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  • WPF Spellcheck Engine takes up too much memory.

    - by Matt H.
    Each datatemplate in my WPF ItemsControl contains FIVE custom bindable richtextbox controls. It is a data-driven app that for authoring multiple-choice questions -- The question and four answer choices must all support: 1) Spell check 2) Rich formatting (otherwise I'd use regular textboxes) The spell check object in .NET 4 has a Friend constructor that takes a single argument of owner As TextBoxBase This means every richtextbox in the ItemsControl has 5 Spellcheck objects! This is the problem -- every spell check engine is consuming about 500k memory. So after you favor in the spellcheck, bindings, additional controls in the DataTemplate, etc.. a single multi choice question consumes more than 3MB memory. Users with 100--200 questions will quickly see the App raise it's memory consumption to 500+ MB. Management is definitely not OK with this. Is there a way to minimimze this problem? The best suggestion I've heard is to enable/disable spellcheck if the richtextbox is in the ItemsControl's scrollviewer: I haven't gotten an answer to how to go about it: (http://stackoverflow.com/questions/2869012/possible-to-implement-an-isviewportvisible-dependencyproperty-for-an-item-in-an-i) Any good ideas?

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  • Modelling Business Logic with NON-Techies

    - by cbmeeks
    The setup: Winform/ASP.NET MVC projects. Learning NHibernate SQL-Server driven apps I work with clients that have no idea how to model an application. That's what I'm for. However, we have lots of conflicts with validation, mis-understandings, etc. For example, the client will ask for an order entry screen. The screen should require a "product". That's fine and dandy. However, the client didn't know to tell me that the user can't order a product of "Class A" unless it's Tuesday. Or, they need a time entry screen. 2 days before it's rolled into production, they casually forgot to mention that certain activities are only valid for certain situations. These situations being a week of coding. That's of course, some crude examples (not by much!). But the problem is getting these non-technical clients to layout their business logic. They somehow didn't realize that the "Class A" problem would come up two weeks later, etc. I'm all for agile programming but is there an easy way to somehow make business logic like this extremely easy to implement and change on almost a daily basis? I of course am splitting the project into hopefully intelligent pieces, using NHibernate, etc. But making this BI logic so dynamic is really making it hard to project timelines, etc. Any suggestions? I know there will never be a perfect client (or a perfect provider) but how do you guys deal with the constant mis-understandings? Thanks.

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  • Unit Testing Error - The unit test adapter failed to connect to the data source or to read the data

    - by michael.lukatchik
    I'm using VSTS 2K8 and I've set up a Unit Test Project. In it, I have a test class with a method that does a simple assertion. I'm using an Excel 2007 spreadsheet as my data source. My test method looks like this: [DataSource("System.Data.Odbc", "Dsn=Excel Files;dbq=|DataDirectory|\\MyTestData.xlsx;defaultdir=C:\\TestData;driverid=1046;maxbuffersize=2048;pagetimeout=5", "Sheet1", DataAccessMethod.Sequential)] [DeploymentItem("MyTestData.xlsx")] [TestMethod()] public void State_Value_Is_Set() { string expected = "MD"; string actual = TestContext.DataRow["State"] as string; Assert.AreEqual(expected, actual); } As indicated in the method decoration attributes, my Excel spreadsheet is on my local C:/ Drive. In it, the sheet where all of my data is located is named "Sheet1". I've copied the Excel spreadsheet into my project and I've set its Build Action = "Content" and I've set its Copy to Output Directory = "Copy if Newer". When trying to run this simple unit test, I receive the following error: The unit test adapter failed to connect to the data source or to read the data. For more information on troubleshooting this error, see "Troubleshooting Data-Driven Unit Tests" (http://go.microsoft.com/fwlink/?LinkId=62412) in the MSDN Library. Error details: ERROR [42S02] [Microsoft][ODBC Excel Driver] The Microsoft Office Access database engine could not find the object 'Sheet1'. Make sure the object exists and that you spell its name and the path name correctly. I've verified that the sheet name is spelled correctly (i.e. Sheet1) and I've verified that my data sources are set correctly. Web searches haven't turned up much at all. And I'm totally stumped. All help or input is appreciated!!!!

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  • When *not* to use prepared statements?

    - by Ben Blank
    I'm re-engineering a PHP-driven web site which uses a minimal database. The original version used "pseudo-prepared-statements" (PHP functions which did quoting and parameter replacement) to prevent injection attacks and to separate database logic from page logic. It seemed natural to replace these ad-hoc functions with an object which uses PDO and real prepared statements, but after doing my reading on them, I'm not so sure. PDO still seems like a great idea, but one of the primary selling points of prepared statements is being able to reuse them… which I never will. Here's my setup: The statements are all trivially simple. Most are in the form SELECT foo,bar FROM baz WHERE quux = ? ORDER BY bar LIMIT 1. The most complex statement in the lot is simply three such selects joined together with UNION ALLs. Each page hit executes at most one statement and executes it only once. I'm in a hosted environment and therefore leery of slamming their servers by doing any "stress tests" personally. Given that using prepared statements will, at minimum, double the number of database round-trips I'm making, am I better off avoiding them? Can I use PDO::MYSQL_ATTR_DIRECT_QUERY to avoid the overhead of multiple database trips while retaining the benefit of parametrization and injection defense? Or do the binary calls used by the prepared statement API perform well enough compared to executing non-prepared queries that I shouldn't worry about it? EDIT: Thanks for all the good advice, folks. This is one where I wish I could mark more than one answer as "accepted" — lots of different perspectives. Ultimately, though, I have to give rick his due… without his answer I would have blissfully gone off and done the completely Wrong Thing even after following everyone's advice. :-) Emulated prepared statements it is!

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  • What should every developer know about databases?

    - by Aaronaught
    Whether we like it or not, many if not most of us developers either regularly work with databases or may have to work with one someday. And considering the amount of misuse and abuse in the wild, and the volume of database-related questions that come up every day, it's fair to say that there are certain concepts that developers should know - even if they don't design or work with databases today. So: What are the important concepts that developers and other software professionals ought to know about databases? Guidelines for Responses: Keep your list short. One concept per answer is best. Be specific. "Data modelling" may be an important skill, but what does that mean precisely? Explain your rationale. Why is your concept important? Don't just say "use indexes." Don't fall into "best practices." Convince your audience to go learn more. Upvote answers you agree with. Read other people's answers first. One high-ranked answer is a more effective statement than two low-ranked ones. If you have more to add, either add a comment or reference the original. Don't downvote something just because it doesn't apply to you personally. We all work in different domains. The objective here is to provide direction for database novices to gain a well-founded, well-rounded understanding of database design and database-driven development, not to compete for the title of most-important.

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  • Threads, Sockets, and Designing Low-Latency, High Concurrency Servers

    - by lazyconfabulator
    I've been thinking a lot lately about low-latency, high concurrency servers. Specifically, http servers. http servers (fast ones, anyway) can serve thousands of users simultaneously, with very little latency. So how do they do it? As near as I can tell, they all use events. Cherokee and Lighttpd use libevent. Nginx uses it's own event library performing much the same function of libevent, that is, picking a platform optimal strategy for polling events (like kqueue on *bsd, epoll on linux, /dev/poll on Solaris, etc). They all also seem to employ a strategy of multiprocess or multithread once the connection is made - using worker threads to handle the more cpu intensive tasks while another thread continues to listen and handle connections (via events). This is the extent of my understanding and ability to grok the thousand line sources of these applications. What I really want are finer details about how this all works. In examples of using events I've seen (and written) the events are handling both input and output. To this end, do the workers employ some sort of input/output queue to the event handling thread? Or are these worker threads handling their own input and output? I imagine a fixed amount of worker threads are spawned, and connections are lined up and served on demand, but how does the event thread feed these connections to the workers? I've read about FIFO queues and circular buffers, but I've yet to see any implementations to work from. Are there any? Do any use compare-and-swap instructions to avoid locking or is locking less detrimental to event polling than I think? Or have I misread the design entirely? Ultimately, I'd like to take enough away to improve some of my own event-driven network services. Bonus points to anyone providing solid implementation details (especially for stuff like low-latency queues) in C, as that's the language my network services are written in.

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  • Does HttpListener work well on Mono?

    - by billpg
    Hi everyone. I'm looking to write a small web service to run on a small Linux box. I prefer to code in C#, so I'm looking to use Mono. I don't want the overhead of running a full web server or Mono's version of ASP.NET. I'm thinking of having a single process with a thread dealing with each client connection. Shared memory between threads instead of a database. I've read a little on Microsoft's version of HttpListener and how it works with the Http.sys driver. Alas, Mono's documentation on this class is just the automated class interface with no discussion of how it works under the hood. (Linux doesn't have Http.sys, so I imagine it's implemented substantially differently.) Could anyone point me towards some resources discussing this module please? Many thanks, Bill, billpg.com (A little background to my question for the interested.) Some time ago, I asked this question, interested in keeping a long conversation open with lots of back-and-forth. I had settled on designing my own ad-hoc protocol, but people I spoke to really wanted a REST interface, even at the cost of the "Okay, send your command now" signal. So, I wondered about running ASP.NET on a Linux/Mono server, but stumbled upon HttpListener. This seemed ideal, as each "conversation" could run in a separate thread. The thread that calls HttpListener in a loop can look for which thread each incomming connection is for and pass the reference to that thread. The alternative for an ASP.NET driven service, would be to have the ASPX code pick up the state from a database, and write back the new state when it finishes. Yes, it would work, but that's a lot of overhead.

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  • C# WinForms. Multiple Forms in separate threads

    - by Calum Murray
    I'm trying to run an ATM Simulation in C# with Windows Forms that can have more than one instance of an ATM machine transacting with a bank account simultaneously. The idea is to use semaphores/locking to block critical code that may lead to race conditions. My question is this: How can I run two Forms simultaneously on separate threads? In particular, how does all of this fit in with the Application.Run() that's already there? Here's my main class: public class Bank { private Account[] ac = new Account[3]; private ATM atm; public Bank() { ac[0] = new Account(300, 1111, 111111); ac[1] = new Account(750, 2222, 222222); ac[2] = new Account(3000, 3333, 333333); Application.Run(new ATM(ac)); } static void Main(string[] args) { new Bank(); } } ...that I want to run two of these forms on separate threads... public partial class ATM : Form { //local reference to the array of accounts private Account[] ac; //this is a reference to the account that is being used private Account activeAccount = null; private static int stepCount = 0; private string buffer = ""; // the ATM constructor takes an array of account objects as a reference public ATM(Account[] ac) { InitializeComponent(); //Sets up Form ATM GUI in ATM.Designer.cs this.ac = ac; } ... I've tried using Thread ATM2 = new Thread(new ThreadStart(/*What goes in here?*/)); But what method do I put in the ThreadStart constructor, since the ATM form is event-driven and there's no one method controlling it? Thanks, Calum

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  • How should a one-man development shop document their code?

    - by CKoenig
    Hi, please let me first describe my situation. I work in an IT department for a small-to-medium sized industrial-company and basically I'm the only real developer (sometimes a second guy joins in for his own projects). I programm mostly in C#/.net. Of course I only programm for internal need (Intranet, reporting, data-driven apps, some mobile apps, ...). My question is how should I document my work? It's a highly dynamic environment (the features and bug fixes I implement are tested by me during production, and go live, often within a day. If I technical documentation like MSDN or even overview diagramms those would take me more time to sync than the whole programming process. Also I feel it's a waste of time because I would be the only one who ever read it. I do understand that if I get sick, leave, or forget this documentation would be valuable. PS:well of course you are right - the quesion is how much and how/where. I try using the XML-docu comments for the public exposed parts but as I'm a believer in self-documenting code the comments mostly restates in plain text what you can read from the method-head itself :(Maybe using the remarks section is the key but if you have 30 lines of code with a 15 line xml-comment in front it just looks dirty (sorry for posting it here but our firewall rejects JSON :( )

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  • Communication between EJB3 Instances (JEE inter-bean communication) possible?

    - by Hank
    I'm designing a part of a JEE6 application, consisting of EJB3 beans. Part of the requirements are multiple parallel (say a few hundred) long running (over days) database hunts. Individual hunts have different search parameters (start time, end time, query filter). Parameters may get changed over time. Currently I'm thinking of the following: SearchController (Stateless Session Bean) formulates a set of search parameters, sends it off to a SearchListener via JMS SearchListener (Message Driven Bean) receives search parameters, instantiates a SearchWorker with the parameters SearchWorker (SLSB) hunts repeatedly through the database; when it finds something, the result is sent off via JMS, and the search continues; when the given 'end-time' has reached, it ends What I'm wondering now: Is there a problem, with EJB3 instances running for days? (Other than that I need to be able to deal with container restarts...) How do I know how many and which EJB instances of SearchWorker are currently running? Is it possible to communicate with them individually (similar to sending a System V signal to a unix process), e.g. to send new parameters, to end an instance, etc..

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  • Publish failed using Ant publisher (Eclipse/datanucleus).

    - by aronp
    Dear All, I am being driven mad the following (apparently hard) error from eclipse. Publish failed using Ant publisher Resource is out of sync with the file system: '/MyServlet/build/classes/com/inver/hotzones/database/BaseNetworkData.class'. I have seen comments on similar errors where refreshing eclipses view of the project helps but it is not helping me. Have tried cleaning the project, removing it from the webserver, deleting war files but cant seem to clear it. I have reset my TMPDIR variable so that it uses a directory on the same filesystem as that appeared to be another possible cause. The error occurs on classes which have been enhanced by datanuculeus. I have auto-enhance on the project. The other references to this problem indicate that it is due to Eclipses view of the project being out of step with the filesystem, and I am guessing that this has something to do with thedata nucleus enhancement. Any ideas? Thanks. I am using Eclipse 3.5.2 with latest datanucleus pluggins. Stack trace org.eclipse.core.runtime.CoreException: Resource is out of sync with the file system: '/MyServlet/build/classes/com/inver/hotzones/database/BaseNetworkData.class'. at org.eclipse.jst.server.generic.core.internal.publishers.AbstractModuleAssembler.copyModule(AbstractModuleAssembler.java:172) at org.eclipse.jst.server.generic.core.internal.publishers.WarModuleAssembler.assemble(WarModuleAssembler.java:31) at org.eclipse.jst.server.generic.core.internal.publishers.AntPublisher.assembleModule(AntPublisher.java:167) at org.eclipse.jst.server.generic.core.internal.publishers.AntPublisher.publish(AntPublisher.java:128) at org.eclipse.jst.server.generic.core.internal.GenericServerBehaviour.publishModule(GenericServerBehaviour.java:82) at org.eclipse.wst.server.core.model.ServerBehaviourDelegate.publishModule(ServerBehaviourDelegate.java:949) at org.eclipse.wst.server.core.model.ServerBehaviourDelegate.publishModules(ServerBehaviourDelegate.java:1039) at org.eclipse.wst.server.core.model.ServerBehaviourDelegate.publish(ServerBehaviourDelegate.java:872) at org.eclipse.wst.server.core.model.ServerBehaviourDelegate.publish(ServerBehaviourDelegate.java:708) at org.eclipse.wst.server.core.internal.Server.publishImpl(Server.java:2731) at org.eclipse.wst.server.core.internal.Server$PublishJob.run(Server.java:278) at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)

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  • Splitting EJBs and interfaces into separate module -- deployment fails

    - by Hank
    I'm having trouble following this guide to "extract" my interfaces and entities from my EAR to use them from another Web Application: I use NetBeans 6.8 and Glassfish 3.0.1 "Java Class Library" project contains all the entities and interfaces "Java EE Application" project class library added to the project, is packaged into the EAR contains EJB implementations, MDBs, Test "Java Web Application" project class library added to the project, is packaged into the WAR contains REST interface When I build and deploy the Web Application, all goes well. When I build the JEE application, I can see the jar-file (interfaces, entities) being included. But when I try to deploy the EAR, Glassfish refuses it with a java.lang.NoClassDefFoundError error: [#|2010-03-28T18:25:59.875+0200|WARNING|glassfishv3.0|javax.enterprise.system.tools.deployment.org.glassfish.deployment.common|_ThreadID=28;_ThreadName=Thread-1;|Error in annotation processing: java.lang.NoClassDefFoundError: mvs/core/StoreServiceLocal|#] [#|2010-03-28T18:25:59.876+0200|SEVERE|glassfishv3.0|javax.enterprise.system.core.com.sun.enterprise.v3.server|_ThreadID=28;_ThreadName=Thread-1;|Exception while deploying the app java.lang.IllegalArgumentException: Invalid ejb jar [CoreServer]: it contains zero ejb. Note: 1. A valid ejb jar requires at least one session, entity (1.x/2.x style), or message-driven bean. 2. EJB3+ entity beans (@Entity) are POJOs and please package them as library jar. 3. If the jar file contains valid EJBs which are annotated with EJB component level annotations (@Stateless, @Stateful, @MessageDriven, @Singleton), please check server.log to see whether the annotations were processed properly. 'mvs/core/StoreServiceLocal' is an interface which is defined in the library jar file. What am I doing wrong?

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  • PHP CodeIgniter Framework - Thoughts on developing with it?

    - by Sootah
    I've been reviewing different frameworks to use for my next couple of major web applications, and after days of research am almost set on using CodeIgniter. The reason I'm leaning towards CI is that so far it looks to be the best suited for me. It doesn't require constant command-line access (I am currently using shared hosting; the projects do not warrant a dedicate server yet), nothing special has to be installed on the server running it (you just upload the framework to the root of whatever your developing), and they appear to have some excellent documentation, videos, and tutorials on how to get started. Do any of you have experience with CodeIgniter? If so, what is your opinion of it and its features? What had you developed with it, and what types of applications is it best suited to create? I certainly don't want to get into a situation where I'm trying to bend a framework to do something that it isn't well-suited for. Both of my projects will be database-driven apps that will require user registration, the ability to manipulate data that is specific to their account (their posts, listings, user account details, etc), amongst other things. Also, if you have any other PHP framework suggestions, I am open to them. Thanks in advance for your help! -Sootah

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  • Rails : fighting long http response times with ajax. Is it a good idea? Please, help with implementa

    - by baranov
    Hi, everybody! I've googled some tutorials, browsed some SO answers, and was unable to find a recipe for my problem. I'm writing a web site which is supposed to display almost realtime stock chart. Data is stored in constantly updating MySQL database, I wrote a find_by_sql query code which fetches all the data I need to get my chart drawn. Everything is ok, except performance - it takes from one second to one minute for different queries to fetch all the data from the database, this time includes necessary (My)SQL-server side calculations. This is simply unacceptable. I got the following idea: if the data is queried from the MySQL server one point a time instead of entire dataset, it takes only about 1-100ms to get an individual point. I imagine the data fetch process might be browser-driven. After the user presses the button in order to get a chart drawn, controller makes one request to the database and renders, say, a progress bar, say 1% ready. When the browser gets the response, it immediately makes an (ajax) request, and the server fetches the next piece of data and renders "2%". And so on, until all the data is ready and the server displays the requested chart. Could this be implemented in rails+js, is there a tutorial for solving a similar problem on the Web? I suppose if the thing is feasible at all, somebody should have already done this before. I have read several articles about ajax, I believe I do understand general principles, but never did nontrivial ajax programming myself. Thanks for your time!

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  • Learning Clojure - What should I know about Java and more.

    - by kartan
    Hello, I have started learning Clojure recently, my main programming language is Ruby and I have no Java experience whatsoever. Which Java standard classes are a must to know when working with Clojure? Obviously Clojure doesn't come with a wrapper for everything and a lot of functionality is provided by Java's libraries. There's like a gazillion of them on javadocs - which ones should I explore? Where do I look for and how do I install third party libraries? In Ruby I'd visit Rubyforge or Rubytoolbox and then just gem install the package I found interesting. Which editor/ide for Clojure would you recommend (with the lowest learning curve)? I am trying to use Netbeans with Enclojure and paradoxally it's my biggest obstacle so far: Each generated project has some xml files, folders, library dependencies etc. the purpose of I have no clue. I am doing some labrepl exercises and wanted to try out some of the bundled libraries separately in a new project, but this simple task I cannot accomplish :/ Are there any clojure community driven blogs with news, code tips etc?

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  • Class 'org.springframework.http.converter.ResourceHttpMessageConverter' not found - how to correct?

    - by Ash Kim
    Eclipse STS is reporting I have problem with my spring project. It's a fresh project generated from the Spring Web MVC Project Template (File-New-Spring Template Project-Spring Web MVC ). When I create the project it has no problems - it's only once I modify the pom (by adding the hibernate dependencies) that STS then picks up the spring problem. Strangely if I revert the pom the problem remains. Also I can run the project on a spring tc server and all works correctly. Any ideas how I can satisfy this problem report? "Class 'org.springframework.http.converter.ResourceHttpMessageConverter' not found" mvc-config.xml /src/main/webapp/WEB-INF/spring line 9 Spring Beans Problem mvc-config.xml: <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"> <mvc:annotation-driven /> <!-- <= PROBLEMATIC LINE REPORTED BY STS --> <!-- Resolves view names to protected .jsp resources within the /WEB-INF/views directory --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/views/"/> <property name="suffix" value=".jsp"/> </bean> </beans>

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  • Java Client .class File Protection

    - by Zac
    I am in the requirements phase of building a JEE application that will most likely run on a GlassFish/JBoss backend (doesn't matter for now). I know I shouldn't be thinking about architecture at requirements time, but one can't help but start to imagine how the components would all snap together :-) Here are some hard, non-flexible requirements on the client-side: (1) The client application will be a Swing box (2) The client is free to download, but will use a subscription model (thus requiring a login mechanism with server-side authentication/authorization, etc.) (3) Yes, Java is the best platform solution for the problem at hand for reasons outside the scope of this post (4) The client-side .class files need safeguarding against decompiling That last (4th) requirement is the basis of this post. I'm not really worried about someone actually decompiling and getting at my source code: in the end, it's just Swing controls driven by some lightweight business logic. I'm worried about a scenario where someone decompiles my code, modifies it to exploit/attack the server, re-compiles, and fires it up. I've envisioned all sorts of nasty solutions, but didn't know if this was a common problem with a common solution for JEE developers. Any thoughts? Not interested in "code obfuscation" techniques! Thanks for any input!

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  • Message queue proxy in Python + Twisted

    - by gasper_k
    Hi, I want to implement a lightweight Message Queue proxy. It's job is to receive messages from a web application (PHP) and send them to the Message Queue server asynchronously. The reason for this proxy is that the MQ isn't always avaliable and is sometimes lagging, or even down, but I want to make sure the messages are delivered, and the web application returns immediately. So, PHP would send the message to the MQ proxy running on the same host. That proxy would save the messages to SQLite for persistence, in case of crashes. At the same time it would send the messages from SQLite to the MQ in batches when the connection is available, and delete them from SQLite. Now, the way I understand, there are these components in this service: message listener (listens to the messages from PHP and writes them to a Incoming Queue) DB flusher (reads messages from the Incoming Queue and saves them to a database; due to SQLite single-threadedness) MQ connection handler (keeps the connection to the MQ server online by reconnecting) message sender (collects messages from SQlite db and sends them to the MQ server, then removes them from db) I was thinking of using Twisted for #1 (TCPServer), but I'm having problem with integrating it with other points, which aren't event-driven. Intuition tells me that each of these points should be running in a separate thread, because all are IO-bound and independent of each other, but I could easily put them in a single thread. Even though, I couldn't find any good and clear (to me) examples on how to implement this worker thread aside of Twisted's main loop. The example I've started with is the chatserver.py, which uses service.Application and internet.TCPServer objects. If I start my own thread prior to creating TCPServer service, it runs a few times, but the it stops and never runs again. I'm not sure, why this is happening, but it's probably because I don't use threads with Twisted correctly. Any suggestions on how to implement a separate worker thread and keep Twisted? Do you have any alternative architectures in mind?

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  • Can LINQ expression classes implement the observer pattern instead of deferred execution?

    - by Tormod
    Hi. We have issues within an application using a state machine. The application is implemented as a windows service and is iteration based (it "foreaches" itself through everything) and there are myriads of instances being processed by the state machine. As I'm reading the MEAP version of Jon Skeets book "C# in Depth, 2nd ed", I'm wondering if I can change the whole thing to use linq expression instances so that guards and conditions are represented using expression trees. We are building many applications on this state machine engine and would probably greatly benefit from the new Expression tree visualizer in VS 2010 Now, simple example. If I have an expression tree where there is an OR Expression condition with two sub nodes, is there any way that these can implement the observer pattern so that the expression tree becomes event driven? If a condition change, it should notify its parent node (the OR node). Since the OR node then changes from "false" to "true", then it should notify ITS parent and so on. I love the declarative model of expression trees, but the deferred execution model works in opposite direction of the control flow if you want event based "live" conditions. Am I off on a wild goose chase here? Or is there some concept in the BCL that may help me achieve this?

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  • Injecting Dependencies into Domain Model classes with Nhibernate (ASP.NET MVC + IOC)

    - by Sunday Ironfoot
    I'm building an ASP.NET MVC application that uses a DDD (Domain Driven Design) approach with database access handled by NHibernate. I have domain model class (Administrator) that I want to inject a dependency into via an IOC Container such as Castle Windsor, something like this: public class Administrator { public virtual int Id { get; set; } //.. snip ..// public virtual string HashedPassword { get; protected set; } public void SetPassword(string plainTextPassword) { IHashingService hasher = IocContainer.Resolve<IHashingService>(); this.HashedPassword = hasher.Hash(plainTextPassword); } } I basically want to inject IHashingService for the SetPassword method without calling the IOC Container directly (because this is suppose to be an IOC Anti-pattern). But I'm not sure how to go about doing it. My Administrator object either gets instantiated via new Administrator(); or it gets loaded via NHibernate, so how would I inject the IHashingService into the Administrator class? On second thoughts, am I going about this the right way? I was hoping to avoid having my codebase littered with... currentAdmin.Password = HashUtils.Hash(password, Algorithm.Sha512); ...and instead get the domain model itself to take care of hashing and neatly encapsulate it away. I can envisage another developer accidently choosing the wrong algorithm and having some passwords as Sha512, and some as MD5, some with one salt, and some with a different salt etc. etc. Instead if developers are writing... currentAdmin.SetPassword(password); ...then that would hide those details away and take care of those problems listed above would it not?

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  • Should client-server code be written in one "project" or two?

    - by Ricket
    I've been beginning a client-server application. At first I naturally created two projects in Eclipse, two source control repositories, etc. But I'm quickly seeing that there is a bit of shared code between the two that would probably benefit to sharing instead of copying. In addition, I've been learning and trying test-driven development, and it seems to me that it would be easier to test based on real client components rather than having to set up a huge amount of code just to mock something, when the code is probably mostly in the client. My biggest concern in merging the client and server is of security; how do I ensure that the server pieces of the code do not reach an user's computer? So especially if you are writing client-server applications yourself (and especially in Java, though this can turn into a language-agnostic question if you'd like to share your experience with this in other languages), what sort of separation do you keep between your client and server code? Are they just in different packages/namespaces or completely different binaries using shared libraries, or something else entirely? How do you test the code together and yet ship separately?

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  • Integrating Magento with a simple static website.

    - by ExtraLean
    Magento is an awesomely powerful ecommerce platform. That said, it is also very complex, and I'd like to know if there is a relatively simple way to utilize Magento as our mISV site's backend to fulfill orders without actually "using" Magento's framework to build the site, run the site, etc. In other words, I don't want to use the built-in CMS, etc. since we have a static website already built. I'd just like our Buy Now buttons to utilize the checkout stuff, and would like to be able to use the back-end part to keep track of orders etc. I was able to accomplish this "fairly" easily with osCommerce, but Magento is proving to be a little more difficult to wrap my head around since I've only started looking at it for a few days now. I found another person asking this same exact question on the Magento wiki (along with several others in the forum), and none of them ever receive a reply for some reason. I noticed that there are may Magento experts on Stack Overflow, so I thought I'd give it a go here. This is an example of one question asked by someone on their wiki, and it captures the essence of what I'm trying to accomplish: Hi, as far as I understand, all shopping cart/eCommerce solutions I see are full featured PHP driven web sites. This means that all the pages the user interacts with, are server generated, and thus, the experience, is tied to the magento framework/workflow. I’d like to integrate bits and pieces of eCommerce/shopping cart in my existing website. Effectively, I’d like to have: 1) on a product information page, a “buy now/add to cart” button that adds to a cart 2) on every page, a view cart/checkout option 3) on a checkout page, with additional content already in place, having the magento “checkout” block integrated in the page (and not the entire page generated from Magento). Have any of you done this with Magento? This is for a simple one-product website so any advice you could share would be highly appreciated.

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  • Generic FSM for game in C++ ?

    - by Mr.Gando
    Hello, I was wondering if there's a way I could code some kind of "generic" FSM for a game with C++?. My game has a component oriented design, so I use a FSM Component. my Finite State Machine (FSM) Component, looks more or less this way. class gecFSM : public gecBehaviour { public: //Constructors gecFSM() { state = kEntityState_walk; } gecFSM(kEntityState s) { state = s; } //Interface void setRule(kEntityState initialState, int inputAction, kEntityState resultingState); void performAction(int action); private: kEntityState fsmTable[MAX_STATES][MAX_ACTIONS]; }; I would love to hear your opinions/ideas or suggestions about how to make this FSM component, generic. With generic I mean: 1) Creating the fsmTable from an xml file is really easy, I mean it's just a bunch of integers that can be loaded to create an MAX_STATESxMAX_ACTION matrix. void gecFSM::setRule(kEntityState initialState, int inputAction, kEntityState resultingState) { fsmTable[initialState][inputAction] = resultingState; } 2) But what about the "perform Action" method ? void gecFSM::performAction(int action) { switch( smTable[ ownerEntity->getState() ][ action ] ) { case WALK: /*Walk action*/ break; case STAND: /*Stand action*/ break; case JUMP: /*Jump action*/ break; case RUN: /*Run action*/ break; } } What if I wanted to make the "actions" and the switch generic? This in order to avoid creating a different FSM component class for each GameEntity? (gecFSMZombie, gecFSMDryad, gecFSMBoss etc ?). That would allow me to go "Data Driven" and construct my generic FSM's from files for example. What do you people suggest?

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  • Webforms vs. MVC. Once you start using MVC.. Do you ever go back to webforms?

    - by punkouter
    I checked out MVC months ago and didn't really get it.. but recently as I have become a better programmer I think it is making sense.. Here is my theory.. tell me if I got it Right In the 90s for Microsoft Devs we had Classic ASP. This mixed VBscript and HTML on the same page. So you needed to create all the HTML yourself and mix HTML and VBScript. This was not considered Ideal. Then .NET came along and everyone liked it because it was similiar to event driven VB 6 style programming. It created this abstraction of binding data to ASP Servier controls. It made getting Enumerated data easy to get on the screen with one line. Then recently Jquery and SOA concepts are mixed together.. Now people think.. Why create this extra layer of abstraction when I can just directly use .NET as a data provider and use jquery AJAX calls to get the data and create the HTML with it directly .. no need for the Webforms abstraction layer.. Sowe are back to creating HTML directly like we did in 1999. So MVC is all about saying Stop pretending like WEb programming is a VB6 app! Generate HTML directly! Am I missing anything? So I wonder.. for you people out there using MVC... is it the sort of things that once you get used to it you never want to go back to webforms??

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  • Creating parallel selenium tests in C# and using Nunit as the runner application

    - by damianmartin
    I am writing a new test suite for the company to test a very complex ASP.NET application which is heavily AJAX driven. We have decided to use Selenium (Grid & Remote Control) and Nunit to run these tests. The actually tests are dynamically created at run time from a spreadsheet. Each Column in an excel spreadsheet relates to a new test and each row relates to a selenium command (but in plain English and the dll converts this into Selenium code). My problem i have at the moment is getting the tests running in parallel. There will be 1000+ tests so it is too time consuming to have 1 test run at a time. Selenium Grid and Selenium Remote Control(s) are setup correctly because I can run there demo. From what i have read I need to use Punit but i can not find any documentation on what a test in punit should look like. Nunit tests are [SetUp] [TearDown] [Test]. Can anyone point me in the right direction. Thanks in advance.

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