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• Experiences with (free) embedded TCP / IP stacks?

  - by Dan

  Does anyone have especially good (or bad) experiences with any of the following embedded TCP / IP stacks? uIP lwIP Bentham's TCP/IP Lean implementation The TCP/IP stack from this book My needs are for a solid, easy-to-port stack. Code size isn't terribly important, performance is relatively important, but ease of use & porting is very important. The system will probably use an RTOS, that hasn't been decided, but in my experience most stacks can be used with or without an RTOS. Most likely the platform will be an ARM variant (ARM7 or CM3 in all likelihood). Not too concerned about bolting the stack to the Ethernet driver, so that isn't a big priority in the selection. I'm not terribly interested in extracting a stack out of an OS, such as Linux, RTEMS, etc. I'm also not interested in commercial offerings such as Interniche, Micrium, etc... The stack doesn't need all sorts of bells & whistles, doesn't need IPv6, and I don't need any stuff on top of it (web servers, FTP servers, etc..) In fact it's possible that I'll only use UDP, although I can envision a couple scenarios where TCP would be preferable. Experiences with other stacks I've missed are of course also very much of interest. Thanks for your time & input.

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• Endless problems with a very simple python subprocess.Popen task

  - by Thomas

  I'd like python to send around a half-million integers in the range 0-255 each to an executable written in C++. This executable will then respond with a few thousand integers. Each on one line. This seems like it should be very simple to do with subprocess but i've had endless troubles. Right now im testing with code: // main() u32 num; std::cin >> num; u8* data = new u8[num]; for (u32 i = 0; i < num; ++i) std::cin >> data[i]; // test output / spit it back out for (u32 i = 0; i < num; ++i) std::cout << data[i] << std::endl; return 0; Building an array of strings ("data"), each like "255\n", in python and then using: output = proc.communicate("".join(data))[0] ...doesn't work (says stdin is closed, maybe too much at one time). Neither has using proc.stdin and proc.stdout worked. This should be so very simple, but I'm getting constant exceptions, and/or no output data returned to me. My Popen is currently: proc = Popen('aux/test_cpp_program', stdin=PIPE, stdout=PIPE, bufsize=1) Advise me before I pull my hair out. ;)

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• What type of webapp is the sweet spot for Scala's Lift framework?

  - by ajay

  What kind of applications are the sweet spot for Scala's lift web framework. My requirements: Ease of development and maintainability Ready for production purposes. i.e. good active online community, regular patches and updates for security and performance fixes etc. Framework should survive a few years. I don't want to write a app in a framework for which no updates/patches are available after 1 year. Has good UI templating engines Interoperation with Java (Scala satisfies this arleady. Just mentioning here for completeness sake) Good component oriented development. Time required to develop should be proportion to the complexity of web application. Should not be totally configuration based. I hate it when code gets automatically generated for me and does all sorts of magic under the hood. That is a debugging nightmare. Amount of Lift knowledge required to develop a webapp should be proportional to the complexity of the web application. i.e I should't have to spend 10+ hours learning Lift just to develop a simple TODO application. (I have knowledge of Databases, Scala) Does Lift satisfy these requirements?

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• How to implement properly plugins in C#?

  - by MartyIX

  I'm trying to add plugins to my game and what I'm trying to implement is this: Plugins will be either mine or 3rd party's so I would like a solution where crashing of the plugin would not mean crashing of the main application. Methods of plugins are called very often (for example because of drawing of game objects). What I've found so far: 1) http://www.codeproject.com/KB/cs/pluginsincsharp.aspx - simple concept that seems like it should work nicely. Since plugins are used in my game for every round I would suffice to add the Restart() method and if a plugin is no longer needed Unload() method + GC should take care of that. 2) http://mef.codeplex.com/Wikipage - Managed Extensibility Framework - my program should work on .NET 3.5 and I don't want to add any other framework separately I want to write my plugin system myself. Therefore this solution is out of question. 3) Microsoft provides: http://msdn.microsoft.com/en-us/library/system.addin.aspx but according to a few articles I've read it is very complex. 4) Different AppDomains for plugins. According to Marc Gravell ( http://stackoverflow.com/questions/665668/usage-of-appdomain-in-c ) different AppDomains allow isolation. Unloading of plugins would be easy. What would the performance load be? I need to call methods of plugins very often (to draw objects for example). Using Application Domains - http://msdn.microsoft.com/en-us/library/yb506139.aspx A few tutorials on java2s.com Could you please comment on my findings? New approaches are also welcomed! Thanks!

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• My OpenCL kernel is slower on faster hardware.. But why?

  - by matdumsa

  Hi folks, As I was finishing coding my project for a multicore programming class I came up upon something really weird I wanted to discuss with you. We were asked to create any program that would show significant improvement in being programmed for a multi-core platform. I’ve decided to try and code something on the GPU to try out OpenCL. I’ve chosen the matrix convolution problem since I’m quite familiar with it (I’ve parallelized it before with open_mpi with great speedup for large images). So here it is, I select a large GIF file (2.5 MB) [2816X2112] and I run the sequential version (original code) and I get an average of 15.3 seconds. I then run the new OpenCL version I just wrote on my MBP integrated GeForce 9400M and I get timings of 1.26s in average.. So far so good, it’s a speedup of 12X!! But now I go in my energy saver panel to turn on the “Graphic Performance Mode” That mode turns off the GeForce 9400M and turns on the Geforce 9600M GT my system has. Apple says this card is twice as fast as the integrated one. Guess what, my timing using the kick-ass graphic card are 3.2 seconds in average… My 9600M GT seems to be more than two times slower than the 9400M.. For those of you that are OpenCL inclined, I copy all data to remote buffers before starting, so the actual computation doesn’t require roundtrip to main ram. Also, I let OpenCL determine the optimal local-worksize as I’ve read they’ve done a pretty good implementation at figuring that parameter out.. Anyone has a clue? edit: full source code with makefiles here http://www.mathieusavard.info/convolution.zip cd gimage make cd ../clconvolute make put a large input.gif in clconvolute and run it to see results

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• Is there any way to optimize this LINQ where clause that searches for multiple keywords on multiple

  - by Daniel T.

  I have a LINQ query that searches for multiple keywords on multiple columns. The intention is that the user can search for multiple keywords and it will search for the keywords on every property in my Media entity. Here is a simplified example: var result = repository.GetAll<Media>().Where(x => x.Title.Contains("Apples") || x.Description.Contains("Apples") || x.Tags.Contains("Apples") || x.Title.Contains("Oranges") || x.Description.Contains("Oranges") || x.Tags.Contains("Oranges") || x.Title.Contains("Pears") || x.Description.Contains("Pears") || x.Tags.Contains("Pears") ); In other words, I want to search for the keywords Apples, Oranges, and Pears on the columns Title, Description, and Tags. The outputted SQL looks like this: SELECT * FROM Media this_ WHERE (((((((( this_.Title like '%Apples%' or this_.Description like '%Apples%') or this_.Tags like '%Apples%') or this_.Title like '%Oranges%') or this_.Description like '%Oranges%') or this_.Tags like '%Oranges%') or this_.Title like '%Pears%') or this_.Description like '%Pears%') or this_.Tags like '%Pears%') Is this the most optimal SQL in this case? If not, how do I rewrite the LINQ query to create the most optimal SQL statement? I'm using SQLite for testing and SQL Server for actual deployment.

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• video streaming infrastructure

  - by alchemical

  We would like to set-up a live video-chat web site and are looking for basic architectural advice and/or a recomendation for a particular framework to use. Here are the basic features of the site: Most streams will be broadcast live from a single person with a web cam, etc., and viewed by typically 1-10 people, although there could be up to 100+ viewers on the high side. Audio and video do not have to be super-high quality, but do need to be "good enough". The main point is to convey the basic info in the video (and audio). If occasionally the frame-rate drops low and then goes back to normal fairly soon, we could live with that. Budget is an issue, so we are in general looking for a lower cost solution that will give us most of what we need in temers of performance and quality. We are looking at Peer1 for co-lo. The rest of our web site will be .Net / Windows platform. We are open to looking at any platform for the best streaming solution, although our technical expertise is currently more on the Windows side.

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• How does MSN filter spam?

  - by Marius

  I am trying to create a newsletter for our business. The last few days have been spent testing, and one of things I have noticed is that MSN seemingly randomly filters out some of my test messages. This is super-frustrating. I like the PEAR Mail MIME-package, and have been using that. I may send one email from one of our servers, resulting in the message getting through, and in the next minute, the same message sent from our other server ends up in the junk folder. Then if I add an attachment to the email, and the same message passes though the filter from the server that was previously blocked. I think. What the ####? Is this like throwing a dice, without me having any control over what is trash, and what isn't? I have sent email from several servers, all of which are shared. But I am unsure this is the problem. The problem is that it is seemingly random how MSN filters email. Some emails get through, and some other don't for seemingly irrational reasons. I am running out of ideas, but I am not giving up. Therefore I am writing to you for HARDCORE technical info on how MSN filters spam.

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• SQLite on iPhone - Techniques for tracking down multithreading-related bugs

  - by Jasarien

  Hey guys, I'm working with an Objective-C wrapper around SQLite that I didn't write, and documentation is sparse... It's not FMDB. The people writing this wrapper weren't aware of FMDB when writing this code. It seems that the code is suffering from a bug where database connections are being accessed from multiple threads -- which according to the SQLite documentation won't work if the if SQLite is compiled with SQLITE_THREADSAFE 2. I have tested the libsqlite3.dylib provided as part of the iPhone SDK and seen that it is compiled in this manner, using the sqlite_threadsafe() routine. Using the provided sqlite library, the code regularly hits SQLITE_BUSY and SQLITE_LOCKED return codes when performing routines. To combat this, I added some code to wait a couple of milliseconds and try again, with a maximum retry count of 50. The code didn't contain any retry logic prior to this. Now when a sqlite call returns SQLITE_BUSY or SQLITE_LOCKED, the retry loop is invoked and the retry returns SQLITE_MISUSE. Not good. Grasping at straws, I replaced the provided sqlite library with a version compiled by myself setting SQLITE_THREADSAFE to 1 - which according to the documentation means sqlite is safe to be used in a multithreaded environment, effectively serialising all of the operations. It incurs a performance hit, that which I haven't measured, but it ridded the app of the SQLITE_MISUSE happening and seemed to not need the retry logic as it never hit a busy or locked state. What I would rather do is fix the problem of accessing a single db connection from multiple threads, but I can't for the life of me find where it's occurring. So if anyone has any tips on locating multithreaded bugs I would be extremely appreciative. Thanks in advance.

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• What encoding does InstallShield expect non-latin-alphabet string table entries to use?

  - by DNS

  I work on an app that gets distributed via a single installer containing multiple localizations. The build process includes a script that updates the .ism string table with translations for each supported language. This works fine for languages like French and German. But when testing the installer in, i.e. Japanese, the text shows up as a series of squares. It's unlikely to be a font problem, since the InstallShield-supplied strings show up fine; only the string table entries are mangled. So the problem seems to be that the strings are in the wrong encoding. The .ism is in XML format, with UTF-8 declared as its encoding, so I assumed the strings needed to be UTF-8 encoded as well. Do they actually need to use the encoding of the target platform? Is there any concern, then, about targets having different encodings, i.e. Chinese systems using one GB-encoding versus another? What is the right thing to do here?

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• Javascript error when attempting to open a modal window in a modal window

  - by The Sheek Geek

  The application is running on a windows server 2003 box using asp.net 2.0 and is an IE specific web app. There is a button that opens a form in an iframe using showModalDialog(...) from a function call located in the javascript. Here is an example of the fucntion: function ShowBusinessHoursSubForm( source ) { var retval = window.showModalDialog("htm/" + locLocaleID + "/SubFormHostFrame.htm", source, "dialogWidth:265px;dialogHeight:261px;help:no;scroll:no;status:no;"); } The host frame is loading an aspx page which contains the actual form that is being used. On the form that is opened there is a button that, when clicked, submits changed to the form. However, if no changed were made before the form was submitted, another modal window pops up stating that there were no changed to the form. This modal window is opened through registration of some javascript in the button click event. The code is as follows (C#): string l_S_ErrorScript = "<script type='text/javascript' language='javascript'>window.showModalDialog('htm/" + l_S_Culture + "/NotChangedErrorDialog.htm', '../../" + l_S_SkinPath + "', 'dialogWidth:310px;dialogHeight:145px;scroll:no;help:no;status:no;');</script>"; if(!m_Page.ClientScript.IsStartupScriptRegistered("ErrorScript")) { m_Page.ClientScript.RegisterStartupScript(this.GetType(), "ErrorScript", l_S_ErrorScript); } When the button is clicked and this dialog needs to appear the following javascript error appears: Error: Object doesn't support this property or method The weird thing is, if I access the application locally and try it everything works fine, but accessing from another computer causes the error. Also, depending on what server (we have many servers for testing all with windows server 2003) the error may not occur on another computer either. These computers are running the same software version using the same version of IE with the same settings. I'm inclined to believe that there is some configuration issue somewhere, but with the settings being the same it is hard to tell. I cannot really change how the app works or the technologies used either. Anyone have any ideas as to what may be causing this?

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• Non-blocking TCP buffer issues.

  - by Poni

  Hi! I think I'm in a problem. I have two TCP apps connected to each other which use winsock I/O completion ports to send/receive data (non-blocking sockets). Everything works just fine until there's a data transfer burst. The sender starts sending incorrect/malformed data. I allocate the buffers I'm sending on the stack, and if I understand correctly, that's a wrong to do, because these buffers should remain as I sent them until I get the "write complete" notification from IOCP. Take this for example: void some_function() { char cBuff[1024]; // filling cBuff with some data WSASend(...); // sending cBuff, non-blocking mode // filling cBuff with other data WSASend(...); // again, sending cBuff // ..... and so forth! } If I understand correctly, each of these WSASend() calls should have its own unique buffer, and that buffer can be reused only when the send completes. Correct? Now, what strategies can I implement in order to maintain a big sack of such buffers, how should I handle them, how can I avoid performance penalty, etc'? And, if I am to use buffers that means I should copy the data to be sent from the source buffer to the temporary one, thus, I'd set SO_SNDBUF on each socket to zero, so the system will not re-copy what I already copied. Are you with me? Please let me know if I wasn't clear.

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• Restricting dynamically loaded classes and jars based on a security policy

  - by Max

  Hi, I would like to dynamically load a set of jars or classes (i.e. plugins loaded at runtime). At the same time, I would like to restrict what these plugins are able to do in the JVM. For a test case, I would like to restrict them to pretty much everything (right now I'm just allowing one System.getProperty value to be read). I am currently using a security policy file, but I'm having difficulty specifying a policy for one folder or package in my codeBase, but not another. Here is how my policy looks now: grant codeBase "file:/home/max/programming/java/plugin/plugins/" { permission java.util.PropertyPermission "java.version", "read"; }; grant codeBase "file:/home/max/programming/java/plugin/api/" { permission java.security.AllPermission; }; Where (for testing purposes), all files in the plugins package and folder are restricted, but the classes in the api folder are not. Is this possible? Do I have to create a custom class loader? Is there a better way to go about doing this? Thanks.

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• Ruby: add custom properties to built-in classes

  - by dreftymac

  Question: Using Ruby it is simple to add custom methods to existing classes, but how do you add custom properties? Here is an example of what I am trying to do: myarray = Array.new(); myarray.concat([1,2,3]); myarray._meta_ = Hash.new(); # obviously, this wont work myarray._meta_['createdby'] = 'dreftymac'; myarray._meta_['lastupdate'] = '1993-12-12'; ## desired result puts myarray._meta_['createdby']; #=> 'dreftymac' puts myarray.inspect() #=> [1,2,3] The goal is to construct the class definition in such a way that the stuff that does not work in the example above will work as expected. Update: (clarify question) One aspect that was left out of the original question: it is also a goal to add "default values" that would ordinarily be set-up in the initialize method of the class. Update: (why do this) Normally, it is very simple to just create a custom class that inherits from Array (or whatever built-in class you want to emulate). This question derives from some "testing-only" code and is not an attempt to ignore this generally acceptable approach.

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• Ruby: add custom properties to built-in classes

  - by dreftymac

  Question: Using Ruby it is simple to add custom methods to existing classes, but how do you add custom properties? Here is an example of what I am trying to do: myarray = Array.new(); myarray.concat([1,2,3]); myarray._meta_ = Hash.new(); # obviously, this wont work myarray._meta_['createdby'] = 'dreftymac'; myarray._meta_['lastupdate'] = '1993-12-12'; ## desired result puts myarray._meta_['createdby']; #=> 'dreftymac' puts myarray.inspect() #=> [1,2,3] The goal is to construct the class definition in such a way that the stuff that does not work in the example above will work as expected. Update: (clarify question) One aspect that was left out of the original question: it is also a goal to add "default values" that would ordinarily be set-up in the initialize method of the class. Update: (why do this) Normally, it is very simple to just create a custom class that inherits from Array (or whatever built-in class you want to emulate). This question derives from some "testing-only" code and is not an attempt to ignore this generally acceptable approach.

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• Why is Microsoft under-supporting or under-developping VBNET?

  - by Will Marcouiller

  I ran into a situation where the lack of some features has become somewhat frustrating while developping in VB.NET 2.0. Since my first day of programming, I've always been a C programmer, and still am. Naturally, I chose C# as my favorite .NET language. Recently, a customer of mine has obliged that all of his development projects which disregard SharePoint development have to be written in VB.NET 2.0, that is to avoid conflictual systems to come into some problems. That is a legitimate choice of his which I approve somehow, since he's running some old central systems and is slowly migrating toward latest technologies. As for me, I would have prefered to go with C#, but then, never having done much VB in my life, I see it as an opportunity to learn somethings new, how to handle this and that in VBNET, etc. Except that the syntax is really too verbose for me, which is a pain! I got used to it and that is fine. However, I recently wanted to use the InternalsVisibleToAttribute which I discovered lastly here on SO. But then, in addition to not being able to have lambda expression that returns no value, which I discovered months ago, today I learn that I can't use the attribute in VBNET! Here is what I have read in an article: [...] Sorry VB.Net developers, Microsoft is again shunning you guys and this attribute is NOT available to you.... :( And here is the link: InternalsVisibleTo: Testing internal methods in .Net 2.0 I have heard from Anders Hejlsberg mouth while watching a Webcast from his presentation of .NET 4.0 Framework that the VBNET team was working or has worked in collaboration with the C# team (Eric Lippert and others) in order to bring VBNET to offer the same features as C# offers. But then, I say to myself that the VBNET team has a huge step forward to make, if already in .NET 2.0, some of the most important features lacked! So my question is this: Why is Microsoft under-supporting or under-developping VBNET? Will VBNET ever be lacking the C# features?

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• Cucumber Error: Socket Error for Test Environment Host in REST API

  - by tmo256

  I posted this to the Cucumber group with no replies, which makes me wonder if this is actually a cucumber issue or not. I'm pretty new to cucumber, and there are a number of things I really don't quite understand about how the cucumber environment is set up and executed within the test environment. I have a REST API rails app I'm testing with cucumber, using the RestClient gem to generate a post to controller create action. When I run the feature with a hard-coded URL pointing to a running localhost server (my local dev server environment; replacing tickets_url with "http:// localhost/tickets" in the snippet below), my cucumber steps execute as expected. However, when the resource URL resolves to the cucumber host I'm declaring, I get a socket error exception. getaddrinfo: nodename nor servname provided, or not known (SocketError) From the steps file: When /^POS Adapter sends JSON data to the Tickets resource$/ do ticket = { :ticket = { ... } } host! "test.host" puts tickets_url RestClient.post tickets_url, ticket.to_json, :content_type = :json, :accepts = :json end (the "puts" statement prints "http://test.host/tickets") Using the following gems: cucumber-0.6.1 webrat-0.6.0 rest-client-1.2.0 I should also say I have a similar set up in another rails app, using test.host as my host, and it seems to work fine. I'd appreciate any insight on what I might be missing in my configuration or what this could be related to.

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• Application passwords and SQLite security

  - by Bryan

  I have been searching on google for information regarding application passwords and SQLite security for some time, and nothing that I have found has really answered my questions. Here is what I am trying to figure out: 1) My application is going to have an optional password activity that will be called when the application is first opened. My questions for this are a) If I store the password via android preference or SQLite database, how can I ensure security and privacy for the password, and b) how should password recovery be handled? Regarding b) from above, I have thought about requiring an email address when the password feature is enabled, and also a password hint question for use when requesting password recovery. Upon successfully answering the hint question, the password is then emailed to the email address that was submitted. I am not completely confident in the security and privacy of the email method, especially if the email is sent when the user is connected to an open, public wireless network. 2) My application will be using an SQLite database, which will be stored on the SD card if the user has one. Regardless of whether it is stored on the phone or the SD card, what options do I have for data encryption, and how does that affect the application performance? Thanks in advance for time taken to answer these questions. I think that there may be other developers struggling with the same concerns.

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• Creating Dependencies Only to be able to Unit Test

  - by arin

  I just created a Manager that deals with a SuperClass that is extended all over the code base and registered with some sort of SuperClassManager (SCM). Now I would like to test my Manager that is aware of only the SuperClass. I tried to create a concrete SCM, however, that depends on a third party library and therefore I failed to do that in my jUnit test. Now the option is to mock all instances of this SCM. All is good until now, however, when my Manager deals with the SCM, it returns children of the SuperClass that my Manager does not know or care about. Nevertheless, the identities of these children are vital for my tests (for equality, etc.). Since I cannot use the concrete SCM, I have to mock the results of calls to the appropriate functions of the SCM, however, this means that my tests and therefore my Manager need to know and care about the children of the SuperClass. Checking the code base, there does not seem to be a more appropriate location for my test (that already maintains the appropriate real dependencies). Is it worth it to introduce unnecessary dependencies for the sake of unit testing?

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• How do I Unit Test Actions without Mocking that use UpdateModel?

  - by Hellfire

  I have been working my way through Scott Guthrie's excellent post on ASP.NET MVC Beta 1. In it he shows the improvements made to the UpdateModel method and how they improve unit testing. I have recreated a similar project however anytime I run a UnitTest that contains a call to UpdateModel I receive an ArgumentNullException naming the controllerContext parameter. Here's the relevant bits, starting with my model: public class Country { public Int32 ID { get; set; } public String Name { get; set; } public String Iso3166 { get; set; } } The controller action: [AcceptVerbs(HttpVerbs.Post)] public ActionResult Edit(Int32 id, FormCollection form) { using ( ModelBindingDataContext db = new ModelBindingDataContext() ) { Country country = db.Countries.Where(c => c.CountryID == id).SingleOrDefault(); try { UpdateModel(country, form); db.SubmitChanges(); return RedirectToAction("Index"); } catch { return View(country); } } } And finally my unit test that's failing: [TestMethod] public void Edit() { CountryController controller = new CountryController(); FormCollection form = new FormCollection(); form.Add("Name", "Canada"); form.Add("Iso3166", "CA"); var result = controller.Edit(2 /*Canada*/, form) as RedirectToRouteResult; Assert.IsNotNull(result, "Expected to be redirected on successful POST."); Assert.AreEqual("Show", result.RouteName, "Expected to redirect to the View action."); } ArgumentNullException is thrown by the call to UpdateModel with the message "Value cannot be null. Parameter name: controllerContext". I'm assuming that somewhere the UpdateModel requires the System.Web.Mvc.ControllerContext which isn't present during execution of the test. I'm also assuming that I'm doing something wrong somewhere and just need to pointed in the right direction. Help Please!

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• Writing a JMS Publisher without "public static void main"

  - by The Elite Gentleman

  Hi guys, Every example I've seen on the web, e.g. http://www.codeproject.com/KB/docview/jms_to_jms_bridge_activem.aspx, creates a publisher and subscriber with a public static void main method. I don't think that'll work for my web application. I'm learning JMS and I've setup Apache ActiveMQ to run on JBoss 5 and Tomcat 6 (with no glitches). I'm writing a messaging JMS service that needs to send email asynchronously. I've already written a JMS subscriber that receives the message (the class inherits MessageListener). My question is simple: How do I write a publisher that will so that my web applications can call it? Does it have to be published somewhere? My thought is to create a publisher with a no-attribute constructor (in there) and get the MessageQueue Factory, etc. from the JNDI pool (in the constructor). Is my idea correct? How do I subscribe my subscriber to the Queue Receiver? (So far, the subscriber has no constructor, and if I write a constructor, do I always subscribe myself to the Queue receiver?) Thanks for your help, sorry if my terminology is not up to scratch, there are too many java terminologies that I get lost sometimes (maybe a java GPS will do! :-) ) PS Is there a tutorial out there that explains how to write a "better" (better can mean anything, but in my case it's all about performance in high demand requests) JMS Publisher and Subscriber that I can run on Application Server such as JBoss or Glassfish? Don't forget that the JMS application will needs a "guarantee" uptime as many applications will use this.

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• Best approach to storing image pixels in bottom-up order in Java

  - by finnw

  I have an array of bytes representing an image in Windows BMP format and I would like my library to present it to the Java application as a BufferedImage, without copying the pixel data. The main problem is that all implementations of Raster in the JDK store image pixels in top-down, left-to-right order whereas BMP pixel data is stored bottom-up, left-to-right. If this is not compensated for, the resulting image will be flipped vertically. The most obvious "solution" is to set the SampleModel's scanlineStride property to a negative value and change the band offsets (or the DataBuffer's array offset) to point to the top-left pixel, i.e. the first pixel of the last line in the array. Unfortunately this does not work because all of the SampleModel constructors throw an exception if given a negative scanlineStride argument. I am currently working around it by forcing the scanlineStride field to a negative value using reflection, but I would like to do it in a cleaner and more portable way if possible. e.g. is there another way to fool the Raster or SampleModel into arranging the pixels in bottom-up order but without breaking encapsulation? Or is there a library somewhere that will wrap the Raster and SampleModel, presenting the pixel rows in reverse order? I would prefer to avoid the following approaches: Copying the whole image (for performance reasons. The code must process hundreds of large (= 1Mpixels) images per second and although the whole image must be available to the application, it will normally access only a tiny (but hard-to-predict) portion of the image.) Modifying the DataBuffer to perform coordinate transformation (this actually works but is another "dirty" solution because the buffer should not need to know about the scanline/pixel layout.) Re-implementing the Raster and/or SampleModel interfaces from scratch (but I have a hunch that I will be unable to avoid this.)

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• Data in linux FIFO seems lost

  - by Utoah

  Hi, I have a bash script which wants to do some work in parallel, I did this by putting each job in an subshell which is run in the background. While the number of job running simultaneously should under some limit, I achieve this by first put some lines in a FIFO, then just before forking the subshell, the parent script is required to read a line from this FIFO. Only after it gets a line can it fork the subshell. Up to now, everything works fine. But when I tried to read a line from the FIFO in the subshell, it seems that only one subshell can get a line, even if there are apparently more lines in the FIFO. So I wonder why cannot other subshell(s) read a line even when there are more lines in the FIFO. My testing code looks something like this: #!/bin/sh fifo_path="/tmp/fy_u_test2.fifo" mkfifo $fifo_path #open fifo for r/w at fd 6 exec 6 $fifo_path process_num=5 #put $process_num lines in the FIFO for ((i=0; i<${process_num}; i++)); do echo "$i" done &6 delay_some(){ local index="$1" echo "This is what u can see. $index \n" sleep 20; } #In each iteration, try to read 2 lines from FIFO, one from this shell, #the other from the subshell for i in 1 2 do date /tmp/fy_date #If a line can be read from FIFO, run a subshell in bk, otherwise, block. read -u6 echo " $$ Read --- $REPLY --- from 6 \n" /tmp/fy_date { delay_some $i #Try to read a line from FIFO read -u6 echo " $$ This is in child # $i, read --- $REPLY --- from 6 \n" /tmp/fy_date } & done And the output file /tmp/fy_date has content of: Mon Apr 26 16:02:18 CST 2010 32561 Read --- 0 --- from 6 \n Mon Apr 26 16:02:18 CST 2010 32561 Read --- 1 --- from 6 \n 32561 This is in child # 1, read --- 2 --- from 6 \n

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• .NET regex's not working - 1# check beginning of text entered #2 check structure

  - by Olly

  OK it has unfortunately been a while since I've used REGEX and I am struggling to wonder why its not working with my project. I have used Regex Tester which says my two tests are valid but when it comes to testing in my project they get rejected. 1) Check the text starts with certain characters [RegularExpression("(spAPP)",ErrorMessage = "Stored procedures must begin with spAPP")] This seems to accept spAPP on it's own, but not something like spAPPabcdef which I want it to. I am struggling to find the "Ignore rest of the text" attribute with REGEX. 2) A bit more complicated. I have certain naming conventions for AD groups, so an example would be "UK ROLE IT APPLICATION DEV ADMIN", up to the role name there are standards (so I need the "UK ROLE IT APPLICATION DEV" checked. [RegularExpression(@"((UK|FRANCE|GERMANY|USA)\s(ROLE)\s(IT|NON-IT)\s(APPLICATION)\s(DEV|TEST|LIVE))", ErrorMessage = "Please use AD naming standards.")] I think it might be the fact I am using () around all the words, but its easier to read in my code. The RegexTester I found seems to indicate that it's right, but again, in my .NET project, it rejects it. Thanks,

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• Problem with Binding Multiple Objects on WPF

  - by Diego Modolo Ribeiro

  Hi, I'm developing a user control called SearchBox, that will act as a replacer for ComboBox for multiple records, as the performance in ComboBox is low for this scenario, but I'm having a big binding problem. I have a base control with a DependencyProperty called SelectedItem, and my SearchControl shows that control so that the user can select the record. The SearchControl also has a DependencyProperty called SelectedItem on it, and it is being updated when the user selects something on the base control, but the UI, wich has the SearchControl, is not being updated. I used a null converter so that I could see if the property was updating, but it's not. Below is some of the code: This is the UI: <NectarControles:MaskedSearchControl x:Name="teste" Grid.Row="0" Grid.Column="1" Height="21" ItemsSource="{Binding C001_Lista}" DisplayMember="C001_Codigo" Custom:CustomizadorTextBox.CodigoCampo="C001_Codigo" ViewType="{x:Type C001:C001_Search}" ViewModelType="{x:Type C001_ViewModel:C001_ViewModel}" SelectedItem="{Binding Path=Instancia.C001_Holding, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource DebuggingConverter}}"> </NectarControles:MaskedSearchControl> This is the relevante part of the SearchControl: Binding selectedItemBinding = new Binding("SelectedItem"); selectedItemBinding.Source = this.SearchControlBase; selectedItemBinding.Mode = BindingMode.TwoWay; selectedItemBinding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged; this.SetBinding(SelectedItemProperty, selectedItemBinding); ... public System.Data.Objects.DataClasses.IEntityWithKey SelectedItem { get { return (System.Data.Objects.DataClasses.IEntityWithKey)GetValue(SelectedItemProperty); } set { SetValue(SelectedItemProperty, value); if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("SelectedItem")); } } Please someone help me... Tks...

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