map is  going to be manipulated throughout the lifetime of the application and the rest of the pages. In my application I have a toolbar on the bottom and the rest of the content is replaced/switched out by the Angular Views:The problem is that the map shouldn't be redrawn each time the Location view is activated. It should maintain its state, such as the current position selected (which can move), and shouldn't redraw due to the overhead of re-rendering the initial map.Originally I set up the map, exactly like all my other views - as a partial, that is rendered with a separate file, but that didn't work.The Workaround - Controller Only RoutesThe workaround for this goes decidedly against Angular's way of doing things:Setting up a Template-less RouteIn-lining the map view directly into the main pageHiding and showing the map view manuallyLet's see how this works.Controller Only RouteThe template-less route is basically a route that doesn't have any template to render. This is not directly supported by Angular, but thankfully easy to fake. The end goal here is that I want to simply have the Controller fire and then have the controller manage the display of the already active view by hiding and showing the map and any other view content, in effect bypassing Angular's view display management.In short - I want a controller action, but no view rendering.The controller-only or template-less route looks like this: $routeProvider.when('/map', { template: " ", // just fire controller controller: 'mapController', animation: 'slide' });Notice I'm using the template property rather than templateUrl (used in the first example above), which allows specifying a string template, and leaving it blank. The template property basically allows you to provide a templated string using Angular's HandleBar like binding syntax which can be useful at times. You can use plain strings or strings with template code in the template, or as I'm doing here a blank string to essentially fake 'just clear the view'. In-lined ViewSo if there's no view where does the HTML go? Because I don't want Angular to manage the view the map markup is in-lined directly into the page. So instead of rendering the map into the Angular view container, the content is simply set up as inline HTML to display as a sibling to the view container.<div id="MapContent" data-icon="LocationIcon" ng-controller="mapController" style="display:none"> <div class="headerbar"> <div class="right-header" style="float:right"> <a id="btnShowSaveLocationDialog" class="iconbutton btn btn-sm" href="#/saveLocation" style="margin-right: 2px;"> <i class="icon-ok icon-2x" style="color: lightgreen; "></i> Save Location </a> </div> <div class="left-header">GeoCrumbs</div> </div> <div class="clearfix"></div> <div id="Message"> <i id="MessageIcon"></i> <span id="MessageText"></span> </div> <div id="Map" class="content-area"> </div> </div> <div id="ViewPlaceholder" ng-view></div>Note that there's the #MapContent element and the #ViewPlaceHolder. The #MapContent is my static map view that is always 'live' and is initially hidden. It is initially hidden and doesn't get made visible until the MapController controller activates it which does the initial rendering of the map. After that the element is persisted with the map data already loaded and any future access only updates the map with new locations/pins etc.Note that default route is assigned to the mapController, which means that the mapController is fired right as the page loads, which is actually a good thing in this case, as the map is the cornerstone of this app that is manipulated by some of the other controllers/views.The Controller handles some UISince there's effectively no view activation with the template-less route, the controller unfortunately has to take over some UI interaction directly. Specifically it has to swap the hidden state between the map and any of the other views.Here's what the controller looks like:myApp.controller('mapController', ["$scope", "$routeParams", "locationData", function($scope, $routeParams, locationData) { $scope.locationData = locationData.location; $scope.locationHistory = locationData.locationHistory; if ($routeParams.mode == "currentLocation") { bc.getCurrentLocation(false); } bc.showMap(false,"#LocationIcon"); }]);bc.showMap is responsible for a couple of display tasks that hide/show the views/map and for activating/deactivating icons. The code looks like this:this.showMap = function (hide,selActiveIcon) { if (!hide) $("#MapContent").show(); else { $("#MapContent").hide(); } self.fitContent(); if (selActiveIcon) { $(".iconbutton").removeClass("active"); $(selActiveIcon).addClass("active"); } };Each of the other controllers in the app also call this function when they are activated to basically hide the map and make the View Content area visible. The map controller makes the map.This is UI code and calling this sort of thing from controllers is generally not recommended, but I couldn't figure out a way using directives to make this work any more easily than this. It'd be easy to hide and show the map and view container using a flag an ng-show, but it gets tricky because of scoping of the $scope. I would have to resort to storing this setting on the $rootscope which I try to avoid. The same issues exists with the icons.It sure would be nice if Angular had a way to explicitly specify that a View shouldn't be destroyed when another view is activated, so currently this workaround is required. Searching around, I saw a number of whacky hacks to get around this, but this solution I'm using here seems much easier than any of that I could dig up even if it doesn't quite fit the 'Angular way'.Angular nice, until it's notOverall I really like Angular and the way it works although it took me a bit of time to get my head around how all the pieces fit together. Once I got the idea how the app/routes, the controllers and views snap together, putting together Angular pages becomes fairly straightforward. You can get quite a bit done never going beyond those basics. For most common things Angular's default routing and view presentation works very well.But, when you do something a bit more complex, where there are multiple dependencies or as in this case where Angular doesn't appear to support a feature that's absolutely necessary, you're on your own. Finding information on more advanced topics is not trivial especially since versions are changing so rapidly and the low level behaviors are changing frequently so finding something that works is often an exercise in trial and error. Not that this is surprising. Angular is a complex piece of kit as are all the frameworks that try to hack JavaScript into submission to do something that it was really never designed to. After all everything about a framework like Angular is an elaborate hack. A lot of shit has to happen to make this all work together and at that Angular (and Ember, Durandel etc.) are pretty amazing pieces of JavaScript code. So no harm, no foul, but I just can't help feeling like working in toy sandbox at times :-)© Rick Strahl, West Wind Technologies, 2005-2013Posted in Angular  JavaScript   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• Metro: Dynamically Switching Templates with a WinJS ListView

  - by Stephen.Walther

  Imagine that you want to display a list of products using the WinJS ListView control. Imagine, furthermore, that you want to use different templates to display different products. In particular, when a product is on sale, you want to display the product using a special “On Sale” template. In this blog entry, I explain how you can switch templates dynamically when displaying items with a ListView control. In other words, you learn how to use more than one template when displaying items with a ListView control. Creating the Data Source Let’s start by creating the data source for the ListView. Nothing special here – our data source is a list of products. Two of the products, Oranges and Apples, are on sale. (function () { "use strict"; var products = new WinJS.Binding.List([ { name: "Milk", price: 2.44 }, { name: "Oranges", price: 1.99, onSale: true }, { name: "Wine", price: 8.55 }, { name: "Apples", price: 2.44, onSale: true }, { name: "Steak", price: 1.99 }, { name: "Eggs", price: 2.44 }, { name: "Mushrooms", price: 1.99 }, { name: "Yogurt", price: 2.44 }, { name: "Soup", price: 1.99 }, { name: "Cereal", price: 2.44 }, { name: "Pepsi", price: 1.99 } ]); WinJS.Namespace.define("ListViewDemos", { products: products }); })(); The file above is saved with the name products.js and referenced by the default.html page described below. Declaring the Templates and ListView Control Next, we need to declare the ListView control and the two Template controls which we will use to display template items. The markup below appears in the default.html file: <!-- Templates --> <div id="productItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="product"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> </div> <div id="productOnSaleTemplate" data-win-control="WinJS.Binding.Template"> <div class="product onSale"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> (On Sale!) </div> </div> <!-- ListView --> <div id="productsListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.products.dataSource, layout: { type: WinJS.UI.ListLayout } }"> </div> In the markup above, two Template controls are declared. The first template is used when rendering a normal product and the second template is used when rendering a product which is on sale. The second template, unlike the first template, includes the text “(On Sale!)”. The ListView control is bound to the data source which we created in the previous section. The ListView itemDataSource property is set to the value ListViewDemos.products.dataSource. Notice that we do not set the ListView itemTemplate property. We set this property in the default.js file. Switching Between Templates All of the magic happens in the default.js file. The default.js file contains the JavaScript code used to switch templates dynamically. Here’s the entire contents of the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll().then(function () { var productsListView = document.getElementById("productsListView"); productsListView.winControl.itemTemplate = itemTemplateFunction; });; } }; function itemTemplateFunction(itemPromise) { return itemPromise.then(function (item) { // Select either normal product template or on sale template var itemTemplate = document.getElementById("productItemTemplate"); if (item.data.onSale) { itemTemplate = document.getElementById("productOnSaleTemplate"); }; // Render selected template to DIV container var container = document.createElement("div"); itemTemplate.winControl.render(item.data, container); return container; }); } app.start(); })(); In the code above, a function is assigned to the ListView itemTemplate property with the following line of code: productsListView.winControl.itemTemplate = itemTemplateFunction;   The itemTemplateFunction returns a DOM element which is used for the template item. Depending on the value of the product onSale property, the DOM element is generated from either the productItemTemplate or the productOnSaleTemplate template. Using Binding Converters instead of Multiple Templates In the previous sections, I explained how you can use different templates to render normal products and on sale products. There is an alternative approach to displaying different markup for normal products and on sale products. Instead of creating two templates, you can create a single template which contains separate DIV elements for a normal product and an on sale product. The following default.html file contains a single item template and a ListView control bound to the template. <!-- Template --> <div id="productItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="product" data-win-bind="style.display: onSale ListViewDemos.displayNormalProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> <div class="product onSale" data-win-bind="style.display: onSale ListViewDemos.displayOnSaleProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> (On Sale!) </div> </div> <!-- ListView --> <div id="productsListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.products.dataSource, itemTemplate: select('#productItemTemplate'), layout: { type: WinJS.UI.ListLayout } }"> </div> The first DIV element is used to render a normal product: <div class="product" data-win-bind="style.display: onSale ListViewDemos.displayNormalProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> The second DIV element is used to render an “on sale” product: <div class="product onSale" data-win-bind="style.display: onSale ListViewDemos.displayOnSaleProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> (On Sale!) </div> Notice that both templates include a data-win-bind attribute. These data-win-bind attributes are used to show the “normal” template when a product is not on sale and show the “on sale” template when a product is on sale. These attributes set the Cascading Style Sheet display attribute to either “none” or “block”. The data-win-bind attributes take advantage of binding converters. The binding converters are defined in the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll(); } }; WinJS.Namespace.define("ListViewDemos", { displayNormalProduct: WinJS.Binding.converter(function (onSale) { return onSale ? "none" : "block"; }), displayOnSaleProduct: WinJS.Binding.converter(function (onSale) { return onSale ? "block" : "none"; }) }); app.start(); })(); The ListViewDemos.displayNormalProduct binding converter converts the value true or false to the value “none” or “block”. The ListViewDemos.displayOnSaleProduct binding converter does the opposite; it converts the value true or false to the value “block” or “none” (Sadly, you cannot simply place a NOT operator before the onSale property in the binding expression – you need to create both converters). The end result is that you can display different markup depending on the value of the product onSale property. Either the contents of the first or second DIV element are displayed: Summary In this blog entry, I’ve explored two approaches to displaying different markup in a ListView depending on the value of a data item property. The bulk of this blog entry was devoted to explaining how you can assign a function to the ListView itemTemplate property which returns different templates. We created both a productItemTemplate and productOnSaleTemplate and displayed both templates with the same ListView control. We also discussed how you can create a single template and display different markup by using binding converters. The binding converters are used to set a DIV element’s display property to either “none” or “block”. We created a binding converter which displays normal products and a binding converter which displays “on sale” products.

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