From 6ef2fdb7895b79d12a5fc30c52176c7e3b94d790 Mon Sep 17 00:00:00 2001
From: Markus Ewald <cygon@nuclex.org>
Date: Tue, 1 Sep 2009 19:11:19 +0000
Subject: [PATCH] Fixed a typo; fixed a bug in the plug-in library that would
 see generic types deriving from a required base class as suitable whereas
 they cannot be instantiated without a generic argument; added unit tests that
 reproduce the errors

git-svn-id: file:///srv/devel/repo-conversion/nusu@171 d2e56fa2-650e-0410-a79f-9358c0239efd
---
 Source/Plugins/FactoryEmployer.Test.cs  | 23 +++++++++++++++++++++++
 Source/Plugins/FactoryEmployer.cs       |  8 +++++++-
 Source/Plugins/InstanceEmployer.Test.cs | 23 +++++++++++++++++++++++
 Source/Plugins/InstanceEmployer.cs      |  3 ++-
 Source/Tracking/Transaction.cs          |  2 +-
 5 files changed, 56 insertions(+), 3 deletions(-)

diff --git a/Source/Plugins/FactoryEmployer.Test.cs b/Source/Plugins/FactoryEmployer.Test.cs
index beb5135..ffcd579 100644
--- a/Source/Plugins/FactoryEmployer.Test.cs
+++ b/Source/Plugins/FactoryEmployer.Test.cs
@@ -50,6 +50,16 @@ namespace Nuclex.Support.Plugins {
 
     #endregion // class Derived
 
+    #region class GenericDerived
+
+    /// <summary>
+    ///   Generic class derived from the abstract base to serve as concrete product
+    ///   for testing the factory employer
+    /// </summary>
+    private class GenericDerived<SomeType> : Base { }
+
+    #endregion // class GenericDerived
+
     #region class Unrelated
 
     /// <summary>Unrelated class used to test the factory employer</summary>
@@ -112,6 +122,19 @@ namespace Nuclex.Support.Plugins {
       );
     }
 
+    /// <summary>
+    ///   Tests whether the factory employer throws an exception when it is asked to
+    ///   employ a class that requires generic parameters for instantiation
+    /// </summary>
+    [Test]
+    public void TestThrowOnEmployGenericClass() {
+      FactoryEmployer<Base> testEmployer = new FactoryEmployer<Base>();
+
+      Assert.Throws<ArgumentException>(
+        delegate() { testEmployer.Employ(typeof(GenericDerived<>)); }
+      );
+    }
+
     /// <summary>
     ///   Tests whether the factory employer can employ a class derived from the product
     /// </summary>
diff --git a/Source/Plugins/FactoryEmployer.cs b/Source/Plugins/FactoryEmployer.cs
index c316330..2fd8ab6 100644
--- a/Source/Plugins/FactoryEmployer.cs
+++ b/Source/Plugins/FactoryEmployer.cs
@@ -91,7 +91,8 @@ namespace Nuclex.Support.Plugins {
     public override bool CanEmploy(Type type) {
       return
         PluginHelper.HasDefaultConstructor(type) &&
-        typeof(ProductType).IsAssignableFrom(type);
+        typeof(ProductType).IsAssignableFrom(type) &&
+        !type.ContainsGenericParameters;
     }
 
     /// <summary>Employs the specified plugin type</summary>
@@ -107,6 +108,11 @@ namespace Nuclex.Support.Plugins {
           "Cannot employ type because it cannot be cast to the factory's product type"
         );
       }
+      if(type.ContainsGenericParameters) {
+        throw new ArgumentException(
+          "Cannot employ type because it requires generic parameters", "type"
+        );
+      }
 
       this.employedFactories.Add(new ConcreteFactory(type));
     }
diff --git a/Source/Plugins/InstanceEmployer.Test.cs b/Source/Plugins/InstanceEmployer.Test.cs
index 9e546b5..8959f2c 100644
--- a/Source/Plugins/InstanceEmployer.Test.cs
+++ b/Source/Plugins/InstanceEmployer.Test.cs
@@ -50,6 +50,16 @@ namespace Nuclex.Support.Plugins {
 
     #endregion // class Derived
 
+    #region class GenericDerived
+
+    /// <summary>
+    ///   Generic class derived from the abstract base to serve as concrete product
+    ///   for testing the instance employer
+    /// </summary>
+    private class GenericDerived<SomeType> : Base { }
+
+    #endregion // class GenericDerived
+
     #region class Unrelated
 
     /// <summary>Unrelated class used to test the instance employer</summary>
@@ -96,6 +106,19 @@ namespace Nuclex.Support.Plugins {
       );
     }
 
+    /// <summary>
+    ///   Tests whether the instance employer throws an exception when it is asked to
+    ///   employ a class that requires generic parameters for instantiation
+    /// </summary>
+    [Test]
+    public void TestThrowOnEmployGenericClass() {
+      InstanceEmployer<Base> testEmployer = new InstanceEmployer<Base>();
+
+      Assert.Throws<ArgumentException>(
+        delegate() { testEmployer.Employ(typeof(GenericDerived<>)); }
+      );
+    }
+
     /// <summary>
     ///   Tests whether the instance employer can employ a class derived from the product
     /// </summary>
diff --git a/Source/Plugins/InstanceEmployer.cs b/Source/Plugins/InstanceEmployer.cs
index 5bac170..d8e9dbe 100644
--- a/Source/Plugins/InstanceEmployer.cs
+++ b/Source/Plugins/InstanceEmployer.cs
@@ -62,7 +62,8 @@ namespace Nuclex.Support.Plugins {
     public override bool CanEmploy(Type type) {
       return
         PluginHelper.HasDefaultConstructor(type) &&
-        typeof(T).IsAssignableFrom(type);
+        typeof(T).IsAssignableFrom(type) &&
+        !type.ContainsGenericParameters;
     }
 
     /// <summary>Employs the specified plugin type</summary>
diff --git a/Source/Tracking/Transaction.cs b/Source/Tracking/Transaction.cs
index 09ecfaf..29a63e4 100644
--- a/Source/Tracking/Transaction.cs
+++ b/Source/Tracking/Transaction.cs
@@ -246,7 +246,7 @@ namespace Nuclex.Support.Tracking {
 
     }
 
-    /// <summary>List of event handler which have subscribed to the ended event</summary>
+    /// <summary>Event handlers which have subscribed to the ended event</summary>
     /// <remarks>
     ///   Does not need to be volatile since it's only accessed inside 
     /// </remarks>