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• On StringComparison Values

  - by Jesse

  When you use the .NET Framework’s String.Equals and String.Compare methods do you use an overloStringComparison enumeration value? If not, you should be because the value provided for that StringComparison argument can have a big impact on the results of your string comparison. The StringComparison enumeration defines values that fall into three different major categories: Culture-sensitive comparison using a specific culture, defaulted to the Thread.CurrentThread.CurrentCulture value (StringComparison.CurrentCulture and StringComparison.CurrentCutlureIgnoreCase) Invariant culture comparison (StringComparison.InvariantCulture and StringComparison.InvariantCultureIgnoreCase) Ordinal (byte-by-byte) comparison of  (StringComparison.Ordinal and StringComparison.OrdinalIgnoreCase) There is a lot of great material available that detail the technical ins and outs of these different string comparison approaches. If you’re at all interested in the topic these two MSDN articles are worth a read: Best Practices For Using Strings in the .NET Framework: http://msdn.microsoft.com/en-us/library/dd465121.aspx How To Compare Strings: http://msdn.microsoft.com/en-us/library/cc165449.aspx Those articles cover the technical details of string comparison well enough that I’m not going to reiterate them here other than to say that the upshot is that you typically want to use the culture-sensitive comparison whenever you’re comparing strings that were entered by or will be displayed to users and the ordinal comparison in nearly all other cases. So where does that leave the invariant culture comparisons? The “Best Practices For Using Strings in the .NET Framework” article has the following to say: “On balance, the invariant culture has very few properties that make it useful for comparison. It does comparison in a linguistically relevant manner, which prevents it from guaranteeing full symbolic equivalence, but it is not the choice for display in any culture. One of the few reasons to use StringComparison.InvariantCulture for comparison is to persist ordered data for a cross-culturally identical display. For example, if a large data file that contains a list of sorted identifiers for display accompanies an application, adding to this list would require an insertion with invariant-style sorting.” I don’t know about you, but I feel like that paragraph is a bit lacking. Are there really any “real world” reasons to use the invariant culture comparison? I think the answer to this question is, “yes”, but in order to understand why we should first think about what the invariant culture comparison really does. The invariant culture comparison is really just a culture-sensitive comparison using a special invariant culture (Michael Kaplan has a great post on the history of the invariant culture on his blog: http://blogs.msdn.com/b/michkap/archive/2004/12/29/344136.aspx). This means that the invariant culture comparison will apply the linguistic customs defined by the invariant culture which are guaranteed not to differ between different machines or execution contexts. This sort of consistently does prove useful if you needed to maintain a list of strings that are sorted in a meaningful and consistent way regardless of the user viewing them or the machine on which they are being viewed. Example: Prototype Names Let’s say that you work for a large multi-national toy company with branch offices in 10 different countries. Each year the company would work on 15-25 new toy prototypes each of which is assigned a “code name” while it is under development. Coming up with fun new code names is a big part of the company culture that everyone really enjoys, so to be fair the CEO of the company spent a lot of time coming up with a prototype naming scheme that would be fun for everyone to participate in, fair to all of the different branch locations, and accessible to all members of the organization regardless of the country they were from and the language that they spoke. Each new prototype will get a code name that begins with a letter following the previously created name using the alphabetical order of the Latin/Roman alphabet. Each new year prototype names would start back at “A”. The country that leads the prototype development effort gets to choose the name in their native language. (An appropriate Romanization system will be used for countries where the primary language is not written in the Latin/Roman alphabet. For example, the Pinyin system could be used for Chinese). To avoid repeating names, a list of all current and past prototype names will be maintained on each branch location’s company intranet site. Assuming that maintaining a single pre-sorted list is not feasible among all of the highly distributed intranet implementations, what string comparison method would you use to sort each year’s list of prototype names so that the list is both meaningful and consistent regardless of the country within which the list is being viewed? Sorting the list with a culture-sensitive comparison using the default configured culture on each country’s intranet server the list would probably work most of the time, but subtle differences between cultures could mean that two different people would see a list that was sorted slightly differently. The CEO wants the prototype names to be a unifying aspect of company culture and is adamant that everyone see the the same list sorted in the same order and there’s no way to guarantee a consistent sort across different cultures using the culture-sensitive string comparison rules. The culture-sensitive sort would produce a meaningful list for the specific user viewing it, but it wouldn’t always be consistent between different users. Sorting with the ordinal comparison would certainly be consistent regardless of the user viewing it, but would it be meaningful? Let’s say that the current year’s prototype name list looks like this: Antílope (Spanish) Babouin (French) Cahoun (Czech) Diamond (English) Flosse (German) If you were to sort this list using ordinal rules you’d end up with: Antílope Babouin Diamond Flosse Cahoun This sort is no good because the entry for “C” appears the bottom of the list after “F”. This is because the Czech entry for the letter “C” makes use of a diacritic (accent mark). The ordinal string comparison does a byte-by-byte comparison of the code points that make up each character in the string and the code point for the “C” with the diacritic mark is higher than any letter without a diacritic mark, which pushes that entry to the bottom of the sorted list. The CEO wants each country to be able to create prototype names in their native language, which means we need to allow for names that might begin with letters that have diacritics, so ordinal sorting kills the meaningfulness of the list. As it turns out, this situation is actually well-suited for the invariant culture comparison. The invariant culture accounts for linguistically relevant factors like the use of diacritics but will provide a consistent sort across all machines that perform the sort. Now that we’ve walked through this example, the following line from the “Best Practices For Using Strings in the .NET Framework” makes a lot more sense: One of the few reasons to use StringComparison.InvariantCulture for comparison is to persist ordered data for a cross-culturally identical display That line describes the prototype name example perfectly: we need a way to persist ordered data for a cross-culturally identical display. While this example is 100% made-up, I think it illustrates that there are indeed real-world situations where the invariant culture comparison is useful.

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• New Features in ASP.NET Web API 2 - Part I

  - by dwahlin

  I’m a big fan of ASP.NET Web API. It provides a quick yet powerful way to build RESTful HTTP services that can easily be consumed by a variety of clients. While it’s simple to get started using, it has a wealth of features such as filters, formatters, and message handlers that can be used to extend it when needed. In this post I’m going to provide a quick walk-through of some of the key new features in version 2. I’ll focus on some two of my favorite features that are related to routing and HTTP responses and cover additional features in a future post.   Attribute Routing Routing has been a core feature of Web API since it’s initial release and something that’s built into new Web API projects out-of-the-box. However, there are a few scenarios where defining routes can be challenging such as nested routes (more on that in a moment) and any situation where a lot of custom routes have to be defined. For this example, let’s assume that you’d like to define the following nested route:   /customers/1/orders   This type of route would select a customer with an Id of 1 and then return all of their orders. Defining this type of route in the standard WebApiConfig class is certainly possible, but it isn’t the easiest thing to do for people who don’t understand routing well. Here’s an example of how the route shown above could be defined:   public static class WebApiConfig { public static void Register(HttpConfiguration config) { config.Routes.MapHttpRoute( name: "CustomerOrdersApiGet", routeTemplate: "api/customers/{custID}/orders", defaults: new { custID = 0, controller = "Customers", action = "Orders" } ); config.Routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); GlobalConfiguration.Configuration.Formatters.Insert(0, new JsonpFormatter()); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   With attribute based routing, defining these types of nested routes is greatly simplified. To get started you first need to make a call to the new MapHttpAttributeRoutes() method in the standard WebApiConfig class (or a custom class that you may have created that defines your routes) as shown next:   public static class WebApiConfig { public static void Register(HttpConfiguration config) { // Allow for attribute based routes config.MapHttpAttributeRoutes(); config.Routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); } } Once attribute based routes are configured, you can apply the Route attribute to one or more controller actions. Here’s an example:   [HttpGet] [Route("customers/{custId:int}/orders")] public List<Order> Orders(int custId) { var orders = _Repository.GetOrders(custId); if (orders == null) { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.NotFound)); } return orders; }   This example maps the custId route parameter to the custId parameter in the Orders() method and also ensures that the route parameter is typed as an integer. The Orders() method can be called using the following route: /customers/2/orders   While this is extremely easy to use and gets the job done, it doesn’t include the default “api” string on the front of the route that you might be used to seeing. You could add “api” in front of the route and make it “api/customers/{custId:int}/orders” but then you’d have to repeat that across other attribute-based routes as well. To simply this type of task you can add the RoutePrefix attribute above the controller class as shown next so that “api” (or whatever the custom starting point of your route is) is applied to all attribute routes: [RoutePrefix("api")] public class CustomersController : ApiController { [HttpGet] [Route("customers/{custId:int}/orders")] public List<Order> Orders(int custId) { var orders = _Repository.GetOrders(custId); if (orders == null) { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.NotFound)); } return orders; } }   There’s much more that you can do with attribute-based routing in ASP.NET. Check out the following post by Mike Wasson for more details.   Returning Responses with IHttpActionResult The first version of Web API provided a way to return custom HttpResponseMessage objects which were pretty easy to use overall. However, Web API 2 now wraps some of the functionality available in version 1 to simplify the process even more. A new interface named IHttpActionResult (similar to ActionResult in ASP.NET MVC) has been introduced which can be used as the return type for Web API controller actions. To return a custom response you can use new helper methods exposed through ApiController such as: Ok NotFound Exception Unauthorized BadRequest Conflict Redirect InvalidModelState Here’s an example of how IHttpActionResult and the helper methods can be used to cleanup code. This is the typical way to return a custom HTTP response in version 1:   public HttpResponseMessage Delete(int id) { var status = _Repository.DeleteCustomer(id); if (status) { return new HttpResponseMessage(HttpStatusCode.OK); } else { throw new HttpResponseException(HttpStatusCode.NotFound); } } With version 2 we can replace HttpResponseMessage with IHttpActionResult and simplify the code quite a bit:   public IHttpActionResult Delete(int id) { var status = _Repository.DeleteCustomer(id); if (status) { //return new HttpResponseMessage(HttpStatusCode.OK); return Ok(); } else { //throw new HttpResponseException(HttpStatusCode.NotFound); return NotFound(); } } You can also cleanup post (insert) operations as well using the helper methods. Here’s a version 1 post action:   public HttpResponseMessage Post([FromBody]Customer cust) { var newCust = _Repository.InsertCustomer(cust); if (newCust != null) { var msg = new HttpResponseMessage(HttpStatusCode.Created); msg.Headers.Location = new Uri(Request.RequestUri + newCust.ID.ToString()); return msg; } else { throw new HttpResponseException(HttpStatusCode.Conflict); } } This is what the code looks like in version 2:   public IHttpActionResult Post([FromBody]Customer cust) { var newCust = _Repository.InsertCustomer(cust); if (newCust != null) { return Created<Customer>(Request.RequestUri + newCust.ID.ToString(), newCust); } else { return Conflict(); } } More details on IHttpActionResult and the different helper methods provided by the ApiController base class can be found here. Conclusion Although there are several additional features available in Web API 2 that I could cover (CORS support for example), this post focused on two of my favorites features. If you have .NET 4.5.1 available then I definitely recommend checking the new features out. Additional articles that cover features in ASP.NET Web API 2 can be found here.

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• Fragmented Log files could be slowing down your database

  - by Fatherjack

  Something that is sometimes forgotten by a lot of DBAs is the fact that database log files get fragmented in the same way that you get fragmentation in a data file. The cause is very different but the effect is the same – too much effort reading and writing data. Data files get fragmented as data is changed through normal system activity, INSERTs, UPDATEs and DELETEs cause fragmentation and most experienced DBAs are monitoring their indexes for fragmentation and dealing with it accordingly. However, you don’t hear about so many working on their log files. How can a log file get fragmented? I’m glad you asked. When you create a database there are at least two files created on the disk storage; an mdf for the data and an ldf for the log file (you can also have ndf files for extra data storage but that’s off topic for now). It is wholly possible to have more than one log file but in most cases there is little point in creating more than one as the log file is written to in a ‘wrap-around’ method (more on that later). When a log file is created at the time that a database is created the file is actually sub divided into a number of virtual log files (VLFs). The number and size of these VLFs depends on the size chosen for the log file. VLFs are also created in the space added to a log file when a log file growth event takes place. Do you have your log files set to auto grow? Then you have potentially been introducing many VLFs into your log file. Let’s get to see how many VLFs we have in a brand new database. USE master GO CREATE DATABASE VLF_Test ON ( NAME = VLF_Test, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test.mdf', SIZE = 100, MAXSIZE = 500, FILEGROWTH = 50 ) LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 5MB, MAXSIZE = 250MB, FILEGROWTH = 5MB ); go USE VLF_Test go DBCC LOGINFO; The results of this are firstly a new database is created with specified files sizes and the the DBCC LOGINFO results are returned to the script editor. The DBCC LOGINFO results have plenty of interesting information in them but lets first note there are 4 rows of information, this relates to the fact that 4 VLFs have been created in the log file. The values in the FileSize column are the sizes of each VLF in bytes, you will see that the last one to be created is slightly larger than the others. So, a 5MB log file has 4 VLFs of roughly 1.25 MB. Lets alter the CREATE DATABASE script to create a log file that’s a bit bigger and see what happens. Alter the code above so that the log file details are replaced by LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 1GB, MAXSIZE = 25GB, FILEGROWTH = 1GB ); With a bigger log file specified we get more VLFs What if we make it bigger again? LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 5GB, MAXSIZE = 250GB, FILEGROWTH = 5GB ); This time we see more VLFs are created within our log file. We now have our 5GB log file comprised of 16 files of 320MB each. In fact these sizes fall into all the ranges that control the VLF creation criteria – what a coincidence! The rules that are followed when a log file is created or has it’s size increased are pretty basic. If the file growth is lower than 64MB then 4 VLFs are created If the growth is between 64MB and 1GB then 8 VLFs are created If the growth is greater than 1GB then 16 VLFs are created. Now the potential for chaos comes if the default values and settings for log file growth are used. By default a database log file gets a 1MB log file with unlimited growth in steps of 10%. The database we just created is 6 MB, let’s add some data and see what happens. USE vlf_test go -- we need somewhere to put the data so, a table is in order IF OBJECT_ID('A_Table') IS NOT NULL DROP TABLE A_Table go CREATE TABLE A_Table ( Col_A int IDENTITY, Col_B CHAR(8000) ) GO -- Let's check the state of the log file -- 4 VLFs found EXECUTE ('DBCC LOGINFO'); go -- We can go ahead and insert some data and then check the state of the log file again INSERT A_Table (col_b) SELECT TOP 500 REPLICATE('a',2000) FROM sys.columns AS sc, sys.columns AS sc2 GO -- insert 500 rows and we get 22 VLFs EXECUTE ('DBCC LOGINFO'); go -- Let's insert more rows INSERT A_Table (col_b) SELECT TOP 2000 REPLICATE('a',2000) FROM sys.columns AS sc, sys.columns AS sc2 GO 10 -- insert 2000 rows, in 10 batches and we suddenly have 107 VLFs EXECUTE ('DBCC LOGINFO'); Well, that escalated quickly! Our log file is split, internally, into 107 fragments after a few thousand inserts. The same happens with any logged transactions, I just chose to illustrate this with INSERTs. Having too many VLFs can cause performance degradation at times of database start up, log backup and log restore operations so it’s well worth keeping a check on this property. How do we prevent excessive VLF creation? Creating the database with larger files and also with larger growth steps and actively choosing to grow your databases rather than leaving it to the Auto Grow event can make sure that the growths are made with a size that is optimal. How do we resolve a situation of a database with too many VLFs? This process needs to be done when the database is under little or no stress so that you don’t affect system users. The steps are: BACKUP LOG YourDBName TO YourBackupDestinationOfChoice Shrink the log file to its smallest possible size DBCC SHRINKFILE(FileNameOfTLogHere, TRUNCATEONLY) * Re-size the log file to the size you want it to, taking in to account your expected needs for the coming months or year. ALTER DATABASE YourDBName MODIFY FILE ( NAME = FileNameOfTLogHere, SIZE = TheSizeYouWantItToBeIn_MB) * – If you don’t know the file name of your log file then run sp_helpfile while you are connected to the database that you want to work on and you will get the details you need. The resize step can take quite a while This is already detailed far better than I can explain it by Kimberley Tripp in her blog 8-Steps-to-better-Transaction-Log-throughput.aspx. The result of this will be a log file with a VLF count according to the bullet list above. Knowing when VLFs are being created By complete coincidence while I have been writing this blog (it’s been quite some time from it’s inception to going live) Jonathan Kehayias from SQLSkills.com has written a great article on how to track database file growth using Event Notifications and Service Broker. I strongly recommend taking a look at it as this is going to catch any sneaky auto grows that take place and let you know about them right away. Hassle free monitoring of VLFs If you are lucky or wise enough to be using SQL Monitor or another monitoring tool that let’s you write your own custom metrics then you can keep an eye on this very easily. There is a custom metric for VLFs (written by Stuart Ainsworth) already on the site and there are some others there are very useful so take a moment or two to look around while you are there. Resources MSDN – http://msdn.microsoft.com/en-us/library/ms179355(v=sql.105).aspx Kimberly Tripp from SQLSkills.com – http://www.sqlskills.com/BLOGS/KIMBERLY/post/8-Steps-to-better-Transaction-Log-throughput.aspx Thomas LaRock at Simple-Talk.com – http://www.simple-talk.com/sql/database-administration/monitoring-sql-server-virtual-log-file-fragmentation/ Disclosure I am a Friend of Red Gate. This means that I am more than likely to say good things about Red Gate DBA and Developer tools. No matter how awesome I make them sound, take the time to compare them with other products before you contact the Red Gate sales team to make your order.

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• Using Unity – Part 6

  - by nmarun

  This is the last of the ‘Unity’ series and I’ll be talking about generics here. If you’ve been following the previous articles, you must have noticed that I’m just adding more and more ‘Product’ classes to the project. I’ll change that trend in this blog where I’ll be adding an ICaller interface and a Caller class. 1: public interface ICaller<T> where T : IProduct 2: { 3: string CallMethod<T>(string typeName); 4: } 5:  6: public class Caller<T> : ICaller<T> where T:IProduct 7: { 8: public string CallMethod<T>(string typeName) 9: { 10: //... 11: } 12: } We’ll fill-in the implementation of the CallMethod in a few, but first, here’s what we’re going to do: create an instance of the Caller class pass it the IProduct as a generic parameter in the CallMethod method, we’ll use Unity to dynamically create an instance of IProduct implemented object I need to add the config information for ICaller and Caller types. 1: <typeAlias alias="ICaller`1" type="ProductModel.ICaller`1, ProductModel" /> 2: <typeAlias alias="Caller`1" type="ProductModel.Caller`1, ProductModel" /> The .NET Framework’s convention to express generic types is ICaller`1, where the digit following the "`" matches the number of types contained in the generic type. So a generic type that contains 4 types contained in the generic type would be declared as: 1: <typeAlias alias="Caller`4" type="ProductModel.Caller`4, ProductModel" /> On my .aspx page, I have the following UI design: 1: <asp:RadioButton ID="LegacyProduct" Text="Product" runat="server" GroupName="ProductWeb" 2: AutoPostBack="true" OnCheckedChanged="RadioButton_CheckedChanged" /> 3: <br /> 4: <asp:RadioButton ID="NewProduct" Text="Product 2" runat="server" GroupName="ProductWeb" 5: AutoPostBack="true" OnCheckedChanged="RadioButton_CheckedChanged" /> 6: <br /> 7: <asp:RadioButton ID="ComplexProduct" Text="Product 3" runat="server" GroupName="ProductWeb" 8: AutoPostBack="true" OnCheckedChanged="RadioButton_CheckedChanged" /> 9: <br /> 10: <asp:RadioButton ID="ArrayConstructor" Text="Product 4" runat="server" GroupName="ProductWeb" 11: AutoPostBack="true" OnCheckedChanged="RadioButton_CheckedChanged" /> Things to note here are that all these radio buttons belong to the same GroupName => only one of these four can be clicked. Next, all four controls postback to the same ‘OnCheckedChanged’ event and lastly the ID’s point to named types of IProduct (already added to the web.config file). 1: <type type="IProduct" mapTo="Product" name="LegacyProduct" /> 2:  3: <type type="IProduct" mapTo="Product2" name="NewProduct" /> 4:  5: <type type="IProduct" mapTo="Product3" name="ComplexProduct"> 6: ... 7: </type> 8:  9: <type type="IProduct" mapTo="Product4" name="ArrayConstructor"> 10: ... 11: </type> In my calling code, I see which radio button was clicked, pass that as an argument to the CallMethod method. 1: protected void RadioButton_CheckedChanged(object sender, EventArgs e) 2: { 3: string typeName = ((RadioButton)sender).ID; 4: ICaller<IProduct> caller = unityContainer.Resolve<ICaller<IProduct>>(); 5: productDetailsLabel.Text = caller.CallMethod<IProduct>(typeName); 6: } What’s basically happening here is that the ID of the control gets passed on to the typeName which will be one of “LegacyProduct”, “NewProduct”, “ComplexProduct” or “ArrayConstructor”. I then create an instance of an ICaller and pass the typeName to it. Now, we’ll fill in the blank for the CallMethod method (sorry for the naming guys). 1: public string CallMethod<T>(string typeName) 2: { 3: IUnityContainer unityContainer = HttpContext.Current.Application["UnityContainer"] as IUnityContainer; 4: T productInstance = unityContainer.Resolve<T>(typeName); 5: return ((IProduct)productInstance).WriteProductDetails(); 6: } This is where I’ll resolve the IProduct by passing the type name and calling the WriteProductDetails() method. With all things in place, when I run the application and choose different radio buttons, the output should look something like below:          Basically this is how generics come to play in Unity. Please see the code I’ve used for this here. This marks the end of the ‘Unity’ series. I’ll definitely post any updates that I find, but for now I don’t have anything planned.

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• Too Many Kittens To Juggle At Once

  - by Bil Simser

  Ahh, the Internet. That crazy, mixed up place where one tweet turns into a conversation between dozens of people and spawns a blogpost. This is the direct result of such an event this morning. It started innocently enough, with this: Then followed up by a blog post by Joel here. In the post, Joel introduces us to the term Business Solutions Architect with mad skillz like InfoPath, Access Services, Excel Services, building Workflows, and SSRS report creation, all while meeting the business needs of users in a SharePoint environment. I somewhat disagreed with Joel that this really wasn’t a new role (at least IMHO) and that a good Architect or BA should really be doing this job. As Joel pointed out when you’re building a SharePoint team this kind of role is often overlooked. Engineers might be able to build workflows but is the right workflow for the right problem? Michael Pisarek wrote about a SharePoint Business Architect a few months ago and it’s a pretty solid assessment. Again, I argue you really shouldn’t be looking for roles that don’t exist and I don’t suggest anyone create roles to hire people to fill them. That’s basically creating a solution looking for problems. Michael’s article does have some great points if you’re lost in the quagmire of SharePoint duties though (and I especially like John Ross’ quote “The coolest shit is worthless if it doesn’t meet business needs”). SharePoinTony summed it up nicely with “SharePoint Solutions knowledge is both lacking and underrated in most environments. Roles help”. Having someone on the team who can dance between a business user and a coder can be difficult. Remember the idea of telling something to someone and them passing it on to the next person. By the time the story comes round the circle it’s a shadow of it’s former self with little resemblance to the original tale. This is very much business requirements as they’re told by the user to a business analyst, written down on paper, read by an architect, tuned into a solution plan, and implemented by a developer. Transformations between what was said, what was heard, what was written down, and what was developed can be distant cousins. Not everyone has the skill of communication and even less have negotiation skills to suit the SharePoint platform. Negotiation is important because not everything can be (or should be) done in SharePoint. Sometimes it’s just not appropriate to build it on the SharePoint platform but someone needs to know enough about the platform and what limitations it might have, then communicate that (and/or negotiate) with a customer or user so it’s not about “You can’t have this” to “Let’s try it this way”. Visualize the possible instead of denying the impossible. So what is the right SharePoint team? My cromag brain came with a fairly simpleton answer (and I’m sure people will just say this is a cop-out). The perfect SharePoint team is just enough people to do the job that know the technology and business problem they’re solving. Bridge the gap between business need and technology platform and you have an architect. Communicate the needs of the business effectively so the entire team understands it and you have a business analyst. Can you get this with full time workers? Maybe but don’t expect miracles out of the gate. Also don’t take a consultant’s word as gospel. Some consultants just don’t have the diversity of the SharePoint platform to be worth their value so be careful. You really need someone who knows enough about SharePoint to be able to validate a consultants knowledge level. This is basically try for any consultant, not just a SharePoint one. Specialization is good and needed. A good, well-balanced SharePoint team is one of people that can solve problems with work with the technology, not against it. Having a top developer is great, but don’t rely on them to solve world hunger if they can’t communicate very well with users. An expert business analyst might be great at gathering requirements so the entire team can understand them, but if it means building 100% custom solutions because they don’t fit inside the SharePoint boundaries isn’t of much value. Just repeat. There is no silver bullet. There is no silver bullet. There is no silver bullet. A few people pointed out Nick Inglis’ article Excluding The Information Professional In SharePoint. It’s a good read too and hits home that maybe some developers and IT pros need some extra help in the information space. If you’re in an organization that needs labels on people, come up with something everyone understands and go with it. If that’s Business Solutions Architect, SharePoint Advisor, or Guy Who Knows A Lot About Portals, make it work for you. We all wish that one person could master all that is SharePoint but we also know that doesn’t scale very well and you quickly get into the hit-by-a-bus syndrome (with the organization coming to a full crawl when the guy or girl goes on vacation, gets sick, or pops out a baby). There are too many gaps in SharePoint knowledge to have any one person know it all and too many kittens to juggle all at once. We like to consider ourselves experts in our field, but trying to tackle too many roles at once and we end up being mediocre jack of all trades, master of none. Don't fall into this pit. It's a deep, dark hole you don't want to try to claw your way out of. Trust me. Been there. Done that. Got the t-shirt. In the end I don’t disagree with Joel. SharePoint is a beast and not something that should be taken on by newbies. If you just read “Teach Yourself SharePoint in 24 Hours” and want to go build your corporate intranet or the next killer business solution with all your new found knowledge plan to pony up consultant dollars a few months later when everything goes to Hell in a handbasket and falls over. I’m not saying don’t build solutions in SharePoint. I’m just saying that building effective ones takes skill like any craft and not something you can just cobble together with a little bit of cursory knowledge. Thanks to *everyone* who participated in this tweet rush. It was fun and educational.

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• Dynamic Code for type casting Generic Types 'generically' in C#

  - by Rick Strahl

  C# is a strongly typed language and while that's a fundamental feature of the language there are more and more situations where dynamic types make a lot of sense. I've written quite a bit about how I use dynamic for creating new type extensions: Dynamic Types and DynamicObject References in C# Creating a dynamic, extensible C# Expando Object Creating a dynamic DataReader for dynamic Property Access Today I want to point out an example of a much simpler usage for dynamic that I use occasionally to get around potential static typing issues in C# code especially those concerning generic types. TypeCasting Generics Generic types have been around since .NET 2.0 I've run into a number of situations in the past - especially with generic types that don't implement specific interfaces that can be cast to - where I've been unable to properly cast an object when it's passed to a method or assigned to a property. Granted often this can be a sign of bad design, but in at least some situations the code that needs to be integrated is not under my control so I have to make due with what's available or the parent object is too complex or intermingled to be easily refactored to a new usage scenario. Here's an example that I ran into in my own RazorHosting library - so I have really no excuse, but I also don't see another clean way around it in this case. A Generic Example Imagine I've implemented a generic type like this: public class RazorEngine<TBaseTemplateType> where TBaseTemplateType : RazorTemplateBase, new() You can now happily instantiate new generic versions of this type with custom template bases or even a non-generic version which is implemented like this: public class RazorEngine : RazorEngine<RazorTemplateBase> { public RazorEngine() : base() { } } To instantiate one: var engine = new RazorEngine<MyCustomRazorTemplate>(); Now imagine that the template class receives a reference to the engine when it's instantiated. This code is fired as part of the Engine pipeline when it gets ready to execute the template. It instantiates the template and assigns itself to the template: var template = new TBaseTemplateType() { Engine = this } The problem here is that possibly many variations of RazorEngine<T> can be passed. I can have RazorTemplateBase, RazorFolderHostTemplateBase, CustomRazorTemplateBase etc. as generic parameters and the Engine property has to reflect that somehow. So, how would I cast that? My first inclination was to use an interface on the engine class and then cast to the interface.  Generally that works, but unfortunately here the engine class is generic and has a few members that require the template type in the member signatures. So while I certainly can implement an interface: public interface IRazorEngine<TBaseTemplateType> it doesn't really help for passing this generically templated object to the template class - I still can't cast it if multiple differently typed versions of the generic type could be passed. I have the exact same issue in that I can't specify a 'generic' generic parameter, since there's no underlying base type that's common. In light of this I decided on using object and the following syntax for the property (and the same would be true for a method parameter): public class RazorTemplateBase :MarshalByRefObject,IDisposable { public object Engine {get;set; } } Now because the Engine property is a non-typed object, when I need to do something with this value, I still have no way to cast it explicitly. What I really would need is: public RazorEngine<> Engine { get; set; } but that's not possible. Dynamic to the Rescue Luckily with the dynamic type this sort of thing can be mitigated fairly easily. For example here's a method that uses the Engine property and uses the well known class interface by simply casting the plain object reference to dynamic and then firing away on the properties and methods of the base template class that are common to all templates:/// <summary> /// Allows rendering a dynamic template from a string template /// passing in a model. This is like rendering a partial /// but providing the input as a /// </summary> public virtual string RenderTemplate(string template,object model) { if (template == null) return string.Empty; // if there's no template markup if(!template.Contains("@")) return template; // use dynamic to get around generic type casting dynamic engine = Engine; string result = engine.RenderTemplate(template, model); if (result == null) throw new ApplicationException("RenderTemplate failed: " + engine.ErrorMessage); return result; } Prior to .NET 4.0  I would have had to use Reflection for this sort of thing which would have a been a heck of a lot more verbose, but dynamic makes this so much easier and cleaner and in this case at least the overhead is negliable since it's a single dynamic operation on an otherwise very complex operation call. Dynamic as  a Bailout Sometimes this sort of thing often reeks of a design flaw, and I agree that in hindsight this could have been designed differently. But as is often the case this particular scenario wasn't planned for originally and removing the generic signatures from the base type would break a ton of other code in the framework. Given the existing fairly complex engine design, refactoring an interface to remove generic types just to make this particular code work would have been overkill. Instead dynamic provides a nice and simple and relatively clean solution. Now if there were many other places where this occurs I would probably consider reworking the code to make this cleaner but given this isolated instance and relatively low profile operation use of dynamic seems a valid choice for me. This solution really works anywhere where you might end up with an inheritance structure that doesn't have a common base or interface that is sufficient. In the example above I know what I'm getting but there's no common base type that I can cast to. All that said, it's a good idea to think about use of dynamic before you rush in. In many situations there are alternatives that can still work with static typing. Dynamic definitely has some overhead compared to direct static access of objects, so if possible we should definitely stick to static typing. In the example above the application already uses dynamics extensively for dynamic page page templating and passing models around so introducing dynamics here has very little additional overhead. The operation itself also fires of a fairly resource heavy operation where the overhead of a couple of dynamic member accesses are not a performance issue. So, what's your experience with dynamic as a bailout mechanism? © Rick Strahl, West Wind Technologies, 2005-2012Posted in CSharp   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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• Networking in VirtualBox

  - by Fat Bloke

  Networking in VirtualBox is extremely powerful, but can also be a bit daunting, so here's a quick overview of the different ways you can setup networking in VirtualBox, with a few pointers as to which configurations should be used and when. VirtualBox allows you to configure up to 8 virtual NICs (Network Interface Controllers) for each guest vm (although only 4 are exposed in the GUI) and for each of these NICs you can configure: Which virtualized NIC-type is exposed to the Guest. Examples include: Intel PRO/1000 MT Server (82545EM),  AMD PCNet FAST III (Am79C973, the default) or  a Paravirtualized network adapter (virtio-net). How the NIC operates with respect to your Host's physical networking. The main modes are: Network Address Translation (NAT) Bridged networking Internal networking Host-only networking NAT with Port-forwarding The choice of NIC-type comes down to whether the guest has drivers for that NIC.  VirtualBox, suggests a NIC based on the guest OS-type that you specify during creation of the vm, and you rarely need to modify this. But the choice of networking mode depends on how you want to use your vm (client or server) and whether you want other machines on your network to see it. So let's look at each mode in a bit more detail... Network Address Translation (NAT) This is the default mode for new vm's and works great in most situations when the Guest is a "client" type of vm. (i.e. most network connections are outbound). Here's how it works: When the guest OS boots,  it typically uses DHCP to get an IP address. VirtualBox will field this DHCP request and tell the guest OS its assigned IP address and the gateway address for routing outbound connections. In this mode, every vm is assigned the same IP address (10.0.2.15) because each vm thinks they are on their own isolated network. And when they send their traffic via the gateway (10.0.2.2) VirtualBox rewrites the packets to make them appear as though they originated from the Host, rather than the Guest (running inside the Host). This means that the Guest will work even as the Host moves from network to network (e.g. laptop moving between locations), and from wireless to wired connections too. However, how does another computer initiate a connection into a Guest?  e.g. connecting to a web server running in the Guest. This is not (normally) possible using NAT mode as there is no route into the Guest OS. So for vm's running servers we need a different networking mode.... Bridged Networking Bridged Networking is used when you want your vm to be a full network citizen, i.e. to be an equal to your host machine on the network. In this mode, a virtual NIC is "bridged" to a physical NIC on your host, like this: The effect of this is that each VM has access to the physical network in the same way as your host. It can access any service on the network such as external DHCP services, name lookup services, and routing information just as the host does. Logically, the network looks like this: The downside of this mode is that if you run many vm's you can quickly run out of IP addresses or your network administrator gets fed up with you asking for statically assigned IP addresses. Secondly, if your host has multiple physical NICs (e.g. Wireless and Wired) you must reconfigure the bridge when your host jumps networks.  Hmm, so what if you want to run servers in vm's but don't want to involve your network administrator? Maybe one of the next 2 modes is for you... Internal Networking When you configure one or more vm's to sit on an Internal network, VirtualBox ensures that all traffic on that network stays within the host and is only visible to vm's on that virtual network. Configuration looks like this: The internal network ( in this example "intnet" ) is a totally isolated network and so is very "quiet". This is good for testing when you need a separate, clean network, and you can create sophisticated internal networks with vm's that provide their own services to the internal network. (e.g. Active Directory, DHCP, etc). Note that not even the Host is a member of the internal network, but this mode allows vm's to function even when the Host is not connected to a network (e.g. on a plane). Note that in this mode, VirtualBox provides no "convenience" services such as DHCP, so your machines must be statically configured or one of the vm's needs to provide a DHCP/Name service. Multiple internal networks are possible and you can configure vm's to have multiple NICs to sit across internal and other network modes and thereby provide routes if needed. But all this sounds tricky. What if you want an Internal Network that the host participates on with VirtualBox providing IP addresses to the Guests? Ah, then for this, you might want to consider Host-only Networking... Host-only Networking Host-only Networking is like Internal Networking in that you indicate which network the Guest sits on, in this case, "vboxnet0": All vm's sitting on this "vboxnet0" network will see each other, and additionally, the host can see these vm's too. However, other external machines cannot see Guests on this network, hence the name "Host-only". Logically, the network looks like this: This looks very similar to Internal Networking but the host is now on "vboxnet0" and can provide DHCP services. To configure how a Host-only network behaves, look in the VirtualBox Manager...Preferences...Network dialog: Port-Forwarding with NAT Networking Now you may think that we've provided enough modes here to handle every eventuality but here's just one more... What if you cart around a mobile-demo or dev environment on, say, a laptop and you have one or more vm's that you need other machines to connect into? And you are continually hopping onto different (customer?) networks. In this scenario: NAT - won't work because external machines need to connect in. Bridged - possibly an option, but does your customer want you eating IP addresses and can your software cope with changing networks? Internal - we need the vm(s) to be visible on the network, so this is no good. Host-only - same problem as above, we want external machines to connect in to the vm's. Enter Port-forwarding to save the day! Configure your vm's to use NAT networking; Add Port Forwarding rules; External machines connect to "host":"port number" and connections are forwarded by VirtualBox to the guest:port number specified. For example, if your vm runs a web server on port 80, you could set up rules like this:  ...which reads: "any connections on port 8080 on the Host will be forwarded onto this vm's port 80".  This provides a mobile demo system which won't need re-configuring every time you open your laptop lid. Summary VirtualBox has a very powerful set of options allowing you to set up almost any configuration your heart desires. For more information, check out the VirtualBox User Manual on Virtual Networking. -FB 

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• CodePlex Daily Summary for Sunday, April 18, 2010

  CodePlex Daily Summary for Sunday, April 18, 2010New ProjectsBare Bones Email Trace Listener: Bare Bones Email Trace Listener is about the simplest email trace listener you can have. No bells, no whistles, and no good if you need authenticat...Cartellino: Scopo del progetto è la realizzazione di un software in grado di rilevare i dati dai rilevatori 3Tec (www.3tec.it) e stampare i cartellini presenza...Castle Windsor app.config Properties: The Castle Windsor app.config Properties library makes it possible for users of Castle Windsor to reference appSettings values in Windsor's XML pro...DeskD: This is a simple desktop dictionary application(something like WordWeb) created in Java using Netbeans IDE. Since i am new to codeplex all updates ...FunPokerMakerOnline: It is a play of poker online with a game editor. It is done with .net 4 and WPF and SOAP or WCF. KLOCS Team GIN Project: This is a Master's Degree program group project. It may have academic interest, but won't be maintained after June 2010KNN: This is KNN projectProject Santa: Program to organize teams using mysql databases and c# in a clean and robust task and group system. For more information see my blog post at http:/...ProjetoIntegradoJuridico: Sistema Integrado de Acompanhamento JurídicoRSSR for Windows Phone 7: This is a simple RSS reader application, the project aims to show people that it is easy to build application for windows phones. The applicatio...Simple Rcon: Simple Rcon is a simple lightweight rcon client for HL1/HL2 Servers. It is developed in C# and WPFTAB METHOD SQL Create a data dictionary from your Transact SQL code: TABMETHODSQL makes it easier for data/information workers to document their work. Create a data governance solution that maps sql data process, inc...TM BF Tournament: WPF software to manage Trackmania tournament with Battle France RulesviBlog: visinia plugin, this plugin is used to add blogging facility in visinia cmsviNews: visinia plugin, this plugin can be used to create a news portal like cnn.com nytimeVolumeMaster: VolumeMaster is an On Screen Display (OSD) that gets activated whenever the volume changes. It's written in WPF and uses Vista Core Audio API by Ra...WiiCIS.NET: This is a managed port of WiiCIS, which is a Nintendo Wiimote library originally created by TheOboeNerd and posted on Sourceforge.New ReleasesCastle Windsor app.config Properties: Version 1.0: Initial release.Code for Rapid C# Windows Development eBook: Enumerable Debugger Visualizer Version 1.1: Second release of the Enumerable Debugger Visualizer. There are more classes registered and it is more robust. The list of classes I have register...Convection Game Engine (Basic Edition): Convection Basic (40223): Compiled version of Convection Basic change set 40223.CycleMania Starter Kit EAP - ASP.NET 4 Problem - Design - Solution: Cyclemania 0.08.59: See Source Code tab for recent change history.DbEntry.Net (Lephone Framework): DbEntry.Net 3.9: DbEntry.Net is a lightweight Object Relational Mapping (ORM) database access compnent for .Net 3.5. It has clearly and easily programing interface ...Hash Calculator: HashCalculator 2.0: Upgraded to .NET Framework 4.0 Added support to calculate CRC32 hash function Added "Cancel" button in the Windows 7 taskbar thumbnailHKGolden Express: HKGoldenExpress (Build 201004172120): New features: Added jump links at top of page of message. Bug fix: Fixed page count bug. Improvements: HKGolden Express now uses DocumentBuild...HTML Ruby: 6.21.4: Styles added to override those on some sites for better rendering of ruby Fix regression on complex ruby annotation rendering Better spacingHTML Ruby: 6.21.5: Removed debug code in preference handling Status bar indicator now resets for each action Replace ruby in place without using document fragment...IceChat: IceChat 2009 Alpha 12.4 EXE Update: This is simply an update to the main IceChat program files and DLL. Simpply overwrite the ones in the place where IceChat 2009 is installed.IceChat: IceChat 2009 Alpha 12.4 Full Install: Build Alpha 12.4 - April 17 2010 Added IceChatScript.dll , needs to be added in same folder with EXE and IPluginIceChat.dll Added Self Notice in ...PokeIn Comet Ajax Library: PokeIn Library v05 x64: With this version, PokeIn library has become a stable. Numerous tests have completed. This is the first release candidate of PokeIn. Cheers!PokeIn Comet Ajax Library: PokeIn Library v05 x86: PokeIn Library version 0.5 (x86) With this version, PokeIn library has become a stable. Numerous tests have completed. This is the first release c...Project Santa: Project Santa V1.0: The first initial release of my project manager program, for more information see http://coderplex.blogspot.com/2010/04/project-manager-using-mysq...Salient: TestingWithVSDevServer v1: Using code from Salient, I have assembled a few strategies for programmatic contol of the Visual Studio Development Server (WebDev.WebServer.exe). ...SharePoint Navigation Menu: spNavigationMenu 1.1: Changed the CAML query so it will order by Link Order, then Title. Added the ability to override the On Hover event on the parent menu to use On ...Simple Rcon: Simple Rcon Version 1: Version 1TAB METHOD SQL Create a data dictionary from your Transact SQL code: RELEASE 1: TESTING THE RELEASE SYSTEMTribe.Cache: Tribe.Cache Beta 0.1: Beta release of Tribe.Cache - Now with cache expiration serviceviBlog: viBlog_beta: visinia plugin to add blogging facility in visinia cmsviNews: viNews_beta: visinia plugin.visinia: visinia_beta2: visinia beta 2 released with many new feature.Visual Studio DSite: Visual C++ 2008 Login Form: A simple login form made in visual c 2008. Source code only.WiiCIS.NET: WiiCIS.NET v0.11: 0.11 Removed an unnecessary function from the Wiimote class, and improved the demo. You will need the latest version of SlimDX to compile the sourc...WinControls TreeListView: TreeListView 1.5.1: -fixes issue #5837 -Preliminary feature #5874WoW Character Viewer: Viewer Setup: Finally, I've brought out the next setup of WoW Viewer. Most loose ends have been tied up. Loading and Saving of character files has been fixed.Most Popular ProjectsRawrAJAX Control ToolkitMicrosoft SQL Server Product Samples: DatabaseMicrosoft SQL Server Community & Samplespatterns & practices – Enterprise LibraryPHPExcelFacebook Developer ToolkitBlogEngine.NETMvcContrib: a Codeplex Foundation projectIronPythonMost Active ProjectsRawrpatterns & practices – Enterprise LibraryIndustrial DashboardFarseer Physics EnginejQuery Library for SharePoint Web ServicesIonics Isapi Rewrite FilterGMap.NET - Great Maps for Windows Forms & PresentationProxi [Proxy Interface]BlogEngine.NETCaliburn: An Application Framework for WPF and Silverlight

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• Adding RSS to tags in Orchard

  - by Bertrand Le Roy

  A year ago, I wrote a scary post about RSS in Orchard. RSS was one of the first features we implemented in our CMS, and it has stood the test of time rather well, but the post was explaining things at a level that was probably too abstract whereas my readers were expecting something a little more practical. Well, this post is going to correct this by showing how I built a module that adds RSS feeds for each tag on the site. Hopefully it will show that it's not very complicated in practice, and also that the infrastructure is pretty well thought out. In order to provide RSS, we need to do two things: generate the XML for the feed, and inject the address of that feed into the existing tag listing page, in order to make the feed discoverable. Let's start with the discoverability part. One might be tempted to replace the controller or the view that are responsible for the listing of the items under a tag. Fortunately, there is no need to do any of that, and we can be a lot less obtrusive. Instead, we can implement a filter: public class TagRssFilter : FilterProvider, IResultFilter .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } On this filter, we can implement the OnResultExecuting method and simply check whether the current request is targeting the list of items under a tag. If that is the case, we can just register our new feed: public void OnResultExecuting(ResultExecutingContext filterContext) { var routeValues = filterContext.RouteData.Values; if (routeValues["area"] as string == "Orchard.Tags" && routeValues["controller"] as string == "Home" && routeValues["action"] as string == "Search") { var tag = routeValues["tagName"] as string; if (! string.IsNullOrWhiteSpace(tag)) { var workContext = _wca.GetContext(); _feedManager.Register( workContext.CurrentSite + " – " + tag, "rss", new RouteValueDictionary { { "tag", tag } } ); } } } The registration of the new feed is just specifying the title of the feed, its format (RSS) and the parameters that it will need (the tag). _wca and _feedManager are just instances of IWorkContextAccessor and IFeedManager that Orchard injected for us. That is all that's needed to get the following tag to be added to the head of our page, without touching an existing controller or view: <link rel="alternate" type="application/rss+xml" title="VuLu - Science" href="/rss?tag=Science"/> Nifty. Of course, if we navigate to the URL of that feed, we'll get a 404. This is because no implementation of IFeedQueryProvider knows about the tag parameter yet. Let's build one that does: public class TagFeedQuery : IFeedQueryProvider, IFeedQuery IFeedQueryProvider has one method, Match, that we can implement to take over any feed request that has a tag parameter: public FeedQueryMatch Match(FeedContext context) { var tagName = context.ValueProvider.GetValue("tag"); if (tagName == null) return null; return new FeedQueryMatch { FeedQuery = this, Priority = -5 }; } This is just saying that if there is a tag parameter, we will handle it. All that remains to be done is the actual building of the feed now that we have accepted to handle it. This is done by implementing the Execute method of the IFeedQuery interface: public void Execute(FeedContext context) { var tagValue = context.ValueProvider.GetValue("tag"); if (tagValue == null) return; var tagName = (string)tagValue.ConvertTo(typeof (string)); var tag = _tagService.GetTagByName(tagName); if (tag == null) return; var site = _services.WorkContext.CurrentSite; var link = new XElement("link"); context.Response.Element.SetElementValue("title", site.SiteName + " - " + tagName); context.Response.Element.Add(link); context.Response.Element.SetElementValue("description", site.SiteName + " - " + tagName); context.Response.Contextualize(requestContext => link.Add(GetTagUrl(tagName, requestContext))); var items = _tagService.GetTaggedContentItems(tag.Id, 0, 20); foreach (var item in items) { context.Builder.AddItem(context, item.ContentItem); } } This code is resolving the tag content item from its name and then gets content items tagged with it, using the tag services provided by the Orchard.Tags module. Then we add those items to the feed. And that is it. To summarize, we handled the request unobtrusively in order to inject the feed's link, then handled requests for feeds with a tag parameter and generated the list of items for that tag. It remains fairly simple and still it is able to handle arbitrary content types. That makes me quite happy about our little piece of over-engineered code from last year. The full code for this can be found in the Vandelay.TagCloud module: http://orchardproject.net/gallery/List/Modules/ Orchard.Module.Vandelay.TagCloud/1.2

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• Using JDialog with Tabbed Pane to draw different pictures [migrated]

  - by Bryam Ulloa

  I am using NetBeans, and I have a class that extends to JDialog, inside that Dialog box I have created a Tabbed Pane. The Tabbed Pane contains 6 different tabs, with 6 different panels of course. What I want to do is when I click on the different tabs, a diagram is supposed to be drawn with the paint method. My question is how can I draw on the different panels with just one paint method in another class being called from the Dialog class? Here is my code for the Dialog class: package GUI; public class NewJDialog extends javax.swing.JDialog{ /** * Creates new form NewJDialog */ public NewJDialog(java.awt.Frame parent, boolean modal) { super(parent, modal); initComponents(); } /** * This method is called from within the constructor to initialize the form. * WARNING: Do NOT modify this code. The content of this method is always * regenerated by the Form Editor. */ @SuppressWarnings("unchecked") // <editor-fold defaultstate="collapsed" desc="Generated Code"> private void initComponents() { jTabbedPane1 = new javax.swing.JTabbedPane(); jPanel1 = new javax.swing.JPanel(); jPanel2 = new javax.swing.JPanel(); jPanel3 = new javax.swing.JPanel(); jPanel4 = new javax.swing.JPanel(); jPanel5 = new javax.swing.JPanel(); jPanel6 = new javax.swing.JPanel(); jPanel7 = new javax.swing.JPanel(); jLabel1 = new javax.swing.JLabel(); jLabel2 = new javax.swing.JLabel(); setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE); javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1); jPanel1.setLayout(jPanel1Layout); jPanel1Layout.setHorizontalGroup( jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 466, Short.MAX_VALUE) ); jPanel1Layout.setVerticalGroup( jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 242, Short.MAX_VALUE) ); jTabbedPane1.addTab("FCFS", jPanel1); javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2); jPanel2.setLayout(jPanel2Layout); jPanel2Layout.setHorizontalGroup( jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 466, Short.MAX_VALUE) ); jPanel2Layout.setVerticalGroup( jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 242, Short.MAX_VALUE) ); jTabbedPane1.addTab("SSTF", jPanel2); javax.swing.GroupLayout jPanel3Layout = new javax.swing.GroupLayout(jPanel3); jPanel3.setLayout(jPanel3Layout); jPanel3Layout.setHorizontalGroup( jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 466, Short.MAX_VALUE) ); jPanel3Layout.setVerticalGroup( jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 242, Short.MAX_VALUE) ); jTabbedPane1.addTab("LOOK", jPanel3); javax.swing.GroupLayout jPanel4Layout = new javax.swing.GroupLayout(jPanel4); jPanel4.setLayout(jPanel4Layout); jPanel4Layout.setHorizontalGroup( jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 466, Short.MAX_VALUE) ); jPanel4Layout.setVerticalGroup( jPanel4Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 242, Short.MAX_VALUE) ); jTabbedPane1.addTab("LOOK C", jPanel4); javax.swing.GroupLayout jPanel5Layout = new javax.swing.GroupLayout(jPanel5); jPanel5.setLayout(jPanel5Layout); jPanel5Layout.setHorizontalGroup( jPanel5Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 466, Short.MAX_VALUE) ); jPanel5Layout.setVerticalGroup( jPanel5Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 242, Short.MAX_VALUE) ); jTabbedPane1.addTab("SCAN", jPanel5); javax.swing.GroupLayout jPanel6Layout = new javax.swing.GroupLayout(jPanel6); jPanel6.setLayout(jPanel6Layout); jPanel6Layout.setHorizontalGroup( jPanel6Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 466, Short.MAX_VALUE) ); jPanel6Layout.setVerticalGroup( jPanel6Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 242, Short.MAX_VALUE) ); jTabbedPane1.addTab("SCAN C", jPanel6); getContentPane().add(jTabbedPane1, java.awt.BorderLayout.CENTER); jLabel1.setText("Distancia:"); jLabel2.setText("___________"); javax.swing.GroupLayout jPanel7Layout = new javax.swing.GroupLayout(jPanel7); jPanel7.setLayout(jPanel7Layout); jPanel7Layout.setHorizontalGroup( jPanel7Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(jPanel7Layout.createSequentialGroup() .addGap(21, 21, 21) .addComponent(jLabel1) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(jLabel2) .addContainerGap(331, Short.MAX_VALUE)) ); jPanel7Layout.setVerticalGroup( jPanel7Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(jPanel7Layout.createSequentialGroup() .addContainerGap() .addGroup(jPanel7Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) .addComponent(jLabel1) .addComponent(jLabel2)) .addContainerGap(15, Short.MAX_VALUE)) ); getContentPane().add(jPanel7, java.awt.BorderLayout.PAGE_START); pack(); }// </editor-fold> /** * @param args the command line arguments */ public static void main(String args[]) { /* Set the Nimbus look and feel */ //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) "> /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel. * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html */ try { for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) { if ("Nimbus".equals(info.getName())) { javax.swing.UIManager.setLookAndFeel(info.getClassName()); break; } } } catch (ClassNotFoundException ex) { java.util.logging.Logger.getLogger(NewJDialog.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); } catch (InstantiationException ex) { java.util.logging.Logger.getLogger(NewJDialog.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); } catch (IllegalAccessException ex) { java.util.logging.Logger.getLogger(NewJDialog.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); } catch (javax.swing.UnsupportedLookAndFeelException ex) { java.util.logging.Logger.getLogger(NewJDialog.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); } //</editor-fold> /* Create and display the dialog */ java.awt.EventQueue.invokeLater(new Runnable() { public void run() { NewJDialog dialog = new NewJDialog(new javax.swing.JFrame(), true); dialog.addWindowListener(new java.awt.event.WindowAdapter() { @Override public void windowClosing(java.awt.event.WindowEvent e) { System.exit(0); } }); dialog.setVisible(true); } }); } // Variables declaration - do not modify private javax.swing.JLabel jLabel1; private javax.swing.JLabel jLabel2; private javax.swing.JPanel jPanel1; private javax.swing.JPanel jPanel2; private javax.swing.JPanel jPanel3; private javax.swing.JPanel jPanel4; private javax.swing.JPanel jPanel5; private javax.swing.JPanel jPanel6; private javax.swing.JPanel jPanel7; private javax.swing.JTabbedPane jTabbedPane1; // End of variables declaration } This is another class that I have created for the paint method: package GUI; import java.awt.Graphics; import javax.swing.JPanel; /** * * @author TOSHIBA */ public class Lienzo { private int width = 5; private int height = 5; private int y = 5; private int x = 0; private int x1 = 0; public Graphics Draw(Graphics g, int[] pistas) { //Im not sure if this is the correct way to do it //The diagram gets drawn according to values from an array //The array is not always the same thats why I used the different Panels for (int i = 0; i < pistas.length; i++) { x = pistas[i]; x1 = pistas[i + 1]; g.drawOval(x, y, width, height); g.drawString(Integer.toString(x), x, y); g.drawLine(x, y, x1, y); } return g; } } I hope you guys understand what I am trying to do with my program.

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• Generate Strongly Typed Observable Events for the Reactive Extensions for .NET (Rx)

  - by Bobby Diaz

  I must have tried reading through the various explanations and introductions to the new Reactive Extensions for .NET before the concepts finally started sinking in.  The article that gave me the ah-ha moment was over on SilverlightShow.net and titled Using Reactive Extensions in Silverlight.  The author did a good job comparing the "normal" way of handling events vs. the new "reactive" methods. Admittedly, I still have more to learn about the Rx Framework, but I wanted to put together a sample project so I could start playing with the new Observable and IObservable<T> constructs.  I decided to throw together a whiteboard application in Silverlight based on the Drawing with Rx example on the aforementioned article.  At the very least, I figured I would learn a thing or two about a new technology, but my real goal is to create a fun application that I can share with the kids since they love drawing and coloring so much! Here is the code sample that I borrowed from the article: var mouseMoveEvent = Observable.FromEvent<MouseEventArgs>(this, "MouseMove"); var mouseLeftButtonDown = Observable.FromEvent<MouseButtonEventArgs>(this, "MouseLeftButtonDown"); var mouseLeftButtonUp = Observable.FromEvent<MouseButtonEventArgs>(this, "MouseLeftButtonUp");       var draggingEvents = from pos in mouseMoveEvent                              .SkipUntil(mouseLeftButtonDown)                              .TakeUntil(mouseLeftButtonUp)                              .Let(mm => mm.Zip(mm.Skip(1), (prev, cur) =>                                  new                                  {                                      X2 = cur.EventArgs.GetPosition(this).X,                                      X1 = prev.EventArgs.GetPosition(this).X,                                      Y2 = cur.EventArgs.GetPosition(this).Y,                                      Y1 = prev.EventArgs.GetPosition(this).Y                                  })).Repeat()                          select pos;       draggingEvents.Subscribe(p =>     {         Line line = new Line();         line.Stroke = new SolidColorBrush(Colors.Black);         line.StrokeEndLineCap = PenLineCap.Round;         line.StrokeLineJoin = PenLineJoin.Round;         line.StrokeThickness = 5;         line.X1 = p.X1;         line.Y1 = p.Y1;         line.X2 = p.X2;         line.Y2 = p.Y2;         this.LayoutRoot.Children.Add(line);     }); One thing that was nagging at the back of my mind was having to deal with the event names as strings, as well as the verbose syntax for the Observable.FromEvent<TEventArgs>() method.  I came up with a couple of static/helper classes to resolve both issues and also created a T4 template to auto-generate these helpers for any .NET type.  Take the following code from the above example: var mouseMoveEvent = Observable.FromEvent<MouseEventArgs>(this, "MouseMove"); var mouseLeftButtonDown = Observable.FromEvent<MouseButtonEventArgs>(this, "MouseLeftButtonDown"); var mouseLeftButtonUp = Observable.FromEvent<MouseButtonEventArgs>(this, "MouseLeftButtonUp"); Turns into this with the new static Events class: var mouseMoveEvent = Events.Mouse.Move.On(this); var mouseLeftButtonDown = Events.Mouse.LeftButtonDown.On(this); var mouseLeftButtonUp = Events.Mouse.LeftButtonUp.On(this); Or better yet, just remove the variable declarations altogether:     var draggingEvents = from pos in Events.Mouse.Move.On(this)                              .SkipUntil(Events.Mouse.LeftButtonDown.On(this))                              .TakeUntil(Events.Mouse.LeftButtonUp.On(this))                              .Let(mm => mm.Zip(mm.Skip(1), (prev, cur) =>                                  new                                  {                                      X2 = cur.EventArgs.GetPosition(this).X,                                      X1 = prev.EventArgs.GetPosition(this).X,                                      Y2 = cur.EventArgs.GetPosition(this).Y,                                      Y1 = prev.EventArgs.GetPosition(this).Y                                  })).Repeat()                          select pos; The Move, LeftButtonDown and LeftButtonUp members of the Events.Mouse class are readonly instances of the ObservableEvent<TTarget, TEventArgs> class that provide type-safe access to the events via the On() method.  Here is the code for the class: using System; using System.Collections.Generic; using System.Linq;   namespace System.Linq {     /// <summary>     /// Represents an event that can be managed via the <see cref="Observable"/> API.     /// </summary>     /// <typeparam name="TTarget">The type of the target.</typeparam>     /// <typeparam name="TEventArgs">The type of the event args.</typeparam>     public class ObservableEvent<TTarget, TEventArgs> where TEventArgs : EventArgs     {         /// <summary>         /// Initializes a new instance of the <see cref="ObservableEvent"/> class.         /// </summary>         /// <param name="eventName">Name of the event.</param>         protected ObservableEvent(String eventName)         {             EventName = eventName;         }           /// <summary>         /// Registers the specified event name.         /// </summary>         /// <param name="eventName">Name of the event.</param>         /// <returns></returns>         public static ObservableEvent<TTarget, TEventArgs> Register(String eventName)         {             return new ObservableEvent<TTarget, TEventArgs>(eventName);         }           /// <summary>         /// Creates an enumerable sequence of event values for the specified target.         /// </summary>         /// <param name="target">The target.</param>         /// <returns></returns>         public IObservable<IEvent<TEventArgs>> On(TTarget target)         {             return Observable.FromEvent<TEventArgs>(target, EventName);         }           /// <summary>         /// Gets or sets the name of the event.         /// </summary>         /// <value>The name of the event.</value>         public string EventName { get; private set; }     } } And this is how it's used:     /// <summary>     /// Categorizes <see cref="ObservableEvents"/> by class and/or functionality.     /// </summary>     public static partial class Events     {         /// <summary>         /// Implements a set of predefined <see cref="ObservableEvent"/>s         /// for the <see cref="System.Windows.System.Windows.UIElement"/> class         /// that represent mouse related events.         /// </summary>         public static partial class Mouse         {             /// <summary>Represents the MouseMove event.</summary>             public static readonly ObservableEvent<UIElement, MouseEventArgs> Move =                 ObservableEvent<UIElement, MouseEventArgs>.Register("MouseMove");               // additional members omitted...         }     } The source code contains a static Events class with prefedined members for various categories (Key, Mouse, etc.).  There is also an Events.tt template that you can customize to generate additional event categories for any .NET type.  All you should have to do is add the name of your class to the types collection near the top of the template:     types = new Dictionary<String, Type>()     {         //{ "Microsoft.Maps.MapControl.Map, Microsoft.Maps.MapControl", null }         { "System.Windows.FrameworkElement, System.Windows", null },         { "Whiteboard.MainPage, Whiteboard", null }     }; The template is also a bit rough at this point, but at least it generates code that *should* compile.  Please let me know if you run into any issues with it.  Some people have reported errors when trying to use T4 templates within a Silverlight project, but I was able to get it to work with a little black magic...  You can download the source code for this project or play around with the live demo.  Just be warned that it is at a very early stage so don't expect to find much today.  I plan on adding alot more options like pen colors and sizes, saving, printing, etc. as time permits.  HINT: hold down the ESC key to erase! Enjoy! Additional Resources Using Reactive Extensions in Silverlight DevLabs: Reactive Extensions for .NET (Rx) Rx Framework Part III - LINQ to Events - Generating GetEventName() Wrapper Methods using T4

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• Documenting C# Library using GhostDoc and SandCastle

  - by sreejukg

  Documentation is an essential part of any IT project, especially when you are creating reusable components that will be used by other developers (such as class libraries). Without documentation re-using a class library is almost impossible. Just think of coding .net applications without MSDN documentation (Ooops I can’t think of it). Normally developers, who know the bits and pieces of their classes, see this as a boring work to write details again to generate the documentation. Also the amount of work to make this and manage it changes made the process of manual creation of Documentation impossible or tedious. So what is the effective solution? Let me divide this into two steps 1. Generate comments for your code while you are writing the code. 2. Create documentation file using these comments. Now I am going to examine these processes. Step 1: Generate XML Comments automatically Most of the developers write comments for their code. The best thing is that the comments will be entered during the development process. Additionally comments give a good reference to the code, make your code more manageable/readable. Later these comments can be converted into documentation, along with your source code by identifying properties and methods I found an add-in for visual studio, GhostDoc that automatically generates XML documentation comments for C#. The add-in is available in Visual Studio Gallery at MSDN. You can download this from the url http://visualstudiogallery.msdn.microsoft.com/en-us/46A20578-F0D5-4B1E-B55D-F001A6345748. I downloaded the free version from the above url. The free version suits my requirement. There is a professional version (you need to pay some $ for this) available that gives you some more features. I found the free version itself suits my requirements. The installation process is straight forward. A couple of clicks will do the work for you. The best thing with GhostDoc is that it supports multiple versions of visual studio such as 2005, 2008 and 2010. After Installing GhostDoc, when you start Visual studio, the GhostDoc configuration dialog will appear. The first screen asks you to assign a hot key, pressing this hotkey will enter the comment to your code file with the necessary structure required by GhostDoc. Click Assign to go to the next step where you configure the rules for generating the documentation from the code file. Click Create to start creating the rules. Click finish button to close this wizard. Now you performed the necessary configuration required by GhostDoc. Now In Visual Studio tools menu you can find the GhostDoc that gives you some options. Now let us examine how GhostDoc generate comments for a method. I have write the below code in my code behind file. public Char GetChar(string str, int pos) { return str[pos]; } Now I need to generate the comments for this function. Select the function and enter the hot key assigned during the configuration. GhostDoc will generate the comments as follows. /// <summary> /// Gets the char. /// </summary> /// <param name="str">The STR.</param> /// <param name="pos">The pos.</param> /// <returns></returns> public Char GetChar(string str, int pos) { return str[pos]; } So this is a very handy tool that helps developers writing comments easily. You can generate the xml documentation file separately while compiling the project. This will be done by the C# compiler. You can enable the xml documentation creation option (checkbox) under Project properties -> Build tab. Now when you compile, the xml file will created under the bin folder. Step 2: Generate the documentation from the XML file Now you have generated the xml file documentation. Sandcastle is the tool from Microsoft that generates MSDN style documentation from the compiler produced XML file. The project is available in codeplex http://sandcastle.codeplex.com/. Download and install Sandcastle to your computer. Sandcastle is a command line tool that doesn’t have a rich GUI. If you want to automate the documentation generation, definitely you will be using the command line tools. Since I want to generate the documentation from the xml file generated in the previous step, I was expecting a GUI where I can see the options. There is a GUI available for Sandcastle called Sandcastle Help File Builder. See the link to the project in codeplex. http://www.codeplex.com/wikipage?ProjectName=SHFB. You need to install Sandcastle and then the Sandcastle Help file builder. From here I assume that you have installed both sandcastle and Sandcastle help file builder successfully. Once you installed the help file builder, it will be available in your all programs list. Click on the Sandcastle Help File Builder GUI, will launch application. First you need to create a project. Click on File -> New project The New project dialog will appear. Choose a folder to store your project file and give a name for your documentation project. Click the save button. Now you will see your project properties. Now from the Project explorer, right click on the Documentation Sources, Click on the Add Documentation Source link. A documentation source is a file such as an assembly or a Visual Studio solution or project from which information will be extracted to produce API documentation. From the Add Documentation source dialog, I have selected the XML file generated by my project. Once you add the xml file to the project, you will see the dll file automatically added by the help file builder. Now click on the build button. Now the application will generate the help file. The Build window gives to the result of each steps. Once the process completed successfully, you will have the following output in the build window. Now navigate to your Help Project (I have selected the folder My Documents\Documentation), inside help folder, you can find the chm file. Open the chm file will give you MSDN like documentation. Documentation is an important part of development life cycle. Sandcastle with GhostDoc make this process easier so that developers can implement the documentation in the projects with simple to use steps.

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• OpenCV install problems on Studio 12.04 - broken dependencies

  - by Will

  I'm trying to follow the Ubuntu OpenCV documentation at OpenCV. The provided script has a line which executed for some time, taking away more packages than I expected (such as ubuntu-studio video); sudo apt-get -qq remove ffmpeg x264 libx264-dev When the script gets to the line below, it bombs; sudo apt-get -qq install libopencv-dev build-essential checkinstall cmake pkg-config yasm libtiff4-dev libjpeg-dev libjasper-dev libavcodec-dev libavformat-dev libswscale-dev libdc1394-22-dev libxine-dev libgstreamer0.10-dev libgstreamer-plugins-base0.10-dev libv4l-dev python-dev python-numpy libtbb-dev libqt4-dev libgtk2.0-dev libfaac-dev libmp3lame-dev libopencore-amrnb-dev libopencore-amrwb-dev libtheora-dev libvorbis-dev libxvidcore-dev x264 v4l-utils ffmpeg The error msg is; E: Unable to correct problems, you have held broken packages. I've since run Update-Manager, run sudo apt-get updates, rebooted, tried the above script line manually, and still no change. I've just run sudo apt-get install -f and nothing seemed to change. It did mention that some packages were no longer needed and could be removed by apt-get autoremove, so I ran that. It removed a number of packages, so I reran the install command above. Still same problem of held broken packages. I just ran sudo apt-get -u dist-upgrade Part of the response was; The following packages have been kept back: gstreamer0.10-ffmpeg I'm not sure what that means. I do know that it shows up in my Update-Manager and cannot be checked I then ran sudo dpkg --configure -a and then reran sudo apt-get -f install and the package was still not upgraded, though there was this very interesting comment; Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: gstreamer0.10-ffmpeg : Depends: libavcodec53 (< 5:0) but it is not going to be installed or libavcodec-extra-53 (< 5:0) but 5:0.7.2-1ubuntu1+codecs1~oneiric2 is to be installed E: Unable to correct problems, you have held broken packages. Then I ran sudo apt-get -u dist-upgrade It showed I had one held package, so I ran; sudo apt-get -o Debug::pkgProblemResolver=yes dist-upgrade It also exited without upgrading the package, so I ran; sudo apt-get remove --dry-run gstreamer0.10-ffmpeg:i386 And it gave me; *The following packages will be REMOVED: arista gstreamer0.10-ffmpeg 0 upgraded, 0 newly installed, 2 to remove and 0 not upgraded. Remv arista [0.9.7-3ubuntu1] Remv gstreamer0.10-ffmpeg [0.10.12-1ubuntu1]* But when I reran sudo apt-get -u dist-upgrade It showed the package was still there. *The following packages have been kept back: gstreamer0.10-ffmpeg 0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.* Update: Just went into Synaptic PM and completely removed gstreamer0.10-ffmpeg Reran sudo apt-get -u dist-upgrade And was told; 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. However, when I ran the original apt-get to install opencv (first code at the top of this question), it still gave me the same broken package errors. So I tried $ cat /etc/apt/sources.list # # deb cdrom:[Ubuntu-Studio 11.10 _Oneiric Ocelot_ - Release i386 (20111011.1)]/ oneiric main multiverse restricted universe # deb cdrom:[Ubuntu-Studio 11.10 _Oneiric Ocelot_ - Release i386 (20111011.1)]/ oneiric main multiverse restricted universe # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to # newer versions of the distribution. deb http://us.archive.ubuntu.com/ubuntu/ precise main restricted deb-src http://us.archive.ubuntu.com/ubuntu/ precise main restricted ## Major bug fix updates produced after the final release of the ## distribution. deb http://us.archive.ubuntu.com/ubuntu/ precise-updates main restricted deb-src http://us.archive.ubuntu.com/ubuntu/ precise-updates main restricted ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team. Also, please note that software in universe WILL NOT receive any ## review or updates from the Ubuntu security team. deb http://us.archive.ubuntu.com/ubuntu/ precise universe deb-src http://us.archive.ubuntu.com/ubuntu/ precise universe deb http://us.archive.ubuntu.com/ubuntu/ precise-updates universe deb-src http://us.archive.ubuntu.com/ubuntu/ precise-updates universe ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team, and may not be under a free licence. Please satisfy yourself as to ## your rights to use the software. Also, please note that software in ## multiverse WILL NOT receive any review or updates from the Ubuntu ## security team. deb http://us.archive.ubuntu.com/ubuntu/ precise multiverse deb-src http://us.archive.ubuntu.com/ubuntu/ precise multiverse deb http://us.archive.ubuntu.com/ubuntu/ precise-updates multiverse deb-src http://us.archive.ubuntu.com/ubuntu/ precise-updates multiverse ## N.B. software from this repository may not have been tested as ## extensively as that contained in the main release, although it includes ## newer versions of some applications which may provide useful features. ## Also, please note that software in backports WILL NOT receive any review ## or updates from the Ubuntu security team. deb http://security.ubuntu.com/ubuntu precise-security main restricted deb-src http://security.ubuntu.com/ubuntu precise-security main restricted deb http://security.ubuntu.com/ubuntu precise-security universe deb-src http://security.ubuntu.com/ubuntu precise-security universe deb http://security.ubuntu.com/ubuntu precise-security multiverse deb-src http://security.ubuntu.com/ubuntu precise-security multiverse ## Uncomment the following two lines to add software from Canonical's ## 'partner' repository. ## This software is not part of Ubuntu, but is offered by Canonical and the ## respective vendors as a service to Ubuntu users. deb http://archive.canonical.com/ubuntu precise partner # deb-src http://archive.canonical.com/ubuntu oneiric partner ## Uncomment the following two lines to add software from Ubuntu's ## 'extras' repository. ## This software is not part of Ubuntu, but is offered by third-party ## developers who want to ship their latest software. # deb http://extras.ubuntu.com/ubuntu oneiric main # deb-src http://extras.ubuntu.com/ubuntu oneiric main # deb http://download.opensuse.org/repositories/home:/popinet/xUbuntu_11.04 ./ # disabled on upgrade to precise and then; $ cat /etc/apt/sources.list.d/* But I don't have enough reputation to post the results here (it says I need at least 10 reputation points to post more than 2 links), so I don't know how to provide the requested feedback. Then tried; $ sudo apt-get check [sudo] password for <abcd>: Reading package lists... Done Building dependency tree Reading state information... Done However, no resolution of the problem yet. What else do I need to do? Will an upgrade to Ubuntu Studio 13.xx solve this problem (or compound it)?

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• Move penetrating OBB out of another OBB to resolve collision

  - by Milo

  I'm working on collision resolution for my game. I just need a good way to get an object out of another object if it gets stuck. In this case a car. Here is a typical scenario. The red car is in the green object. How do I correctly get it out so the car can slide along the edge of the object as it should. I tried: if(buildings.size() > 0) { Entity e = buildings.get(0); Vector2D vel = new Vector2D(); vel.x = vehicle.getVelocity().x; vel.y = vehicle.getVelocity().y; vel.normalize(); while(vehicle.getRect().overlaps(e.getRect())) { vehicle.setCenter(vehicle.getCenterX() - vel.x * 0.1f, vehicle.getCenterY() - vel.y * 0.1f); } colided = true; } But that does not work too well. Is there some sort of vector I could calculate to use as the vector to move the car away from the object? Thanks Here is my OBB2D class: public class OBB2D { // Corners of the box, where 0 is the lower left. private Vector2D corner[] = new Vector2D[4]; private Vector2D center = new Vector2D(); private Vector2D extents = new Vector2D(); private RectF boundingRect = new RectF(); private float angle; //Two edges of the box extended away from corner[0]. private Vector2D axis[] = new Vector2D[2]; private double origin[] = new double[2]; public OBB2D(Vector2D center, float w, float h, float angle) { set(center,w,h,angle); } public OBB2D(float left, float top, float width, float height) { set(new Vector2D(left + (width / 2), top + (height / 2)),width,height,0.0f); } public void set(Vector2D center,float w, float h,float angle) { Vector2D X = new Vector2D( (float)Math.cos(angle), (float)Math.sin(angle)); Vector2D Y = new Vector2D((float)-Math.sin(angle), (float)Math.cos(angle)); X = X.multiply( w / 2); Y = Y.multiply( h / 2); corner[0] = center.subtract(X).subtract(Y); corner[1] = center.add(X).subtract(Y); corner[2] = center.add(X).add(Y); corner[3] = center.subtract(X).add(Y); computeAxes(); extents.x = w / 2; extents.y = h / 2; computeDimensions(center,angle); } private void computeDimensions(Vector2D center,float angle) { this.center.x = center.x; this.center.y = center.y; this.angle = angle; boundingRect.left = Math.min(Math.min(corner[0].x, corner[3].x), Math.min(corner[1].x, corner[2].x)); boundingRect.top = Math.min(Math.min(corner[0].y, corner[1].y),Math.min(corner[2].y, corner[3].y)); boundingRect.right = Math.max(Math.max(corner[1].x, corner[2].x), Math.max(corner[0].x, corner[3].x)); boundingRect.bottom = Math.max(Math.max(corner[2].y, corner[3].y),Math.max(corner[0].y, corner[1].y)); } public void set(RectF rect) { set(new Vector2D(rect.centerX(),rect.centerY()),rect.width(),rect.height(),0.0f); } // Returns true if other overlaps one dimension of this. private boolean overlaps1Way(OBB2D other) { for (int a = 0; a < axis.length; ++a) { double t = other.corner[0].dot(axis[a]); // Find the extent of box 2 on axis a double tMin = t; double tMax = t; for (int c = 1; c < corner.length; ++c) { t = other.corner[c].dot(axis[a]); if (t < tMin) { tMin = t; } else if (t > tMax) { tMax = t; } } // We have to subtract off the origin // See if [tMin, tMax] intersects [0, 1] if ((tMin > 1 + origin[a]) || (tMax < origin[a])) { // There was no intersection along this dimension; // the boxes cannot possibly overlap. return false; } } // There was no dimension along which there is no intersection. // Therefore the boxes overlap. return true; } //Updates the axes after the corners move. Assumes the //corners actually form a rectangle. private void computeAxes() { axis[0] = corner[1].subtract(corner[0]); axis[1] = corner[3].subtract(corner[0]); // Make the length of each axis 1/edge length so we know any // dot product must be less than 1 to fall within the edge. for (int a = 0; a < axis.length; ++a) { axis[a] = axis[a].divide((axis[a].length() * axis[a].length())); origin[a] = corner[0].dot(axis[a]); } } public void moveTo(Vector2D center) { Vector2D centroid = (corner[0].add(corner[1]).add(corner[2]).add(corner[3])).divide(4.0f); Vector2D translation = center.subtract(centroid); for (int c = 0; c < 4; ++c) { corner[c] = corner[c].add(translation); } computeAxes(); computeDimensions(center,angle); } // Returns true if the intersection of the boxes is non-empty. public boolean overlaps(OBB2D other) { if(right() < other.left()) { return false; } if(bottom() < other.top()) { return false; } if(left() > other.right()) { return false; } if(top() > other.bottom()) { return false; } if(other.getAngle() == 0.0f && getAngle() == 0.0f) { return true; } return overlaps1Way(other) && other.overlaps1Way(this); } public Vector2D getCenter() { return center; } public float getWidth() { return extents.x * 2; } public float getHeight() { return extents.y * 2; } public void setAngle(float angle) { set(center,getWidth(),getHeight(),angle); } public float getAngle() { return angle; } public void setSize(float w,float h) { set(center,w,h,angle); } public float left() { return boundingRect.left; } public float right() { return boundingRect.right; } public float bottom() { return boundingRect.bottom; } public float top() { return boundingRect.top; } public RectF getBoundingRect() { return boundingRect; } public boolean overlaps(float left, float top, float right, float bottom) { if(right() < left) { return false; } if(bottom() < top) { return false; } if(left() > right) { return false; } if(top() > bottom) { return false; } return true; } };

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• Segfault when iterating over a map<string, string> and drawing its contents using SDL_TTF

  - by Michael Stahre

  I'm not entirely sure this question belongs on gamedev.stackexchange, but I'm technically working on a game and working with SDL, so it might not be entirely offtopic. I've written a class called DebugText. The point of the class is to have a nice way of printing values of variables to the game screen. The idea is to call SetDebugText() with the variables in question every time they change or, as is currently the case, every time the game's Update() is called. The issue is that when iterating over the map that contains my variables and their latest updated values, I get segfaults. See the comments in DrawDebugText() below, it specifies where the error happens. I've tried splitting the calls to it-first and it-second into separate lines and found that the problem doesn't always happen when calling it-first. It alters between it-first and it-second. I can't find a pattern. It doesn't fail on every call to DrawDebugText() either. It might fail on the third time DrawDebugText() is called, or it might fail on the fourth. Class header: #ifndef CLIENT_DEBUGTEXT_H #define CLIENT_DEBUGTEXT_H #include <Map> #include <Math.h> #include <sstream> #include <SDL.h> #include <SDL_ttf.h> #include "vector2.h" using std::string; using std::stringstream; using std::map; using std::pair; using game::Vector2; namespace game { class DebugText { private: TTF_Font* debug_text_font; map<string, string>* debug_text_list; public: void SetDebugText(string var, bool value); void SetDebugText(string var, float value); void SetDebugText(string var, int value); void SetDebugText(string var, Vector2 value); void SetDebugText(string var, string value); int DrawDebugText(SDL_Surface*, SDL_Rect*); void InitDebugText(); void Clear(); }; } #endif Class source file: #include "debugtext.h" namespace game { // Copypasta function for handling the toString conversion template <class T> inline string to_string (const T& t) { stringstream ss (stringstream::in | stringstream::out); ss << t; return ss.str(); } // Initializes SDL_TTF and sets its font void DebugText::InitDebugText() { if(TTF_WasInit()) TTF_Quit(); TTF_Init(); debug_text_font = TTF_OpenFont("LiberationSans-Regular.ttf", 16); TTF_SetFontStyle(debug_text_font, TTF_STYLE_NORMAL); } // Iterates over the current debug_text_list and draws every element on the screen. // After drawing with SDL you need to get a rect specifying the area on the screen that was changed and tell SDL that this part of the screen needs to be updated. this is done in the game's Draw() function // This function sets rects_to_update to the new list of rects provided by all of the surfaces and returns the number of rects in the list. These two parameters are used in Draw() when calling on SDL_UpdateRects(), which takes an SDL_Rect* and a list length int DebugText::DrawDebugText(SDL_Surface* screen, SDL_Rect* rects_to_update) { if(debug_text_list == NULL) return 0; if(!TTF_WasInit()) InitDebugText(); rects_to_update = NULL; // Specifying the font color SDL_Color font_color = {0xff, 0x00, 0x00, 0x00}; // r, g, b, unused int row_count = 0; string line; // The iterator variable map<string, string>::iterator it; // Gets the iterator and iterates over it for(it = debug_text_list->begin(); it != debug_text_list->end(); it++) { // Takes the first value (the name of the variable) and the second value (the value of the parameter in string form) //---------THIS LINE GIVES ME SEGFAULTS----- line = it->first + ": " + it->second; //------------------------------------------ // Creates a surface with the text on it that in turn can be rendered to the screen itself later SDL_Surface* debug_surface = TTF_RenderText_Solid(debug_text_font, line.c_str(), font_color); if(debug_surface == NULL) { // A standard check for errors fprintf(stderr, "Error: %s", TTF_GetError()); return NULL; } else { // If SDL_TTF did its job right, then we now set a destination rect row_count++; SDL_Rect dstrect = {5, 5, 0, 0}; // x, y, w, h dstrect.x = 20; dstrect.y = 20*row_count; // Draws the surface with the text on it to the screen int res = SDL_BlitSurface(debug_surface,NULL,screen,&dstrect); if(res != 0) { //Just an error check fprintf(stderr, "Error: %s", SDL_GetError()); return NULL; } // Creates a new rect to specify the area that needs to be updated with SDL_Rect* new_rect_to_update = (SDL_Rect*) malloc(sizeof(SDL_Rect)); new_rect_to_update->h = debug_surface->h; new_rect_to_update->w = debug_surface->w; new_rect_to_update->x = dstrect.x; new_rect_to_update->y = dstrect.y; // Just freeing the surface since it isn't necessary anymore SDL_FreeSurface(debug_surface); // Creates a new list of rects with room for the new rect SDL_Rect* newtemp = (SDL_Rect*) malloc(row_count*sizeof(SDL_Rect)); // Copies the data from the old list of rects to the new one memcpy(newtemp, rects_to_update, (row_count-1)*sizeof(SDL_Rect)); // Adds the new rect to the new list newtemp[row_count-1] = *new_rect_to_update; // Frees the memory used by the old list free(rects_to_update); // And finally redirects the pointer to the old list to the new list rects_to_update = newtemp; newtemp = NULL; } } // When the entire map has been iterated over, return the number of lines that were drawn, ie. the number of rects in the returned rect list return row_count; } // The SetDebugText used by all the SetDebugText overloads // Takes two strings, inserts them into the map as a pair void DebugText::SetDebugText(string var, string value) { if (debug_text_list == NULL) { debug_text_list = new map<string, string>(); } debug_text_list->erase(var); debug_text_list->insert(pair<string, string>(var, value)); } // Writes the bool to a string and calls SetDebugText(string, string) void DebugText::SetDebugText(string var, bool value) { string result; if (value) result = "True"; else result = "False"; SetDebugText(var, result); } // Does the same thing, but uses to_string() to convert the float void DebugText::SetDebugText(string var, float value) { SetDebugText(var, to_string(value)); } // Same as above, but int void DebugText::SetDebugText(string var, int value) { SetDebugText(var, to_string(value)); } // Vector2 is a struct of my own making. It contains the two float vars x and y void DebugText::SetDebugText(string var, Vector2 value) { SetDebugText(var + ".x", to_string(value.x)); SetDebugText(var + ".y", to_string(value.y)); } // Empties the list. I don't actually use this in my code. Shame on me for writing something I don't use. void DebugText::Clear() { if(debug_text_list != NULL) debug_text_list->clear(); } }

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• readonly keyword

  - by nmarun

  This is something new that I learned about the readonly keyword. Have a look at the following class: 1: public class MyClass 2: { 3: public string Name { get; set; } 4: public int Age { get; set; } 5:  6: private readonly double Delta; 7:  8: public MyClass() 9: { 10: Initializer(); 11: } 12:  13: public MyClass(string name = "", int age = 0) 14: { 15: Name = name; 16: Age = age; 17: Initializer(); 18: } 19:  20: private void Initializer() 21: { 22: Delta = 0.2; 23: } 24: } I have a couple of public properties and a private readonly member. There are two constructors – one that doesn’t take any parameters and the other takes two parameters to initialize the public properties. I’m also calling the Initializer method in both constructors to initialize the readonly member. Now when I build this, the code breaks and the Error window says: “A readonly field cannot be assigned to (except in a constructor or a variable initializer)” Two things after I read this message: It’s such a negative statement. I’d prefer something like: “A readonly field can be assigned to (or initialized) only in a constructor or through a variable initializer” But in my defense, I AM assigning it in a constructor (only indirectly). All I’m doing is creating a method that does it and calling it in a constructor. Turns out, .net was not ‘frameworked’ this way. We need to have the member initialized directly in the constructor. If you have multiple constructors, you can just use the ‘this’ keyword on all except the default constructors to call the default constructor. This default constructor can then initialize your readonly members. This will ensure you’re not repeating the code in multiple places. A snippet of what I’m talking can be seen below: 1: public class Person 2: { 3: public int UniqueNumber { get; set; } 4: public string Name { get; set; } 5: public int Age { get; set; } 6: public DateTime DateOfBirth { get; set; } 7: public string InvoiceNumber { get; set; } 8:  9: private readonly string Alpha; 10: private readonly int Beta; 11: private readonly double Delta; 12: private readonly double Gamma; 13:  14: public Person() 15: { 16: Alpha = "FDSA"; 17: Beta = 2; 18: Delta = 3.0; 19: Gamma = 0.0989; 20: } 21:  22: public Person(int uniqueNumber) : this() 23: { 24: UniqueNumber = uniqueNumber; 25: } 26: } See the syntax in line 22 and you’ll know what I’m talking about. So the default constructor gets called before the one in line 22. These are known as constructor initializers and they allow one constructor to call another. The other ‘myth’ I had about readonly members is that you can set it’s value only once. This was busted as well (I recall Adam and Jamie’s show). Say you’ve initialized the readonly member through a variable initializer. You can over-write this value in any of the constructors any number of times. 1: public class Person 2: { 3: public int UniqueNumber { get; set; } 4: public string Name { get; set; } 5: public int Age { get; set; } 6: public DateTime DateOfBirth { get; set; } 7: public string InvoiceNumber { get; set; } 8:  9: private readonly string Alpha = "asdf"; 10: private readonly int Beta = 15; 11: private readonly double Delta = 0.077; 12: private readonly double Gamma = 1.0; 13:  14: public Person() 15: { 16: Alpha = "FDSA"; 17: Beta = 2; 18: Delta = 3.0; 19: Gamma = 0.0989; 20: } 21:  22: public Person(int uniqueNumber) : this() 23: { 24: UniqueNumber = uniqueNumber; 25: Beta = 3; 26: } 27:  28: public Person(string name, DateTime dob) : this() 29: { 30: Name = name; 31: DateOfBirth = dob; 32:  33: Alpha = ";LKJ"; 34: Gamma = 0.0898; 35: } 36:  37: public Person(int uniqueNumber, string name, int age, DateTime dob, string invoiceNumber) : this() 38: { 39: UniqueNumber = uniqueNumber; 40: Name = name; 41: Age = age; 42: DateOfBirth = dob; 43: InvoiceNumber = invoiceNumber; 44:  45: Alpha = "QWER"; 46: Beta = 5; 47: Delta = 1.0; 48: Gamma = 0.0; 49: } 50: } In the above example, every constructor over-writes the values for the readonly members. This is perfectly valid. There is a possibility that based on the way the object is instantiated, the readonly member will have a different value. Well, that’s all I have for today and read this as it’s on a related topic.

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• Charms and the App Bar

  - by Dennis Vroegop

  Ok. I admit. I made a mistake in the last post about our planespotter app. I have dedicated a full part of the hub to Social. I also had a section called Friends but that made sense since I said that “Friends” is a special group of people that connect to each other through our app and only our app. Social however is sharing our spots with Twitter, Facebook and so on. Now, we could write that functionality in our app in a different section but there is one small problem with that: users don’t expect that. Ok, I admit. The mistake was quite deliberate to give me an excuse to write this part. But still: the mistake is one I see a lot. People are trying to do stuff in their application that they shouldn’t be doing. This always strike me as slightly odd: why do some work when others have already done it for you and you can just use it? After all: good developers are lazy (lazy people will always try to find the easiest way to do something and in development land this usually means the cleanest and best to support way…) So. What is that part that Microsoft has done for us and we don’t have to do ourselves? The answer lies on the right hand of your Win8 screen: This is a screenshot of my tablet (as you can see I am writing this right now….) When I swipe my finger from out of the screen on the right inside the screen (or move the mouse to the upper right corner) this menu will appear. Next to settings and the start menu button we’ll find the Search and the Share charms. These are two ways that your app can share the information it contains with the rest of the world, or at least: the rest of your system. So don’t write a Search feature in your app. Don’t write a Share feature in your app. It’s here already. Users, once they are used to Windows 8, will use that feature and expect it to work. If it doesn’t, they won’t like your app and you can kiss you dreams of everlasting fame goodbye. So use these two. What are they? Well, simply they are parts of a contract. In your app you say somewhere in code that you are supporting Search and Share. So when the user selects Share the system will interrogate the current app in the foreground if it supports this feature. Your app will say “But why, yes, I do!” Then the system will ask the app “Ok then, wisecrack, then share!” and you will have to provide the system with some information about the format. Other applications have subscribed to be at the receiving end of the Share contract. They have told the system that they support Sharing (receiving) and which formats they understand. If one or more of them support the formats you specify, the user will see them. The user clicks / taps on the app of their choice and data is moved from your app to the new one. So if you say you support Facebook and Twitter users can post data from your app to these networks by selecting Share. The same applies to Search. Don’t make a “search” button in your app but use the contract to tell the system that you support search and use that instead. Users will be grateful (remember that bar with men/women/creatures that are waiting for you?) The more and more people get to know Windows 8, the more they will use this. And if you are one of the people who wrote an app that helped them learn the system, well, that’s even better. So. We don’t have a Share or a Search button. We do have other buttons. Most important: we probably need a “New Spot” button. And a “Filter” might be useful. Or someway to open the camera so you can add a picture to the spot. Where will be put those? The answer is the “Appbar” . This is a application / context aware menu that slides up from the bottom of the screen when you move your finger / mouse from below the screen into it. From above downwards works just as well. Here you see an example of the appbar from the People app. (click on it for a larger version). This appears whenever you slide your finger up from below of down from above. This is where you put your commands. Remember, this is context aware so this menu will change when you are in different parts of your app or when you have selected different items. There are a few conventions when you create this appbar. First, the items on the right are “General” items, meaning they have little to do with what is on the screen right now. I think this would be a great place to add our “New Spot” icon. On the far left are items associated with the current selected item or screen. So if you have a spot selected, the button for Add Photo should be visible here and on the left hand side. Not everything is as clear as this, but this is what you should strive for. Group items together. And please note: this is the only place in Metro design where we are allowed to use lines as separators. So when you want to separate a group of icons from another group, add a line. Also note the simplicity of the buttons. No colors, no lights or shadows, no 3D. After a couple of years of fancy almost realistic looking icons people have finally decided that hey, this is a virtual world: it’s ok to look virtual as well. So make things as readable and clear as possible and don’t try to duplicate nature. It’s all about the information, remember? (If you don’t remember I’d like to point you to a older blog post of mine about the what and why of Metro). So.. think about the buttons a bit and think about Share and Search. What will you put there? Remember: this is the way the users interact with your apps and while you shouldn’t judge a book by its covers when it comes to people, this isn’t entirely so when it comes to apps. People DO judge an app by its looks and the way it feels. Take advantage of that. History has learned that a crappy app with a GREAT user interface gets better reviews than a GREAT app with a lousy UI… I know: developers will find this extremely unfair but that’s the world we live in (No, I am not saying you should deliver rubbish apps). Next time: we’ll start by building the darn thing!

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• European Interoperability Framework - a new beginning?

  - by trond-arne.undheim

  The most controversial document in the history of the European Commission's IT policy is out. EIF is here, wrapped in the Communication "Towards interoperability for European public services", and including the new feature European Interoperability Strategy (EIS), arguably a higher strategic take on the same topic. Leaving EIS aside for a moment, the EIF controversy has been around IPR, defining open standards and about the proper terminology around standardization deliverables. Today, as the document finally emerges, what is the verdict? First of all, to be fair to those among you who do not spend your lives in the intricate labyrinths of Commission IT policy documents on interoperability, let's define what we are talking about. According to the Communication: "An interoperability framework is an agreed approach to interoperability for organisations that want to collaborate to provide joint delivery of public services. Within its scope of applicability, it specifies common elements such as vocabulary, concepts, principles, policies, guidelines, recommendations, standards, specifications and practices." The Good - EIF reconfirms that "The Digital Agenda can only take off if interoperability based on standards and open platforms is ensured" and also confirms that "The positive effect of open specifications is also demonstrated by the Internet ecosystem." - EIF takes a productive and pragmatic stance on openness: "In the context of the EIF, openness is the willingness of persons, organisations or other members of a community of interest to share knowledge and stimulate debate within that community, the ultimate goal being to advance knowledge and the use of this knowledge to solve problems" (p.11). "If the openness principle is applied in full: - All stakeholders have the same possibility of contributing to the development of the specification and public review is part of the decision-making process; - The specification is available for everybody to study; - Intellectual property rights related to the specification are licensed on FRAND terms or on a royalty-free basis in a way that allows implementation in both proprietary and open source software" (p. 26). - EIF is a formal Commission document. The former EIF 1.0 was a semi-formal deliverable from the PEGSCO, a working group of Member State representatives. - EIF tackles interoperability head-on and takes a clear stance: "Recommendation 22. When establishing European public services, public administrations should prefer open specifications, taking due account of the coverage of functional needs, maturity and market support." - The Commission will continue to support the National Interoperability Framework Observatory (NIFO), reconfirming the importance of coordinating such approaches across borders. - The Commission will align its internal interoperability strategy with the EIS through the eCommission initiative. - One cannot stress the importance of using open standards enough, whether in the context of open source or non-open source software. The EIF seems to have picked up on this fact: What does the EIF says about the relation between open specifications and open source software? The EIF introduces, as one of the characteristics of an open specification, the requirement that IPRs related to the specification have to be licensed on FRAND terms or on a royalty-free basis in a way that allows implementation in both proprietary and open source software. In this way, companies working under various business models can compete on an equal footing when providing solutions to public administrations while administrations that implement the standard in their own software (software that they own) can share such software with others under an open source licence if they so decide. - EIF is now among the center pieces of the Digital Agenda (even though this demands extensive inter-agency coordination in the Commission): "The EIS and the EIF will be maintained under the ISA Programme and kept in line with the results of other relevant Digital Agenda actions on interoperability and standards such as the ones on the reform of rules on implementation of ICT standards in Europe to allow use of certain ICT fora and consortia standards, on issuing guidelines on essential intellectual property rights and licensing conditions in standard-setting, including for ex-ante disclosure, and on providing guidance on the link between ICT standardisation and public procurement to help public authorities to use standards to promote efficiency and reduce lock-in.(Communication, p.7)" All in all, quite a few good things have happened to the document in the two years it has been on the shelf or was being re-written, depending on your perspective, in any case, awaiting the storms to calm. The Bad - While a certain pragmatism is required, and governments cannot migrate to full openness overnight, EIF gives a bit too much room for governments not to apply the openness principle in full. Plenty of reasons are given, which should maybe have been put as challenges to be overcome: "However, public administrations may decide to use less open specifications, if open specifications do not exist or do not meet functional interoperability needs. In all cases, specifications should be mature and sufficiently supported by the market, except if used in the context of creating innovative solutions". - EIF does not use the internationally established terminology: open standards. Rather, the EIF introduces the notion of "formalised specification". How do "formalised specifications" relate to "standards"? According to the FAQ provided: The word "standard" has a specific meaning in Europe as defined by Directive 98/34/EC. Only technical specifications approved by a recognised standardisation body can be called a standard. Many ICT systems rely on the use of specifications developed by other organisations such as a forum or consortium. The EIF introduces the notion of "formalised specification", which is either a standard pursuant to Directive 98/34/EC or a specification established by ICT fora and consortia. The term "open specification" used in the EIF, on the one hand, avoids terminological confusion with the Directive and, on the other, states the main features that comply with the basic principle of openness laid down in the EIF for European Public Services. Well, this may be somewhat true, but in reality, Europe is 30 year behind in terminology. Unless the European Standardization Reform gets completed in the next few months, most Member States will likely conclude that they will go on referencing and using standards beyond those created by the three European endorsed monopolists of standardization, CEN, CENELEC and ETSI. Who can afford to begin following the strict Brussels rules for what they can call open standards when, in reality, standards stemming from global standardization organizations, so-called fora/consortia, dominate in the IT industry. What exactly is EIF saying? Does it encourage Member States to go on using non-ESO standards as long as they call it something else? I guess I am all for it, although it is a bit cumbersome, no? Why was there so much interest around the EIF? The FAQ attempts to explain: Some Member States have begun to adopt policies to achieve interoperability for their public services. These actions have had a significant impact on the ecosystem built around the provision of such services, e.g. providers of ICT goods and services, standardisation bodies, industry fora and consortia, etc... The Commission identified a clear need for action at European level to ensure that actions by individual Member States would not create new electronic barriers that would hinder the development of interoperable European public services. As a result, all stakeholders involved in the delivery of electronic public services in Europe have expressed their opinions on how to increase interoperability for public services provided by the different public administrations in Europe. Well, it does not take two years to read 50 consultation documents, and the EU Standardization Reform is not yet completed, so, more pragmatically, you finally had to release the document. Ok, let's leave some of that aside because the document is out and some people are happy (and others definitely not). The Verdict Considering the controversy, the delays, the lobbying, and the interests at stake both in the EU, in Member States and among vendors large and small, this document is pretty impressive. As with a good wine that has not yet come to full maturity, let's say that it seems to be coming in in the 85-88/100 range, but only a more fine-grained analysis, enjoyment in good company, and ultimately, implementation, will tell. The European Commission has today adopted a significant interoperability initiative to encourage public administrations across the EU to maximise the social and economic potential of information and communication technologies. Today, we should rally around this achievement. Tomorrow, let's sit down and figure out what it means for the future.

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• Changing an HTML Form's Target with jQuery

  - by Rick Strahl

  This is a question that comes up quite frequently: I have a form with several submit or link buttons and one or more of the buttons needs to open a new Window. How do I get several buttons to all post to the right window? If you're building ASP.NET forms you probably know that by default the Web Forms engine sends button clicks back to the server as a POST operation. A server form has a <form> tag which expands to this: <form method="post" action="default.aspx" id="form1"> Now you CAN change the target of the form and point it to a different window or frame, but the problem with that is that it still affects ALL submissions of the current form. If you multiple buttons/links and they need to go to different target windows/frames you can't do it easily through the <form runat="server"> tag. Although this discussion uses ASP.NET WebForms as an example, realistically this is a general HTML problem although likely more common in WebForms due to the single form metaphor it uses. In ASP.NET MVC for example you'd have more options by breaking out each button into separate forms with its own distinct target tag. However, even with that option it's not always possible to break up forms - for example if multiple targets are required but all targets require the same form data to the be posted. A common scenario here is that you might have a button (or link) that you click where you still want some server code to fire but at the end of the request you actually want to display the content in a new window. A common operation where this happens is report generation: You click a button and the server generates a report say in PDF format and you then want to display the PDF result in a new window without killing the content in the current window. Assuming you have other buttons on the same Page that need to post to base window how do you get the button click to go to a new window? Can't  you just use a LinkButton or other Link Control? At first glance you might think an easy way to do this is to use an ASP.NET LinkButton to do this - after all a LinkButton creates a hyper link that CAN accept a target and it also posts back to the server, right? However, there's no Target property, although you can set the target HTML attribute easily enough. Code like this looks reasonable: <asp:LinkButton runat="server" ID="btnNewTarget" Text="New Target" target="_blank" OnClick="bnNewTarget_Click" /> But if you try this you'll find that it doesn't work. Why? Because ASP.NET creates postbacks with JavaScript code that operates on the current window/frame: <a id="btnNewTarget" target="_blank" href="javascript:__doPostBack(&#39;btnNewTarget&#39;,&#39;&#39;)">New Target</a> What happens with a target tag is that before the JavaScript actually executes a new window is opened and the focus shifts to the new window. The new window of course is empty and has no __doPostBack() function nor access to the old document. So when you click the link a new window opens but the window remains blank without content - no server postback actually occurs. Natch that idea. Setting the Form Target for a Button Control or LinkButton So, in order to send Postback link controls and buttons to another window/frame, both require that the target of the form gets changed dynamically when the button or link is clicked. Luckily this is rather easy to do however using a little bit of script code and jQuery. Imagine you have two buttons like this that should go to another window: <asp:LinkButton runat="server" ID="btnNewTarget" Text="New Target" OnClick="ClickHandler" /> <asp:Button runat="server" ID="btnButtonNewTarget" Text="New Target Button" OnClick="ClickHandler" /> ClickHandler in this case is any routine that generates the output you want to display in the new window. Generally this output will not come from the current page markup but is generated externally - like a PDF report or some report generated by another application component or tool. The output generally will be either generated by hand or something that was generated to disk to be displayed with Response.Redirect() or Response.TransmitFile() etc. Here's the dummy handler that just generates some HTML by hand and displays it: protected void ClickHandler(object sender, EventArgs e) { // Perform some operation that generates HTML or Redirects somewhere else Response.Write("Some custom output would be generated here (PDF, non-Page HTML etc.)"); // Make sure this response doesn't display the page content // Call Response.End() or Response.Redirect() Response.End(); } To route this oh so sophisticated output to an alternate window for both the LinkButton and Button Controls, you can use the following simple script code: <script type="text/javascript"> $("#btnButtonNewTarget,#btnNewTarget").click(function () { $("form").attr("target", "_blank"); }); </script> So why does this work where the target attribute did not? The difference here is that the script fires BEFORE the target is changed to the new window. When you put a target attribute on a link or form the target is changed as the very first thing before the link actually executes. IOW, the link literally executes in the new window when it's done this way. By attaching a click handler, though we're not navigating yet so all the operations the script code performs (ie. __doPostBack()) and the collection of Form variables to post to the server all occurs in the current page. By changing the target from within script code the target change fires as part of the form submission process which means it runs in the correct context of the current page. IOW - the input for the POST is from the current page, but the output is routed to a new window/frame. Just what we want in this scenario. Voila you can dynamically route output to the appropriate window.© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  HTML  jQuery  

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• FTP Publishing with the new Windows Azure Release

  - by Harish Ranganathan

  There is a good chance you might have stumbled upon the new Windows Azure Release that we made on June 6th.  Scott Guthrie’s Post quite summarizes the overall new features. One of my favorite features is the Windows Azure Websites and the ability to do publish files to Azure using your FTP Client. Windows Azure Websites offers low cost (free upto 10 websites) web hosting where you can deploy any website that can run on IIS 7.0, quickly. The earlier releases of Azure SDKs and the Azure platform support .NET 3.5 & above for running your applications.  This was a constraint for many since there are/were a lot of ASP.NET 2.0 applications built over time and simply to put it on Azure, many of you were skeptical to migrate it to .NET 4. Windows Azure Websites offer the flexibility of running IIS 7.0 supported .NET Versions which means you can run .NET 1.1, 2.0, 3.5 and .NET 4.  Not just that! You can also run classic ASP Applications. Windows Azure Websites don’t need you to go through the complexity of adding the Cloud Project Template and then publishing the Configuration Files.  Lets take a step by step understanding of Websites and publishing using FTP. I downloaded the Club Website Starter Kit from http://www.asp.net/downloads/starter-kits/club It also requires a database and I downloaded the SQL Scripts and created a SQL Server Database called Club. This installs a Web Site Project Template.  Note that I am running Windows 8 Release Preview and Visual Studio 2012 RC.  After installing the template, select File – New – Website and don’t forget to choose the Framework version as .NET 2.0 You can see the “Club Website Starter Kit” .  Once you select the Website gets created.  You would encounter a warning indicating that the Club Website Starter Kit uses SQL Express and the recommended database is LocalDB Express.  Click ok to continue.  Once the Website is created open up the Web.config and locate the “ClubSiteDB” connection string.  By default, it points to a SQL Express Database.  Instead configure it to use your local SQL Server. Also, open up Global.asax and comment out the following line if (!Roles.RoleExists("Administrators")) Roles.CreateRole("Administrators"); There seems to be an issue in the code that doesn’t create the role.  Post that, hit CTRL+F5 and you should be able to see the Website Running, as below So, now we have the Club Starter Kit site up running locally.  Moving to Azure Visit http://manage.windowsazure.com/ and sign up for a trial account.  This allows you to host up to 10 websites for free and a host of other benefits.  The free Websites can be extended to an year without any charge.  Once you have signed up, sign in to the portal using the Live ID used for sign up. After signing in, you would be presented with the “All Items” listing page which lists, Websites, Cloud Services, Databases etc.,  If this is the first time, you wouldn’t find anything. Click on the “Websites” link from the left menu.  Click on “New” in the bottom and it should show up a dialog.  In the same, select Website and click on “Quick Create” and in the URL Textbox, specify “MyFirstDemo” and click the “Create Web Site” link below. It should take a few seconds to create the Website.  Once the Website is created, click on the listing and it should open up the Dashboard.  Since we haven’t done anything yet, there shouldn’t be any statistics Click on the “Download publish profile” link in the right bottom.  This file has the FTP publishing settings. Also, if you scroll down you can see the FTP URL for this site.  It should typically start ftp://waws-xxxx-xxx-xxxx In the downloaded publish profile file, you can also find the ftp URL.  Pick the following from this file publishUrl (the 2nd one, the one that features after publishMethod =”FTP”) and the userName and userPWD that follows. Note that we have everything required to publish the files.  But since the Club Starter Kit uses Databases, we need to have the Database running on SQL Azure.  Go back to the Main Menu and click on “New” in the bottom but this time select “SQL Database” and provide “Club” as Database name for “Quick Create” If this is the first time a Server would be created.  Otherwise, it would pickup the existing server name. Once the database is created, you can use the SQL Azure Migration Wizard http://sqlazuremw.codeplex.com/ and provide the credentials to connect to local database and then the SQL Azure database for migrating the “Club” database.  The migration wizard UI hasn’t changed much and is the same as explained by me in one my posts earlier http://geekswithblogs.net/ranganh/archive/2009/09/29/taking-your-northwind-database-to-sql-azure-and-binding-it.aspx Once the database is migrated, come back to the main screen and click on the Database base in the Azure Management Portal.  It opens up the dashboard of the database.  Click on “Show connection Strings” and it would popup a list of connection string formats.  Choose the ADO.NET connection string and after editing the password with the password that you provided when creating the database server in the Azure Portal, paste it into the config file of the Club Starter Kit Website.  Just to reiterate, the connection string key is ClubSiteDB. Try running the Website once to ensure that the application though running locally could connect to the SQL Database running on Azure. Once you are able to run the website successfully, we are all set to do the FTP Publishing. Download your favorite FTP tool.  I use http://filezilla-project.org/ In the Host Textbox, paste the FTP URL that you picked up from the publish profile file and also paste the username and password.  Click on “QuickConnect”.  If everything is fine, you should be able to connect to the remote server.  If it is successfully connected, you can see the wwwroot folder of the Website, running in Azure Make sure on the “Local Site” in the left, you choose the path to the folder of your Website.  Open up the Website folder on the left such that it lists all the files and folders inside.  Select all of them and click select “Upload” or simply drag and drop all the files to the root folder that is listed above.  Once the publishing is done, you should be able to hit the SiteURL that you can find the dashboard page of the website.  In our case, it would be http://MyFirstDemo.azurewebsites.net That’s it, we have now done FTP publishing in Azure and that too we are running a .NET 2.0 Website on Azure. Cheers !!!

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• Announcing: Improvements to the Windows Azure Portal

  - by ScottGu

  Earlier today we released a number of enhancements to the new Windows Azure Management Portal.  These new capabilities include: Service Bus Management and Monitoring Support for Managing Co-administrators Import/Export support for SQL Databases Virtual Machine Experience Enhancements Improved Cloud Service Status Notifications Media Services Monitoring Support Storage Container Creation and Access Control Support All of these improvements are now live in production and available to start using immediately.  Below are more details on them: Service Bus Management and Monitoring The new Windows Azure Management Portal now supports Service Bus management and monitoring. Service Bus provides rich messaging infrastructure that can sit between applications (or between cloud and on-premise environments) and allow them to communicate in a loosely coupled way for improved scale and resiliency. With the new Service Bus experience, you can now create and manage Service Bus Namespaces, Queues, Topics, Relays and Subscriptions. You can also get rich monitoring for Service Bus Queues, Topics and Subscriptions. To create a Service Bus namespace, you can now select the “Service Bus” tab in the Windows Azure portal and then simply select the CREATE command: Doing so will bring up a new “Create a Namespace” dialog that allows you to name and create a new Service Bus Namespace: Once created, you can obtain security credentials associated with the Namespace via the ACCESS KEY command. This gives you the ability to obtain the connection string associated with the service namespace. You can copy and paste these values into any application that requires these credentials: It is also now easy to create Service Bus Queues and Topics via the NEW experience in the portal drawer.  Simply click the NEW command and navigate to the “App Services” category to create a new Service Bus entity: Once you provision a new Queue or Topic it can be managed in the portal.  Clicking on a namespace will display all queues and topics within it: Clicking on an item in the list will allow you to drill down into a dashboard view that allows you to monitor the activity and traffic within it, as well as perform operations on it. For example, below is a view of an “orders” queue – note how we now surface both the incoming and outgoing message flow rate, as well as the total queue length and queue size: To monitor pub/sub subscriptions you can use the ADD METRICS command within a topic and select a specific subscription to monitor. Support for Managing Co-Administrators You can now add co-administrators for your Windows Azure subscription using the new Windows Azure Portal. This allows you to share management of your Windows Azure services with other users. Subscription co-administrators share the same administrative rights and permissions that service administrator have - except a co-administrator cannot change or view billing details about the account, nor remove the service administrator from a subscription. In the SETTINGS section, click on the ADMINISTRATORS tab, and select the ADD button to add a co-administrator to your subscription: To add a co-administrator, you specify the email address for a Microsoft account (formerly Windows Live ID) or an organizational account, and choose the subscription you want to add them to: You can later update the subscriptions that the co-administrator has access to by clicking on the EDIT button, and then select or deselect the subscriptions to which they belong. Import/Export Support for SQL Databases The Windows Azure administration portal now supports importing and exporting SQL Databases to/from Blob Storage.  Databases can be imported/exported to blob storage using the same BACPAC file format that is supported with SQL Server 2012.  Among other benefits, this makes it easy to copy and migrate databases between on-premise and cloud environments. SQL Databases now have an EXPORT command in the bottom drawer that when pressed will prompt you to save your database to a Windows Azure storage container: The UI allows you to choose an existing storage account or create a new one, as well as the name of the BACPAC file to persist in blob storage: You can also now import and create a new SQL Database by using the NEW command.  This will prompt you to select the storage container and file to import the database from: The Windows Azure Portal enables you to monitor the progress of import and export operations. If you choose to log out of the portal, you can come back later and check on the status of all of the operations in the new history tab of the SQL Database server – this shows your entire import and export history and the status (success/fail) of each: Enhancements to the Virtual Machine Experience One of the common pain-points we have heard from customers using the preview of our new Virtual Machine support has been the inability to delete the associated VHDs when a VM instance (or VM drive) gets deleted. Prior to today’s release the VHDs would continue to be in your storage account and accumulate storage charges. You can now navigate to the Disks tab within the Virtual Machine extension, select a VM disk to delete, and click the DELETE DISK command: When you click the DELETE DISK button you have the option to delete the disk + associated .VHD file (completely clearing it from storage).  Alternatively you can delete the disk but still retain a .VHD copy of it in storage. Improved Cloud Service Status Notifications The Windows Azure portal now exposes more information of the health status of role instances.  If any of the instances are in a non-running state, the status at the top of the dashboard will summarize the status (and update automatically as the role health changes): Clicking the instance hyperlink within this status summary view will navigate you to a detailed role instance view, and allow you to get more detailed health status of each of the instances.  The portal has been updated to provide more specific status information within this detailed view – giving you better visibility into the health of your app: Monitoring Support for Media Services Windows Azure Media Services allows you to create media processing jobs (for example: encoding media files) in your Windows Azure Media Services account. In the Windows Azure Portal, you can now monitor the number of encoding jobs that are queued up for processing as well as active, failed and queued tasks for encoding jobs. On your media services account dashboard, you can visualize the monitoring data for last 6 hours, 24 hours or 7 days. Storage Container Creation and Access Control Support You can now create Windows Azure Storage storage containers from within the Windows Azure Portal.  After selecting a storage account, you can navigate to the CONTAINERS tab and click the ADD CONTAINER command: This will display a dialog that lets you name the new container and control access to it: You can also update the access setting as well as container metadata of existing containers by selecting one and then using the new EDIT CONTAINER command: This will then bring up the edit container dialog that allows you to change and save its settings: In addition to creating and editing containers, you can click on them within the portal to drill-in and view blobs within them.  Summary The above features are all now live in production and available to use immediately.  If you don’t already have a Windows Azure account, you can sign-up for a free trial and start using them today.  Visit the Windows Azure Developer Center to learn more about how to build apps with it. We’ll have even more new features and enhancements coming later this month – including support for the recent Windows Server 2012 and .NET 4.5 releases (we will enable new web and worker role images with Windows Server 2012 and .NET 4.5, and support .NET 4.5 with Websites).  Keep an eye out on my blog for details as these new features become available. 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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• Using Node.js as an accelerator for WCF REST services

  - by Elton Stoneman

  Node.js is a server-side JavaScript platform "for easily building fast, scalable network applications". It's built on Google's V8 JavaScript engine and uses an (almost) entirely async event-driven processing model, running in a single thread. If you're new to Node and your reaction is "why would I want to run JavaScript on the server side?", this is the headline answer: in 150 lines of JavaScript you can build a Node.js app which works as an accelerator for WCF REST services*. It can double your messages-per-second throughput, halve your CPU workload and use one-fifth of the memory footprint, compared to the WCF services direct.   Well, it can if: 1) your WCF services are first-class HTTP citizens, honouring client cache ETag headers in request and response; 2) your services do a reasonable amount of work to build a response; 3) your data is read more often than it's written. In one of my projects I have a set of REST services in WCF which deal with data that only gets updated weekly, but which can be read hundreds of times an hour. The services issue ETags and will return a 304 if the client sends a request with the current ETag, which means in the most common scenario the client uses its local cached copy. But when the weekly update happens, then all the client caches are invalidated and they all need the same new data. Then the service will get hundreds of requests with old ETags, and they go through the full service stack to build the same response for each, taking up threads and processing time. Part of that processing means going off to a database on a separate cloud, which introduces more latency and downtime potential.   We can use ASP.NET output caching with WCF to solve the repeated processing problem, but the server will still be thread-bound on incoming requests, and to get the current ETags reliably needs a database call per request. The accelerator solves that by running as a proxy - all client calls come into the proxy, and the proxy routes calls to the underlying REST service. We could use Node as a straight passthrough proxy and expect some benefit, as the server would be less thread-bound, but we would still have one WCF and one database call per proxy call. But add some smart caching logic to the proxy, and share ETags between Node and WCF (so the proxy doesn't even need to call the servcie to get the current ETag), and the underlying service will only be invoked when data has changed, and then only once - all subsequent client requests will be served from the proxy cache.   I've built this as a sample up on GitHub: NodeWcfAccelerator on sixeyed.codegallery. Here's how the architecture looks:     The code is very simple. The Node proxy runs on port 8010 and all client requests target the proxy. If the client request has an ETag header then the proxy looks up the ETag in the tag cache to see if it is current - the sample uses memcached to share ETags between .NET and Node. If the ETag from the client matches the current server tag, the proxy sends a 304 response with an empty body to the client, telling it to use its own cached version of the data. If the ETag from the client is stale, the proxy looks for a local cached version of the response, checking for a file named after the current ETag. If that file exists, its contents are returned to the client as the body in a 200 response, which includes the current ETag in the header. If the proxy does not have a local cached file for the service response, it calls the service, and writes the WCF response to the local cache file, and to the body of a 200 response for the client. So the WCF service is only troubled if both client and proxy have stale (or no) caches.   The only (vaguely) clever bit in the sample is using the ETag cache, so the proxy can serve cached requests without any communication with the underlying service, which it does completely generically, so the proxy has no notion of what it is serving or what the services it proxies are doing. The relative path from the URL is used as the lookup key, so there's no shared key-generation logic between .NET and Node, and when WCF stores a tag it also stores the "read" URL against the ETag so it can be used for a reverse lookup, e.g:   Key Value /WcfSampleService/PersonService.svc/rest/fetch/3 "28cd4796-76b8-451b-adfd-75cb50a50fa6" "28cd4796-76b8-451b-adfd-75cb50a50fa6" /WcfSampleService/PersonService.svc/rest/fetch/3    In Node we read the cache using the incoming URL path as the key and we know that "28cd4796-76b8-451b-adfd-75cb50a50fa6" is the current ETag; we look for a local cached response in /caches/28cd4796-76b8-451b-adfd-75cb50a50fa6.body (and the corresponding .header file which contains the original service response headers, so the proxy response is exactly the same as the underlying service). When the data is updated, we need to invalidate the ETag cache – which is why we need the reverse lookup in the cache. In the WCF update service, we don't need to know the URL of the related read service - we fetch the entity from the database, do a reverse lookup on the tag cache using the old ETag to get the read URL, update the new ETag against the URL, store the new reverse lookup and delete the old one.   Running Apache Bench against the two endpoints gives the headline performance comparison. Making 1000 requests with concurrency of 100, and not sending any ETag headers in the requests, with the Node proxy I get 102 requests handled per second, average response time of 975 milliseconds with 90% of responses served within 850 milliseconds; going direct to WCF with the same parameters, I get 53 requests handled per second, mean response time of 1853 milliseconds, with 90% of response served within 3260 milliseconds. Informally monitoring server usage during the tests, Node maxed at 20% CPU and 20Mb memory; IIS maxed at 60% CPU and 100Mb memory.   Note that the sample WCF service does a database read and sleeps for 250 milliseconds to simulate a moderate processing load, so this is *not* a baseline Node-vs-WCF comparison, but for similar scenarios where the  service call is expensive but applicable to numerous clients for a long timespan, the performance boost from the accelerator is considerable.     * - actually, the accelerator will work nicely for any HTTP request, where the URL (path + querystring) uniquely identifies a resource. In the sample, there is an assumption that the ETag is a GUID wrapped in double-quotes (e.g. "28cd4796-76b8-451b-adfd-75cb50a50fa6") – which is the default for WCF services. I use that assumption to name the cache files uniquely, but it is a trivial change to adapt to other ETag formats.

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• C#: Does an IDisposable in a Halted Iterator Dispose?

  - by James Michael Hare

  If that sounds confusing, let me give you an example. Let's say you expose a method to read a database of products, and instead of returning a List<Product> you return an IEnumerable<Product> in iterator form (yield return). This accomplishes several good things: The IDataReader is not passed out of the Data Access Layer which prevents abstraction leak and resource leak potentials. You don't need to construct a full List<Product> in memory (which could be very big) if you just want to forward iterate once. If you only want to consume up to a certain point in the list, you won't incur the database cost of looking up the other items. This could give us an example like: 1: // a sample data access object class to do standard CRUD operations. 2: public class ProductDao 3: { 4: private DbProviderFactory _factory = SqlClientFactory.Instance 5:  6: // a method that would retrieve all available products 7: public IEnumerable<Product> GetAvailableProducts() 8: { 9: // must create the connection 10: using (var con = _factory.CreateConnection()) 11: { 12: con.ConnectionString = _productsConnectionString; 13: con.Open(); 14:  15: // create the command 16: using (var cmd = _factory.CreateCommand()) 17: { 18: cmd.Connection = con; 19: cmd.CommandText = _getAllProductsStoredProc; 20: cmd.CommandType = CommandType.StoredProcedure; 21:  22: // get a reader and pass back all results 23: using (var reader = cmd.ExecuteReader()) 24: { 25: while(reader.Read()) 26: { 27: yield return new Product 28: { 29: Name = reader["product_name"].ToString(), 30: ... 31: }; 32: } 33: } 34: } 35: } 36: } 37: } The database details themselves are irrelevant. I will say, though, that I'm a big fan of using the System.Data.Common classes instead of your provider specific counterparts directly (SqlCommand, OracleCommand, etc). This lets you mock your data sources easily in unit testing and also allows you to swap out your provider in one line of code. In fact, one of the shared components I'm most proud of implementing was our group's DatabaseUtility library that simplifies all the database access above into one line of code in a thread-safe and provider-neutral way. I went with my own flavor instead of the EL due to the fact I didn't want to force internal company consumers to use the EL if they didn't want to, and it made it easy to allow them to mock their database for unit testing by providing a MockCommand, MockConnection, etc that followed the System.Data.Common model. One of these days I'll blog on that if anyone's interested. Regardless, you often have situations like the above where you are consuming and iterating through a resource that must be closed once you are finished iterating. For the reasons stated above, I didn't want to return IDataReader (that would force them to remember to Dispose it), and I didn't want to return List<Product> (that would force them to hold all products in memory) -- but the first time I wrote this, I was worried. What if you never consume the last item and exit the loop? Are the reader, command, and connection all disposed correctly? Of course, I was 99.999999% sure the creators of C# had already thought of this and taken care of it, but inspection in Reflector was difficult due to the nature of the state machines yield return generates, so I decided to try a quick example program to verify whether or not Dispose() will be called when an iterator is broken from outside the iterator itself -- i.e. before the iterator reports there are no more items. So I wrote a quick Sequencer class with a Dispose() method and an iterator for it. Yes, it is COMPLETELY contrived: 1: // A disposable sequence of int -- yes this is completely contrived... 2: internal class Sequencer : IDisposable 3: { 4: private int _i = 0; 5: private readonly object _mutex = new object(); 6:  7: // Constructs an int sequence. 8: public Sequencer(int start) 9: { 10: _i = start; 11: } 12:  13: // Gets the next integer 14: public int GetNext() 15: { 16: lock (_mutex) 17: { 18: return _i++; 19: } 20: } 21:  22: // Dispose the sequence of integers. 23: public void Dispose() 24: { 25: // force output immediately (flush the buffer) 26: Console.WriteLine("Disposed with last sequence number of {0}!", _i); 27: Console.Out.Flush(); 28: } 29: } And then I created a generator (infinite-loop iterator) that did the using block for auto-Disposal: 1: // simply defines an extension method off of an int to start a sequence 2: public static class SequencerExtensions 3: { 4: // generates an infinite sequence starting at the specified number 5: public static IEnumerable<int> GetSequence(this int starter) 6: { 7: // note the using here, will call Dispose() when block terminated. 8: using (var seq = new Sequencer(starter)) 9: { 10: // infinite loop on this generator, means must be bounded by caller! 11: while(true) 12: { 13: yield return seq.GetNext(); 14: } 15: } 16: } 17: } This is really the same conundrum as the database problem originally posed. Here we are using iteration (yield return) over a large collection (infinite sequence of integers). If we cut the sequence short by breaking iteration, will that using block exit and hence, Dispose be called? Well, let's see: 1: // The test program class 2: public class IteratorTest 3: { 4: // The main test method. 5: public static void Main() 6: { 7: Console.WriteLine("Going to consume 10 of infinite items"); 8: Console.Out.Flush(); 9:  10: foreach(var i in 0.GetSequence()) 11: { 12: // could use TakeWhile, but wanted to output right at break... 13: if(i >= 10) 14: { 15: Console.WriteLine("Breaking now!"); 16: Console.Out.Flush(); 17: break; 18: } 19:  20: Console.WriteLine(i); 21: Console.Out.Flush(); 22: } 23:  24: Console.WriteLine("Done with loop."); 25: Console.Out.Flush(); 26: } 27: } So, what do we see? Do we see the "Disposed" message from our dispose, or did the Dispose get skipped because from an "eyeball" perspective we should be locked in that infinite generator loop? Here's the results: 1: Going to consume 10 of infinite items 2: 0 3: 1 4: 2 5: 3 6: 4 7: 5 8: 6 9: 7 10: 8 11: 9 12: Breaking now! 13: Disposed with last sequence number of 11! 14: Done with loop. Yes indeed, when we break the loop, the state machine that C# generates for yield iterate exits the iteration through the using blocks and auto-disposes the IDisposable correctly. I must admit, though, the first time I wrote one, I began to wonder and that led to this test. If you've never seen iterators before (I wrote a previous entry here) the infinite loop may throw you, but you have to keep in mind it is not a linear piece of code, that every time you hit a "yield return" it cedes control back to the state machine generated for the iterator. And this state machine, I'm happy to say, is smart enough to clean up the using blocks correctly. I suspected those wily guys and gals at Microsoft engineered it well, and I wasn't disappointed. But, I've been bitten by assumptions before, so it's good to test and see. Yes, maybe you knew it would or figured it would, but isn't it nice to know? And as those campy 80s G.I. Joe cartoon public service reminders always taught us, "Knowing is half the battle...". Technorati Tags: C#,.NET

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• Why did Ubuntu suddenly get so slow?

  - by user101383

  12.10 has been slowing down mysteriously. Normally, in past versions, I can log in, open Firefox, and it will pop up within seconds. 12.10 is like that upon install too, though once I install my old apps, it gets very slow by Ubuntu standards. After login the hard drive will just make noise for a while before the OS will do anything. Hardware: enter description: Desktop Computer product: XPS 8300 () vendor: Dell Inc. serial: B6G2WR1 width: 64 bits capabilities: smbios-2.6 dmi-2.6 vsyscall32 configuration: boot=normal chassis=desktop uuid=44454C4C-3600-1047-8032-C2C04F575231 core description: Motherboard product: 0Y2MRG vendor: Dell Inc. physical id: 0 version: A00 serial: ..CN7360419G04VQ. slot: To Be Filled By O.E.M. *cpu description: CPU product: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz vendor: Intel Corp. physical id: 4 bus info: cpu@0 version: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz serial: To Be Filled By O.E.M. slot: CPU 1 size: 1600MHz capacity: 1600MHz width: 64 bits clock: 100MHz capabilities: x86-64 fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx lahf_lm ida arat epb xsaveopt pln pts dtherm tpr_shadow vnmi flexpriority ept vpid cpufreq configuration: cores=4 enabledcores=1 threads=2 *-cache:0 description: L1 cache physical id: 5 slot: L1-Cache size: 256KiB capacity: 256KiB capabilities: internal write-through unified *-cache:1 description: L2 cache physical id: 6 slot: L2-Cache size: 1MiB capacity: 1MiB capabilities: internal write-through unified *-cache:2 DISABLED description: L3 cache physical id: 7 slot: L3-Cache size: 8MiB capacity: 8MiB capabilities: internal write-back unified *-memory description: System Memory physical id: 20 slot: System board or motherboard size: 8GiB *-bank:0 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: NT2GC64B88B0NF-CG vendor: Nanya physical id: 0 serial: 7228183 slot: DIMM3 size: 2GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:1 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: NT2GC64B88B0NF-CG vendor: Nanya physical id: 1 serial: 1E28183 slot: DIMM1 size: 2GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:2 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: NT2GC64B88B0NF-CG vendor: Nanya physical id: 2 serial: 9E28183 slot: DIMM4 size: 2GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:3 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: NT2GC64B88B0NF-CG vendor: Nanya physical id: 3 serial: 5527183 slot: DIMM2 size: 2GiB width: 64 bits clock: 1333MHz (0.8ns) *-firmware description: BIOS vendor: Dell Inc. physical id: 0 version: A05 date: 09/21/2011 size: 64KiB capacity: 4032KiB capabilities: mca pci upgrade shadowing escd cdboot bootselect socketedrom edd int13floppy1200 int13floppy720 int13floppy2880 int5printscreen int9keyboard int14serial int17printer int10video acpi usb zipboot biosbootspecification *-pci description: Host bridge product: 2nd Generation Core Processor Family DRAM Controller vendor: Intel Corporation physical id: 100 bus info: pci@0000:00:00.0 version: 09 width: 32 bits clock: 33MHz *-pci:0 description: PCI bridge product: Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port vendor: Intel Corporation physical id: 1 bus info: pci@0000:00:01.0 version: 09 width: 32 bits clock: 33MHz capabilities: pci pm msi pciexpress normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:40 ioport:e000(size=4096) memory:fe600000-fe6fffff ioport:d0000000(size=268435456) *-display description: VGA compatible controller product: Juniper [Radeon HD 5700 Series] vendor: Advanced Micro Devices [AMD] nee ATI physical id: 0 bus info: pci@0000:01:00.0 version: 00 width: 64 bits clock: 33MHz capabilities: pm pciexpress msi vga_controller bus_master cap_list rom configuration: driver=radeon latency=0 resources: irq:44 memory:d0000000-dfffffff memory:fe620000-fe63ffff ioport:e000(size=256) memory:fe600000-fe61ffff *-multimedia description: Audio device product: Juniper HDMI Audio [Radeon HD 5700 Series] vendor: Advanced Micro Devices [AMD] nee ATI physical id: 0.1 bus info: pci@0000:01:00.1 version: 00 width: 64 bits clock: 33MHz capabilities: pm pciexpress msi bus_master cap_list configuration: driver=snd_hda_intel latency=0 resources: irq:48 memory:fe640000-fe643fff *-communication description: Communication controller product: 6 Series/C200 Series Chipset Family MEI Controller #1 vendor: Intel Corporation physical id: 16 bus info: pci@0000:00:16.0 version: 04 width: 64 bits clock: 33MHz capabilities: pm msi bus_master cap_list configuration: driver=mei latency=0 resources: irq:45 memory:fe708000-fe70800f *-usb:0 description: USB controller product: 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 vendor: Intel Corporation physical id: 1a bus info: pci@0000:00:1a.0 version: 05 width: 32 bits clock: 33MHz capabilities: pm debug ehci bus_master cap_list configuration: driver=ehci_hcd latency=0 resources: irq:16 memory:fe707000-fe7073ff *-multimedia description: Audio device product: 6 Series/C200 Series Chipset Family High Definition Audio Controller vendor: Intel Corporation physical id: 1b bus info: pci@0000:00:1b.0 version: 05 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=snd_hda_intel latency=0 resources: irq:46 memory:fe700000-fe703fff *-pci:1 description: PCI bridge product: 6 Series/C200 Series Chipset Family PCI Express Root Port 1 vendor: Intel Corporation physical id: 1c bus info: pci@0000:00:1c.0 version: b5 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:41 memory:fe500000-fe5fffff *-network description: Network controller product: BCM4313 802.11b/g/n Wireless LAN Controller vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:02:00.0 version: 01 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=bcma-pci-bridge latency=0 resources: irq:16 memory:fe500000-fe503fff *-pci:2 description: PCI bridge product: 6 Series/C200 Series Chipset Family PCI Express Root Port 4 vendor: Intel Corporation physical id: 1c.3 bus info: pci@0000:00:1c.3 version: b5 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:42 memory:fe400000-fe4fffff *-network description: Ethernet interface product: NetLink BCM57788 Gigabit Ethernet PCIe vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: eth0 version: 01 serial: 18:03:73:e1:a7:71 size: 100Mbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=tg3 driverversion=3.123 duplex=full firmware=sb ip=192.168.1.3 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s resources: irq:47 memory:fe400000-fe40ffff *-usb:1 description: USB controller product: 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 vendor: Intel Corporation physical id: 1d bus info: pci@0000:00:1d.0 version: 05 width: 32 bits clock: 33MHz capabilities: pm debug ehci bus_master cap_list configuration: driver=ehci_hcd latency=0 resources: irq:23 memory:fe706000-fe7063ff *-isa description: ISA bridge product: H67 Express Chipset Family LPC Controller vendor: Intel Corporation physical id: 1f bus info: pci@0000:00:1f.0 version: 05 width: 32 bits clock: 33MHz capabilities: isa bus_master cap_list configuration: latency=0 *-storage description: SATA controller product: 6 Series/C200 Series Chipset Family SATA AHCI Controller vendor: Intel Corporation physical id: 1f.2 bus info: pci@0000:00:1f.2 version: 05 width: 32 bits clock: 66MHz capabilities: storage msi pm ahci_1.0 bus_master cap_list configuration: driver=ahci latency=0 resources: irq:43 ioport:f070(size=8) ioport:f060(size=4) ioport:f050(size=8) ioport:f040(size=4) ioport:f020(size=32) memory:fe705000-fe7057ff *-serial UNCLAIMED description: SMBus product: 6 Series/C200 Series Chipset Family SMBus Controller vendor: Intel Corporation physical id: 1f.3 bus info: pci@0000:00:1f.3 version: 05 width: 64 bits clock: 33MHz configuration: latency=0 resources: memory:fe704000-fe7040ff ioport:f000(size=32) *-scsi:0 physical id: 1 logical name: scsi0 capabilities: emulated *-disk description: ATA Disk product: Hitachi HUA72201 vendor: Hitachi physical id: 0.0.0 bus info: scsi@0:0.0.0 logical name: /dev/sda version: JP4O serial: JPW9J0HD21BTZC size: 931GiB (1TB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 sectorsize=512 signature=000641dc *-volume:0 description: EXT4 volume vendor: Linux physical id: 1 bus info: scsi@0:0.0.0,1 logical name: /dev/sda1 logical name: / version: 1.0 serial: 4e3d91b7-fd38-4f44-a9e9-ba3c39b926ec size: 585GiB capacity: 585GiB capabilities: primary journaled extended_attributes large_files huge_files dir_nlink recover extents ext4 ext2 initialized configuration: created=2012-10-21 16:26:50 filesystem=ext4 lastmountpoint=/ modified=2012-10-29 18:12:08 mount.fstype=ext4 mount.options=rw,relatime,errors=remount-ro,data=ordered mounted=2012-10-29 18:12:08 state=mounted *-volume:1 description: Extended partition physical id: 2 bus info: scsi@0:0.0.0,2 logical name: /dev/sda2 size: 7823MiB capacity: 7823MiB capabilities: primary extended partitioned partitioned:extended *-logicalvolume description: Linux swap / Solaris partition physical id: 5 logical name: /dev/sda5 capacity: 7823MiB capabilities: nofs *-volume:2 description: Windows NTFS volume physical id: 3 bus info: scsi@0:0.0.0,3 logical name: /dev/sda3 version: 3.1 serial: 84a92aae-347b-7940-a2d1-f4745b885ef2 size: 337GiB capacity: 337GiB capabilities: primary bootable ntfs initialized configuration: clustersize=4096 created=2012-10-21 18:43:39 filesystem=ntfs modified_by_chkdsk=true mounted_on_nt4=true resize_log_file=true state=dirty upgrade_on_mount=true *-scsi:1 physical id: 2 logical name: scsi1 capabilities: emulated *-cdrom description: DVD-RAM writer product: DVDRWBD DH-12E3S vendor: PLDS physical id: 0.0.0 bus info: scsi@1:0.0.0 logical name: /dev/cdrom logical name: /dev/cdrw logical name: /dev/dvd logical name: /dev/dvdrw logical name: /dev/sr0 version: MD11 capabilities: removable audio cd-r cd-rw dvd dvd-r dvd-ram configuration: ansiversion=5 status=nodisc *-scsi:2 physical id: 3 bus info: usb@2:1.8 logical name: scsi6 capabilities: emulated scsi-host configuration: driver=usb-storage *-disk:0 description: SCSI Disk physical id: 0.0.0 bus info: scsi@6:0.0.0 logical name: /dev/sdb configuration: sectorsize=512 *-disk:1 description: SCSI Disk physical id: 0.0.1 bus info: scsi@6:0.0.1 logical name: /dev/sdc configuration: sectorsize=512 *-disk:2 description: SCSI Disk physical id: 0.0.2 bus info: scsi@6:0.0.2 logical name: /dev/sdd configuration: sectorsize=512 *-disk:3 description: SCSI Disk product: MS/MS-Pro vendor: Generic- physical id: 0.0.3 bus info: scsi@6:0.0.3 logical name: /dev/sde version: 1.03 serial: 3 capabilities: removable configuration: sectorsize=512 *-medium physical id: 0 logical name: /dev/sde

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• Android - Create a custom multi-line ListView bound to an ArrayList

  - by Bill Osuch

  The Android HelloListView tutorial shows how to bind a ListView to an array of string objects, but you'll probably outgrow that pretty quickly. This post will show you how to bind the ListView to an ArrayList of custom objects, as well as create a multi-line ListView. Let's say you have some sort of search functionality that returns a list of people, along with addresses and phone numbers. We're going to display that data in three formatted lines for each result, and make it clickable. First, create your new Android project, and create two layout files. Main.xml will probably already be created by default, so paste this in: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:orientation="vertical"  android:layout_width="fill_parent"   android:layout_height="fill_parent">  <TextView   android:layout_height="wrap_content"   android:text="Custom ListView Contents"   android:gravity="center_vertical|center_horizontal"   android:layout_width="fill_parent" />   <ListView    android:id="@+id/ListView01"    android:layout_height="wrap_content"    android:layout_width="fill_parent"/> </LinearLayout> Next, create a layout file called custom_row_view.xml. This layout will be the template for each individual row in the ListView. You can use pretty much any type of layout - Relative, Table, etc., but for this we'll just use Linear: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:orientation="vertical"  android:layout_width="fill_parent"   android:layout_height="fill_parent">   <TextView android:id="@+id/name"   android:textSize="14sp"   android:textStyle="bold"   android:textColor="#FFFF00"   android:layout_width="wrap_content"   android:layout_height="wrap_content"/>  <TextView android:id="@+id/cityState"   android:layout_width="wrap_content"   android:layout_height="wrap_content"/>  <TextView android:id="@+id/phone"   android:layout_width="wrap_content"   android:layout_height="wrap_content"/> </LinearLayout> Now, add an object called SearchResults. Paste this code in: public class SearchResults {  private String name = "";  private String cityState = "";  private String phone = "";  public void setName(String name) {   this.name = name;  }  public String getName() {   return name;  }  public void setCityState(String cityState) {   this.cityState = cityState;  }  public String getCityState() {   return cityState;  }  public void setPhone(String phone) {   this.phone = phone;  }  public String getPhone() {   return phone;  } } This is the class that we'll be filling with our data, and loading into an ArrayList. Next, you'll need a custom adapter. This one just extends the BaseAdapter, but you could extend the ArrayAdapter if you prefer. public class MyCustomBaseAdapter extends BaseAdapter {  private static ArrayList<SearchResults> searchArrayList;    private LayoutInflater mInflater;  public MyCustomBaseAdapter(Context context, ArrayList<SearchResults> results) {   searchArrayList = results;   mInflater = LayoutInflater.from(context);  }  public int getCount() {   return searchArrayList.size();  }  public Object getItem(int position) {   return searchArrayList.get(position);  }  public long getItemId(int position) {   return position;  }  public View getView(int position, View convertView, ViewGroup parent) {   ViewHolder holder;   if (convertView == null) {    convertView = mInflater.inflate(R.layout.custom_row_view, null);    holder = new ViewHolder();    holder.txtName = (TextView) convertView.findViewById(R.id.name);    holder.txtCityState = (TextView) convertView.findViewById(R.id.cityState);    holder.txtPhone = (TextView) convertView.findViewById(R.id.phone);    convertView.setTag(holder);   } else {    holder = (ViewHolder) convertView.getTag();   }      holder.txtName.setText(searchArrayList.get(position).getName());   holder.txtCityState.setText(searchArrayList.get(position).getCityState());   holder.txtPhone.setText(searchArrayList.get(position).getPhone());   return convertView;  }  static class ViewHolder {   TextView txtName;   TextView txtCityState;   TextView txtPhone;  } } (This is basically the same as the List14.java API demo) Finally, we'll wire it all up in the main class file: public class CustomListView extends Activity {     @Override     public void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.main);                 ArrayList<SearchResults> searchResults = GetSearchResults();                 final ListView lv1 = (ListView) findViewById(R.id.ListView01);         lv1.setAdapter(new MyCustomBaseAdapter(this, searchResults));                 lv1.setOnItemClickListener(new OnItemClickListener() {          @Override          public void onItemClick(AdapterView<?> a, View v, int position, long id) {           Object o = lv1.getItemAtPosition(position);           SearchResults fullObject = (SearchResults)o;           Toast.makeText(ListViewBlogPost.this, "You have chosen: " + " " + fullObject.getName(), Toast.LENGTH_LONG).show();          }          });     }         private ArrayList<SearchResults> GetSearchResults(){      ArrayList<SearchResults> results = new ArrayList<SearchResults>();            SearchResults sr1 = new SearchResults();      sr1.setName("John Smith");      sr1.setCityState("Dallas, TX");      sr1.setPhone("214-555-1234");      results.add(sr1);            sr1 = new SearchResults();      sr1.setName("Jane Doe");      sr1.setCityState("Atlanta, GA");      sr1.setPhone("469-555-2587");      results.add(sr1);            sr1 = new SearchResults();      sr1.setName("Steve Young");      sr1.setCityState("Miami, FL");      sr1.setPhone("305-555-7895");      results.add(sr1);            sr1 = new SearchResults();      sr1.setName("Fred Jones");      sr1.setCityState("Las Vegas, NV");      sr1.setPhone("612-555-8214");      results.add(sr1);            return results;     } } Notice that we first get an ArrayList of SearchResults objects (normally this would be from an external data source...), pass it to the custom adapter, then set up a click listener. The listener gets the item that was clicked, converts it back to a SearchResults object, and does whatever it needs to do. Fire it up in the emulator, and you should wind up with something like this:

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