exception duck - Page 89

Code Contracts: Hiding ContractException

- by DigiMortal

It’s time to move on and improve my randomizer I wrote for an example of static checking of code contracts. In this posting I will modify contracts and give some explanations about pre-conditions and post-conditions. Also I will show you how to avoid ContractExceptions and how to replace them with your own exceptions. As a first thing let’s take a look at my randomizer. public class Randomizer { public static int GetRandomFromRange(int min, int max) { var rnd = new Random(); return rnd.Next(min, max); } public static int GetRandomFromRangeContracted(int min, int max) { Contract.Requires(min < max, "Min must be less than max"); var rnd = new Random(); return rnd.Next(min, max); } } We have some problems here. We need contract for method output and we also need some better exception handling mechanism. As ContractException as type is hidden from us we have to switch from ContractException to some other Exception type that we can catch. Adding post-condition Pre-conditions are contracts for method’s input interface. Read it as follows: pre-conditions make sure that all conditions for method’s successful run are met. Post-conditions are contracts for output interface of method. So, post-conditions are for output arguments and return value. My code misses the post-condition that checks return value. Return value in this case must be greater or equal to minimum value and less or equal to maximum value. To make sure that method can run only the correct value I added call to Contract.Ensures() method. public static int GetRandomFromRangeContracted(int min, int max) { Contract.Requires(min < max, "Min must be less than max"); Contract.Ensures( Contract.Result<int>() >= min && Contract.Result<int>() <= max, "Return value is out of range" ); var rnd = new Random(); return rnd.Next(min, max); } I think that the line I added does not need any further comments. Avoiding ContractException for input interface ContractException lives in hidden namespace and we cannot see it at design time. But it is common exception type for all contract exceptions that we do not switch over to some other type. The case of Contract.Requires() method is simple: we can tell it what kind of exception we need if something goes wrong with contract it ensures. public static int GetRandomFromRangeContracted(int min, int max) { Contract.Requires<ArgumentOutOfRangeException>( min < max, "Min must be less than max" ); Contract.Ensures( Contract.Result<int>() >= min && Contract.Result<int>() <= max, "Return value is out of range" ); var rnd = new Random(); return rnd.Next(min, max); } Now, if we violate the input interface contract giving min value that is not less than max value we get ArgumentOutOfRangeException. Avoiding ContractException for output interface Output interface is more complex to control. We cannot give exception type there and hope that this type of exception will be thrown if something goes wrong. Instead we have to use delegate that gathers information about problem and throws the exception we expect to be thrown. From documentation you can find the following example about the delegate I mentioned. Contract.ContractFailed += (sender, e) => { e.SetHandled(); e.SetUnwind(); // cause code to abort after event Assert.Fail(e.FailureKind.ToString() + ":" + e.DebugMessage); }; We can use this delegate to throw the Exception. Let’s move the code to separate method too. Here is our method that uses now ContractException hiding. public static int GetRandomFromRangeContracted(int min, int max) { Contract.Requires(min < max, "Min must be less than max"); Contract.Ensures( Contract.Result<int>() >= min && Contract.Result<int>() <= max, "Return value is out of range" ); Contract.ContractFailed += Contract_ContractFailed; var rnd = new Random(); return rnd.Next(min, max)+1000; } And here is the delegate that creates exception. public static void Contract_ContractFailed(object sender, ContractFailedEventArgs e) { e.SetHandled(); e.SetUnwind(); throw new Exception(e.FailureKind.ToString() + ":" + e.Message); } Basically we can do in this delegate whatever we like to do with output interface errors. We can even introduce our own contract exception type. As you can see later then ContractFailed event is very useful at unit testing.

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SpringMvc java.lang.NullPointerException When Posting Form To Server [closed]

- by dev_darin

I have a form with a user name field on it when i tab out of the field i use a RESTFUL Web Service that makes a call to a handler method in the controller. The method makes a call to a DAO class that checks the database if the user name exists. This works fine, however when the form is posted to the server i call the same exact function i would call in the handler method however i get a java.lang.NullPointerException when it accesses the class that makes a call to the DAO object. So it does not even access the DAO object the second time. I have exception handlers around the calls in all my classes that makes calls. Any ideas as to whats happening here why i would get the java.lang.NullPointerException the second time the function is called.Does this have anything to do with Spring instantiating DAO classes using a Singleton method or something to that effect? What can be done to resolve this? This is what happens the First Time The Method is called using the Web Service(this is suppose to happen): 13011 [http-8084-2] INFO com.crimetrack.jdbc.JdbcOfficersDAO - Inside jdbcOfficersDAO 13031 [http-8084-2] DEBUG org.springframework.jdbc.core.JdbcTemplate - Executing prepared SQL query 13034 [http-8084-2] DEBUG org.springframework.jdbc.core.JdbcTemplate - Executing prepared SQL statement [SELECT userName FROM crimetrack.tblofficers WHERE userName = ?] 13071 [http-8084-2] DEBUG org.springframework.jdbc.datasource.DataSourceUtils - Fetching JDBC Connection from DataSource 13496 [http-8084-2] DEBUG org.springframework.jdbc.core.StatementCreatorUtils - Setting SQL statement parameter value: column index 1, parameter value [adminz], value class [java.lang.String], SQL type unknown 13534 [http-8084-2] DEBUG org.springframework.jdbc.datasource.DataSourceUtils - Returning JDBC Connection to DataSource 13537 [http-8084-2] INFO com.crimetrack.jdbc.JdbcOfficersDAO - No username was found in exception 13537 [http-8084-2] INFO com.crimetrack.service.ValidateUserNameManager - UserName :adminz does NOT exist The Second time When The Form Is 'Post' and a validation method handles the form and calls the same method the web service would call: 17199 [http-8084-2] INFO com.crimetrack.service.OfficerRegistrationValidation - UserName is not null so going to check if its valid for :adminz 17199 [http-8084-2] INFO com.crimetrack.service.OfficerRegistrationValidation - User Name in try.....catch block is adminz 17199 [http-8084-2] INFO com.crimetrack.service.ValidateUserNameManager - Inside Do UserNameExist about to validate with username : adminz 17199 [http-8084-2] INFO com.crimetrack.service.ValidateUserNameManager - UserName :adminz EXCEPTION OCCURED java.lang.NullPointerException ValidateUserNameManager.java public class ValidateUserNameManager implements ValidateUserNameIFace { private OfficersDAO officerDao; private final Logger logger = Logger.getLogger(getClass()); public boolean DoesUserNameExist(String userName) throws Exception { logger.info("Inside Do UserNameExist about to validate with username : " + userName); try{ if(officerDao.OfficerExist(userName) == true){ logger.info("UserName :" + userName + " does exist"); return true; }else{ logger.info("UserName :" + userName + " does NOT exist"); return false; } }catch(Exception e){ logger.info("UserName :" + userName + " EXCEPTION OCCURED " + e.toString()); return false; } } /** * @return the officerDao */ public OfficersDAO getOfficerDao() { return officerDao; } /** * @param officerdao the officerDao to set */ public void setOfficerDao(OfficersDAO officerDao) { this.officerDao = officerDao; } } JdbcOfficersDAO.java public boolean OfficerExist(String userName){ String dbUserName; try{ logger.info("Inside jdbcOfficersDAO"); String sql = "SELECT userName FROM crimetrack.tblofficers WHERE userName = ?"; try{ dbUserName = (String)getJdbcTemplate().queryForObject(sql, new Object[]{userName},String.class); logger.info("Just Returned from database"); }catch(Exception e){ logger.info("No username was found in exception"); return false; } if(dbUserName == null){ logger.info("Database did not find any matching records"); } logger.info("after JdbcTemplate"); if (dbUserName.equals(userName)) { logger.info("User Name Exists"); return true; }else{ logger.info("User Name Does NOT Exists"); return false; } }catch(Exception e){ logger.info("Exception Message in JdbcOfficersDAO is "+e.getMessage()); return false; } } OfficerRegistrationValidation.java public class OfficerRegistrationValidation implements Validator{ private final Logger logger = Logger.getLogger(getClass()); private ValidateUserNameManager validateUserNameManager; public boolean supports(Class<?> clazz) { return Officers.class.equals(clazz); } public void validate(Object target, Errors errors) { Officers officer = (Officers) target; if (officer.getUserName() == null){ errors.rejectValue("userName", "userName.required"); }else{ String userName = officer.getUserName(); logger.info("UserName is not null so going to check if its valid for :" + userName); try { logger.info("User Name in try.....catch block is " + userName); if (validateUserNameManager.DoesUserNameExist(userName)== true){ errors.rejectValue("userName", "userName.exist"); } } catch (Exception e) { logger.info("Error Occured When validating UserName"); errors.rejectValue("userName", "userName.error"); } } if(officer.getPassword()== null){ errors.rejectValue("password", "password.required"); } if(officer.getPassword2()== null){ errors.rejectValue("password2", "password2.required"); } if(officer.getfName() == null){ errors.rejectValue("fName","fName.required"); } if(officer.getlName() == null){ errors.rejectValue("lName", "lName.required"); } if (officer.getoName() == null){ errors.rejectValue("oName", "oName.required"); } if (officer.getEmailAdd() == null){ errors.rejectValue("emailAdd", "emailAdd.required"); } if (officer.getDob() == null){ errors.rejectValue("dob", "dob.required"); } if (officer.getGenderId().equals("A")){ errors.rejectValue("genderId","genderId.required"); } if(officer.getDivisionNo() == 1){ errors.rejectValue("divisionNo", "divisionNo.required"); } if(officer.getPositionId() == 1){ errors.rejectValue("positionId", "positionId.required"); } if (officer.getStartDate() == null){ errors.rejectValue("startDate","startDate.required"); } if(officer.getEndDate() == null){ errors.rejectValue("endDate","endDate.required"); } logger.info("The Gender ID is " + officer.getGenderId().toString()); if(officer.getPhoneNo() == null){ errors.rejectValue("phoneNo", "phoneNo.required"); } } /** * @return the validateUserNameManager */ public ValidateUserNameManager getValidateUserNameManager() { return validateUserNameManager; } /** * @param validateUserNameManager the validateUserNameManager to set */ public void setValidateUserNameManager( ValidateUserNameManager validateUserNameManager) { this.validateUserNameManager = validateUserNameManager; } } Update Error Log using Logger.Error("Message", e): 39024 [http-8084-2] INFO com.crimetrack.service.OfficerRegistrationValidation - UserName is not null so going to check if its valid for :adminz 39025 [http-8084-2] INFO com.crimetrack.service.OfficerRegistrationValidation - User Name in try.....catch block is adminz 39025 [http-8084-2] ERROR com.crimetrack.service.OfficerRegistrationValidation - Message java.lang.NullPointerException at com.crimetrack.service.OfficerRegistrationValidation.validate(OfficerRegistrationValidation.java:47) at org.springframework.validation.DataBinder.validate(DataBinder.java:725) at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.doBind(HandlerMethodInvoker.java:815) at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.resolveHandlerArguments(HandlerMethodInvoker.java:367) at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:171) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:436) at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:424) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789) at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) at java.lang.Thread.run(Unknown Source) 39025 [http-8084-2] INFO com.crimetrack.service.OfficerRegistrationValidation - Error Occured When validating UserName

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TCP: Address already in use exception - possible causes for client port? NO PORT EXHAUSTION

- by TomTom

Hello, stupid problem. I get those from a client connecting to a server. Sadly, the setup is complicated making debugging complex - and we run out of options. The environment: *Client/Server system, both running on the same machine. The client is actually a service doing some database manipulation at specific times. * The cnonection comes from C# going through OleDb to an EasySoft JDBC driver to a custom written JDBC server that then hosts logic in C++. Yeah, compelx - but the third party supplier decided to expose the extension mechanisms for their server through a JDBC interface. Not a lot can be done here ;) The Symptom: At (ir)regular intervals we get a "Address already in use: connect" told from the JDBC driver. They seem to come from one particular service we run. Now, I did read all the stuff about port exhaustion. This is why we have a little tool running now that counts ports and their states every minute. Last time this happened, we had an astonishing 370 ports in use, with the count rising to about 900 AFTER the error. We aleady patched the registry (it is a windows machine) to allow more than the 5000 client ports standard, but even then, we are far far from that limit to start with. Which is why I am asking here. Ayneone an ide what ELSE could cause this? It is a Windows 2003 Server machine, 64 bit. The only other thing I can see that may cause it (but this functionality is supposedly disabled) is Symantec Endpoint Protection that is installed on the server - and being capable of actinc as a firewall, it could possibly intercept network traffic. I dont want to open a can of worms by pointing to Symantec prematurely (if pointing to Symantec can ever be seen as such). So, anyone an idea what else may be the cause? Thanks

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How to add exception for backup MX to tumgreyspf?

- by Waleed Hamra

I have an Ubuntu raring server running postfix/dovecot as an email server, with tumgreyspf doing greylisting and SPF checks. My problem is that I also have a backup MX server, that is supposed to store my emails temporarily, should my main server ever fails. It usually rejects receiving emails if it finds the main server online and functional. The problem is when it does need to do its job, tumgreyspf rejects all emails from the backup MX with an error like this: Jun 27 16:18:13 hamra postfix/smtpd[28732]: NOQUEUE: reject: RCPT from mxbackup.mydomain.com[x.x.x.x]: 550 5.7.1 <[email protected]>: Recipient address rejected: QUEUE_ID="" SPF Reports: 'SPF fail - not authorized'; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<mxbackup.mydomain.com> any ideas?

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A DirectoryCatalog class for Silverlight MEF (Managed Extensibility Framework)

- by Dixin

In the MEF (Managed Extension Framework) for .NET, there are useful ComposablePartCatalog implementations in System.ComponentModel.Composition.dll, like: System.ComponentModel.Composition.Hosting.AggregateCatalog System.ComponentModel.Composition.Hosting.AssemblyCatalog System.ComponentModel.Composition.Hosting.DirectoryCatalog System.ComponentModel.Composition.Hosting.TypeCatalog While in Silverlight, there is a extra System.ComponentModel.Composition.Hosting.DeploymentCatalog. As a wrapper of AssemblyCatalog, it can load all assemblies in a XAP file in the web server side. Unfortunately, in silverlight there is no DirectoryCatalog to load a folder. Background There are scenarios that Silverlight application may need to load all XAP files in a folder in the web server side, for example: If the Silverlight application is extensible and supports plug-ins, there would be a /ClinetBin/Plugins/ folder in the web server, and each pluin would be an individual XAP file in the folder. In this scenario, after the application is loaded and started up, it would like to load all XAP files in /ClinetBin/Plugins/ folder. If the aplication supports themes, there would be a /ClinetBin/Themes/ folder, and each theme would be an individual XAP file too. The application would qalso need to load all XAP files in /ClinetBin/Themes/. It is useful if we have a DirectoryCatalog: DirectoryCatalog catalog = new DirectoryCatalog("/Plugins"); catalog.DownloadCompleted += (sender, e) => { }; catalog.DownloadAsync(); Obviously, the implementation of DirectoryCatalog is easy. It is just a collection of DeploymentCatalog class. Retrieve file list from a directory Of course, to retrieve file list from a web folder, the folder’s “Directory Browsing” feature must be enabled: So when the folder is requested, it responses a list of its files and folders: This is nothing but a simple HTML page: <html> <head> <title>localhost - /Folder/</title> </head> <body> <h1>localhost - /Folder/</h1> <hr> <pre> <a href="/">[To Parent Directory]</a><br> <br> 1/3/2011 7:22 PM 185 <a href="/Folder/File.txt">File.txt</a><br> 1/3/2011 7:22 PM <dir> <a href="/Folder/Folder/">Folder</a><br> </pre> <hr> </body> </html> For the ASP.NET Deployment Server of Visual Studio, directory browsing is enabled by default: The HTML <Body> is almost the same: <body bgcolor="white"> <h2><i>Directory Listing -- /ClientBin/</i></h2> <hr width="100%" size="1" color="silver"> <pre> <a href="/">[To Parent Directory]</a> Thursday, January 27, 2011 11:51 PM 282,538 <a href="Test.xap">Test.xap</a> Tuesday, January 04, 2011 02:06 AM <dir> <a href="TestFolder/">TestFolder</a> </pre> <hr width="100%" size="1" color="silver"> <b>Version Information:</b> ASP.NET Development Server 10.0.0.0 </body> The only difference is, IIS’s links start with slash, but here the links do not. Here one way to get the file list is read the href attributes of the links: [Pure] private IEnumerable<Uri> GetFilesFromDirectory(string html) { Contract.Requires(html != null); Contract.Ensures(Contract.Result<IEnumerable<Uri>>() != null); return new Regex( "<a href=\"(?<uriRelative>[^\"]*)\">[^<]*</a>", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant) .Matches(html) .OfType<Match>() .Where(match => match.Success) .Select(match => match.Groups["uriRelative"].Value) .Where(uriRelative => uriRelative.EndsWith(".xap", StringComparison.Ordinal)) .Select(uriRelative => { Uri baseUri = this.Uri.IsAbsoluteUri ? this.Uri : new Uri(Application.Current.Host.Source, this.Uri); uriRelative = uriRelative.StartsWith("/", StringComparison.Ordinal) ? uriRelative : (baseUri.LocalPath.EndsWith("/", StringComparison.Ordinal) ? baseUri.LocalPath + uriRelative : baseUri.LocalPath + "/" + uriRelative); return new Uri(baseUri, uriRelative); }); } Please notice the folders’ links end with a slash. They are filtered by the second Where() query. The above method can find files’ URIs from the specified IIS folder, or ASP.NET Deployment Server folder while debugging. To support other formats of file list, a constructor is needed to pass into a customized method: /// <summary> /// Initializes a new instance of the <see cref="T:System.ComponentModel.Composition.Hosting.DirectoryCatalog" /> class with <see cref="T:System.ComponentModel.Composition.Primitives.ComposablePartDefinition" /> objects based on all the XAP files in the specified directory URI. /// </summary> /// <param name="uri"> /// URI to the directory to scan for XAPs to add to the catalog. /// The URI must be absolute, or relative to <see cref="P:System.Windows.Interop.SilverlightHost.Source" />. /// </param> /// <param name="getFilesFromDirectory"> /// The method to find files' URIs in the specified directory. /// </param> public DirectoryCatalog(Uri uri, Func<string, IEnumerable<Uri>> getFilesFromDirectory) { Contract.Requires(uri != null); this._uri = uri; this._getFilesFromDirectory = getFilesFromDirectory ?? this.GetFilesFromDirectory; this._webClient = new Lazy<WebClient>(() => new WebClient()); // Initializes other members. } When the getFilesFromDirectory parameter is null, the above GetFilesFromDirectory() method will be used as default. Download the directory’s XAP file list Now a public method can be created to start the downloading: /// <summary> /// Begins downloading the XAP files in the directory. /// </summary> public void DownloadAsync() { this.ThrowIfDisposed(); if (Interlocked.CompareExchange(ref this._state, State.DownloadStarted, State.Created) == 0) { this._webClient.Value.OpenReadCompleted += this.HandleOpenReadCompleted; this._webClient.Value.OpenReadAsync(this.Uri, this); } else { this.MutateStateOrThrow(State.DownloadCompleted, State.Initialized); this.OnDownloadCompleted(new AsyncCompletedEventArgs(null, false, this)); } } Here the HandleOpenReadCompleted() method is invoked when the file list HTML is downloaded. Download all XAP files After retrieving all files’ URIs, the next thing becomes even easier. HandleOpenReadCompleted() just uses built in DeploymentCatalog to download the XAPs, and aggregate them into one AggregateCatalog: private void HandleOpenReadCompleted(object sender, OpenReadCompletedEventArgs e) { Exception error = e.Error; bool cancelled = e.Cancelled; if (Interlocked.CompareExchange(ref this._state, State.DownloadCompleted, State.DownloadStarted) != State.DownloadStarted) { cancelled = true; } if (error == null && !cancelled) { try { using (StreamReader reader = new StreamReader(e.Result)) { string html = reader.ReadToEnd(); IEnumerable<Uri> uris = this._getFilesFromDirectory(html); Contract.Assume(uris != null); IEnumerable<DeploymentCatalog> deploymentCatalogs = uris.Select(uri => new DeploymentCatalog(uri)); deploymentCatalogs.ForEach( deploymentCatalog => { this._aggregateCatalog.Catalogs.Add(deploymentCatalog); deploymentCatalog.DownloadCompleted += this.HandleDownloadCompleted; }); deploymentCatalogs.ForEach(deploymentCatalog => deploymentCatalog.DownloadAsync()); } } catch (Exception exception) { error = new InvalidOperationException(Resources.InvalidOperationException_ErrorReadingDirectory, exception); } } // Exception handling. } In HandleDownloadCompleted(), if all XAPs are downloaded without exception, OnDownloadCompleted() callback method will be invoked. private void HandleDownloadCompleted(object sender, AsyncCompletedEventArgs e) { if (Interlocked.Increment(ref this._downloaded) == this._aggregateCatalog.Catalogs.Count) { this.OnDownloadCompleted(e); } } Exception handling Whether this DirectoryCatelog can work only if the directory browsing feature is enabled. It is important to inform caller when directory cannot be browsed for XAP downloading. private void HandleOpenReadCompleted(object sender, OpenReadCompletedEventArgs e) { Exception error = e.Error; bool cancelled = e.Cancelled; if (Interlocked.CompareExchange(ref this._state, State.DownloadCompleted, State.DownloadStarted) != State.DownloadStarted) { cancelled = true; } if (error == null && !cancelled) { try { // No exception thrown when browsing directory. Downloads the listed XAPs. } catch (Exception exception) { error = new InvalidOperationException(Resources.InvalidOperationException_ErrorReadingDirectory, exception); } } WebException webException = error as WebException; if (webException != null) { HttpWebResponse webResponse = webException.Response as HttpWebResponse; if (webResponse != null) { // Internally, WebClient uses WebRequest.Create() to create the WebRequest object. Here does the same thing. WebRequest request = WebRequest.Create(Application.Current.Host.Source); Contract.Assume(request != null); if (request.CreatorInstance == WebRequestCreator.ClientHttp && // Silverlight is in client HTTP handling, all HTTP status codes are supported. webResponse.StatusCode == HttpStatusCode.Forbidden) { // When directory browsing is disabled, the HTTP status code is 403 (forbidden). error = new InvalidOperationException( Resources.InvalidOperationException_ErrorListingDirectory_ClientHttp, webException); } else if (request.CreatorInstance == WebRequestCreator.BrowserHttp && // Silverlight is in browser HTTP handling, only 200 and 404 are supported. webResponse.StatusCode == HttpStatusCode.NotFound) { // When directory browsing is disabled, the HTTP status code is 404 (not found). error = new InvalidOperationException( Resources.InvalidOperationException_ErrorListingDirectory_BrowserHttp, webException); } } } this.OnDownloadCompleted(new AsyncCompletedEventArgs(error, cancelled, this)); } Please notice Silverlight 3+ application can work either in client HTTP handling, or browser HTTP handling. One difference is: In browser HTTP handling, only HTTP status code 200 (OK) and 404 (not OK, including 500, 403, etc.) are supported In client HTTP handling, all HTTP status code are supported So in above code, exceptions in 2 modes are handled differently. Conclusion Here is the whole DirectoryCatelog’s looking: Please click here to download the source code, a simple unit test is included. This is a rough implementation. And, for convenience, some design and coding are just following the built in AggregateCatalog class and Deployment class. Please feel free to modify the code, and please kindly tell me if any issue is found.

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Migrating BizTalk 2006 R2 to BizTalk 2010 XLANGs Issue

- by SURESH GIRIRAJAN

When we migrate some BizTalk apps from BizTalk 2006 R2 to BizTalk 2010, and we ran into issue when a .net component called inside the orchestration. In the .net component we are trying to retrieve some promoted property and we also checked in the BizTalk group hub to validate it was promoted, no issues there. Only when we try to access the data into the .net component we had issue. We just moved all the assembly what we had in BizTalk 2006 R2 to BizTalk 2010, didn’t recompile anything in BizTalk 2010 environment. But looking further there is couple of new namespace added to the Microsoft.XLANGs… in BizTalk 2010 compared to BizTalk 2006 R2 caused the issue. So all we did to fix the issue is recompile the project in 2010 environment and it worked fine. So it looks like some backward compatibility issue. public static void Load(XLANGMessage msg) { try { // get the process id from context. object ctxVal = msg.GetPropertyValue(typeof(ProcessID)); … } BizTalk 2010: Error Message in the event viewer: The service instance will remain suspended until administratively resumed or terminated. If resumed the instance will continue from its last persisted state and may re-throw the same unexpected exception. InstanceId: 441d73d3-2e84-49d2-b6bd-7218065b5e1d Shape name: Bulk Load ShapeId: bb959e56-9221-48be-a80f-24051196617d Exception thrown from: segment 1, progress 65 Inner exception: A property cannot be associated with the type 'Tellago.Common.Schemas.ProcessId'. Exception type: InvalidPropertyTypeException Source: Microsoft.XLANGs.Engine Target Site: Microsoft.XLANGs.RuntimeTypes.MessagePropertyDefinition _getMessagePropertyDefinition(System.Type) The following is a stack trace that identifies the location where the exception occured at Microsoft.XLANGs.Core.XMessage._getMessagePropertyDefinition(Type propType) at Microsoft.XLANGs.Core.XMessage.GetContentProperty(Type propType) at Microsoft.XLANGs.Core.XMessage.GetPropertyValue(Type propType) at Microsoft.BizTalk.XLANGs.BTXEngine.BTXMessage.GetPropertyValue(Type propType) at Microsoft.XLANGs.Core.MessageWrapperForUserCode.GetPropertyValue(Type propType) at Tellago.Common.Components.Load(XLANGMessage msg) at Tellago.SuspensionProcess.segment1(StopConditions stopOn) at Microsoft.XLANGs.Core.SegmentScheduler.RunASegment(Segment s, StopConditions stopCond, Exception& exp)

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Why do I get "Sequence contains no elements"?

- by Gary McGill

NOTE: see edits at bottom. I am an idiot. I had the following code to process set of tag names and identify/process new ones: IEnumberable<string> tagNames = GetTagNames(); List<Tag> allTags = GetAllTags(); var newTagNames = tagNames.Where(n => !allTags.Any(t => t.Name == n)); foreach (var tagName in newTagNames) { // ... } ...and this worked fine, except that it failed to deal with cases where there's a tag called "Foo" and the list contains "foo". In other words, it wasn't doing a case-insensitive comparison. I changed the test to use a case-insensitive comparison, as follows: var newTagNames = tagNames.Where(n => !allTags.Any(t => t.Name.Equals(n, StringComparison.InvariantCultureIgnoreCase))); ... and suddenly I get an exception thrown when the foreach runs (and calls MoveNext on) newTagNames. The exception says: Sequence has no elements I'm confused by this. Why would foreach insist on the sequence being non-empty? I'd expect to see that error if I was calling First(), but not when using foreach? EDIT: more info. This is getting weirder by the minute. Because my code is in an async method, and I'm superstitious, I decided that there was too much "distance" between the point at which the exception is raised, and the point at which it's caught and reported. So, I put a try/catch around the offending code, in the hope of verifying that the exception being thrown really was what I thought it was. So now I can step through in the debugger to the foreach line, I can verify that the sequence is empty, and I can step right up to the bit where the debugger highlights the word "in". One more step, and I'm in my exception handler. But, not the exception handler I just added, no! It lands in my outermost exception handler, without visiting my recently-added one! It doesn't match catch (Exception ex) and nor does it match a plain catch. (I did also put in a finally, and verified that it does visit that on the way out). I've always taken it on faith that an Exception handler such as those would catch any exception. I'm scared now. I need an adult. EDIT 2: OK, so um, false alarm... The exception was not being caught by my local try/catch simply because it was not being raised by the code I thought. As I said above, I watched the execution in the debugger jump from the "in" of the foreach straight to the outer exception handler, hence my (wrong) assumption that that was where the error lay. However, with the empty enumeration, that was simply the last statement executed within the function, and for some reason the debugger did not show me the step out of the function or the execution of the next statement at the point of call - which was in fact the one causing the error. Apologies to all those who responded, and if you would like to create an answer saying that I am an idoit, I will gladly accept it. That is, if I ever show my face on SO again...

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BinaryWrite exception "OutputStream is not available when a custom TextWriter is used" in MVC 2 ASP.

- by Grant

Hi, I have a view rendering a stream using the response BinaryWrite method. This all worked fine under ASP.NET 4 using the Beta 2 but throws this exception in the RC release: "HttpException" , "OutputStream is not available when a custom TextWriter is used." <%@ Page Title="" Language="C#" Inherits="System.Web.Mvc.ViewPage" %> <%@ Import Namespace="System.IO" %> <script runat="server"> protected void Page_Load(object sender, EventArgs e) { if (ViewData["Error"] == null) { Response.Buffer = true; Response.Clear(); Response.ContentType = ViewData["DocType"] as string; Response.AddHeader("content-disposition", ViewData["Disposition"] as string); Response.CacheControl = "No-cache"; MemoryStream stream = ViewData["DocAsStream"] as MemoryStream; Response.BinaryWrite(stream.ToArray()); Response.Flush(); Response.Close(); } } </script> </script> The view is generated from a client side redirect (jquery replace location call in the previous page using Url.Action helper to render the link of course). This is all in an iframe. Anyone have an idea why this occurs?

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System.Net.WebException: The remote server returned an error: (405) Method Not Allowed .exception occurred during the execution of the web request

- by user88

When I ran my web application code I got this error on this line. using (HttpWebResponse response = (HttpWebResponse)request.GetResponse()){} Actually when I ran my url directly on browser.It will give proper o/p but when I ran my url in code. It will give exception. Here MyCode is :- string service = "http://api.ean.com/ean-services/rs/hotel/"; string version = "v3/"; string method = "info/"; string hotelId1 = "188603"; int hotelId = Convert.ToInt32(hotelId1); string otherElemntsStr = "&cid=411931&minorRev=[12]&customerUserAgent=[hotel]&locale=en_US&currencyCode=INR"; string apiKey = "tzyw4x2zspckjayrbjekb397"; string sig = "a6f828b696ae6a9f7c742b34538259b0"; string url = service + version + method + "?&type=xml" + "&apiKey=" + apiKey + "&sig=" + sig + otherElemntsStr + "&hotelId=" + hotelId; HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url) as HttpWebRequest; request.Method = "POST"; request.ContentType = "text/xml"; request.ContentLength = 0; XmlDocument xmldoc = new XmlDocument(); using (HttpWebResponse response = (HttpWebResponse)request.GetResponse()) { StreamReader responsereader = new StreamReader(response.GetResponseStream()); var responsedata = responsereader.ReadToEnd(); xmldoc = (XmlDocument)JsonConvert.DeserializeXmlNode(responsedata); xmldoc.Save(@"D:\FlightSearch\myfile.xml"); xmldoc.Load(@"D:\FlightSearch\myfile.xml"); DataSet ds = new DataSet(); ds.ReadXml(Request.PhysicalApplicationPath + "myfile.xml"); GridView1.DataSource = ds.Tables["HotelSummary"]; GridView1.DataBind(); }

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How to solve this nullPointer Exception in jasper report?

- by Kumar

Hi, I am new to jasper report, I need to create pdf document with BeanDatasource and subreport. I refer the following blog " http://knol.google.com/k/jasper-reports-working-with-beans-and-sub-report# " . I followed all the steps perfectly. While i am running the report using IReport i can get the pdf document with the content. But when we try to create from java program i m getting exception in the following line Line number 110: " JasperFillManager.fillReportToFile("C:/JasperReports/contacts.jasper", parameters, new JRBeanCollectionDataSource(TestPerson.getBeanCollection())); " and this is the following error i am getting in my Eclipse Console window . java.lang.NullPointerException at net.sf.jasperreports.engine.JRPropertiesMap.readObject(JRPropertiesMap.java:185) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at java.io.ObjectStreamClass.invokeReadObject(Unknown Source) at java.io.ObjectInputStream.readSerialData(Unknown Source) at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source) at java.io.ObjectInputStream.readObject0(Unknown Source) at java.io.ObjectInputStream.defaultReadFields(Unknown Source) at java.io.ObjectInputStream.readSerialData(Unknown Source) at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source) at java.io.ObjectInputStream.readObject0(Unknown Source) at java.io.ObjectInputStream.readArray(Unknown Source) at java.io.ObjectInputStream.readObject0(Unknown Source) at java.io.ObjectInputStream.defaultReadFields(Unknown Source) at java.io.ObjectInputStream.readSerialData(Unknown Source) at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source) at java.io.ObjectInputStream.readObject0(Unknown Source) at java.io.ObjectInputStream.defaultReadFields(Unknown Source) at java.io.ObjectInputStream.readSerialData(Unknown Source) at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source) at java.io.ObjectInputStream.readObject0(Unknown Source) at java.io.ObjectInputStream.readObject(Unknown Source) at net.sf.jasperreports.engine.util.JRLoader.loadObject(JRLoader.java:88) at net.sf.jasperreports.engine.util.JRLoader.loadObjectFromLocation(JRLoader.java:257) at net.sf.jasperreports.engine.fill.JRFillSubreport.evaluateSubreport(JRFillSubreport.java:308) at net.sf.jasperreports.engine.fill.JRFillSubreport.evaluate(JRFillSubreport.java:257) at net.sf.jasperreports.engine.fill.JRFillElementContainer.evaluate(JRFillElementContainer.java:275) at net.sf.jasperreports.engine.fill.JRFillBand.evaluate(JRFillBand.java:426) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillColumnBand(JRVerticalFiller.java:1380) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillDetail(JRVerticalFiller.java:692) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReportStart(JRVerticalFiller.java:255) at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReport(JRVerticalFiller.java:113) at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:891) at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:814) at net.sf.jasperreports.engine.fill.JRFiller.fillReport(JRFiller.java:89) at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager.java:601) at test.TestJasperReport.main(TestJasperReport.java:110)

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Why does ObservableCollection throws an exception when being modified?

- by Oliver Hanappi

Hi! My application uses a WPF DataGrid. One of the columns is a template column that containts a combobox bound to an ObservableCollection of the entity which feeds the row. When I add a value to the ObservableCollection, a NullReferenceException is thrown. Has anybody an idea why this happens? Here is the stacktrace of the exception: at MS.Internal.Data.PropertyPathWorker.DetermineWhetherDBNullIsValid() at MS.Internal.Data.PropertyPathWorker.get_IsDBNullValidForUpdate() at MS.Internal.Data.ClrBindingWorker.get_IsDBNullValidForUpdate() at System.Windows.Data.BindingExpression.ConvertProposedValue(Object value) at System.Windows.Data.BindingExpressionBase.UpdateValue() at System.Windows.Data.BindingExpression.Update(Boolean synchronous) at System.Windows.Data.BindingExpressionBase.Dirty() at System.Windows.Data.BindingExpression.SetValue(DependencyObject d, DependencyProperty dp, Object value) at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, OperationType operationType, Boolean isInternal) at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value) at System.Windows.Controls.Primitives.Selector.UpdatePublicSelectionProperties() at System.Windows.Controls.Primitives.Selector.SelectionChanger.End() at System.Windows.Controls.Primitives.Selector.OnItemsChanged(NotifyCollectionChangedEventArgs e) at System.Windows.Controls.ItemsControl.OnItemCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e) at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e) at System.Windows.Data.CollectionView.OnCollectionChanged(NotifyCollectionChangedEventArgs args) at System.Windows.Controls.ItemCollection.System.Windows.IWeakEventListener.ReceiveWeakEvent(Type managerType, Object sender, EventArgs e) at System.Windows.WeakEventManager.DeliverEventToList(Object sender, EventArgs args, ListenerList list) at System.Windows.WeakEventManager.DeliverEvent(Object sender, EventArgs args) at System.Collections.Specialized.CollectionChangedEventManager.OnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs args) at System.Windows.Data.CollectionView.OnCollectionChanged(NotifyCollectionChangedEventArgs args) at System.Windows.Data.ListCollectionView.ProcessCollectionChangedWithAdjustedIndex(NotifyCollectionChangedEventArgs args, Int32 adjustedOldIndex, Int32 adjustedNewIndex) at System.Windows.Data.ListCollectionView.ProcessCollectionChanged(NotifyCollectionChangedEventArgs args) at System.Windows.Data.CollectionView.OnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs args) at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e) at System.Collections.ObjectModel.ObservableCollection`1.InsertItem(Int32 index, T item) at System.Collections.ObjectModel.Collection`1.Add(T item) at ORF.PersonBook.IdentityModule.Model.SubsidiaryModel.AddRoom(RoomModel room) in C:\Project\Phoenix\Development\src\ORF.PersonBook.IdentityModule\Model\SubsidiaryModel.cs:line 127

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object reference not set to an instance of object exception coming at runtime.

- by amby

Hi, I am getting this error at runtime: object reference not set to an instance of object my question is that am i using stringbuilder array correctly here. Because I am new in C#. and i think its the problem with my stringbuilder array. Below is the code: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Services; using System.Web.UI; using System.Web.UI.WebControls; using System.Data; using System.Text; using System.Web.Script.Serialization; using System.Web.Script.Services; using System.Collections; public partial class Testing : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } [WebMethod] public static string SendMessage() { try { al2c00.ldap ws = new al2c00.ldap(); Hashtable htPeople = new Hashtable(); //DataTable dt = ws.GetEmployeeDetailsBy_NTID("650FA25C-9561-430B-B757-835D043EA5E5", "john"); StringBuilder[] empDetails = new StringBuilder[100]; string num = "ambreen"; empDetails[0].Append("amby"); num = empDetails[0].ToString(); htPeople.Add("bellempposreport", num); JavaScriptSerializer jss = new JavaScriptSerializer(); string output = jss.Serialize(htPeople); return output; } catch(Exception ex) { return ex.Message + "-" + ex.StackTrace; } } } please reply me what i am doing wrong here.

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JDBC ODBC.. (Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException)

- by enthudrives

private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) { PreparedStatement p1; String s="insert into reg values(?,?)"; try { p1 = conn.prepareStatement(s); System.out.println("hi?"); p1.setString(1, num.getText()); p1.setString(2, name.getText()); p1.executeUpdate(); // TODO add your handling code here: } catch (SQLException ex) { Logger.getLogger(sample.class.getName()).log(Level.SEVERE, null, ex); } } This is my insert module.. This works in my friend's laptop. But not in mine :( I get the following error: Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at sample.jButton1ActionPerformed(sample.java:197) at sample.access$200(sample.java:20) at sample$3.actionPerformed(sample.java:92) at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995) at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318) at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387) at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236) at java.awt.Component.processMouseEvent(Component.java:6263) at javax.swing.JComponent.processMouseEvent(JComponent.java:3267) at java.awt.Component.processEvent(Component.java:6028) at java.awt.Container.processEvent(Container.java:2041) at java.awt.Component.dispatchEventImpl(Component.java:4630) at java.awt.Container.dispatchEventImpl(Container.java:2099) at java.awt.Component.dispatchEvent(Component.java:4460) at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4574) at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238) at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168) at java.awt.Container.dispatchEventImpl(Container.java:2085) at java.awt.Window.dispatchEventImpl(Window.java:2478) at java.awt.Component.dispatchEvent(Component.java:4460) at java.awt.EventQueue.dispatchEvent(EventQueue.java:599) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161) at java.awt.EventDispatchThread.run(EventDispatchThread.java:122) Java Result: 1 PS: I am totally new to java. Is it a problem with my ODBC?

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.NET Speech recognition plugin Runtime Error: Unhandled Exception. What could possibly cause it?

- by manuel

I'm writing a plugin (dll file) for speech recognition, and I'm creating a WinForm as its interface/dialog. When I run the plugin and click the 'Speak' to start the initialization, I get an unhandled exception. Here is a piece of the code: public ref class Dialog : public System::Windows::Forms::Form { public: SpeechRecognitionEngine^ sre; private: System::Void btnSpeak_Click(System::Object^ sender, System::EventArgs^ e) { Initialize(); } protected: void Initialize() { if (System::Threading::Thread::CurrentThread->GetApartmentState() != System::Threading::ApartmentState::STA) { throw gcnew InvalidOperationException("UI thread required"); } //create the recognition engine sre = gcnew SpeechRecognitionEngine(); //set our recognition engine to use the default audio device sre->SetInputToDefaultAudioDevice(); //create a new GrammarBuilder to specify which commands we want to use GrammarBuilder^ grammarBuilder = gcnew GrammarBuilder(); //append all the choices we want for commands. //we want to be able to move, stop, quit the game, and check for the cake. grammarBuilder->Append(gcnew Choices("play", "stop")); //create the Grammar from th GrammarBuilder Grammar^ customGrammar = gcnew Grammar(grammarBuilder); //unload any grammars from the recognition engine sre->UnloadAllGrammars(); //load our new Grammar sre->LoadGrammar(customGrammar); //add an event handler so we get events whenever the engine recognizes spoken commands sre->SpeechRecognized += gcnew EventHandler<SpeechRecognizedEventArgs^> (this, &Dialog::sre_SpeechRecognized); //set the recognition engine to keep running after recognizing a command. //if we had used RecognizeMode.Single, the engine would quite listening after //the first recognized command. sre->RecognizeAsync(RecognizeMode::Multiple); //this->init(); } void sre_SpeechRecognized(Object^ sender, SpeechRecognizedEventArgs^ e) { //simple check to see what the result of the recognition was if (e->Result->Text == "play") { MessageBox(plugin.hwndParent, L"play", 0, 0); } if (e->Result->Text == "stop") { MessageBox(plugin.hwndParent, L"stop", 0, 0); } } };

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Exception while hosting a WCF Service in a DependencyInjection Module ?

- by Maciek

Hello, I've written a small just-for-fun console project using Ninject, I'm pasting some of the code below just so that you get the idea : Program.cs using System; using Ninject; using Ninjectionn.Modules; // My namespace for my modules namespace Ninjections { class Program { static void Main(string[] args) { IKernel kernel = new StandardKernel(); kernel.Load<ServicesHostModule>(); Console.ReadKey(); } } } ServicesHostModule.cs using System; using System.ServiceModel; using Ninject; using Ninject.Modules; namespace Ninjections.Modules { public class ServicesHostModule : INinjectModule { #region INinjectModule Members public string Name { get { return "ServicesHost"; }} public void OnLoad(IKernel kernel) { if(m_host != null) m_host.Close(); else m_host = new ServiceHost(typeof(WCFTestService)); m_host.Open(); // (!) EXCEPTION HERE } public void OnUnLoad(IKernel kernel) { m_host.Close(); } #endregion } } ITestWCFService.cs using System.ServiceModel; namespace Ninjections.Modules { [ServiceContract] public interface ITestWCFService { [OperationContract] string GetString1(); [OperationContract] string GetString2(); } } An auto-generated App.config is in the ServicesHostModule project. I've "added" an existing item (the app config) as link in the main project. Q: at the m_host.Open(); line, an InvalidOperationException occurs. The message says : "Service "Ninjections.Modules.TestWCFService" has zero application endopints. What's wrong?

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Messages not forwarded to error queue when exception is thrown in handler (it works on my machine)

- by darthjit

e are using NServicebus 4.0.5 with sql server(sql server 2012) as transport. When the handler throws an exception, NSB does not retry or move the message to the error queue. Successful messages make it to the audit queue but the failed/errored ones don't! . Interestingly, all this works on our local machines(windows 7 ,sql server localdb) but not on windows server 2012 (sql server 2012). Here is the config info on the subscriber: <add name="NServiceBus/Transport" connectionString="Data Source=xxx;Initial Catalog=NServiceBus;Integrated Security=SSPI;Enlist=false;" /> <add name="NServiceBus/Persistence" connectionString="Data Source=xxx;Initial Catalog=NServiceBus;Integrated Security=SSPI;Enlist=false;" /> <MessageForwardingInCaseOfFaultConfig ErrorQueue="error" /> <UnicastBusConfig ForwardReceivedMessagesTo="audit"> <MessageEndpointMappings> <add Assembly="Services.Section.Messages" Endpoint= "Services.ACL.Worker" /> </MessageEndpointMappings> </UnicastBusConfig> And in code it is configured as follows: public class EndpointConfig : IConfigureThisEndpoint, AsA_Server, IWantCustomInitialization { public void Init() { IContainer container = ContainerInstanceProvider. GetContainerInstance(); Configure .Transactions.Enable(); Configure.With() .AutofacBuilder(container) .UseTransport<SqlServer>() .Log4Net() //.Serialization.Json() .UseNHibernateSubscriptionPersister() .UseNHibernateTimeoutPersister() .MessageForwardingInCaseOfFault() .RijndaelEncryptionService() .DefiningCommandsAs(type => type.Namespace != null &&type .Namespace.EndsWith("Commands")) .DefiningEventsAs(type => type.Namespace != null &&type .Namespace.EndsWith("Events")) .UnicastBus(); } } Any ideas on how to fix this? here is the log info (there is a lot there, search for error to see the relevant parts) https://gist.github.com/ranji/7378249

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Adding cancel ability and exception handling to async code.

- by Rob

I have this sample code for async operations (copied from the interwebs) public class LongRunningTask { public LongRunningTask() { //do nowt } public int FetchInt() { Thread.Sleep(2000); return 5; } } public delegate TOutput SomeMethod<TOutput>(); public class GoodPerformance { public void BeginFetchInt() { LongRunningTask lr = new LongRunningTask(); SomeMethod<int> method = new SomeMethod<int>(lr.FetchInt); // method is state object used to transfer result //of long running operation method.BeginInvoke(EndFetchInt, method); } public void EndFetchInt(IAsyncResult result) { SomeMethod<int> method = result.AsyncState as SomeMethod<int>; Value = method.EndInvoke(result); } public int Value { get; set; } } Other async approaches I tried required the aysnc page attribute, they also seemed to cancel if other page elements where actioned on (a button clicked), this approach just seemed to work. I’d like to add a cancel ability and exception handling for the longRunningTask class, but don’t erm, really know how.

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Understanding C# async / await (1) Compilation

- by Dixin

Now the async / await keywords are in C#. Just like the async and ! in F#, this new C# feature provides great convenience. There are many nice documents talking about how to use async / await in specific scenarios, like using async methods in ASP.NET 4.5 and in ASP.NET MVC 4, etc. In this article we will look at the real code working behind the syntax sugar. According to MSDN: The async modifier indicates that the method, lambda expression, or anonymous method that it modifies is asynchronous. Since lambda expression / anonymous method will be compiled to normal method, we will focus on normal async method. Preparation First of all, Some helper methods need to make up. internal class HelperMethods { internal static int Method(int arg0, int arg1) { // Do some IO. WebClient client = new WebClient(); Enumerable.Repeat("http://weblogs.asp.net/dixin", 10) .Select(client.DownloadString).ToArray(); int result = arg0 + arg1; return result; } internal static Task<int> MethodTask(int arg0, int arg1) { Task<int> task = new Task<int>(() => Method(arg0, arg1)); task.Start(); // Hot task (started task) should always be returned. return task; } internal static void Before() { } internal static void Continuation1(int arg) { } internal static void Continuation2(int arg) { } } Here Method() is a long running method doing some IO. Then MethodTask() wraps it into a Task and return that Task. Nothing special here. Await something in async method Since MethodTask() returns Task, let’s try to await it: internal class AsyncMethods { internal static async Task<int> MethodAsync(int arg0, int arg1) { int result = await HelperMethods.MethodTask(arg0, arg1); return result; } } Because we used await in the method, async must be put on the method. Now we get the first async method. According to the naming convenience, it is called MethodAsync. Of course a async method can be awaited. So we have a CallMethodAsync() to call MethodAsync(): internal class AsyncMethods { internal static async Task<int> CallMethodAsync(int arg0, int arg1) { int result = await MethodAsync(arg0, arg1); return result; } } After compilation, MethodAsync() and CallMethodAsync() becomes the same logic. This is the code of MethodAsyc(): internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(MethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MethodAsync(int arg0, int arg1) { MethodAsyncStateMachine methodAsyncStateMachine = new MethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; methodAsyncStateMachine.Builder.Start(ref methodAsyncStateMachine); return methodAsyncStateMachine.Builder.Task; } } It just creates and starts a state machine MethodAsyncStateMachine: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MethodAsyncStateMachine : IAsyncStateMachine { public int State; public AsyncTaskMethodBuilder<int> Builder; public int Arg0; public int Arg1; public int Result; private TaskAwaiter<int> awaitor; void IAsyncStateMachine.MoveNext() { try { if (this.State != 0) { this.awaitor = HelperMethods.MethodTask(this.Arg0, this.Arg1).GetAwaiter(); if (!this.awaitor.IsCompleted) { this.State = 0; this.Builder.AwaitUnsafeOnCompleted(ref this.awaitor, ref this); return; } } else { this.State = -1; } this.Result = this.awaitor.GetResult(); } catch (Exception exception) { this.State = -2; this.Builder.SetException(exception); return; } this.State = -2; this.Builder.SetResult(this.Result); } [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine param0) { this.Builder.SetStateMachine(param0); } } The generated code has been cleaned up so it is readable and can be compiled. Several things can be observed here: The async modifier is gone, which shows, unlike other modifiers (e.g. static), there is no such IL/CLR level “async” stuff. It becomes a AsyncStateMachineAttribute. This is similar to the compilation of extension method. The generated state machine is very similar to the state machine of C# yield syntax sugar. The local variables (arg0, arg1, result) are compiled to fields of the state machine. The real code (await HelperMethods.MethodTask(arg0, arg1)) is compiled into MoveNext(): HelperMethods.MethodTask(this.Arg0, this.Arg1).GetAwaiter(). CallMethodAsync() will create and start its own state machine CallMethodAsyncStateMachine: internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(CallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> CallMethodAsync(int arg0, int arg1) { CallMethodAsyncStateMachine callMethodAsyncStateMachine = new CallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; callMethodAsyncStateMachine.Builder.Start(ref callMethodAsyncStateMachine); return callMethodAsyncStateMachine.Builder.Task; } } CallMethodAsyncStateMachine has the same logic as MethodAsyncStateMachine above. The detail of the state machine will be discussed soon. Now it is clear that: async /await is a C# level syntax sugar. There is no difference to await a async method or a normal method. A method returning Task will be awaitable. State machine and continuation To demonstrate more details in the state machine, a more complex method is created: internal class AsyncMethods { internal static async Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { HelperMethods.Before(); int resultOfAwait1 = await MethodAsync(arg0, arg1); HelperMethods.Continuation1(resultOfAwait1); int resultOfAwait2 = await MethodAsync(arg2, arg3); HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; return resultToReturn; } } In this method: There are multiple awaits. There are code before the awaits, and continuation code after each await After compilation, this multi-await method becomes the same as above single-await methods: internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(MultiCallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { MultiCallMethodAsyncStateMachine multiCallMethodAsyncStateMachine = new MultiCallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Arg2 = arg2, Arg3 = arg3, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; multiCallMethodAsyncStateMachine.Builder.Start(ref multiCallMethodAsyncStateMachine); return multiCallMethodAsyncStateMachine.Builder.Task; } } It creates and starts one single state machine, MultiCallMethodAsyncStateMachine: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MultiCallMethodAsyncStateMachine : IAsyncStateMachine { public int State; public AsyncTaskMethodBuilder<int> Builder; public int Arg0; public int Arg1; public int Arg2; public int Arg3; public int ResultOfAwait1; public int ResultOfAwait2; public int ResultToReturn; private TaskAwaiter<int> awaiter; void IAsyncStateMachine.MoveNext() { try { switch (this.State) { case -1: HelperMethods.Before(); this.awaiter = AsyncMethods.MethodAsync(this.Arg0, this.Arg1).GetAwaiter(); if (!this.awaiter.IsCompleted) { this.State = 0; this.Builder.AwaitUnsafeOnCompleted(ref this.awaiter, ref this); } break; case 0: this.ResultOfAwait1 = this.awaiter.GetResult(); HelperMethods.Continuation1(this.ResultOfAwait1); this.awaiter = AsyncMethods.MethodAsync(this.Arg2, this.Arg3).GetAwaiter(); if (!this.awaiter.IsCompleted) { this.State = 1; this.Builder.AwaitUnsafeOnCompleted(ref this.awaiter, ref this); } break; case 1: this.ResultOfAwait2 = this.awaiter.GetResult(); HelperMethods.Continuation2(this.ResultOfAwait2); this.ResultToReturn = this.ResultOfAwait1 + this.ResultOfAwait2; this.State = -2; this.Builder.SetResult(this.ResultToReturn); break; } } catch (Exception exception) { this.State = -2; this.Builder.SetException(exception); } } [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine stateMachine) { this.Builder.SetStateMachine(stateMachine); } } The above code is already cleaned up, but there are still a lot of things. More clean up can be done, and the state machine can be very simple: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MultiCallMethodAsyncStateMachine : IAsyncStateMachine { // State: // -1: Begin // 0: 1st await is done // 1: 2nd await is done // ... // -2: End public int State; public TaskCompletionSource<int> ResultToReturn; // int resultToReturn ... public int Arg0; // int Arg0 public int Arg1; // int arg1 public int Arg2; // int arg2 public int Arg3; // int arg3 public int ResultOfAwait1; // int resultOfAwait1 ... public int ResultOfAwait2; // int resultOfAwait2 ... private Task<int> currentTaskToAwait; /// <summary> /// Moves the state machine to its next state. /// </summary> void IAsyncStateMachine.MoveNext() { try { switch (this.State) { // Orginal code is splitted by "case"s: // case -1: // HelperMethods.Before(); // MethodAsync(Arg0, arg1); // case 0: // int resultOfAwait1 = await ... // HelperMethods.Continuation1(resultOfAwait1); // MethodAsync(arg2, arg3); // case 1: // int resultOfAwait2 = await ... // HelperMethods.Continuation2(resultOfAwait2); // int resultToReturn = resultOfAwait1 + resultOfAwait2; // return resultToReturn; case -1: // -1 is begin. HelperMethods.Before(); // Code before 1st await. this.currentTaskToAwait = AsyncMethods.MethodAsync(this.Arg0, this.Arg1); // 1st task to await // When this.currentTaskToAwait is done, run this.MoveNext() and go to case 0. this.State = 0; IAsyncStateMachine this1 = this; // Cannot use "this" in lambda so create a local variable. this.currentTaskToAwait.ContinueWith(_ => this1.MoveNext()); // Callback break; case 0: // Now 1st await is done. this.ResultOfAwait1 = this.currentTaskToAwait.Result; // Get 1st await's result. HelperMethods.Continuation1(this.ResultOfAwait1); // Code after 1st await and before 2nd await. this.currentTaskToAwait = AsyncMethods.MethodAsync(this.Arg2, this.Arg3); // 2nd task to await // When this.currentTaskToAwait is done, run this.MoveNext() and go to case 1. this.State = 1; IAsyncStateMachine this2 = this; // Cannot use "this" in lambda so create a local variable. this.currentTaskToAwait.ContinueWith(_ => this2.MoveNext()); // Callback break; case 1: // Now 2nd await is done. this.ResultOfAwait2 = this.currentTaskToAwait.Result; // Get 2nd await's result. HelperMethods.Continuation2(this.ResultOfAwait2); // Code after 2nd await. int resultToReturn = this.ResultOfAwait1 + this.ResultOfAwait2; // Code after 2nd await. // End with resultToReturn. this.State = -2; // -2 is end. this.ResultToReturn.SetResult(resultToReturn); break; } } catch (Exception exception) { // End with exception. this.State = -2; // -2 is end. this.ResultToReturn.SetException(exception); } } /// <summary> /// Configures the state machine with a heap-allocated replica. /// </summary> /// <param name="stateMachine">The heap-allocated replica.</param> [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine stateMachine) { // No core logic. } } Only Task and TaskCompletionSource are involved in this version. And MultiCallMethodAsync() can be simplified to: [DebuggerStepThrough] [AsyncStateMachine(typeof(MultiCallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MultiCallMethodAsync_(int arg0, int arg1, int arg2, int arg3) { MultiCallMethodAsyncStateMachine multiCallMethodAsyncStateMachine = new MultiCallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Arg2 = arg2, Arg3 = arg3, ResultToReturn = new TaskCompletionSource<int>(), // -1: Begin // 0: 1st await is done // 1: 2nd await is done // ... // -2: End State = -1 }; (multiCallMethodAsyncStateMachine as IAsyncStateMachine).MoveNext(); // Original code are in this method. return multiCallMethodAsyncStateMachine.ResultToReturn.Task; } Now the whole state machine becomes very clear - it is about callback: Original code are split into pieces by “await”s, and each piece is put into each “case” in the state machine. Here the 2 awaits split the code into 3 pieces, so there are 3 “case”s. The “piece”s are chained by callback, that is done by Builder.AwaitUnsafeOnCompleted(callback), or currentTaskToAwait.ContinueWith(callback) in the simplified code. A previous “piece” will end with a Task (which is to be awaited), when the task is done, it will callback the next “piece”. The state machine’s state works with the “case”s to ensure the code “piece”s executes one after another. Callback Since it is about callback, the simplification can go even further – the entire state machine can be completely purged. Now MultiCallMethodAsync() becomes: internal static Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { TaskCompletionSource<int> taskCompletionSource = new TaskCompletionSource<int>(); try { // Oringinal code begins. HelperMethods.Before(); MethodAsync(arg0, arg1).ContinueWith(await1 => { int resultOfAwait1 = await1.Result; HelperMethods.Continuation1(resultOfAwait1); MethodAsync(arg2, arg3).ContinueWith(await2 => { int resultOfAwait2 = await2.Result; HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; // Oringinal code ends. taskCompletionSource.SetResult(resultToReturn); }); }); } catch (Exception exception) { taskCompletionSource.SetException(exception); } return taskCompletionSource.Task; } Please compare with the original async / await code: HelperMethods.Before(); int resultOfAwait1 = await MethodAsync(arg0, arg1); HelperMethods.Continuation1(resultOfAwait1); int resultOfAwait2 = await MethodAsync(arg2, arg3); HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; return resultToReturn; Yeah that is the magic of C# async / await: Await is literally pretending to wait. In a await expression, a Task object will be return immediately so that caller is not blocked. The continuation code is compiled as that Task’s callback code. When that task is done, continuation code will execute. Please notice that many details inside the state machine are omitted for simplicity, like context caring, etc. If you want to have a detailed picture, please do check out the source code of AsyncTaskMethodBuilder and TaskAwaiter.

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Understanding C# async / await (1) Compilation

- by Dixin

Now the async / await keywords are in C#. Just like the async and ! in F#, this new C# feature provides great convenience. There are many nice documents talking about how to use async / await in specific scenarios, like using async methods in ASP.NET 4.5 and in ASP.NET MVC 4, etc. In this article we will look at the real code working behind the syntax sugar. According to MSDN: The async modifier indicates that the method, lambda expression, or anonymous method that it modifies is asynchronous. Since lambda expression / anonymous method will be compiled to normal method, we will focus on normal async method. Preparation First of all, Some helper methods need to make up. internal class HelperMethods { internal static int Method(int arg0, int arg1) { // Do some IO. WebClient client = new WebClient(); Enumerable.Repeat("http://weblogs.asp.net/dixin", 10) .Select(client.DownloadString).ToArray(); int result = arg0 + arg1; return result; } internal static Task<int> MethodTask(int arg0, int arg1) { Task<int> task = new Task<int>(() => Method(arg0, arg1)); task.Start(); // Hot task (started task) should always be returned. return task; } internal static void Before() { } internal static void Continuation1(int arg) { } internal static void Continuation2(int arg) { } } Here Method() is a long running method doing some IO. Then MethodTask() wraps it into a Task and return that Task. Nothing special here. Await something in async method Since MethodTask() returns Task, let’s try to await it: internal class AsyncMethods { internal static async Task<int> MethodAsync(int arg0, int arg1) { int result = await HelperMethods.MethodTask(arg0, arg1); return result; } } Because we used await in the method, async must be put on the method. Now we get the first async method. According to the naming convenience, it is named MethodAsync. Of course a async method can be awaited. So we have a CallMethodAsync() to call MethodAsync(): internal class AsyncMethods { internal static async Task<int> CallMethodAsync(int arg0, int arg1) { int result = await MethodAsync(arg0, arg1); return result; } } After compilation, MethodAsync() and CallMethodAsync() becomes the same logic. This is the code of MethodAsyc(): internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(MethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MethodAsync(int arg0, int arg1) { MethodAsyncStateMachine methodAsyncStateMachine = new MethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; methodAsyncStateMachine.Builder.Start(ref methodAsyncStateMachine); return methodAsyncStateMachine.Builder.Task; } } It just creates and starts a state machine, MethodAsyncStateMachine: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MethodAsyncStateMachine : IAsyncStateMachine { public int State; public AsyncTaskMethodBuilder<int> Builder; public int Arg0; public int Arg1; public int Result; private TaskAwaiter<int> awaitor; void IAsyncStateMachine.MoveNext() { try { if (this.State != 0) { this.awaitor = HelperMethods.MethodTask(this.Arg0, this.Arg1).GetAwaiter(); if (!this.awaitor.IsCompleted) { this.State = 0; this.Builder.AwaitUnsafeOnCompleted(ref this.awaitor, ref this); return; } } else { this.State = -1; } this.Result = this.awaitor.GetResult(); } catch (Exception exception) { this.State = -2; this.Builder.SetException(exception); return; } this.State = -2; this.Builder.SetResult(this.Result); } [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine param0) { this.Builder.SetStateMachine(param0); } } The generated code has been refactored, so it is readable and can be compiled. Several things can be observed here: The async modifier is gone, which shows, unlike other modifiers (e.g. static), there is no such IL/CLR level “async” stuff. It becomes a AsyncStateMachineAttribute. This is similar to the compilation of extension method. The generated state machine is very similar to the state machine of C# yield syntax sugar. The local variables (arg0, arg1, result) are compiled to fields of the state machine. The real code (await HelperMethods.MethodTask(arg0, arg1)) is compiled into MoveNext(): HelperMethods.MethodTask(this.Arg0, this.Arg1).GetAwaiter(). CallMethodAsync() will create and start its own state machine CallMethodAsyncStateMachine: internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(CallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> CallMethodAsync(int arg0, int arg1) { CallMethodAsyncStateMachine callMethodAsyncStateMachine = new CallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; callMethodAsyncStateMachine.Builder.Start(ref callMethodAsyncStateMachine); return callMethodAsyncStateMachine.Builder.Task; } } CallMethodAsyncStateMachine has the same logic as MethodAsyncStateMachine above. The detail of the state machine will be discussed soon. Now it is clear that: async /await is a C# language level syntax sugar. There is no difference to await a async method or a normal method. As long as a method returns Task, it is awaitable. State machine and continuation To demonstrate more details in the state machine, a more complex method is created: internal class AsyncMethods { internal static async Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { HelperMethods.Before(); int resultOfAwait1 = await MethodAsync(arg0, arg1); HelperMethods.Continuation1(resultOfAwait1); int resultOfAwait2 = await MethodAsync(arg2, arg3); HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; return resultToReturn; } } In this method: There are multiple awaits. There are code before the awaits, and continuation code after each await After compilation, this multi-await method becomes the same as above single-await methods: internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(MultiCallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { MultiCallMethodAsyncStateMachine multiCallMethodAsyncStateMachine = new MultiCallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Arg2 = arg2, Arg3 = arg3, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; multiCallMethodAsyncStateMachine.Builder.Start(ref multiCallMethodAsyncStateMachine); return multiCallMethodAsyncStateMachine.Builder.Task; } } It creates and starts one single state machine, MultiCallMethodAsyncStateMachine: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MultiCallMethodAsyncStateMachine : IAsyncStateMachine { public int State; public AsyncTaskMethodBuilder<int> Builder; public int Arg0; public int Arg1; public int Arg2; public int Arg3; public int ResultOfAwait1; public int ResultOfAwait2; public int ResultToReturn; private TaskAwaiter<int> awaiter; void IAsyncStateMachine.MoveNext() { try { switch (this.State) { case -1: HelperMethods.Before(); this.awaiter = AsyncMethods.MethodAsync(this.Arg0, this.Arg1).GetAwaiter(); if (!this.awaiter.IsCompleted) { this.State = 0; this.Builder.AwaitUnsafeOnCompleted(ref this.awaiter, ref this); } break; case 0: this.ResultOfAwait1 = this.awaiter.GetResult(); HelperMethods.Continuation1(this.ResultOfAwait1); this.awaiter = AsyncMethods.MethodAsync(this.Arg2, this.Arg3).GetAwaiter(); if (!this.awaiter.IsCompleted) { this.State = 1; this.Builder.AwaitUnsafeOnCompleted(ref this.awaiter, ref this); } break; case 1: this.ResultOfAwait2 = this.awaiter.GetResult(); HelperMethods.Continuation2(this.ResultOfAwait2); this.ResultToReturn = this.ResultOfAwait1 + this.ResultOfAwait2; this.State = -2; this.Builder.SetResult(this.ResultToReturn); break; } } catch (Exception exception) { this.State = -2; this.Builder.SetException(exception); } } [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine stateMachine) { this.Builder.SetStateMachine(stateMachine); } } Once again, the above state machine code is already refactored, but it still has a lot of things. More clean up can be done if we only keep the core logic, and the state machine can become very simple: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MultiCallMethodAsyncStateMachine : IAsyncStateMachine { // State: // -1: Begin // 0: 1st await is done // 1: 2nd await is done // ... // -2: End public int State; public TaskCompletionSource<int> ResultToReturn; // int resultToReturn ... public int Arg0; // int Arg0 public int Arg1; // int arg1 public int Arg2; // int arg2 public int Arg3; // int arg3 public int ResultOfAwait1; // int resultOfAwait1 ... public int ResultOfAwait2; // int resultOfAwait2 ... private Task<int> currentTaskToAwait; /// <summary> /// Moves the state machine to its next state. /// </summary> public void MoveNext() // IAsyncStateMachine member. { try { switch (this.State) { // Original code is split by "await"s into "case"s: // case -1: // HelperMethods.Before(); // MethodAsync(Arg0, arg1); // case 0: // int resultOfAwait1 = await ... // HelperMethods.Continuation1(resultOfAwait1); // MethodAsync(arg2, arg3); // case 1: // int resultOfAwait2 = await ... // HelperMethods.Continuation2(resultOfAwait2); // int resultToReturn = resultOfAwait1 + resultOfAwait2; // return resultToReturn; case -1: // -1 is begin. HelperMethods.Before(); // Code before 1st await. this.currentTaskToAwait = AsyncMethods.MethodAsync(this.Arg0, this.Arg1); // 1st task to await // When this.currentTaskToAwait is done, run this.MoveNext() and go to case 0. this.State = 0; MultiCallMethodAsyncStateMachine that1 = this; // Cannot use "this" in lambda so create a local variable. this.currentTaskToAwait.ContinueWith(_ => that1.MoveNext()); break; case 0: // Now 1st await is done. this.ResultOfAwait1 = this.currentTaskToAwait.Result; // Get 1st await's result. HelperMethods.Continuation1(this.ResultOfAwait1); // Code after 1st await and before 2nd await. this.currentTaskToAwait = AsyncMethods.MethodAsync(this.Arg2, this.Arg3); // 2nd task to await // When this.currentTaskToAwait is done, run this.MoveNext() and go to case 1. this.State = 1; MultiCallMethodAsyncStateMachine that2 = this; this.currentTaskToAwait.ContinueWith(_ => that2.MoveNext()); break; case 1: // Now 2nd await is done. this.ResultOfAwait2 = this.currentTaskToAwait.Result; // Get 2nd await's result. HelperMethods.Continuation2(this.ResultOfAwait2); // Code after 2nd await. int resultToReturn = this.ResultOfAwait1 + this.ResultOfAwait2; // Code after 2nd await. // End with resultToReturn. this.State = -2; // -2 is end. this.ResultToReturn.SetResult(resultToReturn); break; } } catch (Exception exception) { // End with exception. this.State = -2; // -2 is end. this.ResultToReturn.SetException(exception); } } /// <summary> /// Configures the state machine with a heap-allocated replica. /// </summary> /// <param name="stateMachine">The heap-allocated replica.</param> [DebuggerHidden] public void SetStateMachine(IAsyncStateMachine stateMachine) // IAsyncStateMachine member. { // No core logic. } } Only Task and TaskCompletionSource are involved in this version. And MultiCallMethodAsync() can be simplified to: [DebuggerStepThrough] [AsyncStateMachine(typeof(MultiCallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { MultiCallMethodAsyncStateMachine multiCallMethodAsyncStateMachine = new MultiCallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Arg2 = arg2, Arg3 = arg3, ResultToReturn = new TaskCompletionSource<int>(), // -1: Begin // 0: 1st await is done // 1: 2nd await is done // ... // -2: End State = -1 }; multiCallMethodAsyncStateMachine.MoveNext(); // Original code are moved into this method. return multiCallMethodAsyncStateMachine.ResultToReturn.Task; } Now the whole state machine becomes very clean - it is about callback: Original code are split into pieces by “await”s, and each piece is put into each “case” in the state machine. Here the 2 awaits split the code into 3 pieces, so there are 3 “case”s. The “piece”s are chained by callback, that is done by Builder.AwaitUnsafeOnCompleted(callback), or currentTaskToAwait.ContinueWith(callback) in the simplified code. A previous “piece” will end with a Task (which is to be awaited), when the task is done, it will callback the next “piece”. The state machine’s state works with the “case”s to ensure the code “piece”s executes one after another. Callback If we focus on the point of callback, the simplification can go even further – the entire state machine can be completely purged, and we can just keep the code inside MoveNext(). Now MultiCallMethodAsync() becomes: internal static Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { TaskCompletionSource<int> taskCompletionSource = new TaskCompletionSource<int>(); try { // Oringinal code begins. HelperMethods.Before(); MethodAsync(arg0, arg1).ContinueWith(await1 => { int resultOfAwait1 = await1.Result; HelperMethods.Continuation1(resultOfAwait1); MethodAsync(arg2, arg3).ContinueWith(await2 => { int resultOfAwait2 = await2.Result; HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; // Oringinal code ends. taskCompletionSource.SetResult(resultToReturn); }); }); } catch (Exception exception) { taskCompletionSource.SetException(exception); } return taskCompletionSource.Task; } Please compare with the original async / await code: HelperMethods.Before(); int resultOfAwait1 = await MethodAsync(arg0, arg1); HelperMethods.Continuation1(resultOfAwait1); int resultOfAwait2 = await MethodAsync(arg2, arg3); HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; return resultToReturn; Yeah that is the magic of C# async / await: Await is not to wait. In a await expression, a Task object will be return immediately so that execution is not blocked. The continuation code is compiled as that Task’s callback code. When that task is done, continuation code will execute. Please notice that many details inside the state machine are omitted for simplicity, like context caring, etc. If you want to have a detailed picture, please do check out the source code of AsyncTaskMethodBuilder and TaskAwaiter.

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Garbage Collector not doing its job. Memory Consumption = 1.5GB & OutOFMemory Exception.

- by imageWorker

I'm working with images (each of size = 5MB). The following code extract some information from each image that is present in the given directory. I'm getting out of memory exception. The size of the process is around (1.5GB). I don't know why garbage collector is not freeing memory. I even tried adding GC.Collect() as last line of foreach loop. Still I'm getting 'OutOFMemory' using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading; using System.IO; using System.Drawing; using System.Drawing.Imaging; namespace TrainSVM { class Program { static void Main(string[] args) { FileStream fs = new FileStream("dg.train",FileMode.OpenOrCreate,FileAccess.Write); StreamWriter sw = new StreamWriter(fs); String[] filePathArr = Directory.GetFiles("E:\\images\\"); foreach (string filePath in filePathArr) { if (filePath.Contains("lmn")) { sw.Write("1 "); Console.Write("1 "); } else { sw.Write("1 "); Console.Write("1 "); } Bitmap originalBMP = new Bitmap(filePath); /***********************/ Bitmap imageBody; ImageBody.ImageBody im = new ImageBody.ImageBody(originalBMP); imageBody = im.GetImageBody(-1); /* white coat */ Bitmap whiteCoatBitmap = Rgb2Hsi.Rgb2Hsi.GetHuePlane(imageBody); float WhiteCoatPixelPercentage = Rgb2Hsi.Rgb2Hsi.GetWhiteCoatPixelPercentage(whiteCoatBitmap); //Console.Write("whiteDone\t"); sw.Write("1:" + WhiteCoatPixelPercentage + " "); Console.Write("1:" + WhiteCoatPixelPercentage + " "); /******************/ Quaternion.Quaternion qtr = new Quaternion.Quaternion(-15); Bitmap yellowCoatBMP = qtr.processImage(imageBody); //yellowCoatBMP.Save("yellowCoat.bmp"); float yellowCoatPixelPercentage = qtr.GetYellowCoatPixelPercentage(yellowCoatBMP); //Console.Write("yellowCoatDone\t"); sw.Write("2:" + yellowCoatPixelPercentage + " "); Console.Write("2:" + yellowCoatPixelPercentage + " "); /**********************/ Bitmap balckPatchBitmap = BlackPatchDetection.BlackPatchDetector.MarkBlackPatches(imageBody); float BlackPatchPixelPercentage = BlackPatchDetection.BlackPatchDetector.BlackPatchPercentage; //Console.Write("balckPatchDone\n"); sw.Write("3:" + BlackPatchPixelPercentage + "\n"); Console.Write("3:" + BlackPatchPixelPercentage + "\n"); balckPatchBitmap.Dispose(); yellowCoatBMP.Dispose(); whiteCoatBitmap.Dispose(); originalBMP.Dispose(); sw.Flush(); } sw.Dispose(); fs.Dispose(); } } }

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A problem with assertRaises function in Python

- by anton.k.

Hello,guys! I am trying to run the following test self.assertRaises(Exception,lambda: unit_test.testBasic()) where test.testBasic() is class IsPrimeTest(unittest.TestCase): def assertRaises(self,exception,callable,*args,**kwargs): print('dfdf') temp = callable super().assertRaises(exception,temp,*args,**kwargs) def testBasic_helper(self): self.failIf(is_prime(2)) self.assertTrue(is_prime(1)) where prime is a function,and but in self.assertRaises(Exception,lambda: unit_test.testBasic()) the lambda function doesnt throws an exception after the test def testBasic_helper(self): self.failIf(is_prime(2)) self.assertTrue(is_prime(1)) fails Can somebody offers a solution to the problem?

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How do I resolve "Unable to resolve attribute [organizationType.id] against path" exception?

- by Dave

I'm using Spring 3.1.1.RELEASE, Hibernate 4.1.0.Final, JUnit 4.8, and JPA 2.0 (hibernate-jpa-2.0-api). I'm trying to write a query and search based on fields of member fields. What I mean is I have this entity … @GenericGenerator(name = "uuid-strategy", strategy = "uuid.hex") @Entity @Table(name = "cb_organization", uniqueConstraints = {@UniqueConstraint(columnNames={"organization_id"})}) public class Organization implements Serializable { @Id @NotNull @GeneratedValue(generator = "uuid-strategy") @Column(name = "id") /* the database id of the Organization */ private String id; @ManyToOne @JoinColumn(name = "state_id", nullable = true, updatable = false) /* the State for the organization */ private State state; @ManyToOne @JoinColumn(name = "country_id", nullable = false, updatable = false) /* The country the Organization is in */ private Country country; @ManyToOne(optional = false) @JoinColumn(name = "organization_type_id", nullable = false, updatable = false) /* The type of the Organization */ private OrganizationType organizationType; Notice the members "organizationType," "state," and "country," which are all objects. I wish to build a query based on their id fields. This code @Override public List<Organization> findByOrgTypesCountryAndState(Set<String> organizationTypes, String countryId, String stateId) { CriteriaBuilder builder = entityManager.getCriteriaBuilder(); CriteriaQuery<Organization> criteria = builder.createQuery(Organization.class); Root<Organization> org = criteria.from(Organization.class); criteria.select(org).where(builder.and(org.get("organizationType.id").in(organizationTypes), builder.equal(org.get("state.id"), stateId), builder.equal(org.get("country.id"), countryId))); return entityManager.createQuery(criteria).getResultList(); } is throwing the exception below. How do I heal the pain? java.lang.IllegalArgumentException: Unable to resolve attribute [organizationType.id] against path at org.hibernate.ejb.criteria.path.AbstractPathImpl.unknownAttribute(AbstractPathImpl.java:116) at org.hibernate.ejb.criteria.path.AbstractPathImpl.locateAttribute(AbstractPathImpl.java:221) at org.hibernate.ejb.criteria.path.AbstractPathImpl.get(AbstractPathImpl.java:192) at org.mainco.subco.organization.repo.OrganizationDaoImpl.findByOrgTypesCountryAndState(OrganizationDaoImpl.java:248) at org.mainco.subco.organization.repo.OrganizationDaoTest.testFindByOrgTypesCountryAndState(OrganizationDaoTest.java:55) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20) at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74) at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83) at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71) at org.junit.runners.ParentRunner.run(ParentRunner.java:236) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

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Why do I get a null pointer exception from TabWidget?

- by rushinge

I'm writing an android program in which I have an activity that uses tabs. The Activity public class UnitActivity extends TabActivity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); TabHost tabHost = getTabHost(); TabSpec spec; Resources res = getResources(); LayoutInflater.from(this).inflate(R.layout.unit_view, tabHost.getTabContentView(), true); spec = tabHost.newTabSpec("controls"); spec.setIndicator("Control", res.getDrawable(R.drawable.ic_tab_equalizer)); spec.setContent(R.id.txtview); tabHost.addTab(spec); } } The XML referenced by R.layout.unit_view <?xml version="1.0" encoding="utf-8"?> <TabHost xmlns:android="http://schemas.android.com/apk/res/android" android:id="@android:id/tabhost" android:layout_width="fill_parent" android:layout_height="fill_parent"> <LinearLayout android:layout_width="fill_parent" android:layout_height="fill_parent" android:padding="5dp"> <TabWidget android:id="@android:id/tabs" android:layout_width="fill_parent" android:layout_height="wrap_content"/> <FrameLayout android:id="@android:id/tabcontent" android:layout_width="fill_parent" android:layout_height="fill_parent" android:padding="5dp"> <TextView android:id="@+id/txtview" android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="bottom" android:text="nullpointer this!" /> </FrameLayout> </LinearLayout> </TabHost> As far as I can see I'm doing the same thing I see in the tabs1 api sample from the android sdk. I've tried "getLayoutInflator()" instead of "LayoutInflator.from(this)" with the same result. If I replace the LayoutInflater line with "setContentView(R.layout.unit_view)" my program doesn't crash with a null pointer exception but my content is completely blank and empty. I get the tab and that's it. I've checked to make sure R.layout.unit_view and tabHost are not null when it runs the LayoutInflater line and they seem to be fine. They're defenitely not null. I've also checked to make sure LayoutInflater.from(this) returns a valid layout inflater object and it does. The logcat indicating the error says E/AndroidRuntime( 541): java.lang.NullPointerException E/AndroidRuntime( 541): at android.widget.TabWidget.dispatchDraw(TabWidget.java:206) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.View.draw(View.java:6538) E/AndroidRuntime( 541): at android.widget.FrameLayout.draw(FrameLayout.java:352) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1531) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.ViewGroup.drawChild(ViewGroup.java:1529) E/AndroidRuntime( 541): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1258) E/AndroidRuntime( 541): at android.view.View.draw(View.java:6538) E/AndroidRuntime( 541): at android.widget.FrameLayout.draw(FrameLayout.java:352) E/AndroidRuntime( 541): at com.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:1830) E/AndroidRuntime( 541): at android.view.ViewRoot.draw(ViewRoot.java:1349) E/AndroidRuntime( 541): at android.view.ViewRoot.performTraversals(ViewRoot.java:1114) E/AndroidRuntime( 541): at android.view.ViewRoot.handleMessage(ViewRoot.java:1633) E/AndroidRuntime( 541): at android.os.Handler.dispatchMessage(Handler.java:99) E/AndroidRuntime( 541): at android.os.Looper.loop(Looper.java:123) E/AndroidRuntime( 541): at android.app.ActivityThread.main(ActivityThread.java:4363) E/AndroidRuntime( 541): at java.lang.reflect.Method.invokeNative(Native Method) E/AndroidRuntime( 541): at java.lang.reflect.Method.invoke(Method.java:521) E/AndroidRuntime( 541): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) E/AndroidRuntime( 541): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) E/AndroidRuntime( 541): at dalvik.system.NativeStart.main(Native Method) I/Process ( 61): Sending signal. PID: 541 SIG: 3 I/dalvikvm( 541): threadid=7: reacting to signal 3 I/dalvikvm( 541): Wrote stack trace to '/data/anr/traces.txt' Anybody have any idea how I can get this content into a tab without crashing my application? My actual program is more complex and has more than one tab but I simplified it down to this in an attempt to find out why it's crashing but it still crashes and I don't know why. If I don't use LayoutInflator my program doesn't crash but I don't get any content either, just tabs.

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Maze not generating properly. Out of bounds exception. need quick fix

- by Dan Joseph Porcioncula

My maze generator seems to have a problem. I am trying to generate something like the maze from http://mazeworks.com/mazegen/mazetut/index.htm . My program displays this http://a1.sphotos.ak.fbcdn.net/hphotos-ak-snc7/s320x320/374060_426350204045347_100000111130260_1880768_1572427285_n.jpg and the error Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1 at Grid.genRand(Grid.java:73) at Grid.main(Grid.java:35) How do I fix my generator program? import java.awt.*; import java.awt.Color; import java.awt.Component; import java.awt.Graphics; import javax.swing.*; import java.util.ArrayList; public class Grid extends Canvas { Cell[][] maze; int size; int pathSize; double width, height; ArrayList<int[]> coordinates = new ArrayList<int[]>(); public Grid(int size, int h, int w) { this.size = size; maze = new Cell[size][size]; for(int i = 0; i<size; i++){ for(int a =0; a<size; a++){ maze[i][a] = new Cell(); } } setPreferredSize(new Dimension(h, w)); } public static void main(String[] args) { JFrame y = new JFrame(); y.setLayout(new BorderLayout()); Grid f = new Grid(25, 400, 400); y.add(f, BorderLayout.CENTER); y.setSize(450, 450); y.setVisible(true); y.setDefaultCloseOperation(y.EXIT_ON_CLOSE); f.genRand(); f.repaint(); } public void push(int[] xy) { coordinates.add(xy); int i = coordinates.size(); coordinates.ensureCapacity(i++); } public int[] pop() { int[] x = coordinates.get((coordinates.size())-1); coordinates.remove((coordinates.size())-1); return x; } public int[] top() { return coordinates.get((coordinates.size())-1); } public void genRand(){ // create a CellStack (LIFO) to hold a list of cell locations [x] // set TotalCells = number of cells in grid int TotalCells = size*size; // choose a cell at random and call it CurrentCell int m = randomInt(size); int n = randomInt(size); Cell curCel = maze[m][n]; // set VisitedCells = 1 int visCel = 1,d=0; int[] q; int h,o = 0,p = 0; // while VisitedCells < TotalCells while( visCel < TotalCells){ // find all neighbors of CurrentCell with all walls intact if(maze[m-1][n].countWalls() == 4){d++;} if(maze[m+1][n].countWalls() == 4){d++;} if(maze[m][n-1].countWalls() == 4){d++;} if(maze[m][n+1].countWalls() == 4){d++;} // if one or more found if(d!=0){ Point[] ls = new Point[4]; ls[0] = new Point(m-1,n); ls[1] = new Point(m+1,n); ls[2] = new Point(m,n-1); ls[3] = new Point(m,n+1); // knock down the wall between it and CurrentCell h = randomInt(3); switch(h){ case 0: o = (int)(ls[0].getX()); p = (int)(ls[0].getY()); curCel.destroyWall(2); maze[o][p].destroyWall(1); break; case 1: o = (int)(ls[1].getX()); p = (int)(ls[1].getY()); curCel.destroyWall(1); maze[o][p].destroyWall(2); break; case 2: o = (int)(ls[2].getX()); p = (int)(ls[2].getY()); curCel.destroyWall(3); maze[o][p].destroyWall(0); break; case 3: o = (int)(ls[3].getX()); p = (int)(ls[3].getY()); curCel.destroyWall(0); maze[o][p].destroyWall(3); break; } // push CurrentCell location on the CellStack push(new int[] {m,n}); // make the new cell CurrentCell m = o; n = p; curCel = maze[m][n]; // add 1 to VisitedCells visCel++; } // else else{ // pop the most recent cell entry off the CellStack q = pop(); m = q[0]; n = q[1]; curCel = maze[m][n]; // make it CurrentCell // endIf } // endWhile } } public int randomInt(int s) { return (int)(s* Math.random());} public void paint(Graphics g) { int k, j; width = getSize().width; height = getSize().height; double htOfRow = height / (size); double wdOfRow = width / (size); //checks verticals - destroys east border of cell for (k = 0; k < size; k++) { for (j = 0; j < size; j++) { if(maze[k][j].checkWall(2)){ g.drawLine((int) (k * wdOfRow), (int) (j * htOfRow), (int) (k * wdOfRow), (int) ((j+1) * htOfRow)); }} } //checks horizontal - destroys north border of cell for (k = 0; k < size; k++) { for (j = 0; j < size; j++) { if(maze[k][j].checkWall(3)){ g.drawLine((int) (k * wdOfRow), (int) (j * htOfRow), (int) ((k+1) * wdOfRow), (int) (j * htOfRow)); }} } } } class Cell { private final static int NORTH = 0; private final static int EAST = 1; private final static int WEST = 2; private final static int SOUTH = 3; private final static int NO = 4; private final static int START = 1; private final static int END = 2; boolean[] wall = new boolean[4]; boolean[] border = new boolean[4]; boolean[] backtrack = new boolean[4]; boolean[] solution = new boolean[4]; private boolean isVisited = false; private int Key = 0; public Cell(){ for(int i=0;i<4;i++){wall[i] = true;} } public int countWalls(){ int i, k =0; for(i=0; i<4; i++) { if (wall[i] == true) {k++;} } return k;} public boolean checkWall(int x){ switch(x){ case 0: return wall[0]; case 1: return wall[1]; case 2: return wall[2]; case 3: return wall[3]; } return true; } public void destroyWall(int x){ switch(x){ case 0: wall[0] = false; break; case 1: wall[1] = false; break; case 2: wall[2] = false; break; case 3: wall[3] = false; break; } } public void setStart(int i){Key = i;} public int getKey(){return Key;} public boolean checkVisit(){return isVisited;} public void visitCell(){isVisited = true;} }

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Unicenter Software Delivery 4 not able to connect to MS SQL 2000 Database after W2003 SP2 upgrade

- by grub

Hello Everyone Yesterday I installed the Windows Server 2003 Service Pack 2 on a Windows Server 2003 which has Unicenter Software Delivery 4 installed. Prior to the installation I disabled every CA service on the server (Brightstor, SDO , RCO, TNG) and the MS SQL 2000 service. After the installation of the SP2 I enabled the services again but the Unicenter Service is not able to connect to the MS SQL 2000 Database anymore. The database itself is up and running and I can connect to it with the Enterprise Manager. A dbcc checkdb doesnt return any errors on the Unicenter database. The Unicenter service throws the following error messages during startup: IM[1] 27/05 10:38:31,272 Installation Manager in init phase IM[1] 27/05 10:38:31,694 Process IM(L) - [004152] failed to open database SDDATA. dbopen() call failed. IM[1] 27/05 10:38:31,694 sqls error details: IM[1] 27/05 10:38:31,694 (null) IM[1] 27/05 10:38:32,069 ##EXCEPTION## TableError T@:PS_SQLS\isam_db.cxx:744. IM[1] 27/05 10:38:32,069 ##EXCEPTION## TableError C@:TaskmgrL\ASMTML.CXX:596. IM[1] 27/05 10:38:32,069 ##EXCEPTION## ErrorCode: 4711 in SDDATA:Isam::Isam. Process IM(L) - [004152] failed to open database SDDATA. dbopen() call failed. IM[1] 27/05 10:38:32,069 sqls error details: IM[1] 27/05 10:38:32,069 (null) IM[1] 27/05 10:38:32,069 returned 0. IM[1] 27/05 10:38:32,084 Persistent Storage could not be opened. Error cause is found in the ASM Event Log. Restart Task Manager. IM[1] 27/05 10:38:32,084 Failed to open database. IM[1] 27/05 10:38:32,084 Installation Manager ends> If I check the Unicenter configutation with *chkmib_l* the tool throws an exception and creates a small dump file. An Exception Occurred: Time: 27/05 09:49:38,928 Reason: ChkMIB_l.exe caused an UNKNOWN_EXCEPTION in module kernel32.dll at 7C82001B:77E4BEE7 Registers: EAX=0012F908 EBX=00000000 ECX=00000000 EDX=02410004 ESI=0012F998 EDI=0012F998 EBP=0012F958 ESP=0012F904 EIP=77E4BEE7 FLG=00000206 CS =7C82001B DS =B90023 SS =120023 ES =120023 FS =7C82003B GS =3F0000 Call Stack: 7C82001B:77E4BEE7 (0xE06D7363 0x00000001 0x00000003 0x0012F98C) kernel32.dll 7C82001B:77BB3259 (0x0012F9B8 0x2B017C50 0x2B024404 0x00B68C98) MSVCRT.dll 7C82001B:2B010C42 (0x00020003 0x010C00FE 0x003F0190 0x00B69050) PS.dll << SOFTWARE DELIVERY INSTANCE INFO >> TRIGGER 0(1) instances: JCE 0(1) instances: TM 0(1) instances: IM 0(1) instances: DM 0(1) instances: DPU 0(71) instances: NATF 0(1) instances: MIBCONV 0(0) instances: API 0(4) instances: DTSFT 0(0) instances: TNGPOP 0(0) instances: DGATE 0(0) instances: << FLUSHING MEMORY TRACES >> << STOP FLUSHING MEMORY TRACES >> I compared the configuration of the SDO service and the system configuration with another server on which the Windows Server 2003 SP2 is installed and SDO is working. The configuration is the same and the same driver and software versions are used. Do you have any idea what causes the connection issue? Should I deinstall the unicenter service and make a fresh installation on the server or should I remove the Windows Server 2003 SP2? I don't want to remove the SP2 because it's a requirement for WSUS3 SP2 and I really don't want to know how many possible exploits are possible in such an old system ;-) Thank you very much and have a nice day. Below you can find more detailed information about the system and the SDO service. psinfo output (system information) System information for \\CZZAAS1003: Uptime: 0 days 14 hours 38 minutes 50 seconds Kernel version: Microsoft Windows Server 2003, Multiprocessor Free Product type: Standard Edition Product version: 5.2 Service pack: 2 Kernel build number: 3790 Install date: 23.9.2004, 11:16:11s IE version: 6.0000 System root: C:\WINDOWS Processors: 2 Processor speed: 2.3 GHz Processor type: Intel(R) Xeon(TM) CPU Physical memory: 1024 MB Video driver: RAGE XL PCI Family (Microsoft Corporation) sdver output (Unicenter Software delivery version) Unicenter Software Delivery 4.0 SP1 I2 ENU [2901] Copyright 2004 Computer Associates International, Incorporated ms sql 2000 version and odbc driver version MS SQL 2000 Server Standard Edition Product Version: 8.00.760 (SP3) ODBC Driver: SQL Server - Version 2000.86.3959.00 complete Unicenter Software delivery service log file TRIGGER[1] 27/05 10:38:28,366 SD Trigger Agent has started NATF[1] 27/05 10:38:28,928 Initiation phase finished IM[1] 27/05 10:38:31,272 Installation Manager in init phase IM[1] 27/05 10:38:31,694 Process IM(L) - [004152] failed to open database SDDATA. dbopen() call failed. IM[1] 27/05 10:38:31,694 sqls error details: IM[1] 27/05 10:38:31,694 (null) IM[1] 27/05 10:38:32,069 ##EXCEPTION## TableError T@:PS_SQLS\isam_db.cxx:744. IM[1] 27/05 10:38:32,069 ##EXCEPTION## TableError C@:TaskmgrL\ASMTML.CXX:596. IM[1] 27/05 10:38:32,069 ##EXCEPTION## ErrorCode: 4711 in SDDATA:Isam::Isam. Process IM(L) - [004152] failed to open database SDDATA. dbopen() call failed. IM[1] 27/05 10:38:32,069 sqls error details: IM[1] 27/05 10:38:32,069 (null) IM[1] 27/05 10:38:32,069 returned 0. IM[1] 27/05 10:38:32,084 Persistent Storage could not be opened. Error cause is found in the ASM Event Log. Restart Task Manager. IM[1] 27/05 10:38:32,084 Failed to open database. IM[1] 27/05 10:38:32,084 Installation Manager ends TM[1] 27/05 10:38:32,116 Task Manager in init phase TM[1] 27/05 10:38:32,334 Process TM(L) - [006132] failed to open database SDDATA. dbopen() call failed. TM[1] 27/05 10:38:32,334 sqls error details: TM[1] 27/05 10:38:32,334 (null) TM[1] 27/05 10:38:32,381 ##EXCEPTION## TableError T@:PS_SQLS\isam_db.cxx:744. TM[1] 27/05 10:38:32,381 ##EXCEPTION## TableError C@:TaskmgrL\ASMTML.CXX:596. TM[1] 27/05 10:38:32,381 ##EXCEPTION## ErrorCode: 4711 in SDDATA:Isam::Isam. Process TM(L) - [006132] failed to open database SDDATA. dbopen() call failed. TM[1] 27/05 10:38:32,381 sqls error details: TM[1] 27/05 10:38:32,381 (null) TM[1] 27/05 10:38:32,381 returned 0. TM[1] 27/05 10:38:32,381 Persistent Storage could not be opened. Error cause is found in the ASM Event Log. Restart Task Manager. TM[1] 27/05 10:38:32,381 Failed to open database. TM[1] 27/05 10:38:32,381 Task Manager ends DM[1] 27/05 10:38:33,272 Dialogue Manager is now active API[1] 27/05 10:38:34,397 API Server Process in init phase API[1] 27/05 10:38:34,397 API - SDNLS_Init API[1] 27/05 10:38:34,397 API - connectEM API[1] 27/05 10:38:34,412 API - apiServ.init DM[1] 27/05 10:38:34,678 **AND** 1 Agents triggered API[1] 27/05 10:38:34,709 Process API(L) - [005680] failed to open database SDDATA. dbopen() call failed. API[1] 27/05 10:38:34,709 sqls error details: API[1] 27/05 10:38:34,709 (null) API[1] 27/05 10:38:34,756 ##EXCEPTION## TableError T@:PS_SQLS\isam_db.cxx:744. API[1] 27/05 10:38:34,756 ##EXCEPTION## TableError C@:MainAPIL\APISERVL.CXX:246. API[1] 27/05 10:38:34,756 ##EXCEPTION## ErrorCode: 4711 in SDDATA:Isam::Isam. Process API(L) - [005680] failed to open database SDDATA. dbopen() call failed. API[1] 27/05 10:38:34,756 sqls error details: API[1] 27/05 10:38:34,756 (null) API[1] 27/05 10:38:34,756 returned 0. API[1] 27/05 10:38:34,756 Open of the database failed. API[1] 27/05 10:38:34,756 API - apiServ.init complete API[1] 27/05 10:38:34,756 API - start_APIServer DM[1] 27/05 10:38:34,803 CZZAAR1037 DPU[1:CZZAAR1037] 27/05 10:38:35,772 DPU in init phase DPU[1:CZZAAR1037] 27/05 10:38:36,100 >> GetManagerData DPU[1:CZZAAR1037] 27/05 10:38:36,287 >> SetCompInfo DPU[1:CZZAAR1037] 27/05 10:38:36,334 >> GetContainerList DPU[1:CZZAAR1037] 27/05 10:38:36,350 getJobState 3 from 5b6ad DPU[1:CZZAAR1037] 27/05 10:38:36,350 getJobState 3 from 5b6ad DPU[1:CZZAAR1037] 27/05 10:38:36,350 getJobState 3 from 5b6b7 DPU[1:CZZAAR1037] 27/05 10:38:36,350 getJobState 3 from 5b6b7 DPU[1:CZZAAR1037] 27/05 10:38:36,350 getJobState 3 from 5b6c1 DPU[1:CZZAAR1037] 27/05 10:38:36,350 getJobState 3 from 5b6c1 DPU[1:CZZAAR1037] 27/05 10:38:36,366 getJobState 3 from 5b6cb DPU[1:CZZAAR1037] 27/05 10:38:36,366 getJobState 3 from 5b6cb DPU[1:CZZAAR1037] 27/05 10:38:36,366 getJobState 3 from 5b6f9 DPU[1:CZZAAR1037] 27/05 10:38:36,366 getJobState 3 from 5b6f9 DPU[1:CZZAAR1037] 27/05 10:38:36,366 getJobState 3 from 5b71a DPU[1:CZZAAR1037] 27/05 10:38:36,366 getJobState 3 from 5b71a DPU[1:CZZAAR1037] 27/05 10:38:36,366 getJobState 3 from 5b724 DPU[1:CZZAAR1037] 27/05 10:38:36,381 getJobState 3 from 5b724 DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b72e DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b72e DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b738 DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b738 DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b742 DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b742 DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b74c DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b74c DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b756 DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b756 DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b78a DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b78a DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b7af DPU[1:CZZAAR1037] 27/05 10:38:36,397 getJobState 3 from 5b7af DPU[1:CZZAAR1037] 27/05 10:38:36,522 >> SetCompAttr DPU[1:CZZAAR1037] 27/05 10:38:36,569 >> SetDetected DPU[1:CZZAAR1037] 27/05 10:38:36,584 disconnect DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b6ad DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b6b7 DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b6c1 DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b6cb DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b6f9 DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b71a DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b724 DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b72e DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b738 DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b742 DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b74c DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b756 DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b78a DPU[1:CZZAAR1037] 27/05 10:38:36,584 getJobState 3 from 5b7af DPU[1:CZZAAR1037] 27/05 10:38:36,584 DPU ends DM[1] 27/05 10:38:38,006 **AND** 0 Agents triggered JCE[1] 27/05 10:38:38,053 JCE starts DM[1] 27/05 10:38:38,287 CZZAAS1003 DPU[2:CZZAAS1003] 27/05 10:38:38,412 DPU in init phase DPU[2:CZZAAS1003] 27/05 10:38:38,647 >> GetManagerData DPU[2:CZZAAS1003] 27/05 10:38:38,756 >> SetCompInfo DPU[2:CZZAAS1003] 27/05 10:38:38,787 >> GetContainerList DM[1] 27/05 10:38:38,850 **AND** 1 Agents triggered DM[1] 27/05 10:38:38,928 CZZAAR1124 DPU[3:CZZAAR1124] 27/05 10:38:39,053 DPU in init phase DPU[3:CZZAAR1124] 27/05 10:38:39,272 >> GetManagerData DM[1] 27/05 10:38:39,334 **AND** 1 Agents triggered DPU[3:CZZAAR1124] 27/05 10:38:39,381 >> SetCompInfo DPU[3:CZZAAR1124] 27/05 10:38:39,412 >> GetContainerList DM[1] 27/05 10:38:39,412 CZZAAR1125 DPU[3:CZZAAR1124] 27/05 10:38:39,428 getJobState 3 from 5b88e DPU[3:CZZAAR1124] 27/05 10:38:39,428 getJobState 3 from 5b88e DPU[2:CZZAAS1003] 27/05 10:38:39,491 >> SetCompAttr DPU[3:CZZAAR1124] 27/05 10:38:39,522 >> SetCompAttr DPU[4:CZZAAR1125] 27/05 10:38:39,522 DPU in init phase DPU[3:CZZAAR1124] 27/05 10:38:39,584 >> SetDetected DPU[2:CZZAAS1003] 27/05 10:38:39,584 >> SetDetected DPU[3:CZZAAR1124] 27/05 10:38:39,584 disconnect DPU[3:CZZAAR1124] 27/05 10:38:39,600 getJobState 3 from 5b88e DPU[3:CZZAAR1124] 27/05 10:38:39,600 DPU ends DPU[2:CZZAAS1003] 27/05 10:38:39,631 disconnect DPU[2:CZZAAS1003] 27/05 10:38:39,631 DPU ends DPU[4:CZZAAR1125] 27/05 10:38:39,756 >> GetManagerData DPU[4:CZZAAR1125] 27/05 10:38:39,850 >> SetCompInfo DPU[4:CZZAAR1125] 27/05 10:38:39,881 >> GetContainerList DPU[4:CZZAAR1125] 27/05 10:38:39,897 getJobState 3 from 5b8a9 DPU[4:CZZAAR1125] 27/05 10:38:39,897 getJobState 3 from 5b8a9 DPU[4:CZZAAR1125] 27/05 10:38:39,991 >> SetCompAttr DPU[4:CZZAAR1125] 27/05 10:38:40,100 >> SetDetected DPU[4:CZZAAR1125] 27/05 10:38:40,116 disconnect DPU[4:CZZAAR1125] 27/05 10:38:40,116 getJobState 3 from 5b8a9 DPU[4:CZZAAR1125] 27/05 10:38:40,116 DPU ends DM[1] 27/05 10:38:40,741 **AND** 0 Agents triggered JCE[1] 27/05 10:38:42,756 JCE ends DM[1] 27/05 10:38:47,475 **AND** 0 Agents triggered DM[1] 27/05 10:38:54,241 **AND** 0 Agents triggered

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