sdk/samples/WCFSamples/TechnologySamples/Extensibility/Instancing/Durable/CS/extensions/InstanceProvider.cs

   1 using System;
   2 using System.Collections.Generic;
   3 using System.Text;
   4 using System.ServiceModel;
   5 using System.ServiceModel.Dispatcher;
   6 using System.ServiceModel.Channels;
   7
   8 namespace Microsoft.ServiceModel.Samples
   9 {
  10     //This class contains the implementation of an IInstanceProvider
  11     //which provides the instances created by the storage manager.
  12     class InstanceProvider : IInstanceProvider
  13     {
  14         Type serviceType;
  15
  16         public InstanceProvider(Type serviceType)
  17         {
  18             this.serviceType = serviceType;
  19         }
  20
  21         public object GetInstance(InstanceContext instanceContext)
  22         {
  23             return this.GetInstance(instanceContext, null);
  24         }
  25
  26         public void ReleaseInstance(InstanceContext instanceContext, object instance)
  27         {
  28         }
  29
  30         public object GetInstance(InstanceContext instanceContext, Message message)
  31         {
  32             object instance = null;
  33
  34             InstanceContextExtension extension =
  35                 instanceContext.Extensions.Find<InstanceContextExtension>();
  36
  37             string contextId = extension.ContextId;
  38             IStorageManager storageManager = extension.StorageManager;
  39
  40             //Get the instance from the storage manager.
  41             instance = storageManager.GetInstance(contextId, serviceType);
  42
  43             // If the storage manager returns null (which means that there is
  44             // no instance available for the given context id) create a new
  45             // instance and return it.
  46             if (instance == null)
  47             {
  48                 instance = Activator.CreateInstance(serviceType);
  49             }
  50
  51             return instance;
  52         }
  53     }
  54 }