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  • Why does DeviceIoControl throw error 21 (Device Not Ready) from C# when the equivalent in C works fine?

    - by Ragesh
    I'm trying to send an IOCTL_SERVICE_REFRESH command to the GPS Intermediate Driver service using C# like this: handle = CreateFile("GPD0:", GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, IntPtr.Zero, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, IntPtr.Zero); if (handle.ToInt32() == INVALID_HANDLE_VALUE) { rc = Marshal.GetLastWin32Error(); return rc; } int numBytesReturned = 0; rc = DeviceIoControl( handle, IOCTL_SERVICE_REFRESH, null, 0, null, 0, ref numBytesReturned, IntPtr.Zero); int error = Marshal.GetLastWin32Error(); GetLastWin32Error always gives me error 21 (device not ready). However, the equivalent call when made from C++ works fine: HANDLE hGPS = CreateFile(L"GPD0:", GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0); if (hGPS != INVALID_HANDLE_VALUE) { BOOL ret = DeviceIoControl(hGPS,IOCTL_SERVICE_REFRESH,0,0,0,0,0,0); DWORD err = GetLastError(); } I suspected a problem with the PInvoke signatures, but I can't seem to find anything wrong here: [DllImport("coredll.dll", EntryPoint = "DeviceIoControl", SetLastError = true)] public static extern int DeviceIoControl( IntPtr hDevice, uint dwIoControlCode, byte[] lpInBuffer, int nInBufferSize, byte[] lpOutBuffer, int nOutBufferSize, ref int lpBytesReturned, IntPtr lpOverlapped); [DllImport("coredll.dll", SetLastError = true)] public static extern IntPtr CreateFile( String lpFileName, uint dwDesiredAccess, uint dwShareMode, IntPtr attr, uint dwCreationDisposition, uint dwFlagsAndAttributes, IntPtr hTemplateFile); What am I missing here?

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  • Why I cannot create DB in MySQL throw PHP?

    - by Roman
    I have this code: $link = mysql_connect("localhost", "ctman", "blablabla"); if ( ! $link ) die ("I cannot connect to MySQL.<br>\n"); else print "Connection is established.<br>\n"; // Create the "ct" database. mysql_query("create database ct", $link) or die("I cannot create the DB: ".mysql_error()."<br>\n"); And I get this error message: I cannot create the DB: Access denied for user 'ctmanager'@'%' to database 'ct' Does anybody have any idea why I cannot create a DB and why I have '@%' symbols in the error message?

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  • Are there SqlExceptions which throw but commit their data anyway?

    - by Jonn
    I've recently encountered the error: System.Data.SqlClient.SqlException: The transaction log for database 'mydatabase' is full. To find out why space in the log cannot be reused, see the log_reuse_wait_desc column in sys.databases on one of my windows services. It's supposed to retry after catching an Sql Exception, what I didn't expect was that it seemed like the data was still going through (I'm using an SqlBulkCopy btw) regardless of it throwing an exception. I've never encountered this scenario before. I'd like to know if there are other scenarios where such a thing like this might happen, and if this thing is entirely possible at all in the first place? PS. If anyone knows the error code to the above exception, that would help a great deal as well.

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  • how to loop throw all the Fileds in the view to check wheather checkbox is checked or not using jque

    - by kumar
    Hello friends. I have this code I am checking wheather checkbox i checked or not.. $('#btnsubmit').click(function() { $('#Details input[type=checkbox]').each(function() { if ($(this).attr('checked')) { alert("selected"); return false; } else { alert("please select atleast one user"); return false; } }); }); here var checked showing true or false.. I have deatils Fieldset in the view.. like that each field set having one check box.. like that there are three fieldsets with one check box..I need to know how many details checkbox is checked? can I loop each Details Fieldset to know how many details checkboxes are cheked? thanks

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  • C# XNA: What can cause SpriteBatch.End() to throw a NPE?

    - by Rosarch
    I don't understand what I'm doing wrong here: public void Draw(GameTime gameTime) // in ScreenManager { SpriteBatch.Begin(SpriteBlendMode.AlphaBlend); for (int i = 0; i < Screens.Count; i++) { if (Screens[i].State == Screen.ScreenState.HIDDEN) continue; Screens[i].Draw(gameTime); } SpriteBatch.End(); // null ref exception } SpriteBatch itself is not null. Some more context: public class MasterEngine : Microsoft.Xna.Framework.Game { public MasterEngine() { graphicsDeviceManager = new GraphicsDeviceManager(this); Components.Add(new GamerServicesComponent(this)); // ... spriteBatch = new SpriteBatch(graphicsDeviceManager.GraphicsDevice); screenManager = new ScreenManager(assets, gameEngine, graphicsDeviceManager.GraphicsDevice, spriteBatch); } //... protected override void Draw(GameTime gameTime) { screenManager.Draw(gameTime); // calls the problematic method base.Draw(gameTime); } } Am I failing to initialize something properly? UPDATE: As an experiment, I tried this to the constructor of MasterEngine: spriteBatch = new SpriteBatch(graphicsDeviceManager.GraphicsDevice); spriteBatch.Begin(); spriteBatch.DrawString(assets.GetAsset<SpriteFont>("calibri"), "ftw", new Vector2(), Color.White); spriteBatch.End(); This does not cause a NRE. hmm....

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  • Subterranean IL: Fault exception handlers

    - by Simon Cooper
    Fault event handlers are one of the two handler types that aren't available in C#. It behaves exactly like a finally, except it is only run if control flow exits the block due to an exception being thrown. As an example, take the following method: .method public static void FaultExample(bool throwException) { .try { ldstr "Entering try block" call void [mscorlib]System.Console::WriteLine(string) ldarg.0 brfalse.s NormalReturn ThrowException: ldstr "Throwing exception" call void [mscorlib]System.Console::WriteLine(string) newobj void [mscorlib]System.Exception::.ctor() throw NormalReturn: ldstr "Leaving try block" call void [mscorlib]System.Console::WriteLine(string) leave.s Return } fault { ldstr "Fault handler" call void [mscorlib]System.Console::WriteLine(string) endfault } Return: ldstr "Returning from method" call void [mscorlib]System.Console::WriteLine(string) ret } If we pass true to this method the following gets printed: Entering try block Throwing exception Fault handler and the exception gets passed up the call stack. So, the exception gets thrown, the fault handler gets run, and the exception propagates up the stack afterwards in the normal way. If we pass false, we get the following: Entering try block Leaving try block Returning from method Because we are leaving the .try using a leave.s instruction, and not throwing an exception, the fault handler does not get called. Fault handlers and C# So why were these not included in C#? It seems a pretty simple feature; one extra keyword that compiles in exactly the same way, and with the same semantics, as a finally handler. If you think about it, the same behaviour can be replicated using a normal catch block: try { throw new Exception(); } catch { // fault code goes here throw; } The catch block only gets run if an exception is thrown, and the exception gets rethrown and propagates up the call stack afterwards; exactly like a fault block. The only complications that occur is when you want to add a fault handler to a try block with existing catch handlers. Then, you either have to wrap the try in another try: try { try { // ... } catch (DirectoryNotFoundException) { // ... // leave.s as normal... } catch (IOException) { // ... throw; } } catch { // fault logic throw; } or separate out the fault logic into another method and call that from the appropriate handlers: try { // ... } catch (DirectoryNotFoundException ) { // ... } catch (IOException ioe) { // ... HandleFaultLogic(); throw; } catch (Exception e) { HandleFaultLogic(); throw; } To be fair, the number of times that I would have found a fault handler useful is minimal. Still, it's quite annoying knowing such functionality exists, but you're not able to access it from C#. Fortunately, there are some easy workarounds one can use instead. Next time: filter handlers.

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  • OData &ndash; The easiest service I can create: now with updates

    - by Jon Dalberg
    The other day I created a simple NastyWord service exposed via OData. It was read-only and used an in-memory backing store for the words. Today I’ll modify it to use a file instead of a list and I’ll accept new nasty words by implementing IUpdatable directly. The first thing to do is enable the service to accept new entries. This is done at configuration time by adding the “WriteAppend” access rule: 1: public class NastyWords : DataService<NastyWordsDataSource> 2: { 3: // This method is called only once to initialize service-wide policies. 4: public static void InitializeService(DataServiceConfiguration config) 5: { 6: config.SetEntitySetAccessRule("*", EntitySetRights.AllRead | EntitySetRights.WriteAppend); 7: config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2; 8: } 9: }   Next I placed a file, NastyWords.txt, in the “App_Data” folder and added a few *choice* words to start. This required one simple change to our NastyWordDataSource.cs file: 1: public NastyWordsDataSource() 2: { 3: UpdateFromSource(); 4: } 5:   6: private void UpdateFromSource() 7: { 8: var words = File.ReadAllLines(pathToFile); 9: NastyWords = (from w in words 10: select new NastyWord { Word = w }).AsQueryable(); 11: }   Nothing too shocking here, just reading each line from the NastyWords.txt file and exposing them. Next, I implemented IUpdatable which comes with a boat-load of methods. We don’t need all of them for now since we are only concerned with allowing new values. Here are the methods we must implement, all the others throw a NotImplementedException: 1: public object CreateResource(string containerName, string fullTypeName) 2: { 3: var nastyWord = new NastyWord(); 4: pendingUpdates.Add(nastyWord); 5: return nastyWord; 6: } 7:   8: public object ResolveResource(object resource) 9: { 10: return resource; 11: } 12:   13: public void SaveChanges() 14: { 15: var intersect = (from w in pendingUpdates 16: select w.Word).Intersect(from n in NastyWords 17: select n.Word); 18:   19: if (intersect.Count() > 0) 20: throw new DataServiceException(500, "duplicate entry"); 21:   22: var lines = from w in pendingUpdates 23: select w.Word; 24:   25: File.AppendAllLines(pathToFile, 26: lines, 27: Encoding.UTF8); 28:   29: pendingUpdates.Clear(); 30:   31: UpdateFromSource(); 32: } 33:   34: public void SetValue(object targetResource, string propertyName, object propertyValue) 35: { 36: targetResource.GetType().GetProperty(propertyName).SetValue(targetResource, propertyValue, null); 37: }   I use a simple list to contain the pending updates and only commit them when the “SaveChanges” method is called. Here’s the order these methods are called in our service during an insert: CreateResource – here we just instantiate a new NastyWord and stick a reference to it in our pending updates list. SetValue – this is where the “Word” property of the NastyWord instance is set. SaveChanges – get the list of pending updates, barfing on duplicates, write them to the file and clear our pending list. ResolveResource – the newly created resource will be returned directly here since we aren’t dealing with “handles” to objects but the actual objects themselves. Not too bad, eh? I didn’t find this documented anywhere but a little bit of digging in the OData spec and use of Fiddler made it pretty easy to figure out. Here is some client code which would add a new nasty word: 1: static void Main(string[] args) 2: { 3: var svc = new ServiceReference1.NastyWordsDataSource(new Uri("http://localhost.:60921/NastyWords.svc")); 4: svc.AddToNastyWords(new ServiceReference1.NastyWord() { Word = "shat" }); 5:   6: svc.SaveChanges(); 7: }   Here’s all of the code so far for to implement the service: 1: using System; 2: using System.Collections.Generic; 3: using System.Data.Services; 4: using System.Data.Services.Common; 5: using System.Linq; 6: using System.ServiceModel.Web; 7: using System.Web; 8: using System.IO; 9: using System.Text; 10:   11: namespace ONasty 12: { 13: [DataServiceKey("Word")] 14: public class NastyWord 15: { 16: public string Word { get; set; } 17: } 18:   19: public class NastyWordsDataSource : IUpdatable 20: { 21: private List<NastyWord> pendingUpdates = new List<NastyWord>(); 22: private string pathToFile = @"path to your\App_Data\NastyWords.txt"; 23:   24: public NastyWordsDataSource() 25: { 26: UpdateFromSource(); 27: } 28:   29: private void UpdateFromSource() 30: { 31: var words = File.ReadAllLines(pathToFile); 32: NastyWords = (from w in words 33: select new NastyWord { Word = w }).AsQueryable(); 34: } 35:   36: public IQueryable<NastyWord> NastyWords { get; private set; } 37:   38: public void AddReferenceToCollection(object targetResource, string propertyName, object resourceToBeAdded) 39: { 40: throw new NotImplementedException(); 41: } 42:   43: public void ClearChanges() 44: { 45: pendingUpdates.Clear(); 46: } 47:   48: public object CreateResource(string containerName, string fullTypeName) 49: { 50: var nastyWord = new NastyWord(); 51: pendingUpdates.Add(nastyWord); 52: return nastyWord; 53: } 54:   55: public void DeleteResource(object targetResource) 56: { 57: throw new NotImplementedException(); 58: } 59:   60: public object GetResource(IQueryable query, string fullTypeName) 61: { 62: throw new NotImplementedException(); 63: } 64:   65: public object GetValue(object targetResource, string propertyName) 66: { 67: throw new NotImplementedException(); 68: } 69:   70: public void RemoveReferenceFromCollection(object targetResource, string propertyName, object resourceToBeRemoved) 71: { 72: throw new NotImplementedException(); 73: } 74:   75: public object ResetResource(object resource) 76: { 77: throw new NotImplementedException(); 78: } 79:   80: public object ResolveResource(object resource) 81: { 82: return resource; 83: } 84:   85: public void SaveChanges() 86: { 87: var intersect = (from w in pendingUpdates 88: select w.Word).Intersect(from n in NastyWords 89: select n.Word); 90:   91: if (intersect.Count() > 0) 92: throw new DataServiceException(500, "duplicate entry"); 93:   94: var lines = from w in pendingUpdates 95: select w.Word; 96:   97: File.AppendAllLines(pathToFile, 98: lines, 99: Encoding.UTF8); 100:   101: pendingUpdates.Clear(); 102:   103: UpdateFromSource(); 104: } 105:   106: public void SetReference(object targetResource, string propertyName, object propertyValue) 107: { 108: throw new NotImplementedException(); 109: } 110:   111: public void SetValue(object targetResource, string propertyName, object propertyValue) 112: { 113: targetResource.GetType().GetProperty(propertyName).SetValue(targetResource, propertyValue, null); 114: } 115: } 116:   117: public class NastyWords : DataService<NastyWordsDataSource> 118: { 119: // This method is called only once to initialize service-wide policies. 120: public static void InitializeService(DataServiceConfiguration config) 121: { 122: config.SetEntitySetAccessRule("*", EntitySetRights.AllRead | EntitySetRights.WriteAppend); 123: config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2; 124: } 125: } 126: } Next time we’ll allow removing nasty words. Enjoy!

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  • How to turn off power metering in HP ILO2?

    - by Baron Throw
    I have an issue with all of my RHEL 5.3 servers, where HP iLo2 power meter checks the power draw of the power supply on the server. However this gets passed to the /var/log/messages in our host, and eventually fills up the logs. Anyone have any idea how to completely disable power meter option in iLo? I checked google and iLo2 documentation provided from HP, but found nothing that tells you how to disable it / turn it off. Maybe some CLI command? Im not sure. The message is: Aug 18 10:11:03 KAMIL-SERVER1 ipstor_hwmond: IPSTOR||1408371063||E||11788||sensors||Power Meter = 108.000 Watts [ low=na high=na]

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  • Service Discovery in WCF 4.0 &ndash; Part 1

    - by Shaun
    When designing a service oriented architecture (SOA) system, there will be a lot of services with many service contracts, endpoints and behaviors. Besides the client calling the service, in a large distributed system a service may invoke other services. In this case, one service might need to know the endpoints it invokes. This might not be a problem in a small system. But when you have more than 10 services this might be a problem. For example in my current product, there are around 10 services, such as the user authentication service, UI integration service, location service, license service, device monitor service, event monitor service, schedule job service, accounting service, player management service, etc..   Benefit of Discovery Service Since almost all my services need to invoke at least one other service. This would be a difficult task to make sure all services endpoints are configured correctly in every service. And furthermore, it would be a nightmare when a service changed its endpoint at runtime. Hence, we need a discovery service to remove the dependency (configuration dependency). A discovery service plays as a service dictionary which stores the relationship between the contracts and the endpoints for every service. By using the discovery service, when service X wants to invoke service Y, it just need to ask the discovery service where is service Y, then the discovery service will return all proper endpoints of service Y, then service X can use the endpoint to send the request to service Y. And when some services changed their endpoint address, all need to do is to update its records in the discovery service then all others will know its new endpoint. In WCF 4.0 Discovery it supports both managed proxy discovery mode and ad-hoc discovery mode. In ad-hoc mode there is no standalone discovery service. When a client wanted to invoke a service, it will broadcast an message (normally in UDP protocol) to the entire network with the service match criteria. All services which enabled the discovery behavior will receive this message and only those matched services will send their endpoint back to the client. The managed proxy discovery service works as I described above. In this post I will only cover the managed proxy mode, where there’s a discovery service. For more information about the ad-hoc mode please refer to the MSDN.   Service Announcement and Probe The main functionality of discovery service should be return the proper endpoint addresses back to the service who is looking for. In most cases the consume service (as a client) will send the contract which it wanted to request to the discovery service. And then the discovery service will find the endpoint and respond. Sometimes the contract and endpoint are not enough. It also contains versioning, extensions attributes. This post I will only cover the case includes contract and endpoint. When a client (or sometimes a service who need to invoke another service) need to connect to a target service, it will firstly request the discovery service through the “Probe” method with the criteria. Basically the criteria contains the contract type name of the target service. Then the discovery service will search its endpoint repository by the criteria. The repository might be a database, a distributed cache or a flat XML file. If it matches, the discovery service will grab the endpoint information (it’s called discovery endpoint metadata in WCF) and send back. And this is called “Probe”. Finally the client received the discovery endpoint metadata and will use the endpoint to connect to the target service. Besides the probe, discovery service should take the responsible to know there is a new service available when it goes online, as well as stopped when it goes offline. This feature is named “Announcement”. When a service started and stopped, it will announce to the discovery service. So the basic functionality of a discovery service should includes: 1, An endpoint which receive the service online message, and add the service endpoint information in the discovery repository. 2, An endpoint which receive the service offline message, and remove the service endpoint information from the discovery repository. 3, An endpoint which receive the client probe message, and return the matches service endpoints, and return the discovery endpoint metadata. WCF 4.0 discovery service just covers all these features in it's infrastructure classes.   Discovery Service in WCF 4.0 WCF 4.0 introduced a new assembly named System.ServiceModel.Discovery which has all necessary classes and interfaces to build a WS-Discovery compliant discovery service. It supports ad-hoc and managed proxy modes. For the case mentioned in this post, what we need to build is a standalone discovery service, which is the managed proxy discovery service mode. To build a managed discovery service in WCF 4.0 just create a new class inherits from the abstract class System.ServiceModel.Discovery.DiscoveryProxy. This class implemented and abstracted the procedures of service announcement and probe. And it exposes 8 abstract methods where we can implement our own endpoint register, unregister and find logic. These 8 methods are asynchronized, which means all invokes to the discovery service are asynchronously, for better service capability and performance. 1, OnBeginOnlineAnnouncement, OnEndOnlineAnnouncement: Invoked when a service sent the online announcement message. We need to add the endpoint information to the repository in this method. 2, OnBeginOfflineAnnouncement, OnEndOfflineAnnouncement: Invoked when a service sent the offline announcement message. We need to remove the endpoint information from the repository in this method. 3, OnBeginFind, OnEndFind: Invoked when a client sent the probe message that want to find the service endpoint information. We need to look for the proper endpoints by matching the client’s criteria through the repository in this method. 4, OnBeginResolve, OnEndResolve: Invoked then a client sent the resolve message. Different from the find method, when using resolve method the discovery service will return the exactly one service endpoint metadata to the client. In our example we will NOT implement this method.   Let’s create our own discovery service, inherit the base System.ServiceModel.Discovery.DiscoveryProxy. We also need to specify the service behavior in this class. Since the build-in discovery service host class only support the singleton mode, we must set its instance context mode to single. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using System.ServiceModel; 7:  8: namespace Phare.Service 9: { 10: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 11: public class ManagedProxyDiscoveryService : DiscoveryProxy 12: { 13: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 14: { 15: throw new NotImplementedException(); 16: } 17:  18: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 19: { 20: throw new NotImplementedException(); 21: } 22:  23: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 24: { 25: throw new NotImplementedException(); 26: } 27:  28: protected override IAsyncResult OnBeginResolve(ResolveCriteria resolveCriteria, AsyncCallback callback, object state) 29: { 30: throw new NotImplementedException(); 31: } 32:  33: protected override void OnEndFind(IAsyncResult result) 34: { 35: throw new NotImplementedException(); 36: } 37:  38: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 39: { 40: throw new NotImplementedException(); 41: } 42:  43: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 44: { 45: throw new NotImplementedException(); 46: } 47:  48: protected override EndpointDiscoveryMetadata OnEndResolve(IAsyncResult result) 49: { 50: throw new NotImplementedException(); 51: } 52: } 53: } Then let’s implement the online, offline and find methods one by one. WCF discovery service gives us full flexibility to implement the endpoint add, remove and find logic. For the demo purpose we will use an internal dictionary to store the services’ endpoint metadata. In the next post we will see how to serialize and store these information in database. Define a concurrent dictionary inside the service class since our it will be used in the multiple threads scenario. 1: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 2: public class ManagedProxyDiscoveryService : DiscoveryProxy 3: { 4: private ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata> _services; 5:  6: public ManagedProxyDiscoveryService() 7: { 8: _services = new ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata>(); 9: } 10: } Then we can simply implement the logic of service online and offline. 1: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 2: { 3: _services.AddOrUpdate(endpointDiscoveryMetadata.Address, endpointDiscoveryMetadata, (key, value) => endpointDiscoveryMetadata); 4: return new OnOnlineAnnouncementAsyncResult(callback, state); 5: } 6:  7: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 8: { 9: OnOnlineAnnouncementAsyncResult.End(result); 10: } 11:  12: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 13: { 14: EndpointDiscoveryMetadata endpoint = null; 15: _services.TryRemove(endpointDiscoveryMetadata.Address, out endpoint); 16: return new OnOfflineAnnouncementAsyncResult(callback, state); 17: } 18:  19: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 20: { 21: OnOfflineAnnouncementAsyncResult.End(result); 22: } Regards the find method, the parameter FindRequestContext.Criteria has a method named IsMatch, which can be use for us to evaluate which service metadata is satisfied with the criteria. So the implementation of find method would be like this. 1: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 2: { 3: _services.Where(s => findRequestContext.Criteria.IsMatch(s.Value)) 4: .Select(s => s.Value) 5: .All(meta => 6: { 7: findRequestContext.AddMatchingEndpoint(meta); 8: return true; 9: }); 10: return new OnFindAsyncResult(callback, state); 11: } 12:  13: protected override void OnEndFind(IAsyncResult result) 14: { 15: OnFindAsyncResult.End(result); 16: } As you can see, we checked all endpoints metadata in repository by invoking the IsMatch method. Then add all proper endpoints metadata into the parameter. Finally since all these methods are asynchronized we need some AsyncResult classes as well. Below are the base class and the inherited classes used in previous methods. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.Threading; 6:  7: namespace Phare.Service 8: { 9: abstract internal class AsyncResult : IAsyncResult 10: { 11: AsyncCallback callback; 12: bool completedSynchronously; 13: bool endCalled; 14: Exception exception; 15: bool isCompleted; 16: ManualResetEvent manualResetEvent; 17: object state; 18: object thisLock; 19:  20: protected AsyncResult(AsyncCallback callback, object state) 21: { 22: this.callback = callback; 23: this.state = state; 24: this.thisLock = new object(); 25: } 26:  27: public object AsyncState 28: { 29: get 30: { 31: return state; 32: } 33: } 34:  35: public WaitHandle AsyncWaitHandle 36: { 37: get 38: { 39: if (manualResetEvent != null) 40: { 41: return manualResetEvent; 42: } 43: lock (ThisLock) 44: { 45: if (manualResetEvent == null) 46: { 47: manualResetEvent = new ManualResetEvent(isCompleted); 48: } 49: } 50: return manualResetEvent; 51: } 52: } 53:  54: public bool CompletedSynchronously 55: { 56: get 57: { 58: return completedSynchronously; 59: } 60: } 61:  62: public bool IsCompleted 63: { 64: get 65: { 66: return isCompleted; 67: } 68: } 69:  70: object ThisLock 71: { 72: get 73: { 74: return this.thisLock; 75: } 76: } 77:  78: protected static TAsyncResult End<TAsyncResult>(IAsyncResult result) 79: where TAsyncResult : AsyncResult 80: { 81: if (result == null) 82: { 83: throw new ArgumentNullException("result"); 84: } 85:  86: TAsyncResult asyncResult = result as TAsyncResult; 87:  88: if (asyncResult == null) 89: { 90: throw new ArgumentException("Invalid async result.", "result"); 91: } 92:  93: if (asyncResult.endCalled) 94: { 95: throw new InvalidOperationException("Async object already ended."); 96: } 97:  98: asyncResult.endCalled = true; 99:  100: if (!asyncResult.isCompleted) 101: { 102: asyncResult.AsyncWaitHandle.WaitOne(); 103: } 104:  105: if (asyncResult.manualResetEvent != null) 106: { 107: asyncResult.manualResetEvent.Close(); 108: } 109:  110: if (asyncResult.exception != null) 111: { 112: throw asyncResult.exception; 113: } 114:  115: return asyncResult; 116: } 117:  118: protected void Complete(bool completedSynchronously) 119: { 120: if (isCompleted) 121: { 122: throw new InvalidOperationException("This async result is already completed."); 123: } 124:  125: this.completedSynchronously = completedSynchronously; 126:  127: if (completedSynchronously) 128: { 129: this.isCompleted = true; 130: } 131: else 132: { 133: lock (ThisLock) 134: { 135: this.isCompleted = true; 136: if (this.manualResetEvent != null) 137: { 138: this.manualResetEvent.Set(); 139: } 140: } 141: } 142:  143: if (callback != null) 144: { 145: callback(this); 146: } 147: } 148:  149: protected void Complete(bool completedSynchronously, Exception exception) 150: { 151: this.exception = exception; 152: Complete(completedSynchronously); 153: } 154: } 155: } 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using Phare.Service; 7:  8: namespace Phare.Service 9: { 10: internal sealed class OnOnlineAnnouncementAsyncResult : AsyncResult 11: { 12: public OnOnlineAnnouncementAsyncResult(AsyncCallback callback, object state) 13: : base(callback, state) 14: { 15: this.Complete(true); 16: } 17:  18: public static void End(IAsyncResult result) 19: { 20: AsyncResult.End<OnOnlineAnnouncementAsyncResult>(result); 21: } 22:  23: } 24:  25: sealed class OnOfflineAnnouncementAsyncResult : AsyncResult 26: { 27: public OnOfflineAnnouncementAsyncResult(AsyncCallback callback, object state) 28: : base(callback, state) 29: { 30: this.Complete(true); 31: } 32:  33: public static void End(IAsyncResult result) 34: { 35: AsyncResult.End<OnOfflineAnnouncementAsyncResult>(result); 36: } 37: } 38:  39: sealed class OnFindAsyncResult : AsyncResult 40: { 41: public OnFindAsyncResult(AsyncCallback callback, object state) 42: : base(callback, state) 43: { 44: this.Complete(true); 45: } 46:  47: public static void End(IAsyncResult result) 48: { 49: AsyncResult.End<OnFindAsyncResult>(result); 50: } 51: } 52:  53: sealed class OnResolveAsyncResult : AsyncResult 54: { 55: EndpointDiscoveryMetadata matchingEndpoint; 56:  57: public OnResolveAsyncResult(EndpointDiscoveryMetadata matchingEndpoint, AsyncCallback callback, object state) 58: : base(callback, state) 59: { 60: this.matchingEndpoint = matchingEndpoint; 61: this.Complete(true); 62: } 63:  64: public static EndpointDiscoveryMetadata End(IAsyncResult result) 65: { 66: OnResolveAsyncResult thisPtr = AsyncResult.End<OnResolveAsyncResult>(result); 67: return thisPtr.matchingEndpoint; 68: } 69: } 70: } Now we have finished the discovery service. The next step is to host it. The discovery service is a standard WCF service. So we can use ServiceHost on a console application, windows service, or in IIS as usual. The following code is how to host the discovery service we had just created in a console application. 1: static void Main(string[] args) 2: { 3: using (var host = new ServiceHost(new ManagedProxyDiscoveryService())) 4: { 5: host.Opened += (sender, e) => 6: { 7: host.Description.Endpoints.All((ep) => 8: { 9: Console.WriteLine(ep.ListenUri); 10: return true; 11: }); 12: }; 13:  14: try 15: { 16: // retrieve the announcement, probe endpoint and binding from configuration 17: var announcementEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 18: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 19: var binding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 20: var announcementEndpoint = new AnnouncementEndpoint(binding, announcementEndpointAddress); 21: var probeEndpoint = new DiscoveryEndpoint(binding, probeEndpointAddress); 22: probeEndpoint.IsSystemEndpoint = false; 23: // append the service endpoint for announcement and probe 24: host.AddServiceEndpoint(announcementEndpoint); 25: host.AddServiceEndpoint(probeEndpoint); 26:  27: host.Open(); 28:  29: Console.WriteLine("Press any key to exit."); 30: Console.ReadKey(); 31: } 32: catch (Exception ex) 33: { 34: Console.WriteLine(ex.ToString()); 35: } 36: } 37:  38: Console.WriteLine("Done."); 39: Console.ReadKey(); 40: } What we need to notice is that, the discovery service needs two endpoints for announcement and probe. In this example I just retrieve them from the configuration file. I also specified the binding of these two endpoints in configuration file as well. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> And this is the console screen when I ran my discovery service. As you can see there are two endpoints listening for announcement message and probe message.   Discoverable Service and Client Next, let’s create a WCF service that is discoverable, which means it can be found by the discovery service. To do so, we need to let the service send the online announcement message to the discovery service, as well as offline message before it shutdown. Just create a simple service which can make the incoming string to upper. The service contract and implementation would be like this. 1: [ServiceContract] 2: public interface IStringService 3: { 4: [OperationContract] 5: string ToUpper(string content); 6: } 1: public class StringService : IStringService 2: { 3: public string ToUpper(string content) 4: { 5: return content.ToUpper(); 6: } 7: } Then host this service in the console application. In order to make the discovery service easy to be tested the service address will be changed each time it’s started. 1: static void Main(string[] args) 2: { 3: var baseAddress = new Uri(string.Format("net.tcp://localhost:11001/stringservice/{0}/", Guid.NewGuid().ToString())); 4:  5: using (var host = new ServiceHost(typeof(StringService), baseAddress)) 6: { 7: host.Opened += (sender, e) => 8: { 9: Console.WriteLine("Service opened at {0}", host.Description.Endpoints.First().ListenUri); 10: }; 11:  12: host.AddServiceEndpoint(typeof(IStringService), new NetTcpBinding(), string.Empty); 13:  14: host.Open(); 15:  16: Console.WriteLine("Press any key to exit."); 17: Console.ReadKey(); 18: } 19: } Currently this service is NOT discoverable. We need to add a special service behavior so that it could send the online and offline message to the discovery service announcement endpoint when the host is opened and closed. WCF 4.0 introduced a service behavior named ServiceDiscoveryBehavior. When we specified the announcement endpoint address and appended it to the service behaviors this service will be discoverable. 1: var announcementAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 2: var announcementBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 3: var announcementEndpoint = new AnnouncementEndpoint(announcementBinding, announcementAddress); 4: var discoveryBehavior = new ServiceDiscoveryBehavior(); 5: discoveryBehavior.AnnouncementEndpoints.Add(announcementEndpoint); 6: host.Description.Behaviors.Add(discoveryBehavior); The ServiceDiscoveryBehavior utilizes the service extension and channel dispatcher to implement the online and offline announcement logic. In short, it injected the channel open and close procedure and send the online and offline message to the announcement endpoint.   On client side, when we have the discovery service, a client can invoke a service without knowing its endpoint. WCF discovery assembly provides a class named DiscoveryClient, which can be used to find the proper service endpoint by passing the criteria. In the code below I initialized the DiscoveryClient, specified the discovery service probe endpoint address. Then I created the find criteria by specifying the service contract I wanted to use and invoke the Find method. This will send the probe message to the discovery service and it will find the endpoints back to me. The discovery service will return all endpoints that matches the find criteria, which means in the result of the find method there might be more than one endpoints. In this example I just returned the first matched one back. In the next post I will show how to extend our discovery service to make it work like a service load balancer. 1: static EndpointAddress FindServiceEndpoint() 2: { 3: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 4: var probeBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 5: var discoveryEndpoint = new DiscoveryEndpoint(probeBinding, probeEndpointAddress); 6:  7: EndpointAddress address = null; 8: FindResponse result = null; 9: using (var discoveryClient = new DiscoveryClient(discoveryEndpoint)) 10: { 11: result = discoveryClient.Find(new FindCriteria(typeof(IStringService))); 12: } 13:  14: if (result != null && result.Endpoints.Any()) 15: { 16: var endpointMetadata = result.Endpoints.First(); 17: address = endpointMetadata.Address; 18: } 19: return address; 20: } Once we probed the discovery service we will receive the endpoint. So in the client code we can created the channel factory from the endpoint and binding, and invoke to the service. When creating the client side channel factory we need to make sure that the client side binding should be the same as the service side. WCF discovery service can be used to find the endpoint for a service contract, but the binding is NOT included. This is because the binding was not in the WS-Discovery specification. In the next post I will demonstrate how to add the binding information into the discovery service. At that moment the client don’t need to create the binding by itself. Instead it will use the binding received from the discovery service. 1: static void Main(string[] args) 2: { 3: Console.WriteLine("Say something..."); 4: var content = Console.ReadLine(); 5: while (!string.IsNullOrWhiteSpace(content)) 6: { 7: Console.WriteLine("Finding the service endpoint..."); 8: var address = FindServiceEndpoint(); 9: if (address == null) 10: { 11: Console.WriteLine("There is no endpoint matches the criteria."); 12: } 13: else 14: { 15: Console.WriteLine("Found the endpoint {0}", address.Uri); 16:  17: var factory = new ChannelFactory<IStringService>(new NetTcpBinding(), address); 18: factory.Opened += (sender, e) => 19: { 20: Console.WriteLine("Connecting to {0}.", factory.Endpoint.ListenUri); 21: }; 22: var proxy = factory.CreateChannel(); 23: using (proxy as IDisposable) 24: { 25: Console.WriteLine("ToUpper: {0} => {1}", content, proxy.ToUpper(content)); 26: } 27: } 28:  29: Console.WriteLine("Say something..."); 30: content = Console.ReadLine(); 31: } 32: } Similarly, the discovery service probe endpoint and binding were defined in the configuration file. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> OK, now let’s have a test. Firstly start the discovery service, and then start our discoverable service. When it started it will announced to the discovery service and registered its endpoint into the repository, which is the local dictionary. And then start the client and type something. As you can see the client asked the discovery service for the endpoint and then establish the connection to the discoverable service. And more interesting, do NOT close the client console but terminate the discoverable service but press the enter key. This will make the service send the offline message to the discovery service. Then start the discoverable service again. Since we made it use a different address each time it started, currently it should be hosted on another address. If we enter something in the client we could see that it asked the discovery service and retrieve the new endpoint, and connect the the service.   Summary In this post I discussed the benefit of using the discovery service and the procedures of service announcement and probe. I also demonstrated how to leverage the WCF Discovery feature in WCF 4.0 to build a simple managed discovery service. For test purpose, in this example I used the in memory dictionary as the discovery endpoint metadata repository. And when finding I also just return the first matched endpoint back. I also hard coded the bindings between the discoverable service and the client. In next post I will show you how to solve the problem mentioned above, as well as some additional feature for production usage. You can download the code here.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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  • Enumerable Interleave Extension Method

    - by João Angelo
    A recent stackoverflow question, which I didn’t bookmark and now I’m unable to find, inspired me to implement an extension method for Enumerable that allows to insert a constant element between each pair of elements in a sequence. Kind of what String.Join does for strings, but maintaining an enumerable as the return value. Having done the single element part I got a bit carried away and ended up expanding it adding overloads to support interleaving elements of another sequence and support for a predicate to control when interleaving takes place. I have to confess that I did this for fun and now I can’t think of any real usage scenario, nonetheless, it may prove useful for someone. First a simple example: var target = new string[] { "(", ")", "(", ")" }; var result = target.Interleave(".", (f, s) => f == "("); // Prints: (.)(.) Console.WriteLine(String.Join(string.Empty, result)); And now the untested but documented implementation: using System; using System.Collections; using System.Collections.Generic; using System.Linq; public static class EnumerableExtensions { /// <summary> /// Iterates infinitely over a constant element. /// </summary> /// <typeparam name="T"> /// The type of element in the sequence. /// </typeparam> private class InfiniteSequence<T> : IEnumerable<T>, IEnumerator<T> { public InfiniteSequence(T element) { this.Element = element; } public T Element { get; private set; } public IEnumerator<T> GetEnumerator() { return this; } IEnumerator IEnumerable.GetEnumerator() { return this; } T IEnumerator<T>.Current { get { return this.Element; } } void IDisposable.Dispose() { } object IEnumerator.Current { get { return this.Element; } } bool IEnumerator.MoveNext() { return true; } void IEnumerator.Reset() { } } /// <summary> /// Interleaves the specified <paramref name="element"/> between each pair of elements in the <paramref name="target"/> sequence. /// </summary> /// <typeparam name="T"> /// The type of elements in the sequence. /// </typeparam> /// <param name="target"> /// The target sequence to be interleaved. /// </param> /// <param name="element"> /// The element used to perform the interleave operation. /// </param> /// <exception cref="ArgumentNullException"> /// <paramref name="target"/> or <paramref name="element"/> is a null reference. /// </exception> /// <returns> /// The <paramref name="target"/> sequence interleaved with the specified <paramref name="element"/>. /// </returns> public static IEnumerable<T> Interleave<T>( this IEnumerable<T> target, T element) { if (target == null) throw new ArgumentNullException("target"); if (element == null) throw new ArgumentNullException("element"); return InterleaveInternal(target, new InfiniteSequence<T>(element), (f, s) => true); } /// <summary> /// Interleaves the specified <paramref name="element"/> between each pair of elements in the <paramref name="target"/> sequence. /// </summary> /// <remarks> /// The interleave operation is interrupted as soon as the <paramref name="target"/> sequence is exhausted; If the number of <paramref name="elements"/> to be interleaved are not enough to completely interleave the <paramref name="target"/> sequence then the remainder of the sequence is returned without being interleaved. /// </remarks> /// <typeparam name="T"> /// The type of elements in the sequence. /// </typeparam> /// <param name="target"> /// The target sequence to be interleaved. /// </param> /// <param name="elements"> /// The elements used to perform the interleave operation. /// </param> /// <exception cref="ArgumentNullException"> /// <paramref name="target"/> or <paramref name="element"/> is a null reference. /// </exception> /// <returns> /// The <paramref name="target"/> sequence interleaved with the specified <paramref name="elements"/>. /// </returns> public static IEnumerable<T> Interleave<T>( this IEnumerable<T> target, IEnumerable<T> elements) { if (target == null) throw new ArgumentNullException("target"); if (elements == null) throw new ArgumentNullException("elements"); return InterleaveInternal(target, elements, (f, s) => true); } /// <summary> /// Interleaves the specified <paramref name="element"/> between each pair of elements in the <paramref name="target"/> sequence that satisfy <paramref name="predicate"/>. /// </summary> /// <typeparam name="T"> /// The type of elements in the sequence. /// </typeparam> /// <param name="target"> /// The target sequence to be interleaved. /// </param> /// <param name="element"> /// The element used to perform the interleave operation. /// </param> /// <param name="predicate"> /// A predicate used to assert if interleaving should occur between two target elements. /// </param> /// <exception cref="ArgumentNullException"> /// <paramref name="target"/> or <paramref name="element"/> or <paramref name="predicate"/> is a null reference. /// </exception> /// <returns> /// The <paramref name="target"/> sequence interleaved with the specified <paramref name="element"/>. /// </returns> public static IEnumerable<T> Interleave<T>( this IEnumerable<T> target, T element, Func<T, T, bool> predicate) { if (target == null) throw new ArgumentNullException("target"); if (element == null) throw new ArgumentNullException("element"); if (predicate == null) throw new ArgumentNullException("predicate"); return InterleaveInternal(target, new InfiniteSequence<T>(element), predicate); } /// <summary> /// Interleaves the specified <paramref name="element"/> between each pair of elements in the <paramref name="target"/> sequence that satisfy <paramref name="predicate"/>. /// </summary> /// <remarks> /// The interleave operation is interrupted as soon as the <paramref name="target"/> sequence is exhausted; If the number of <paramref name="elements"/> to be interleaved are not enough to completely interleave the <paramref name="target"/> sequence then the remainder of the sequence is returned without being interleaved. /// </remarks> /// <typeparam name="T"> /// The type of elements in the sequence. /// </typeparam> /// <param name="target"> /// The target sequence to be interleaved. /// </param> /// <param name="elements"> /// The elements used to perform the interleave operation. /// </param> /// <param name="predicate"> /// A predicate used to assert if interleaving should occur between two target elements. /// </param> /// <exception cref="ArgumentNullException"> /// <paramref name="target"/> or <paramref name="element"/> or <paramref name="predicate"/> is a null reference. /// </exception> /// <returns> /// The <paramref name="target"/> sequence interleaved with the specified <paramref name="elements"/>. /// </returns> public static IEnumerable<T> Interleave<T>( this IEnumerable<T> target, IEnumerable<T> elements, Func<T, T, bool> predicate) { if (target == null) throw new ArgumentNullException("target"); if (elements == null) throw new ArgumentNullException("elements"); if (predicate == null) throw new ArgumentNullException("predicate"); return InterleaveInternal(target, elements, predicate); } private static IEnumerable<T> InterleaveInternal<T>( this IEnumerable<T> target, IEnumerable<T> elements, Func<T, T, bool> predicate) { var targetEnumerator = target.GetEnumerator(); if (targetEnumerator.MoveNext()) { var elementsEnumerator = elements.GetEnumerator(); while (true) { T first = targetEnumerator.Current; yield return first; if (!targetEnumerator.MoveNext()) yield break; T second = targetEnumerator.Current; bool interleave = true && predicate(first, second) && elementsEnumerator.MoveNext(); if (interleave) yield return elementsEnumerator.Current; } } } }

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  • Original object is also changed when values of cloned object are changed.

    - by fari
    I am trying to use clone but the original object is also changed when values of cloned object are changed. As you can see KalaGameState does not use any objects so a shallow copy should work. /** * This class represents the current state of a Kala game, including * which player's turn it is along with the state of the board; i.e. the * numbers of stones in each side pit, and each player's 'kala'). */ public class KalaGameState implements Cloneable { // your code goes here private int turn; private int[] sidePit; private boolean game; public Object clone() { try { return super.clone(); } catch (CloneNotSupportedException e) { // This should never happen throw new InternalError(e.toString()); } } /** * Constructs a new GameState with a specified number of stones in each * player's side pits. * @param startingStones the number of starting stones in each side pit. * @throws InvalidStartingStonesException if startingStones not in the range 1-10. */ public KalaGameState(int startingStones) throws InvalidStartingStonesException { game=true; turn=0; sidePit=new int[14]; for (int i=0; i <= 13 ; i++) { sidePit[i] = startingStones; } sidePit[6] =0; sidePit[13] =0; // your code goes here } /** * Returns the ID of the player whose turn it is. * @return A value of 0 = Player A, 1 = Player B. */ public int getTurn() { return turn; // your code goes here } /** * Returns the current kala for a specified player. * @param playerNum A value of 0 for Player A, 1 for Player B. * @throws IllegalPlayerNumException if the playerNum parameter * is not 0 or 1. */ public int getKala(int playerNum) throws IllegalPlayerNumException { if(playerNum!=0 || playerNum!=1) throw new IllegalPlayerNumException(playerNum); if(playerNum==0) return sidePit[6]; else return sidePit[13]; // your code goes here } /** * Returns the current number of stones in the specified pit for * the player whose turn it is. * @param sidePitNum the side pit being queried in the range 1-6. * @throws IllegalSidePitNumException if the sidePitNum parameter. * is not in the range 1-6. */ public int getNumStones(int sidePitNum) throws IllegalSidePitNumException { if(turn==0) { if(sidePitNum>6 ) throw new IllegalSidePitNumException(sidePitNum); } else if(sidePitNum>12) throw new IllegalSidePitNumException(sidePitNum); if(turn==0) return sidePit[sidePitNum]; else return sidePit[sidePitNum+6]; // your code goes here } /** * Returns the current number of stones in the specified pit for a specified player. * @param playerNum the player whose kala is sought. (0 = Player A, 1 = Player B). * @param sidePitNum the side pit being queried (in the range 1-6). * @throws IllegalPlayerNumException if the playerNum parameter is not 0 or 1. * @throws IllegalSidePitNumException if the sidePitNum parameter is not in the * range 1-6. */ public int getNumStones(int playerNum, int sidePitNum) throws IllegalPlayerNumException, IllegalSidePitNumException { /*if(playerNum>2) throw new IllegalPlayerNumException(playerNum); if(turn==0) { if(sidePitNum>6 ) throw new IllegalSidePitNumException(sidePitNum); } else if(sidePitNum>12) throw new IllegalSidePitNumException(sidePitNum); */ if(playerNum==0) return sidePit[sidePitNum]; else if(playerNum==1) return sidePit[sidePitNum+7]; else return sidePit[sidePitNum]; } /** * Returns the current score for a specified player - the player's * kala plus the number of stones in each of their side pits. * @param playerNum the player whose kala is sought. (0 = Player A, 1 = Player B). * @throws IllegalPlayerNumException if the playerNum parameter is not 0 or 1. */ public int getScore(int playerNum) throws IllegalPlayerNumException { if(playerNum>1) throw new IllegalPlayerNumException(playerNum); int score=0; if(playerNum==0) { for(int i=0;i<=5;i++) score=score+sidePit[i]; score=score+sidePit[6]; } else { for(int i=7;i<=12;i++) score=score+sidePit[i]; score=score+sidePit[13]; } // your code goes here return score; } private int getSidePitArrayIndex(int sidePitNum) throws IllegalSidePitNumException { if(turn==0) { if(sidePitNum>6 ) throw new IllegalSidePitNumException(sidePitNum); } else if(sidePitNum>12) throw new IllegalSidePitNumException(sidePitNum); if(turn==0) { return sidePitNum--; } else { return sidePitNum+6; } } public boolean gameOver() { int stone=0; if(turn==0) for(int i=0;i<=5;i++) stone=stone+getNumStones(i); else for(int i=7;i<=12;i++) stone=stone+getNumStones(i-7); if (stone==0) game=false; return game; } /** * Makes a move for the player whose turn it is. * @param sidePitNum the side pit being queried (should be in the range 1-6) * @throws IllegalSidePitNumException if the sidePitNum parameter is not in the range 1-6. * @throws IllegalMoveException if the side pit is empty and has no stones in it. */ public void makeMove(int sidePitNum) throws IllegalSidePitNumException, IllegalMoveException { if(turn==0) { if(sidePitNum>6 ) throw new IllegalSidePitNumException(sidePitNum); } else if(sidePitNum>12) throw new IllegalSidePitNumException(sidePitNum); /* if(turn==0) { if(sidePit[sidePitNum-1]==0) throw new IllegalMoveException(sidePitNum); } else { if(sidePit[sidePitNum-1+7]==0) throw new IllegalMoveException(sidePitNum); } */ sidePitNum--; int temp=sidePitNum; int pitNum=sidePitNum+1; int stones=getNumStones(turn,sidePitNum); if(turn==0) sidePit[sidePitNum]=0; else { sidePitNum=sidePitNum+7; sidePit[sidePitNum]=0; pitNum=pitNum+7; } while(stones!=0) { if(turn==0) { sidePit[pitNum]=sidePit[pitNum]+1; stones--; pitNum++; if(pitNum==13) pitNum=0; } else { sidePit[pitNum]=sidePit[pitNum]+1; stones--; pitNum++; if(pitNum==6) pitNum=7; else if(pitNum==14) pitNum=0; } } boolean res=anotherTurn(pitNum); if(!res){ capture(pitNum,temp); if(turn==0) turn=1; else turn=0;} } private boolean anotherTurn(int pitNum) {pitNum--; boolean temp=false; if(turn==0) {if(pitNum==6) {turn=0; temp=true; } } else if(pitNum==-1) {turn=1; temp=true; } return temp; } private void capture(int pitNum, int pit) { pitNum--; if(turn==0){ if(sidePit[pitNum]==1 && pitNum<6) { if(pitNum==0) { sidePit[6]=sidePit[6]+sidePit[12]+1; sidePit[12]=0; } else if(pitNum==1) { sidePit[6]=sidePit[6]+sidePit[11]+1; sidePit[11]=0; } else if(pitNum==2) { sidePit[6]=sidePit[6]+sidePit[10]+1; sidePit[10]=0; } else if(pitNum==3) { sidePit[6]=sidePit[6]+sidePit[9]+1; sidePit[9]=0; } else if(pitNum==4) { sidePit[6]=sidePit[6]+sidePit[8]+1; sidePit[8]=0; } else if(pitNum==5) { sidePit[6]=sidePit[6]+sidePit[7]+1; sidePit[7]=0; } sidePit[pitNum]=0; } } if(turn==1) { //pitNum=pitNum; if(sidePit[pitNum]==1 && pit+7>6) { if(pitNum==7) { sidePit[13]=sidePit[13]+sidePit[5]+1; sidePit[7]=0; } else if(pitNum==8) { sidePit[13]=sidePit[13]+sidePit[4]+1; sidePit[4]=0; } else if(pitNum==9) { sidePit[13]=sidePit[13]+sidePit[3]+1; sidePit[3]=0; } else if(pitNum==10) { sidePit[13]=sidePit[13]+sidePit[2]+1; sidePit[2]=0; } else if(pitNum==11) { sidePit[13]=sidePit[13]+sidePit[1]+1; sidePit[1]=0; } else if(pitNum==12) { sidePit[13]=sidePit[13]+sidePit[0]+1; sidePit[0]=0; } sidePit[pitNum]=0; } } } } import java.io.BufferedReader; import java.io.InputStreamReader; public class RandomPlayer extends KalaPlayer{ //KalaGameState state; public int chooseMove(KalaGameState gs) throws NoMoveAvailableException {int[] moves; moves=getMoves(gs); try{ for(int i=0;i<=5;i++) System.out.println(moves[i]); for(int i=0;i<=5;i++) { if(moves[i]==1) { KalaGameState state=(KalaGameState) gs.clone(); state.makeMove(moves[i]); gs.getTurn(); moves[i]=evalValue(state.getScore(0),state.getScore(1)); } } } catch(IllegalMoveException e) { System.out.println(e); //chooseMove(state); } return 10; } private int evalValue(int score0,int score1) { int score=0; //int score0=0; // int score1=0; //getScore(0); //score1=state.getScore(1); //if((state.getTurn())==0) score=score1-score0; //else //score=score1-score0; System.out.println("score: "+score); return score; } public int[] getMoves(KalaGameState gs) { int[] moves=new int[6]; for(int i=1;i<=6;i++) { if(gs.getNumStones(i)!=0) moves[i-1]=1; else moves[i-1]=0; } return moves; } } Can you explain what is going wrong, please?

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  • why cannot use uncaught_exception in dtor?

    - by camino
    Hi , Herb Sutter in his article http://www.gotw.ca/gotw/047.htm pointed out that we cannot use uncaught_exception in desturctor function, // Why the wrong solution is wrong // U::~U() { try { T t; // do work } catch( ... ) { // clean up } } If a U object is destroyed due to stack unwinding during to exception propagation, T::~T will fail to use the "code that could throw" path even though it safely could. but I write a test program, and T::~T in fact didn't use the "code that could throw" #include <exception> #include <iostream> using namespace std; class T { public: ~T() { if( !std::uncaught_exception() ) { cout<<"can throw"<<endl; throw 1; } else { cout<<"cannot throw"<<endl; } } }; struct U { ~U() { try { T t; } catch( ... ) { } } }; void f() { U u; throw 2; } int main() { try { f(); } catch(...) {} } output is : cannot throw did I miss something? Thanks

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  • C# serial port driver wrapper class code and concept quality

    - by Ruben Trancoso
    Hi folks, Would like to know from all you guys what you think about my Serial Wrapper class. Had be a while I've beem working with serial port but never shared the code what somekind make closed to my very own vision. Would like to know if it's a good/bad approach, if the interface is enough and what more you see on it. I know that Stackoverflow is for question but at the same time there's a lot of very good skilled people here and share code and opinion can also bennefit everybody, it's why I decided to post it anyway. thanks! using System.Text; using System.IO; using System.IO.Ports; using System; namespace Driver { class SerialSingleton { // The singleton instance reference private static SerialSingleton instance = null; // System's serial port interface private SerialPort serial; // Current com port identifier private string comPort = null; // Configuration parameters private int confBaudRate; private int confDataBits; private StopBits confStopBits; private Parity confParityControl; ASCIIEncoding encoding = new ASCIIEncoding(); // ================================================================================== // Constructors public static SerialSingleton getInstance() { if (instance == null) { instance = new SerialSingleton(); } return instance; } private SerialSingleton() { serial = new SerialPort(); } // =================================================================================== // Setup Methods public string ComPort { get { return comPort; } set { if (value == null) { throw new SerialException("Serial port name canot be null."); } if (nameIsComm(value)) { close(); comPort = value; } else { throw new SerialException("Serial Port '" + value + "' is not a valid com port."); } } } public void setSerial(string baudRate, int dataBits, StopBits stopBits, Parity parityControl) { if (baudRate == null) { throw new SerialException("Baud rate cannot be null"); } string[] baudRateRef = { "300", "600", "1200", "1800", "2400", "3600", "4800", "7200", "9600", "14400", "19200", "28800", "38400", "57600", "115200" }; int confBaudRate; if (findString(baudRateRef, baudRate) != -1) { confBaudRate = System.Convert.ToInt32(baudRate); } else { throw new SerialException("Baurate parameter invalid."); } int confDataBits; switch (dataBits) { case 5: confDataBits = 5; break; case 6: confDataBits = 6; break; case 7: confDataBits = 7; break; case 8: confDataBits = 8; break; default: throw new SerialException("Databits parameter invalid"); } if (stopBits == StopBits.None) { throw new SerialException("StopBits parameter cannot be NONE"); } this.confBaudRate = confBaudRate; this.confDataBits = confDataBits; this.confStopBits = stopBits; this.confParityControl = parityControl; } // ================================================================================== public string[] PortList { get { return SerialPort.GetPortNames(); } } public int PortCount { get { return SerialPort.GetPortNames().Length; } } // ================================================================================== // Open/Close Methods public void open() { open(comPort); } private void open(string comPort) { if (isOpen()) { throw new SerialException("Serial Port is Already open"); } else { if (comPort == null) { throw new SerialException("Serial Port not defined. Cannot open"); } bool found = false; if (nameIsComm(comPort)) { string portId; string[] portList = SerialPort.GetPortNames(); for (int i = 0; i < portList.Length; i++) { portId = (portList[i]); if (portId.Equals(comPort)) { found = true; break; } } } else { throw new SerialException("The com port identifier '" + comPort + "' is not a valid serial port identifier"); } if (!found) { throw new SerialException("Serial port '" + comPort + "' not found"); } serial.PortName = comPort; try { serial.Open(); } catch (UnauthorizedAccessException uaex) { throw new SerialException("Cannot open a serial port in use by another application", uaex); } try { serial.BaudRate = confBaudRate; serial.DataBits = confDataBits; serial.Parity = confParityControl; serial.StopBits = confStopBits; } catch (Exception e) { throw new SerialException("Serial port parameter invalid for '" + comPort + "'.\n" + e.Message, e); } } } public void close() { if (serial.IsOpen) { serial.Close(); } } // =================================================================================== // Auxiliary private Methods private int findString(string[] set, string search) { if (set != null) { for (int i = 0; i < set.Length; i++) { if (set[i].Equals(search)) { return i; } } } return -1; } private bool nameIsComm(string name) { int comNumber; int.TryParse(name.Substring(3), out comNumber); if (name.Substring(0, 3).Equals("COM")) { if (comNumber > -1 && comNumber < 256) { return true; } } return false; } // ================================================================================= // Device state Methods public bool isOpen() { return serial.IsOpen; } public bool hasData() { int amount = serial.BytesToRead; if (amount > 0) { return true; } else { return false; } } // ================================================================================== // Input Methods public char getChar() { int data = serial.ReadByte(); return (char)data; } public int getBytes(ref byte[] b) { int size = b.Length; char c; int counter = 0; for (counter = 0; counter < size; counter++) { if (tryGetChar(out c)) { b[counter] = (byte)c; } else { break; } } return counter; } public string getStringUntil(char x) { char c; string response = ""; while (tryGetChar(out c)) { response = response + c; if (c == x) { break; } } return response; } public bool tryGetChar(out char c) { c = (char)0x00; byte[] b = new byte[1]; long to = 10; long ft = System.Environment.TickCount + to; while (System.Environment.TickCount < ft) { if (hasData()) { int data = serial.ReadByte(); c = (char)data; return true; } } return false; } // ================================================================================ // Output Methods public void sendString(string data) { byte[] bytes = encoding.GetBytes(data); serial.Write(bytes, 0, bytes.Length); } public void sendChar(char c) { char[] data = new char[1]; data[0] = c; serial.Write(data, 0, 1); } public void sendBytes(byte[] data) { serial.Write(data, 0, data.Length); } public void clearBuffer() { if (serial.IsOpen) { serial.DiscardInBuffer(); serial.DiscardOutBuffer(); } } } }

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  • php 5.3.2 not throwing exceptions

    - by tipu
    I'm attempting to throw an exception using php 5.3.2 and it is giving me the following error: Parse error: syntax error, unexpected T_THROW I am attempting to throw an exception the following way: throw new Exception('Property ' . $name . ' doesn\'t exist in class Index', ''); Edit: I also tried throw new Exception('Property ' . $name . ' doesn\'t exist in class Index'); it didn't change the error I was getting. The complete method: public function __get($name) { if(property_exists($this, $name) throw new Exception('Property ' . $name . ' doesn\'t exist in class Index'); return $this->$name; }

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  • Preserving original StackTrace/LineNumbers in .NET Exceptions

    - by Sam
    Understanding the difference between throw ex and throw, why is the original StackTrace preserved in this example: static void Main(string[] args) { try { LongFaultyMethod(); } catch (System.Exception ex) { Console.WriteLine(ex.StackTrace); } } static void LongFaultyMethod() { try { int x = 20; SomethingThatThrowsException(x); } catch (Exception) { throw; } } static void SomethingThatThrowsException(int x) { int y = x / (x - x); } But not in this one: static void Main(string[] args) { try { LongFaultyMethod(); } catch (System.Exception ex) { Console.WriteLine(ex.StackTrace); } } static void LongFaultyMethod() { try { int x = 20; int y = x / (x - 20); } catch (Exception) { throw; } } The second scenario is producing the same output as throw ex would? In both cases, one expects to see the line number where y is initialized.

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  • What is the best practice in C# to propagate an exception thrown in a finally block without loosing an exception from a catch block?

    - by Sergey Smolnikov
    When an exception is possible to be thrown in a finally block how to propagate both exceptions - from catch and from finally? As a possible solution - using an AggregateException: internal class MyClass { public void Do() { Exception exception = null; try { //example of an error occured in main logic throw new InvalidOperationException(); } catch (Exception e) { exception = e; throw; } finally { try { //example of an error occured in finally throw new AccessViolationException(); } catch (Exception e) { if (exception != null) throw new AggregateException(exception, e); throw; } } } }

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  • How to simulate inner exception in C++

    - by Siva Chandran
    Basically I want to simulate .NET Exception.InnerException in C++. I want to catch exception from bottom layer and wrap it with another exception and throw again to upper layer. The problem here is I don't know how to wrap the catched exception inside another exception. struct base_exception : public std::exception { std::exception& InnerException; base_exception() : InnerException(???) { } // <---- what to initialize with base_exception(std::exception& innerException) : InnerException(innerException) { } }; struct func1_exception : public base_exception { const char* what() const throw() { return "func1 exception"; } }; struct func2_exception : public base_exception { const char* what() const throw() { return "func2 exception"; } }; void func2() { throw func2_exception(); } void func1() { try { func2(); } catch(std::exception& e) { throw func2_exception(e); // <--- is this correct? will the temporary object will be alive? } } int main(void) { try { func1(); } catch(base_exception& e) { std::cout << "Got exception" << std::endl; std::cout << e.what(); std::cout << "InnerException" << std::endl; std::cout << e.InnerException.what(); // <---- how to make sure it has inner exception ? } } In the above code listing I am not sure how to initialize the "InnerException" member when there is no inner exception. Also I am not sure whether the temporary object that is thrown from func1 will survive even after func2 throw?

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  • VS2010 Implement Generic Interface expansion doesn't use specified type

    - by TJB
    Using the release version of Visual Studio 2010 I think there's a difference in the "Implement Interface" expansion from VS2008 If I speicify an interface and implement it in a class as so: public interface IRepository<T> where T : IModel { T Get<T>(int id); void Update<T>(); int Add<T>(T item); } public class MockRepository : IRepository<MockUser> { // ... } Then use the "Implement Interface" expansion and get this: public class MockRepository : IRepository<MockUser> { public T Get<T>(int id) { throw new NotImplementedException(); } public void Update<T>() { throw new NotImplementedException(); } public int Add<T>(T item) { throw new NotImplementedException(); } } Instead of what I expected public class MockRepository : IRepository<MockUser> { public MockUser Get<MockUser>(int id) { throw new NotImplementedException(); } public void Update<MockUser>() { throw new NotImplementedException(); } public int Add<MockUser>(MockUser item) { throw new NotImplementedException(); } } The IDE uses the type variable name from the generic interface definition T instead of the specified concrete type MockUser. Is this a bug? Or is something new just for VS2010 / .Net 4.0?

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  • Call event from original thread ??

    - by user311883
    Hi all, Here is my problem, I have a class which have a object who throw an event and in this event I throw a custom event from my class. But unfortunately the original object throw the event from another thread and so my event is also throw on another thread. This cause a exception when my custom event try to access from controls. Here is a code sample to better understand : class MyClass { // Original object private OriginalObject myObject; // My event public delegate void StatsUpdatedDelegate(object sender, StatsArgs args); public event StatsUpdatedDelegate StatsUpdated; public MyClass() { // Original object event myObject.AnEvent += new EventHandler(myObject_AnEvent); } // This event is called on another thread private void myObject_AnEvent(object sender, EventArgs e) { // Throw my custom event here StatsArgs args = new StatsArgs(..........); StatsUpdated(this, args); } } So when on my windows form I call try to update a control from the event StatsUpdated I get a cross thread exception cause it has been called on another thread. What I want to do is throw my custom event on the original class thread, so control can be used within it. Anyone can help me ?

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  • Which style is preferable when writing this boolean expression?

    - by Jeppe Stig Nielsen
    I know this question is to some degree a matter of taste. I admit this is not something I don't understand, it's just something I want to hear others' opinion about. I need to write a method that takes two arguments, a boolean and a string. The boolean is in a sense (which will be obvious shortly) redundant, but it is part of a specification that the method must take in both arguments, and must raise an exception with a specific message text if the boolean has the "wrong" value. The bool must be true if and only if the string is not null or empty. So here are some different styles to write (hopefully!) the same thing. Which one do you find is the most readable, and compliant with good coding practice? // option A: Use two if, repeat throw statement and duplication of message string public void SomeMethod(bool useName, string name) { if (useName && string.IsNullOrEmpty(name)) throw new SomeException("..."); if (!useName && !string.IsNullOrEmpty(name)) throw new SomeException("..."); // rest of method } // option B: Long expression but using only && and || public void SomeMethod(bool useName, string name) { if (useName && string.IsNullOrEmpty(name) || !useName && !string.IsNullOrEmpty(name)) throw new SomeException("..."); // rest of method } // option C: With == operator between booleans public void SomeMethod(bool useName, string name) { if (useName == string.IsNullOrEmpty(name)) throw new SomeException("..."); // rest of method } // option D1: With XOR operator public void SomeMethod(bool useName, string name) { if (!(useName ^ string.IsNullOrEmpty(name))) throw new SomeException("..."); // rest of method } // option D2: With XOR operator public void SomeMethod(bool useName, string name) { if (useName ^ !string.IsNullOrEmpty(name)) throw new SomeException("..."); // rest of method } Of course you're welcome to suggest other possibilities too. Message text "..." would be something like "If 'useName' is true a name must be given, and if 'useName' is false no name is allowed".

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  • Abstract exception super type

    - by marcof
    If throwing System.Exception is considered so bad, why wasn't Exception made abstract in the first place? That way, it would not be possible to call: throw new Exception("Error occurred."); This would enforce using derived exceptions to provide more details about the error that occurred. For example, when I want to provide a custom exception hierarchy for a library, I usually declare an abstract base class for my exceptions: public abstract class CustomExceptionBase : Exception { /* some stuff here */ } And then some derived exception with a more specific purpose: public class DerivedCustomException : CustomExceptionBase { /* some more specific stuff here */ } Then when calling any library method, one could have this generic try/catch block to directly catch any error coming from the library: try { /* library calls here */ } catch (CustomExceptionBase ex) { /* exception handling */ } Is this a good practice? Would it be good if Exception was made abstract? EDIT : My point here is that even if an exception class is abstract, you can still catch it in a catch-all block. Making it abstract is only a way to forbid programmers to throw a "super-wide" exception. Usually, when you voluntarily throw an exception, you should know what type it is and why it happened. Thus enforcing to throw a more specific exception type.

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  • Stylecop 4.7.36.0 is out!

    - by TATWORTH
    Stylecop 4.7.36.0 has been released at http://stylecop.codeplex.com/releases/view/79972This is an update to coincide with the latest ReSharper. The full fix list is:4.7.36.0 (508dbac00ffc)=======================Fix for 7344. Don't throw 1126 inside default expressions.Fix for 7371. Compare Namespace parts using the CurrentCulture and not InvariantCulture.Fix for 7386. Don't throw casing violations for filed names in languages that do not support case (like Chinese). Added new tests.fix for 7380. Catch Exception caused by CRM Toolkit.Update ReSharper 7.0 dependency to 7.0.1 (7.0.1098.2760)Fix for 7358. Use the RuleId in the call to MSBuild Logging.Fix for 7348. Update suggestion text for constructors.Fix for 7364. Don't throw 1126 for New Array Expressions.Fix for 7372. Throw 1126 inside catch blocks wasn't working. Add new tests.Fix for 7369. Await is allowed to be inside parenthesis. Add new tests.Fix testsCorrect styling issues.Fix for 7373. Typeparam violations were not being thrown in all cases. Added new tests.Fix for 7361. Rule 1120 was logging against the root element and so Suppressions wouldn't work. Fixed and added tests.Updating de-DE resources - from Michael Diermeier - thank you.Change for 7368. Add the violation count into the Task outputs.Fix for 7383. Fix for memory leak in plugins.Update environment to detect ReSharper 7Fix for 7378. Null reference exception from command line run in message output.Update release history.

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  • Where we should put validation for domain model

    - by adisembiring
    I still looking best practice for domain model validation. Is that good to put the validation in constructor of domain model ? my domain model validation example as follows: public class Order { private readonly List<OrderLine> _lineItems; public virtual Customer Customer { get; private set; } public virtual DateTime OrderDate { get; private set; } public virtual decimal OrderTotal { get; private set; } public Order (Customer customer) { if (customer == null) throw new ArgumentException("Customer name must be defined"); Customer = customer; OrderDate = DateTime.Now; _lineItems = new List<LineItem>(); } public void AddOderLine //.... public IEnumerable<OrderLine> AddOderLine { get {return _lineItems;} } } public class OrderLine { public virtual Order Order { get; set; } public virtual Product Product { get; set; } public virtual int Quantity { get; set; } public virtual decimal UnitPrice { get; set; } public OrderLine(Order order, int quantity, Product product) { if (order == null) throw new ArgumentException("Order name must be defined"); if (quantity <= 0) throw new ArgumentException("Quantity must be greater than zero"); if (product == null) throw new ArgumentException("Product name must be defined"); Order = order; Quantity = quantity; Product = product; } } Thanks for all of your suggestion.

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  • How to create a simple adf dashboard application with EJB 3.0

    - by Rodrigues, Raphael
    In this month's Oracle Magazine, Frank Nimphius wrote a very good article about an Oracle ADF Faces dashboard application to support persistent user personalization. You can read this entire article clicking here. The idea in this article is to extend the dashboard application. My idea here is to create a similar dashboard application, but instead ADF BC model layer, I'm intending to use EJB3.0. There are just a one small trick here and I'll show you. I'm using the HR usual oracle schema. The steps are: 1. Create a ADF Fusion Application with EJB as a layer model 2. Generate the entities from table (I'm using Department and Employees only) 3. Create a new Session Bean. I called it: HRSessionEJB 4. Create a new method like that: public List getAllDepartmentsHavingEmployees(){ JpaEntityManager jpaEntityManager = (JpaEntityManager)em.getDelegate(); Query query = jpaEntityManager.createNamedQuery("Departments.allDepartmentsHavingEmployees"); JavaBeanResult.setQueryResultClass(query, AggregatedDepartment.class); return query.getResultList(); } 5. In the Departments entity, create a new native query annotation: @Entity @NamedQueries( { @NamedQuery(name = "Departments.findAll", query = "select o from Departments o") }) @NamedNativeQueries({ @NamedNativeQuery(name="Departments.allDepartmentsHavingEmployees", query = "select e.department_id, d.department_name , sum(e.salary), avg(e.salary) , max(e.salary), min(e.salary) from departments d , employees e where d.department_id = e.department_id group by e.department_id, d.department_name")}) public class Departments implements Serializable {...} 6. Create a new POJO called AggregatedDepartment: package oramag.sample.dashboard.model; import java.io.Serializable; import java.math.BigDecimal; public class AggregatedDepartment implements Serializable{ @SuppressWarnings("compatibility:5167698678781240729") private static final long serialVersionUID = 1L; private BigDecimal departmentId; private String departmentName; private BigDecimal sum; private BigDecimal avg; private BigDecimal max; private BigDecimal min; public AggregatedDepartment() { super(); } public AggregatedDepartment(BigDecimal departmentId, String departmentName, BigDecimal sum, BigDecimal avg, BigDecimal max, BigDecimal min) { super(); this.departmentId = departmentId; this.departmentName = departmentName; this.sum = sum; this.avg = avg; this.max = max; this.min = min; } public void setDepartmentId(BigDecimal departmentId) { this.departmentId = departmentId; } public BigDecimal getDepartmentId() { return departmentId; } public void setDepartmentName(String departmentName) { this.departmentName = departmentName; } public String getDepartmentName() { return departmentName; } public void setSum(BigDecimal sum) { this.sum = sum; } public BigDecimal getSum() { return sum; } public void setAvg(BigDecimal avg) { this.avg = avg; } public BigDecimal getAvg() { return avg; } public void setMax(BigDecimal max) { this.max = max; } public BigDecimal getMax() { return max; } public void setMin(BigDecimal min) { this.min = min; } public BigDecimal getMin() { return min; } } 7. Create the util java class called JavaBeanResult. The function of this class is to configure a native SQL query to return POJOs in a single line of code using the utility class. Credits: http://onpersistence.blogspot.com.br/2010/07/eclipselink-jpa-native-constructor.html package oramag.sample.dashboard.model.util; /******************************************************************************* * Copyright (c) 2010 Oracle. All rights reserved. * This program and the accompanying materials are made available under the * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0 * which accompanies this distribution. * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html * and the Eclipse Distribution License is available at * http://www.eclipse.org/org/documents/edl-v10.php. * * @author shsmith ******************************************************************************/ import java.lang.reflect.Constructor; import java.lang.reflect.InvocationTargetException; import java.util.ArrayList; import java.util.List; import javax.persistence.Query; import org.eclipse.persistence.exceptions.ConversionException; import org.eclipse.persistence.internal.helper.ConversionManager; import org.eclipse.persistence.internal.sessions.AbstractRecord; import org.eclipse.persistence.internal.sessions.AbstractSession; import org.eclipse.persistence.jpa.JpaHelper; import org.eclipse.persistence.queries.DatabaseQuery; import org.eclipse.persistence.queries.QueryRedirector; import org.eclipse.persistence.sessions.Record; import org.eclipse.persistence.sessions.Session; /*** * This class is a simple query redirector that intercepts the result of a * native query and builds an instance of the specified JavaBean class from each * result row. The order of the selected columns musts match the JavaBean class * constructor arguments order. * * To configure a JavaBeanResult on a native SQL query use: * JavaBeanResult.setQueryResultClass(query, SomeBeanClass.class); * where query is either a JPA SQL Query or native EclipseLink DatabaseQuery. * * @author shsmith * */ public final class JavaBeanResult implements QueryRedirector { private static final long serialVersionUID = 3025874987115503731L; protected Class resultClass; public static void setQueryResultClass(Query query, Class resultClass) { JavaBeanResult javaBeanResult = new JavaBeanResult(resultClass); DatabaseQuery databaseQuery = JpaHelper.getDatabaseQuery(query); databaseQuery.setRedirector(javaBeanResult); } public static void setQueryResultClass(DatabaseQuery query, Class resultClass) { JavaBeanResult javaBeanResult = new JavaBeanResult(resultClass); query.setRedirector(javaBeanResult); } protected JavaBeanResult(Class resultClass) { this.resultClass = resultClass; } @SuppressWarnings("unchecked") public Object invokeQuery(DatabaseQuery query, Record arguments, Session session) { List results = new ArrayList(); try { Constructor[] constructors = resultClass.getDeclaredConstructors(); Constructor javaBeanClassConstructor = null; // (Constructor) resultClass.getDeclaredConstructors()[0]; Class[] constructorParameterTypes = null; // javaBeanClassConstructor.getParameterTypes(); List rows = (List) query.execute( (AbstractSession) session, (AbstractRecord) arguments); for (Object[] columns : rows) { boolean found = false; for (Constructor constructor : constructors) { javaBeanClassConstructor = constructor; constructorParameterTypes = javaBeanClassConstructor.getParameterTypes(); if (columns.length == constructorParameterTypes.length) { found = true; break; } // if (columns.length != constructorParameterTypes.length) { // throw new ColumnParameterNumberMismatchException( // resultClass); // } } if (!found) throw new ColumnParameterNumberMismatchException( resultClass); Object[] constructorArgs = new Object[constructorParameterTypes.length]; for (int j = 0; j < columns.length; j++) { Object columnValue = columns[j]; Class parameterType = constructorParameterTypes[j]; // convert the column value to the correct type--if possible constructorArgs[j] = ConversionManager.getDefaultManager() .convertObject(columnValue, parameterType); } results.add(javaBeanClassConstructor.newInstance(constructorArgs)); } } catch (ConversionException e) { throw new ColumnParameterMismatchException(e); } catch (IllegalArgumentException e) { throw new ColumnParameterMismatchException(e); } catch (InstantiationException e) { throw new ColumnParameterMismatchException(e); } catch (IllegalAccessException e) { throw new ColumnParameterMismatchException(e); } catch (InvocationTargetException e) { throw new ColumnParameterMismatchException(e); } return results; } public final class ColumnParameterMismatchException extends RuntimeException { private static final long serialVersionUID = 4752000720859502868L; public ColumnParameterMismatchException(Throwable t) { super( "Exception while processing query results-ensure column order matches constructor parameter order", t); } } public final class ColumnParameterNumberMismatchException extends RuntimeException { private static final long serialVersionUID = 1776794744797667755L; public ColumnParameterNumberMismatchException(Class clazz) { super( "Number of selected columns does not match number of constructor arguments for: " + clazz.getName()); } } } 8. Create the DataControl and a jsf or jspx page 9. Drag allDepartmentsHavingEmployees from DataControl and drop in your page 10. Choose Graph > Type: Bar (Normal) > any layout 11. In the wizard screen, Bars label, adds: sum, avg, max, min. In the X Axis label, adds: departmentName, and click in OK button 12. Run the page, the result is showed below: You can download the workspace here . It was using the latest jdeveloper version 11.1.2.2.

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