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• .NET WebService IPC - Should it be done to minimise some expensive operations?

  - by Kyle

  I'm looking at a few different approaches to a problem: Client requests work, some stuff gets done, and a result (ok/error) is returned. A .NET web service definitely seems like the way to go, my only issue is that the "stuff" will involve building up and tearing down a session for each request. Does abstracting the "stuff" out to an app (which would keep a single session active, and process the request from the web service) seem like the right way to go? (and if so, what communication method) The work time is negligible, my concern is the hammering the transaction servers in question will probably get if I create/drop a session for each job. Is some form of IPC or socket based communication a feasible solution here? Thoughts/comments/experiences much appreciated. Edit: After a bit more research, it seems like hosting a WCF service in a Windows Service is probably a better way to go...

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• ClassCastException in iterating list returned by Query using Hibernate Query Language

  - by Tushar Paliwal

  I'm beginner in hibernate.I'm trying a simplest example using HQL but it generates exception at line 25 ClassCastException when i try to iterate list.When i try to cast the object returned by next() methode of iterator it generates the same problem.I could not identify the problem.Kindly give me solution of the problem. Employee.java package one; import javax.persistence.Entity; import javax.persistence.Id; @Entity public class Employee { @Id private Long id; private String name; public Long getId() { return id; } public void setId(Long id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Employee(Long id, String name) { super(); this.id = id; this.name = name; } public Employee() { } } Main2.java package one; import java.util.Iterator; import java.util.List; import org.hibernate.Query; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.Transaction; import org.hibernate.cfg.Configuration; public class Main2 { public static void main(String[] args) { SessionFactory sf=new Configuration().configure().buildSessionFactory(); Session s1=sf.openSession(); Query q=s1.createQuery("from Employee "); Transaction tx=s1.beginTransaction(); List l=q.list(); Iterator itr=l.iterator(); while(itr.hasNext()) { Object obj[]=(Object[])itr.next();//Line 25 for(Object temp:obj) { System.out.println(temp); } } tx.commit(); s1.close(); sf.close(); } }

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• SQLBrowser will not start

  - by Oliver

  SQL Server 2005 x64 on Windows Server 2003 x64, with multiple instances (default + 2 named). Engineers moved server to a different domain. Since then, cannot get SQLBrowser to start. Still able to query the default instance, and can access named instances by port (TCP:hostname,port#). When on server, can use SSMS to connect to the instances, all is well from that perspective. No errors in the SQL Server logs. As SQLBrowser is starting, an entry in EventViewer.Application says that one of the named instances has an invalid configuration, but I haven't been able to figure out what is invalid. Startup continues, and next message says "The SQLBrowser service was unable to establish SQL instance and connectivity discovery." Next, it enables instance and connectivity discovery support; next, another message about that same named instance having an invalid configuration; then an event says that SQLBrowser has started; last, an event shows the SQLBrowser service has shutdown. I got SQLBrowser to get past the issue with the first named instance by temporarily renaming a registry entry, and now the second named instance can be accessed by name rather than port. Still, cannot access the first named instance by name. Advice?

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• Hello world/Console Project in Visual Studio 2008 64 bit

  - by grobartn

  So I am trying to run console 64 bit Hello World program. I have Windows 7 Enterprise x64 bit version. I have installed Visual Studio 2008 and have added all of components needed for 64 bit. I want to create simple console application. It turns out to be a problem. I have simple standard hello world project. I have created it using New Project - Empty project. I added main.cpp that contains this: #include <iostream> using namespace std; int main() { cout << "howdy\n"; } I added new configuration to the project by clicking on Config Manager and added x64 config. Compiled and it compiles. Tried running it and cmd.exe shoots up with following error: "The application has failed to start because its side-by-side configuration is in correct. Please see the application event log or use the command-line sxstrace.e xe tool for more detail. Press any key to continue . . . " Which set-up step if any I am missing. What am I doing wrong and how should I go about setting simple console hello world in 64 bit world. Thanks for any help

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• Json to treeview (<ul>)

  - by Pieter

  Hi I get the following data back from my WCF Data Service (I cut out the metadata) { "d" : [ {"CodeId": 6, "Title": "A Child Sub Item", "Parent":}, {"CodeId": 5, "Title": "Another Root Item", "Parent": -1}, {"CodeId": 4, "Title": "Child Item", "Parent": 2}, {"CodeId": 2, "Title": "Root Item", "Parent": -1} ] } I am trying to get this into a <ul> style tree with Parent = -1 as root and then the rest as sub items of their parent id's. Can anyone help me please, preferably in jQuery? I will use this in jstree if someone knows of a better way to do this. Thanks

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• .NET Deployment of Interface/Classes for Command Pattern Question

  - by Jonno

  In theory I would like to produce 2 projects: 1) Asp.net (Sever A) 2) DAL running (Server B) I would like to utilise command objects to comunicate with the DAL. ASP.net instantiates a command class e.g. CmdGetAllUsers which impliments IMyCommand interface and sends it to the DAL (using ASMX or WCF). My question is: Would the class definition of CmdGetAllUsers need to exist on the DAL server? Or would having the interface definition be enough? My goal is to reduce the need to redeploy the DAL code, and have it as a fairly simple pass-through layer. Many thanks for your time.

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• PHP Preserve scope when calling a function

  - by Joshua

  I have a function that includes a file based on the string that gets passed to it i.e. the action variable from the query string. I use this for filtering purposes etc so people can't include files they shouldn't be able to and if the file doesn't exist a default file is loaded instead. The problem is that when the function runs and includes the file scope, is lost because the include ran inside a function. This becomes a problem because I use a global configuration file, then I use specific configuration files for each module on the site. The way I'm doing it at the moment is defining the variables I want to be able to use as global and then adding them into the top of the filtering function. Is there any easier way to do this, i.e. by preserving scope when a function call is made or is there such a thing as PHP macros? Edit: Would it be better to use extract($_GLOBALS); inside my function call instead? Edit 2: For anyone that cared. I realised I was over thinking the problem altogether and that instead of using a function I should just use an include, duh! That way I can keep my scope and have my cake too.

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• very simple WebForm with masterpage

  - by Ryan

  I use method=get to send my data from one webform to the other. But I don't want to have in the URL querry things like: Search.aspx?_EVENTTARGET=&_EVENTARGUMENT=&_VIEWSTATE=%2FwEPDwUKLTYwODIwNTg5MQ9kFgJmD2QWAgIDDxYCHgZtZXRob2QFA2dldGRkGOirvzjoAxt%2BfOb915%2FpsYZXmAxLZZdpnK6UW7A9%2Fk83D&_PREVIOUSPAGE=cog5Yzt_1GerH9r2ERTIPbLWMCwMFYteZjmDYCbBO3vobCG4C_mWM7GZMNuBesyAjw77cvuNKl_aSUYzeajiW6W0CjI0tLB6ikjcM4t5Kbg1&__EVENTVALIDATION=%2FwEWAgKYsPjPDQKY24%2FQBBH4CPejKl3spy0A%2BtpMxb%2BCGVGJf73dYtmaEnIFF4IR&name=Amy&state=24&ctl00%24MainContent%24submit=Searchbut i only want the name and the state to be in the Get querry like: ?name=Amy&state=24 <configuration> <authentication mode="Forms"> <forms loginUrl="~/Account/Login.aspx" timeout="2880" /> </authentication> <membership> <providers> <clear/> <add name="AspNetSqlMembershipProvider" type="System.Web.Security.SqlMembershipProvider" connectionStringName="ApplicationServices" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/" /> </providers> </membership> <profile> <providers> <clear/> <add name="AspNetSqlProfileProvider" type="System.Web.Profile.SqlProfileProvider" connectionStringName="ApplicationServices" applicationName="/"/> </providers> </profile> <roleManager enabled="false"> <providers> <clear/> <add name="AspNetSqlRoleProvider" type="System.Web.Security.SqlRoleProvider" connectionStringName="ApplicationServices" applicationName="/" /> <add name="AspNetWindowsTokenRoleProvider" type="System.Web.Security.WindowsTokenRoleProvider" applicationName="/" /> </providers> </roleManager> </system.web> <system.webServer> <modules runAllManagedModulesForAllRequests="true"/> </system.webServer> </configuration>

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• How to integrate access control with my ORM in a .net windows form application?

  - by Ying

  I am developing a general database query tools, a .Net 3.5 Windows Form application. In order to make the presentation layer is independent of the database layer. I use an ORM framework, XPO from DevExpress. But, I have no access control function built in. I surfed Internet and I found in WCF Data Services, there is an interesting concept, Interceptor, which is following AOP(Aspect Oriented Programming). I am wondering who has such an experience to build access control in ORM. My basic requirement is : It should be a general method and controlled by users in runtime. So any hard coding is not acceptable. It could be based on attribute, database table, or even an external assembly. I am willing to buy a ready solution. According to the idea of AOP, an access control function can be integrated with existing functions easily and nearly not knowingly to the previous developer;) Any suggestions are welcome.

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• How to get around circular references in Visual Studio Web Project?

  - by joebeazelman

  I am trying to create a set of WCF web services for an existing website that uses web site instead of a web application project. I would like to create a DLL that I drop into the Bin folder instead of writing all my code inside the App_Code directory. Ideally, I want to create a project and reference it from the web site, but I am running into a difficult situation. The DLL will need to reference configuration and other DLLs located inside the bin folder of the website causing a circular reference. How do I get around this issue?

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• AppFabric caching's local cache isnt working for us... What are we doing wrong?

  - by Olly

  We are using appfabric as the 2ndlevel cache for an NHibernate asp.net application comprising a customer facing website and an admin website. They are both connected to the same cache so when admin updates something, the customer facing site is updated. It seems to be working OK - we have a CacheCLuster on a seperate server and all is well but we want to enable localcache to get better performance, however, it dosnt seem to be working. We have enabled it like this... bool UseLocalCache = int LocalCacheObjectCount = int.MaxValue; TimeSpan LocalCacheDefaultTimeout = TimeSpan.FromMinutes(3); DataCacheLocalCacheInvalidationPolicy LocalCacheInvalidationPolicy = DataCacheLocalCacheInvalidationPolicy.TimeoutBased; if (UseLocalCache) { configuration.LocalCacheProperties = new DataCacheLocalCacheProperties( LocalCacheObjectCount, LocalCacheDefaultTimeout, LocalCacheInvalidationPolicy ); // configuration.NotificationProperties = new DataCacheNotificationProperties(500, TimeSpan.FromSeconds(300)); } Initially we tried using a timeout invalidation policy (3mins) and our app felt like it was running faster. HOWEVER, we noticed that if we changed something in the admin site, it was immediatley updated in the live site. As we are using timeouts not notifications, this demonstrates that the local cache isnt being queried (or is, but is always missing). The cache.GetType().Name returns "LocalCache" - so the factory has made a local cache. Running "Get-Cache-Statistics MyCache" in PS on my dev environment (asp.net app running local from vs2008, cache cluster running on a seperate w2k8 machine) show a handful of Request Counts. However, on the Production environment, the Request Count increases dramaticaly. We tried following the method here to se the cache cliebt-server traffic... http://blogs.msdn.com/b/appfabriccat/archive/2010/09/20/appfabric-cache-peeking-into-client-amp-server-wcf-communication.aspx but the log file had nothing but the initial header in it - i.e no loggin either. I cant find anything in SO or Google. Have we done something wrong? Have we got a screwy install of AppFabric - we installed it via WebPlatform Installer - I think? (note: the IIS box running ASp.net isnt in yhe cluster - it is just the client). Any insights greatfully received!

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• assistance with fxcop

  - by amateur

  I am at present developing a mvc4 project that comunicates to a set of wcf services. I am setting such up in tfs build for a team of developers. I am very much a newbie to fxcop and code analysis in general. I am currently researching it and have some questions following this: Is it recommended to use the rules that come with fxcop? Should it be included as a build task during builds? What is the value from it? Are there guidelines to what rules to abide by or is it best to go with the default? Is it correct to run the analysis as a post build event? I am a newbie to fxcop and would like some feedback. I am as it is integrating stylecop in to my build.

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• How to notify table-data change to a client program?

  - by JMSA

  Suppose I have an application that access data resident in a central DB server and more than one user access data from client machines networked with the DB server. Suppose two client machines are running a copy of the application and two users are accessing the same DB table. How can I automatically refresh the data on the GUI, that is being viewed by one client, as soon as a change is made by another client in the DB table-data? Which technology should be used to solve this particular scenario in .net? WCF?

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• How to embed revision information using mercurial and maven (and svn)

  - by Zwei Steinen

  Our project had a nice hack (although I'm guessing there are better ways to do it) to embed revision information into the artifacts (jar etc.) when we used svn. Now we have migrated to mercurial, and we want to have a similar thing, but before I start working on a similar hack with mercurial, I wanted to know if there are better ways to do this. Thanks for your answers! <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>exec-maven-plugin</artifactId> <executions> <execution> <phase>process-classes</phase> <id>svninfo</id> <goals> <goal>exec</goal> </goals> <configuration> <executable>svn</executable> <arguments> <argument>info</argument> <argument>../</argument> <argument>></argument> <argument>target/some-project/META-INF/svninfo.txt</argument> </arguments> </configuration> </execution> </executions> </plugin>

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• Accessing Remote ASP.NET Web Services' JSON data

  - by Emon

  How can I best create a webservice method which returns JSON data that is to be consumed by an application on a different domain? The following article talks about how to set it up: http://www.codeproject.com/KB/webservices/ASPNET_JSONP.aspx I havent tried it out yet but it seems like there are a lot of steps and the ajax client has to do some extra work. My question, is there a better way to do this? Also, I dont know too much about WCF services. Would I still have to go through a lot of work to enable JSONP? Thanks in advance.

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• #1146 - Table 'phpmyadmin.pma_recent' doesn't exist

  - by Mumin Ali

  Solution Guys... FYI i am using xampp to use phpmyadmin. and this error happens during the process of creating a database on localhost. Below is the code for config.inc file under phpmyadmin directory: <?php /* * This is needed for cookie based authentication to encrypt password in * cookie */ $cfg['blowfish_secret'] = 'xampp'; /* YOU SHOULD CHANGE THIS FOR A MORE SECURE COOKIE AUTH! */ /* * Servers configuration */ $i = 0; /* * First server */ $i++; /* Authentication type and info */ $cfg['Servers'][$i]['auth_type'] = 'HTTP'; $cfg['Servers'][$i]['user'] = 'root'; $cfg['Servers'][$i]['password'] = 'password'; $cfg['Servers'][$i]['extension'] = 'mysql'; $cfg['Servers'][$i]['AllowNoPassword'] = true; $cfg['Lang'] = ''; /* Bind to the localhost ipv4 address and tcp */ $cfg['Servers'][$i]['host'] = 'localhost'; $cfg['Servers'][$i]['connect_type'] = 'tcp'; /* User for advanced features */ $cfg['Servers'][$i]['controluser'] = 'pma'; $cfg['Servers'][$i]['controlpass'] = ''; /* Advanced phpMyAdmin features */ $cfg['Servers'][$i]['pmadb'] = 'phpmyadmin'; $cfg['Servers'][$i]['bookmarktable'] = 'pma_bookmark'; $cfg['Servers'][$i]['relation'] = 'pma_relation'; $cfg['Servers'][$i]['table_info'] = 'pma_table_info'; $cfg['Servers'][$i]['table_coords'] = 'pma_table_coords'; $cfg['Servers'][$i]['pdf_pages'] = 'pma_pdf_pages'; $cfg['Servers'][$i]['column_info'] = 'pma_column_info'; $cfg['Servers'][$i]['history'] = 'pma_history'; $cfg['Servers'][$i]['designer_coords'] = 'pma_designer_coords'; $cfg['Servers'][$i]['tracking'] = 'pma_tracking'; $cfg['Servers'][$i]['userconfig'] = 'pma_userconfig'; $cfg['Servers'][$i]['recent'] = 'pma_recent'; $cfg['Servers'][$i]['table_uiprefs'] = 'pma_table_uiprefs'; /* * End of servers configuration */ ?>

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• How to Inserting message into View that depends on session value. ASP.NET MVC. Best practice

  - by Andrew Florko

  User have to populate multistep questionnaire web-forms and step messages depend on the option chosen by user at the very beginning. Messages are stored in web.config file. I use asp.net mvc project, strong typed views and keep business logic separated from controller in static class. I don't want to make business logic dependency on web.config. Well, I have to insert message into view that depends on session value. There are at least 2 options how to implement this: View model has property that is populated in controller/businessLogic and rendered in view like <%: Model.HelpMessage1 %>. I have to pass web.config values from controller to businessLogic that makes business logic methods signature too complex. I don't want to make configuration source abstract (in order to let business logic read configuration values from its methods directly) also. Create static helper class that is called from view like <%: ViewHelper.HelpMessage1(Model.Option1) %>. But in this case logic what to show seems to be separated into two classes: business logic & viewHelper. What will you suggest? Thank you in advance!

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• Can I use encrypt web.config with a custom protection provider who's assembly is not in the GAC?

  - by James

  I have written a custom protected configuration provider for my web.config. When I try to encrypt my web.config with it I get the following error from aspnet_iisreg aspnet_regiis.exe -pef appSettings . -prov CustomProvider (This is running in my MSBuild) Could not load file or assembly 'MyCustomProviderNamespace' or one of its dependencies. The system cannot find the file specified. After checking with the Fusion log, I confirm it is checking both the GAC, and 'C:/WINNT/Microsoft.NET/Framework/v2.0.50727/' (the location of aspnet_iisreg). But it cannot find the provider. I do not want to move my component into the GAC, I want to leave the custom assembly in my ApplicationBase to copy around to various servers without having to pull/push from the GAC. Here is my provider configuration in the web.config. <configProtectedData> <providers> <add name="CustomProvider" type="MyCustomProviderNamespace.MyCustomProviderClass, MyCustomProviderNamespace" /> </providers> </configProtectedData> Has anyone got any ideas?

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• PowerPoint PlugIn does not read defaults from .dll.config file

  - by Nick T

  I'm working on a very simple PowerPoint plugin, and I'm quite a bit stumped. In my settings.settings file, I have configured a setting "StartPath", which references where the PowerPoint plugin will navigate to using a Browser component. After I compile the application, and run the installer generated by the Setup project, the application is installed and uses the default value in the settings file. However, if I edit the application.dll.config file, the plugin still uses the old values. How can I set things up such that the plugin references the .dll.config file and not its default settings? The code to access the settings is listed below, including the other variants I have tried: //Attempt 1 string location = MyApplication.Properties.Settings.Default.StartPath; //Attempt 2 string location = ConfigurationManager.AppSettings["StartPath"]; //Attempt 3: Configuration element is inaccessible due to its protection level string applicationName = Environment.GetCommandLineArgs()[0] + ".exe"; string exePath = System.IO.Path.Combine(Environment.CurrentDirectory, applicationName); Configuration config = ConfigurationManager.OpenExeConfiguration(exePath); string location = config.AppSettings["StartPath"];

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• Workflow Foundation: Asynchronous operations (lengthy network I/O)

  - by StormianRootSolver

  I have to create an application that will be started a few times per day (it's non - interactive). To operate, it needs LARGE amounts of data from the Internet (megabytes) via a rather slow connection, so the WCF service calls take quite some time. At the same time, it needs to perform local calculations and has a sophisticated initialization process. So, what I want to do is to create a workflow that asynchronously fetches the data (takes a few minutes) while already initializing / calculating locally. Is there a way to accomplish this?

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• Which Visual Studio 2010 edition for sole developer

  - by bufferz

  I am the sole .net developer for a small company. My projects span many .net technologies including WinForms, WPF, SQL, XNA, Linq, WCF, WTF?, and others. I struggle staying on top of all these projects so I'm looking to make my life easier with the release of VS2010. Without a mentor I rely heavily on StackOverflow and whatever else Google comes up with. Should I convince my company to get an edition with an MSDN subscription? Is it one of those things where once you have it, you can't imagine life without it? What about the source control that comes with VS2010, do you all find it better than an SVN server? We're looking to hire another programmer this year, would I be best off getting a Team edition of VS2010 to be best prepared for that hire? Thanks!

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• Exclude subdirectory from rewrite rule in web.config

  - by Clog

  This question comes up often, but I can only find solutions for PHP, Apache, htaccess etc but not for web.config I would like my pages to return in HTTP not HTTPS, except for forms within certain subdirectories. I have created the following web.config file, but how do I exclude a subdirectory called forms. <configuration> <system.webServer> <rewrite> <rules> <rule name="Force all to HTTP" stopProcessing="true"> <match url="(.*)" /> <conditions> <add input="{HTTPS}" pattern="on" ignoreCase="true" /> </conditions> <action type="Redirect" redirectType="Found" url="http://www.mysite.com/{R:1}" /> </rule> </rules> </rewrite> </system.webServer> </configuration> Many thanks all you clever clogs.

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• PHP.ini Settings Are Ignored By PHP5.3.5 Running With Windows 7 And Apache 2.2.15

  - by Andy

  I did an install of PHP5.3.5 on Windows 7 Home Premium using the MSI installer download. I got it to overwrite a previous version of PHP5 in C:\php5\ When first testing it, the server failed to start. I fixed this by adding the path to PHP in the Apache2.2 httpd file where the installer had inserted 2 lines of coded pointing to the ini file directory and the PHP DLL but had left out the directory path. After doing this, the server starts ok and I can run phpinfo to view the PHP settings in my web browser on local host. In the phpinfo it states that the loaded configuration file is C:\php5\php.ini as expected. But if I make any changes to the settings, and reboot the server, none of the changes are reflected in phpinfo. Yes, I do refresh the browser window. If I rename the php.ini to something else to make it invisible phpinfo then correctly identifies that there is no php.ini file loaded. So the settings in php.ini are being ignored and some default settings are being used (but I have no idea where these are derived from). As far as I can tell, there are no other php.ini files on my computer. In phpinfo it states that the Configuration File (php.ini) Path is C:\Windows but this is the same as on a Windows XP computer that I work on. And in the windows folder I don't see any php.ini file. In the windows registry, there is no mention of PHP5, and the PATH environment variable starts with C:\php5\; So hopefully someone can suggest how I can get PHP5 to take notice of the C:\php5\php.ini settings. :)

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• Maven 3 plugin - How to programatically exclude a dependency and all its transitive dependencies?

  - by electrotype

  I'm developing a Maven 3 plugin and I want to exclude some dependencies, and their transitive dependencies, when a configuration is set to true in the plugin. I don't want to use <exclusions> in the POM itself, even in a profile. I want to exclude those dependencies programatically. In fact, what I want is to prevent the dependency jars to be included in the final war (I'm building a war), when a plugin configuration is set to true. I tried : @Mojo(requiresDependencyResolution=ResolutionScope.COMPILE, name="compileHook",defaultPhase=LifecyclePhase.COMPILE) public class compileHook extends AbstractMojo { @Override public void execute() throws MojoExecutionException, MojoFailureException { // ... Set<Artifact> artifacts = this.project.getArtifacts(); for(Artifact artifact : artifacts) { if("org.package.to.remove".equalsIgnoreCase(artifact.getGroupId())) { artifact.setScope("provided"); } } // ... } } Since this occures at the compile phase, it will indeed remove the artifacts with a group id "org.package.to.remove" from having their jars included in the war when packaged. But this doesn't remove the transitive artifacts those dependencies add! What is the best way to programatically remove some dependencies, and their transitive dependencies, from being included in a final .jar/.war?

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• Is multithreading the right way to go for my case?

  - by Julien Lebosquain

  Hello, I'm currently designing a multi-client / server application. I'm using plain good old sockets because WCF or similar technology is not what I need. Let me explain: it isn't the classical case of a client simply calling a service; all clients can 'interact' with each other by sending a packet to the server, which will then do some action, and possible re-dispatch an answer message to one or more clients. Although doable with WCF, the application will get pretty complex with hundreds of different messages. For each connected client, I'm of course using asynchronous methods to send and receive bytes. I've got the messages fully working, everything's fine. Except that for each line of code I'm writing, my head just burns because of multithreading issues. Since there could be around 200 clients connected at the same time, I chose to go the fully multithreaded way: each received message on a socket is immediately processed on the thread pool thread it was received, not on a single consumer thread. Since each client can interact with other clients, and indirectly with shared objects on the server, I must protect almost every object that is mutable. I first went with a ReaderWriterLockSlim for each resource that must be protected, but quickly noticed that there are more writes overall than reads in the server application, and switched to the well-known Monitor to simplify the code. So far, so good. Each resource is protected, I have helper classes that I must use to get a lock and its protected resource, so I can't use an object without getting a lock. Moreover, each client has its own lock that is entered as soon as a packet is received from its socket. It's done to prevent other clients from making changes to the state of this client while it has some messages being processed, which is something that will happen frequently. Now, I don't just need to protect resources from concurrent accesses. I must keep every client in sync with the server for some collections I have. One tricky part that I'm currently struggling with is the following: I have a collection of clients. Each client has its own unique ID. When a client connects, it must receive the IDs of every connected client, and each one of them must be notified of the newcomer's ID. When a client disconnects, every other client must know it so that its ID is no longer valid for them. Every client must always have, at a given time, the same clients collection as the server so that I can assume that everybody knows everybody. This way if I'm sending a message to client #1 telling "Client #2 has done something", I know that it will always be correctly interpreted: Client 1 will never wonder "but who is Client 2 anyway?". My first attempt for handling the connection of a new client (let's call it X) was this pseudo-code (remember that newClient is already locked here): lock (clients) { foreach (var client in clients) { lock (client) { client.Send("newClient with id X has connected"); } } clients.Add(newClient); newClient.Send("the list of other clients"); } Now imagine that in the same time, another client has sent a packet that translates into a message that must be broadcasted to every connected client, the pseudo-code will be something like this (remember that the current client - let's call it Y - is already locked here): lock (clients) { foreach (var client in clients) { lock (client) { client.Send("something"); } } } An obvious deadlock occurs here: on one thread X is locked, the clients lock has been entered, started looping through the clients, and at one moment must get Y's lock... which is already acquired on the second thread, itself waiting for the clients collection lock to be released! This is not the only case like this in the server application. There are other collections which must be kept in sync with the clients, some properties on a client can be changed by another one, etc. I tried other types of locks, lock-free mechanisms and a bunch of other things. Either there were obvious deadlocks when I'm using too much locks for safety, or obvious race conditions otherwise. When I finally find a good middle point between the two, it usually comes with very subtle race conditions / dead locks and other multi-threading issues... my head hurts very quickly since for any single line of code I'm writing I have to review almost the whole application to ensure everything will behave correctly with any number of threads. So here's my final question: how would you resolve this specific case, the general case, and more importantly: aren't I going the wrong way here? I have little problems with the .NET framework, C#, simple concurrency or algorithms in general. Still, I'm lost here. I know I could use only one thread processing the incoming requests and everything will be fine. However, that won't scale well at all with more clients... But I'm thinking more and more to go this simple way. What do you think? Thanks in advance to you, StackOverflow people which have taken the time to read this huge question. I really had to explain the whole context if I want to get some help.

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