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  • How do I implement aasm in Rails 3 for what I want it to do?

    - by marcamillion
    I am a Rails n00b and have been advised that in order for me to keep track of the status of my user's accounts (i.e. paid, unpaid (and therefore disabled), free trial, etc.) I should use an 'AASM' gem. So I found one that seems to be the most popular: https://github.com/rubyist/aasm But the instructions are pretty vague. I have a Users model and a Plan model. User's model manages everything you might expect (username, password, first name, etc.). Plan model manages the subscription plan that users should be assigned to (with the restrictions). So I am trying to figure out how to use the AASM gem to do what I want to do, but no clue where to start. Do I create a new model ? Then do I setup a relationship between my User model and the model for AASM ? How do I setup a relationship? As in, a user 'has_many' states ? That doesn't seem to make much sense to me. Any guidance would be really appreciated. Thanks. Edit: If anyone else is confused by AASMs like myself, here is a nice explanation of their function in Rails by the fine folks at Envy Labs: http://blog.envylabs.com/2009/08/the-rails-state-machine/ Edit2: How does this look: include AASM aasm_column :current_state aasm_state :paid aasm_state :free_trial aasm_state :disabled #this is for accounts that have exceed free trial and have not paid #aasm_state :free_acct aasm_event :pay do transitions :to => :paid, :from => [:free_trial, :disabled] transitions :to => :disabled, :from => [:free_trial, :paid] end

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  • Search a string in a file and write the matched lines to another file in Java

    - by Geeta
    For searching a string in a file and writing the lines with matched string to another file it takes 15 - 20 mins for a single zip file of 70MB(compressed state). Is there any ways to minimise it. my source code: getting Zip file entries zipFile = new ZipFile(source_file_name); entries = zipFile.entries(); while (entries.hasMoreElements()) { ZipEntry entry = (ZipEntry)entries.nextElement(); if (entry.isDirectory()) { continue; } searchString(Thread.currentThread(),entry.getName(), new BufferedInputStream (zipFile.getInputStream(entry)), Out_File, search_string, stats); } zipFile.close(); Searching String public void searchString(Thread CThread, String Source_File, BufferedInputStream in, File outfile, String search, String stats) throws IOException { int count = 0; int countw = 0; int countl = 0; String s; String[] str; BufferedReader br2 = new BufferedReader(new InputStreamReader(in)); System.out.println(CThread.currentThread()); while ((s = br2.readLine()) != null) { str = s.split(search); count = str.length - 1; countw += count; //word count if (s.contains(search)) { countl++; //line count WriteFile(CThread,s, outfile.toString(), search); } } br2.close(); in.close(); } -------------------------------------------------------------------------------- public void WriteFile(Thread CThread,String line, String out, String search) throws IOException { BufferedWriter bufferedWriter = null; System.out.println("writre thread"+CThread.currentThread()); bufferedWriter = new BufferedWriter(new FileWriter(out, true)); bufferedWriter.write(line); bufferedWriter.newLine(); bufferedWriter.flush(); } Please help me. Its really taking 40 mins for 10 files using threads and 15 - 20 mins for a single file of 70MB after being compressed. Any ways to minimise the time.

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  • How can I improve the performance of LinqToSql queries that use EntitySet properties?

    - by DanM
    I'm using LinqToSql to query a small, simple SQL Server CE database. I've noticed that any operations involving sub-properties are disappointingly slow. For example, if I have a Customer table that is referenced by an Order table, LinqToSql will automatically create an EntitySet<Order> property. This is a nice convenience, allowing me to do things like Customer.Order.Where(o => o.ProductName = "Stopwatch"), but for some reason, SQL Server CE hangs up pretty bad when I try to do stuff like this. One of my queries, which isn't really that complicated takes 3-4 seconds to complete. I can get the speed up to acceptable, even fast, if I just grab the two tables individually and convert them to List<Customer> and List<Order>, then join then manually with my own query, but this is throwing out a lot of what makes LinqToSql so appealing. So, I'm wondering if I can somehow get the whole database into RAM and just query that way, then occasionally save it. Is this possible? How? If not, is there anything else I can do to boost the performance besides resorting to doing all the joins manually? Note: My database in its initial state is about 250K and I don't expect it to grow to more than 1-2Mb. So, loading the data into RAM certainly wouldn't be a problem from a memory point of view. Update Here are the table definitions for the example I used in my question: create table Order ( Id int identity(1, 1) primary key, ProductName ntext null ) create table Customer ( Id int identity(1, 1) primary key, OrderId int null references Order (Id) )

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  • J-Monkey subclass

    - by user2971104
    I'm new in java and J-monkey and I'm trying to make a java game so for the Menu I have made a enum so I can Switch between any of my State but I want to keep the main file shorter so it can be easily to read so I'm making subclass the problem is that when run the game it give me an error that say "Uncaught exception thrown in Thread[LWJGL Renderer Thread,5,main] NullPointerException" I think this problem has to be something whit the pipeline Here is the code of my main file: package mygame; import com.jme3.app.SimpleApplication; import com.jme3.font.BitmapText; import com.jme3.material.Material; import com.jme3.math.ColorRGBA; import com.jme3.math.Vector3f; import com.jme3.renderer.RenderManager; import com.jme3.scene.Spatial; import com.jme3.scene.Geometry; import com.jme3.input.*; import com.jme3.input.controls.*; public class Main extends SimpleApplication { //GameStates enum GameState{Logo, Menu, Playing, Option}; GameState gameState = GameState.Logo; //Class Variables Logo logo; public Main() { logo = new Logo(); } public static void main(String[] args) { Main app = new Main(); app.start(); } public static void logo(String[] args) { Logo app = new Logo(); app.start(); } @Override public void simpleInitApp() { //Load flyCam.setMoveSpeed(20); if(gameState == GameState.Logo){ logo.simpleInitApp(); } } @Override public void simpleUpdate(float tpf) { } @Override public void simpleRender(RenderManager rm) { //TODO: add render code //Load if(gameState == GameState.Logo) { } } } And here is my Logo subclass: package mygame; import com.jme3.app.SimpleApplication; import com.jme3.renderer.RenderManager; import com.jme3.scene.Spatial; public class Logo extends SimpleApplication { @Override public void simpleInitApp() { Spatial Logo_Model = assetManager.loadModel("Models/Teapot/Logo.obj"); rootNode.attachChild(Logo_Model); } public void simpleRender(RenderManager rm) { //Load } }

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  • Django: Paginator + raw SQL query

    - by Silver Light
    Hello! I'm using Django Paginator everywhere on my website and even wrote a special template tag, to make it more convenient. But now I got to a state, where I need to make a complex custom raw SQL query, that without a LIMIT will return about 100K records. How can I use Django Pagintor with custom query? Simplified example of my problem: My model: class PersonManager(models.Manager): def complicated_list(self): from django.db import connection #Real query is much more complex cursor.execute("""SELECT * FROM `myapp_person`"""); result_list = [] for row in cursor.fetchall(): result_list.append(row[0]); return result_list class Person(models.Model): name = models.CharField(max_length=255); surname = models.CharField(max_length=255); age = models.IntegerField(); objects = PersonManager(); The way I use pagintation with Django ORM: all_objects = Person.objects.all(); paginator = Paginator(all_objects, 10); try: page = int(request.GET.get('page', '1')) except ValueError: page = 1 try: persons = paginator.page(page) except (EmptyPage, InvalidPage): persons = paginator.page(paginator.num_pages) This way, Django get very smart, and adds LIMIT to a query when executing it. But when I use custom manager: all_objects = Person.objects.complicated_list(); all data is selected, and only then python list is sliced, which is VERY slow. How can I make my custom manager behave similar like built in one?

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  • question about jQuery droppable/draggable.

    - by FALCONSEYE
    I modified a sample photo manager application. photo manager application Instead of photos, I have employee records coming from a query. My version will let managers mark employees as on vacation, or at work. One of the things I did is to include employee ids like <a href="123">. I get the ids from event.target. This works for the click function but not for the "droppable" function. This is what I have for the click function: $('ul.gallery > li').click(function(ev) { var $item = $(this); var $unid = ev.target; var $target = $(ev.target); if ($target.is('a.ui-icon-suitcase')) { deleteImage($item,$unid); } else if ($target.is('a.ui-icon-arrowreturnthick-1-w')) { recycleImage($item,$unid); } return false; }); ev.target correctly gives the employee id. when i try the same in one of the droppable functions: $gallery.droppable({ accept: '#suitcase li', activeClass: 'custom-state-active', drop: function(ev, ui) { var $unid = ev.target; alert($unid); recycleImage(ui.draggable,$unid); } }); the alert(ui) gives me [object]. What's in this object? How do i get the href out of this? thanks

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  • Two entities with @ManyToOne should join the same table

    - by Ivan Yatskevich
    I have the following entities Student @Entity public class Student implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; //getter and setter for id } Teacher @Entity public class Teacher implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; //getter and setter for id } Task @Entity public class Task implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; @ManyToOne(optional = false) @JoinTable(name = "student_task", inverseJoinColumns = { @JoinColumn(name = "student_id") }) private Student author; @ManyToOne(optional = false) @JoinTable(name = "student_task", inverseJoinColumns = { @JoinColumn(name = "teacher_id") }) private Teacher curator; //getters and setters } Consider that author and curator are already stored in DB and both are in the attached state. I'm trying to persist my Task: Task task = new Task(); task.setAuthor(author); task.setCurator(curator); entityManager.persist(task); Hibernate executes the following SQL: insert into student_task (teacher_id, id) values (?, ?) which, of course, leads to null value in column "student_id" violates not-null constraint Can anyone explain this issue and possible ways to resolve it?

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  • C# Cast Class to Overridden Class

    - by Nathan Tornquist
    I have a class Application that I need to override with INotifyPropertyChanged events. I have written the logic to override the original class and ended up creating SuperApplication I am pulling the data from a library though, and cannot change the loading logic. I just need a way to get the data from the original class into my superClass. I've tried things like superClass = (SuperApplication)standardClass; but it hasn't worked. How would I go about doing this? If it helps, this is the code I'm using to override the original class: public class SuperCreditApplication : CreditApplication { public SuperCreditApplicant Applicant { get; set; } public SuperCreditApplicant CoApplicant { get; set; } } public class SuperCreditApplicant : CreditApplicant { public SuperProspect Prospect { get; set; } } public class SuperProspect : Prospect, INotifyPropertyChanged { public State DriverLicenseState { get { return DriverLicenseState; } set { DriverLicenseState = value; OnPropertyChanged("DriverLicenseState"); } } public event PropertyChangedEventHandler PropertyChanged; private void OnPropertyChanged(string propertyName) { if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } }

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  • What is the best way to handle the Connections to MySql from c#

    - by srk
    I am working on a c# application which connects to MySql server. There are about 20 functions which will connect to database. This application will be deployed in 200 over machines. I am using the below code to connect to my database which is identical for all the functions. The problem is, i can some connections were not closed and still alive when deployed in 200 over machines. Connection String : <add key="Con_Admin" value="server=test-dbserver; database=test_admindb; uid=admin; password=1Password; Use Procedure Bodies=false;" /> Declaration of the connection string Globally in application [Global.cs] : public static MySqlConnection myConn_Instructor = new MySqlConnection(ConfigurationSettings.AppSettings["Con_Admin"]); Function to query database : public static DataSet CheckLogin_Instructor(string UserName, string Password) { DataSet dsValue = new DataSet(); //MySqlConnection myConn = new MySqlConnection(ConfigurationSettings.AppSettings["Con_Admin"]); try { string Query = "SELECT accounts.str_nric AS Nric, accounts.str_password AS `Password`," + " FROM accounts " + " WHERE accounts.str_nric = '" + UserName + "' AND accounts.str_password = '" + Password + "\'"; MySqlCommand cmd = new MySqlCommand(Query, Global.myConn_Instructor); MySqlDataAdapter da = new MySqlDataAdapter(); if (Global.myConn_Instructor.State == ConnectionState.Closed) { Global.myConn_Instructor.Open(); } cmd.ExecuteScalar(); da.SelectCommand = cmd; da.Fill(dsValue); Global.myConn_Instructor.Close(); } catch (Exception ex) { Global.myConn_Instructor.Close(); ExceptionHandler.writeToLogFile(System.Environment.NewLine + "Target : " + ex.TargetSite.ToString() + System.Environment.NewLine + "Message : " + ex.Message.ToString() + System.Environment.NewLine + "Stack : " + ex.StackTrace.ToString()); } return dsValue; }

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  • Distinct or group by on some columns but not others

    - by Nazadus
    I have a view that I'm trying to filter with something similar to DISTINCT on some columns but not others. I have a view like this: Name LastName Zip Street1 HouseholdID (may not be unique because it may have multiple addresses -- think of it in the logical sense as grouping persons but not physical locations; If you lookup HouseholdID 4130, you may get two rows.. or more, because the person may have mutiple mailing locations) City State I need to pull all those columns but filter on LastName,Zip, and Street1. Here's the fun part: The filter is arbitrary -- meaning I don't care which one of the duplicates goes away. This is for a mail out type thing and the other information is not used for any other reason than than to look up a specific person if needed (I have no idea why). So.. given one of the records, you can easily figure out the removed ones. As it stands now, my Sql-Fu fails me and I'm filtering in C# which is incredibly slow and is pretty much a foreach that starts with an empty list and adds the row in if the combined last name, zip, and street aren't are not in the list. I feel like I'm missing a simple / basic part of SQL that I should be understanding.

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  • Why are my connections not closed even if I explicitly dispose of the DataContext?

    - by Chris Simpson
    I encapsulate my linq to sql calls in a repository class which is instantiated in the constructor of my overloaded controller. The constructor of my repository class creates the data context so that for the life of the page load, only one data context is used. In my destructor of the repository class I explicitly call the dispose of the DataContext though I do not believe this is necessary. Using performance monitor, if I watch my User Connections count and repeatedly load a page, the number increases once per page load. Connections do not get closed or reused (for about 20 minutes). I tried putting Pooling=false in my config to see if this had any effect but it did not. In any case with pooling I wouldn't expect a new connection for every load, I would expect it to reuse connections. I've tried putting a break point in the destructor to make sure the dispose is being hit and sure enough it is. So what's happening? Some code to illustrate what I said above: The controller: public class MyController : Controller { protected MyRepository rep; public MyController () { rep = new MyRepository(); } } The repository: public class MyRepository { protected MyDataContext dc; public MyRepository() { dc = getDC(); } ~MyRepository() { if (dc != null) { //if (dc.Connection.State != System.Data.ConnectionState.Closed) //{ // dc.Connection.Close(); //} dc.Dispose(); } } // etc } Note: I add a number of hints and context information to the DC for auditing purposes. This is essentially why I want one connection per page load

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  • Ajax with Jsf 1.1 implementation

    - by Rohan Ved
    I am using JSF1.1 in that, have this code_ <%@ taglib uri="http://java.sun.com/jsf/html" prefix="h"%> <%@ taglib uri="http://java.sun.com/jsf/core" prefix="f"%> <%@ taglib uri="http://www.azureworlds.org" prefix="azure"%> <%@ taglib uri="http://myfaces.apache.org/tomahawk" prefix="x"%> <%@ taglib uri="http://www.asifqamar.com/jsf/asif" prefix="a"%> ... <x:selectOneMenu value="#{hotelBean.state}"> <f:selectItem itemLabel="Select One" itemValue="" /> <f:selectItem value="#{hotelBean.mapStates }" /> <x:ajax update="city" listener="#{hotelBean.handleCityChange}" /> </x:selectOneMenu> <h:outputText value="City* " /> <x:selectOneMenu id="city" value="#{hotelBean.city}"> <f:selectItem itemLabel="Select One" itemValue="" /> <f:selectItem value="#{hotelBean.mapCities }" /> </x:selectOneMenu> line x:ajax update="city" listener="#{hotelBean.handleCityChange}" is not working , i searched but got JSF1.1 not support for Ajax. then what can i do for this? and i have less knowledge of JS. Thanx

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  • Low-level Keyboard Hooks/SendInput with Winkey+L possible? (workstation lockout is intercepted in Vi

    - by Brian Jorgensen
    I work on a project called UAWKS (Unofficial Apple Wireless Keyboard Support) that helps Windows users use Apple's bluetooth keyboard. One of the main goals of UAWKS is to swap the Cmd key (which behaves as Winkey in Windows) with Ctrl, allowing users to do Cmd+C for copy, Cmd+T for new tab, etc. It is currently developed using AutoHotkey, which worked pretty well under Windows XP. However, on Vista and Windows 7, Cmd+L causes problems: Regardless of low-level keyboard hooks, Winkey+L is always intercepted by Windows and normally locks the workstation... You can disable workstation locking with this registry hack, but pressing Winkey+L still can't be rebound in AHK Pressing Winkey+L leaves Winkey in the Keydown state until the next (additional) Winkey Up. Simulating a Keyup event doesn't seem to work either! It seems that Winkey+L is a special chord that messes everything else up. I've looked through the AHK source code, and they try to address this problem in SendKey() in keyboard_mouse.cpp (near line 883 in v1.0.48.05), but it doesn't work. I wrote up my own low-level keyboard hook application in C#, and I see the same problem. Has anyone else run into this? Is there a workaround?

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  • What can i use to journal writes to file system

    - by Dmitry
    Hello, all I need to track all writes to files in order to have synchronized version of files on different place (server or just other directory, not considerable). Let it: all files located in same directory feel free to create some system files (e.g. SomeFileName.Ext~temp-data) no one have concurrent access to synced directory; nobody spoil ours meta-files or change real-files before we do postponed writes (like a commits) do not to care recovering "local" changes in case of crash; system can just rolled back to state of "server" by simple copy from it significant to have it transparent to use (so programmer must just call ordinary fopen(), read(), write()) It must be guaranteed that copy of files which "server" have is consistent. That is whole files scope existed in some moment of time. They may be sufficiently outdated but it must be fair snapshot of all files at some time. As i understand i should overload writing logic to collect data in order sent changes to "server". For example writing to temporary File~tmp. And so i have to overload reads in order program could read actual data of file. It would be great if you suggest some existing library (java or c++, it is unimportant) or solution (VCS customizing?). Or give hints how should i write it by myself. edit: After some reading i have more precision requirements: I need COW (Copy-on-write) wrapper for fopen(),fwrite(),.. or interceptor (hook) WriteFile() and other FS api system calls. Log-structured file system in userspace would be a alternative too.

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  • Bing Maps - Auto update location binding of pushpins

    - by abp
    Hi I'm using the Bing Maps control to display a series of custom pushpins, representing objects which are constantly moving around and changing state. Using databinding the various properties for the objects are being updated as they should, but for some reason this doesn't apply to their locations. I have the map bound to an ObservableCollection as such: <UserControl.Resources> <DataTemplate x:Key="PushpinTemplate"> <v:CustomPushpin /> </DataTemplate> </UserControl.Resources> ... <m:Map Name="map"> <m:MapItemsControl ItemTemplate="{StaticResource PushpinTemplate}" ItemsSource="{Binding Objects}" /> </m:Map> ...and in CustomPushpin: <UserControl ... m:MapLayer.Position="{Binding Location}" m:MapLayer.PositionOrigin="BottomCenter" mc:Ignorable="d" d:DesignHeight="126" d:DesignWidth="85"> Like all other properties, the Location of the individual objects are implemented using INotifyPropertyChanged. private Location _location; public Location Location { get { return _location; } set { _location = value; OnPropertyChanged("Location"); } } When the map is moving, either because of panning or zooming, the objects move, but othersize not. I can't quite figure if I'm doing something wrong here, or if it's a problem with the Bing Maps control. Any thought?

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  • Can someone confirm how Microsoft Excel 2007 internally represents numbers?

    - by Jon
    I know the IEEE 754 floating point standard by heart as I had to learn it for an exam. I know exactly how floating point numbers are used and the problems that they can have. I can manually do any operation on the binary representation of floating point numbers. However, I have not found a single source which unambiguously states that excel uses 64 bit floating point numbers to internally represent every single cell "type" in excel except for text. I have no idea whether some of the types use signed or unsigned integers and some use 64 bit floating point. I have found literally trillions of articles which 1) describe floating point numbers and then 2) talk about being careful with excel because of floating point numbers. I have not found a single statement saying "all types are 64 bit floating point numbers except text". I have not found a single statement which says "changing the type of a cell only changes its visual representation and not its internal representation, unless you change the type from text to some other type which is not text or you change some other type which is not text to text". This is literally all I want to know, and it's so simple and axiomatic that I am amazed that I can find trillions of articles and pages which talk around these statements but do not state them directly.

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  • Generating a canonical path

    - by Joel
    Does any one know of any Java libraries I could use to generate canonical paths (basically remove back-references). I need something that will do the following: Raw Path - Canonical Path /../foo/ -> /foo /foo/ -> /foo /../../../ -> / /./foo/./ -> /foo //foo//bar -> /foo/bar //foo/../bar -> /bar etc... At the moment I lazily rely on using: new File("/", path).getCanonicalPath(); But this resolves the path against the actual file system, and is synchronised. java.lang.Thread.State: BLOCKED (on object monitor) at java.io.ExpiringCache.get(ExpiringCache.java:55) - waiting to lock <0x93a0d180> (a java.io.ExpiringCache) at java.io.UnixFileSystem.canonicalize(UnixFileSystem.java:137) at java.io.File.getCanonicalPath(File.java:559) The paths that I am canonicalising do not exist on my file system, so just the logic of the method will do me fine, thus not requiring any synchronisation. I'm hoping for a well tested library rather than having to write my own.

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  • How can I unit test a PHP class method that executes a command-line program?

    - by acoulton
    For a PHP application I'm developing, I need to read the current git revision SHA which of course I can get easily by using shell_exec or backticks to execute the git command line client. I have obviously put this call into a method of its very own, so that I can easily isolate and mock this for the rest of my unit tests. So my class looks a bit like this: class Task_Bundle { public function execute() { // Do things $revision = $this->git_sha(); // Do more things } protected function git_sha() { return `git rev-parse --short HEAD`; } } Of course, although I can test most of the class by mocking git_sha, I'm struggling to see how to test the actual git_sha() method because I don't see a way to create a known state for it. I don't think there's any real value in a unit test that also calls git rev-parse to compare the results? I was wondering about at least asserting that the command had been run, but I can't see any way to get a history of shell commands executed by PHP - even if I specify that PHP should use BASH rather than SH the history list comes up empty, I presume because the separate backticks executions are separate terminal sessions. I'd love to hear any suggestions for how I might test this, or is it OK to just leave that method untested and be careful with it when the app is being maintained in future?

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  • iOS Cell Label link

    - by hart1994
    Hi I am new to iOS programming and I need a little help. I have a table view cell which is populated by data from a .plist file. I need to be able to make a link within one of the cells. How could I do this? Here is the code which is loading the data into the cells: - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"CustomTableCell"; static NSString *CellNib = @"DetailViewCell"; DetailViewCell *cell = (DetailViewCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { NSArray *nib = [[NSBundle mainBundle] loadNibNamed:CellNib owner:self options:nil]; cell = (DetailViewCell *)[nib objectAtIndex:0]; } cell.accessoryType = UITableViewCellAccessoryNone; cell.cellTitleLabel.textColor = [UIColor blackColor]; cell.cellTitleLabel.font = [UIFont systemFontOfSize:20.0]; cell.cellSubtitleLabel.textColor = [UIColor darkGrayColor]; informations = [[NSArray alloc] initWithObjects:@"City", @"Country", @"State", @"History", @"Link", nil]; subtitles = [[NSArray alloc] initWithObjects:titleString, subtitleString, stateString, populationString, @"Link", nil]; cell.cellTitleLabel.text = [informations objectAtIndex:indexPath.row]; cell.cellSubtitleLabel.text = [subtitles objectAtIndex:indexPath.row]; return (DetailViewCell *) cell; } For the cell "Link" I need it to open a url which is stored in the .plist file. How could i do this? Many thanks Ryan PS: I'm a newbie at this stuff, so be descriptive. Thanks

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  • TicTacToe strategic reduction

    - by NickLarsen
    I decided to write a small program that solves TicTacToe in order to try out the effect of some pruning techniques on a trivial game. The full game tree using minimax to solve it only ends up with 549,946 possible games. With alpha-beta pruning, the number of states required to evaluate was reduced to 18,297. Then I applied a transposition table that brings the number down to 2,592. Now I want to see how low that number can go. The next enhancement I want to apply is a strategic reduction. The basic idea is to combine states that have equivalent strategic value. For instance, on the first move, if X plays first, there is nothing strategically different (assuming your opponent plays optimally) about choosing one corner instead of another. In the same situation, the same is true of the center of the walls of the board, and the center is also significant. By reducing to significant states only, you end up with only 3 states for evaluation on the first move instead of 9. This technique should be very useful since it prunes states near the top of the game tree. This idea came from the GameShrink method created by a group at CMU, only I am trying to avoid writing the general form, and just doing what is needed to apply the technique to TicTacToe. In order to achieve this, I modified my hash function (for the transposition table) to enumerate all strategically equivalent positions (using rotation and flipping functions), and to only return the lowest of the values for each board. Unfortunately now my program thinks X can force a win in 5 moves from an empty board when going first. After a long debugging session, it became apparent to me the program was always returning the move for the lowest strategically significant move (I store the last move in the transposition table as part of my state). Is there a better way I can go about adding this feature, or a simple method for determining the correct move applicable to the current situation with what I have already done?

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  • How to Treat Race Condition of Session in Web Application?

    - by Morgan Cheng
    I was in a ASP.NET application has heavy traffic of AJAX requests. Once a user login our web application, a session is created to store information of this user's state. Currently, our solution to keep session data consistent is quite simple and brutal: each request needs to acquire a exclusive lock before being processed. This works fine for tradition web application. But, when the web application turns to support AJAX, it turns to not efficient. It is quite possible that multiple AJAX requests are sent to server at the same time without reloading the web page. If all AJAX requests are serialized by the exclusive lock, the response is not so quick. Anyway, many AJAX requests that doesn't access same session variables are blocked as well. If we don't have a exclusive lock for each requests, then we need to treat all race condition carefully to avoid dead lock. I'm afraid that would make the code complex and buggy. So, is there any best practice to keep session data consistent and keep code simple and clean?

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  • How To perform a SQL Query to DataTable Operation That Can Be Cancelled

    - by David W
    I tried to make the title as specific as possible. Basically what I have running inside a backgroundworker thread now is some code that looks like: SqlConnection conn = new SqlConnection(connstring); SqlCommand cmd = new SqlCommand(query, conn); conn.Open(); SqlDataAdapter sda = new SqlDataAdapter(cmd); sda.Fill(Results); conn.Close(); sda.Dispose(); Where query is a string representing a large, time consuming query, and conn is the connection object. My problem now is I need a stop button. I've come to realize killing the backgroundworker would be worthless because I still want to keep what results are left over after the query is canceled. Plus it wouldn't be able to check the canceled state until after the query. What I've come up with so far: I've been trying to conceptualize how to handle this efficiently without taking too big of a performance hit. My idea was to use a SqlDataReader to read the data from the query piece at a time so that I had a "loop" to check a flag I could set from the GUI via a button. The problem is as far as I know I can't use the Load() method of a datatable and still be able to cancel the sqlcommand. If I'm wrong please let me know because that would make cancelling slightly easier. In light of what I discovered I came to the realization I may only be able to cancel the sqlcommand mid-query if I did something like the below (pseudo-code): while(reader.Read()) { //check flag status //if it is set to 'kill' fire off the kill thread //otherwise populate the datatable with what was read } However, it would seem to me this would be highly ineffective and possibly costly. Is this the only way to kill a sqlcommand in progress that absolutely needs to be in a datatable? Any help would be appreciated!

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  • one two-directed tcp socket of two one-directed? (linux, high volume, low latency)

    - by osgx
    Hello I need to send (interchange) a high volume of data periodically with the lowest possible latency between 2 machines. The network is rather fast (e.g. 1Gbit or even 2G+). Os is linux. Is it be faster with using 1 tcp socket (for send and recv) or with using 2 uni-directed tcp sockets? The test for this task is very like NetPIPE network benchmark - measure latency and bandwidth for sizes from 2^1 up to 2^13 bytes, each size sent and received 3 times at least (in teal task the number of sends is greater. both processes will be sending and receiving, like ping-pong maybe). The benefit of 2 uni-directed connections come from linux: http://lxr.linux.no/linux+v2.6.18/net/ipv4/tcp_input.c#L3847 3847/* 3848 * TCP receive function for the ESTABLISHED state. 3849 * 3850 * It is split into a fast path and a slow path. The fast path is 3851 * disabled when: ... 3859 * - Data is sent in both directions. Fast path only supports pure senders 3860 * or pure receivers (this means either the sequence number or the ack 3861 * value must stay constant) ... 3863 * 3864 * When these conditions are not satisfied it drops into a standard 3865 * receive procedure patterned after RFC793 to handle all cases. 3866 * The first three cases are guaranteed by proper pred_flags setting, 3867 * the rest is checked inline. Fast processing is turned on in 3868 * tcp_data_queue when everything is OK. All other conditions for disabling fast path is false. And only not-unidirected socket stops kernel from fastpath in receive

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  • Partial slideDown with jQuery

    - by Jon
    I have some buttons that have drawer menus and what I'd like to do is add a state so that when the user hovers over the button, the drawer bumps out slightly (maybe with a little wiggle/rubber-banding) so that they know that there's a drawer with more information. I have the sliding working and a hover function set up, but I don't know how to implement a partial slideDown. Any ideas? FIDDLE. Code: <div class="clause"> <div class="icon"><img src="http://i.imgur.com/rTu40.png"/></div> <div class="label">Location</div> <div class="info">Midwest > Indiana, Kentucky; Southwest > Texas, Nevada, Utah; Pacific > California, Hawaii</div> </div> <div class="drawer">Info 1<br/><br/></div> <div class="drawerBottom"></div> $(".clause").click(function() { var tmp = $(this).next("div.drawer"); if(tmp.is(":hidden")) tmp.slideDown('3s'); else tmp.slideUp('3s'); }); $(".clause").hover(function() { });

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  • Repaint() not calling paint() in Java

    - by Joshua Auriemma
    Let me start off by saying I know I've violated some basic Java principles in this messy code, but I'm desperately trying to finish a program by Tuesday for a social science experiment, and I don't know Java, so I'm basically just fumbling through it for now. With that disclaimer out of the way, I have a separate program working where a circle is moving around the screen and the user must click on it. It works fine when its in its own separate class file, but when I add the code to my main program, it's no longer working. I don't even really understand why repaint() calls my paint() function — as far as I'm concerned, it's magic, but I've noticed that repaint() calls paint() in my test program, but not in the more complicated actual program, and I assume that's why the circle is no longer painting on my program. Entire code is below: import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Rectangle; import javax.swing.*; import java.awt.event.*; import java.awt.geom.Ellipse2D; import java.io.FileReader; import java.io.IOException; import java.util.Calendar; public class Reflexology1 extends JFrame{ private static final long serialVersionUID = -1295261024563143679L; private Ellipse2D ball = new Ellipse2D.Double(0, 0, 25, 25); private Timer moveBallTimer; int _ballXpos, _ballYpos; JButton button1, button2; JButton movingButton; JTextArea textArea1; int buttonAClicked, buttonDClicked; private long _openTime = 0; private long _closeTime = 0; JPanel thePanel = new JPanel(); JPanel thePlacebo = new JPanel(); final JFrame frame = new JFrame("Reflexology"); final JFrame frame2 = new JFrame("The Test"); JLabel label1 = new JLabel("Press X and then click the moving dot as fast as you can."); public static void main(String[] args){ new Reflexology1(); } public Reflexology1(){ frame.setSize(600, 475); frame.setLocationRelativeTo(null); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setTitle("Reflexology 1.0"); frame.setResizable(false); frame2.setSize(600, 475); frame2.setLocationRelativeTo(null); frame2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame2.setTitle("Reflexology 1.0"); frame2.setResizable(false); button1 = new JButton("Accept"); button2 = new JButton("Decline"); //movingButton = new JButton("Click Me"); ListenForAcceptButton lForAButton = new ListenForAcceptButton(); ListenForDeclineButton lForDButton = new ListenForDeclineButton(); button1.addActionListener(lForAButton); button2.addActionListener(lForDButton); //movingButton.addActionListener(lForMButton); JTextArea textArea1 = new JTextArea(24, 50); textArea1.setText("Tracking Events\n"); textArea1.setLineWrap(true); textArea1.setWrapStyleWord(true); textArea1.setSize(15, 50); textArea1.setEditable(false); FileReader reader = null; try { reader = new FileReader("EULA.txt"); textArea1.read(reader, "EULA.txt"); } catch (IOException exception) { System.err.println("Problem loading file"); exception.printStackTrace(); } finally { if (reader != null) { try { reader.close(); } catch (IOException exception) { System.err.println("Error closing reader"); exception.printStackTrace(); } } } JScrollPane scrollBar1 = new JScrollPane(textArea1, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER); AdjustmentListener listener = new MyAdjustmentListener(); thePanel.add(scrollBar1); thePanel.add(button1); thePanel.add(button2); frame.add(thePanel); ListenForMouse lForMouse = new ListenForMouse(); thePlacebo.addMouseListener(lForMouse); thePlacebo.add(label1); frame2.add(thePlacebo); ListenForWindow lForWindow = new ListenForWindow(); frame.addWindowListener(lForWindow); frame2.addKeyListener(new KeyAdapter() { public void keyPressed(KeyEvent e){ if(e.getKeyChar() == 'X' || e.getKeyChar() == 'x') {moveBallTimer.start();} } }); frame.setVisible(true); moveBallTimer = new Timer(1000, new ActionListener() { public void actionPerformed(ActionEvent e) { moveBall(); System.out.println("Timer started!"); repaint(); } }); addKeyListener(new KeyAdapter() { public void keyPressed(KeyEvent e) { if(frame2.isVisible()){ moveBallTimer.start(); } } }); } private class ListenForAcceptButton implements ActionListener{ public void actionPerformed(ActionEvent e){ if (e.getSource() == button1){ Calendar ClCDateTime = Calendar.getInstance(); System.out.println(ClCDateTime.getTimeInMillis() - _openTime); _closeTime = ClCDateTime.getTimeInMillis() - _openTime; //frame.getContentPane().remove(thePanel); //thePlacebo.addKeyListener(lForKeys); //frame.getContentPane().add(thePlacebo); //frame.repaint(); //moveBallTimer.start(); frame.setVisible(false); frame2.setVisible(true); frame2.revalidate(); frame2.repaint(); } } } private class ListenForDeclineButton implements ActionListener{ public void actionPerformed(ActionEvent e){ if (e.getSource() == button2){ JOptionPane.showMessageDialog(Reflexology1.this, "You've declined the license agreement. DO NOT RESTART the program. Please go inform a researcher that you have declined the agreement.", "WARNING", JOptionPane.INFORMATION_MESSAGE); System.exit(0); } } } private class ListenForWindow implements WindowListener{ public void windowActivated(WindowEvent e) { //textArea1.append("Window is active"); } // if this.dispose() is called, this is called: public void windowClosed(WindowEvent arg0) { } // When a window is closed from a menu, this is called: public void windowClosing(WindowEvent arg0) { } // Called when the window is no longer the active window: public void windowDeactivated(WindowEvent arg0) { //textArea1.append("Window is NOT active"); } // Window gone from minimized to normal state public void windowDeiconified(WindowEvent arg0) { //textArea1.append("Window is in normal state"); } // Window has been minimized public void windowIconified(WindowEvent arg0) { //textArea1.append("Window is minimized"); } // Called when the Window is originally created public void windowOpened(WindowEvent arg0) { //textArea1.append("Let there be Window!"); Calendar OlCDateTime = Calendar.getInstance(); _openTime = OlCDateTime.getTimeInMillis(); //System.out.println(_openTime); } } private class MyAdjustmentListener implements AdjustmentListener { public void adjustmentValueChanged(AdjustmentEvent arg0) { AdjustmentEvent scrollBar1; //System.out.println(scrollBar1.getValue())); } } public void paint(Graphics g) { //super.paint(g); frame2.paint(g); Graphics2D g2d = (Graphics2D) g; g2d.setColor(Color.RED); g2d.fill(ball); System.out.println("Calling fill()"); } protected void moveBall() { //System.out.println("I'm in the moveBall() function!"); int width = getWidth(); int height = getHeight(); int min, max, randomX, randomY; min =200; max = -200; randomX = min + (int)(Math.random() * ((max - min)+1)); randomY = min + (int)(Math.random() * ((max - min)+1)); //System.out.println(randomX + ", " + randomY); Rectangle ballBounds = ball.getBounds(); //System.out.println(ballBounds.x + ", " + ballBounds.y); if (ballBounds.x + randomX < 0) { randomX = 200; } else if (ballBounds.x + ballBounds.width + randomX > width) { randomX = -200; } if (ballBounds.y + randomY < 0) { randomY = 200; } else if (ballBounds.y + ballBounds.height + randomY > height) { randomY = -200; } ballBounds.x += randomX; ballBounds.y += randomY; _ballXpos = ballBounds.x; _ballYpos = ballBounds.y; ball.setFrame(ballBounds); } public void start() { moveBallTimer.start(); } public void stop() { moveBallTimer.stop(); } private class ListenForMouse implements MouseListener{ // Called when the mouse is clicked public void mouseClicked(MouseEvent e) { //System.out.println("Mouse Panel pos: " + e.getX() + " " + e.getY() + "\n"); if (e.getX() >=_ballXpos && e.getX() <= _ballXpos + 25 && e.getY() <=_ballYpos && e.getY() >= _ballYpos - 25 ) { System.out.println("TRUE"); } System.out.println("{e.getX(): " + e.getX() + " / " + "_ballXpos: " + _ballXpos + " | " + "{e.getY(): " + e.getY() + " / " + "_ballYpos: " + _ballYpos); } public void mouseEntered(MouseEvent arg0) { // TODO Auto-generated method stub } public void mouseExited(MouseEvent arg0) { // TODO Auto-generated method stub } public void mousePressed(MouseEvent arg0) { // TODO Auto-generated method stub } public void mouseReleased(MouseEvent arg0) { // TODO Auto-generated method stub } } // System.out.println("e.getX(): " + e.getX() + " / " + "_ballXpos: " + _ballXpos); // Mouse over public void mouseEntered(MouseEvent arg0) { // TODO Auto-generated method stub } // Mouse left the mouseover area: public void mouseExited(MouseEvent arg0) { // TODO Auto-generated method stub } public void mousePressed(MouseEvent arg0) { // TODO Auto-generated method stub } public void mouseReleased(MouseEvent arg0) { // TODO Auto-generated method stub } } Could anyone tell me what I need to do to get repaint() to call the paint() method in the above program? I'm assuming the multiple frames is causing the problem, but that's just a guess. Thanks.

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