NH-2218 - Add support for entity names to Query<T>()

Author: hazzik

src/NHibernate.Test/NHSpecificTest/NH2218/Fixture.cs

@@ -0,0 +1,81 @@
+using System.Linq;
+using NHibernate.Linq;
+using NHibernate.Test.NHSpecificTest.NH0000;
+using NUnit.Framework;
+
+namespace NHibernate.Test.NHSpecificTest.NH2218
+{
+	public class Fixture : BugTestCase
+	{
+		protected override void OnSetUp()
+		{
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				for (int i = 0; i < 4; i++)
+				{
+					session.Save("Entity1", new Entity {Name = "Mapping1 -" + i});
+				}
+				for (int i = 0; i < 3; i++)
+				{
+					session.Save("Entity2", new Entity {Name = "Mapping2 -" + i});
+				}
+
+				session.Flush();
+				transaction.Commit();
+			}
+		}
+
+		protected override void OnTearDown()
+		{
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				session.Delete("from System.Object");
+
+				session.Flush();
+				transaction.Commit();
+			}
+		}
+
+		[Test]
+		public void SelectEntitiesByEntityName()
+		{
+			using (var session = OpenSession())
+			using (session.BeginTransaction())
+			{
+				// verify the instance count for both mappings
+				Assert.That(session.Query<Entity>("Entity1").Count(), Is.EqualTo(4));
+				Assert.That(session.Query<Entity>("Entity2").Count(), Is.EqualTo(3));
+
+				// verify that all instances are loaded from the right table
+				Assert.That(session.Query<Entity>("Entity1").Count(x => x.Name.Contains("Mapping1")), Is.EqualTo(4));
+				Assert.That(session.Query<Entity>("Entity2").Count(x => x.Name.Contains("Mapping2")), Is.EqualTo(3));
+
+				// a query for Entity returns instances of both mappings 
+				// Remark: session.Query<Entity>().Count() doesn't work because only the count of the first mapping (4) is returned
+				Assert.That(session.Query<Entity>().ToList().Count, Is.EqualTo(7));
+			}
+		}
+
+		[Test]
+		public void SelectEntitiesByEntityNameFromStatelessSession()
+		{
+			using (var session = sessions.OpenStatelessSession())
+			using (session.BeginTransaction())
+			{
+				// verify the instance count for both mappings
+				Assert.That(session.Query<Entity>("Entity1").Count(), Is.EqualTo(4));
+				Assert.That(session.Query<Entity>("Entity2").Count(), Is.EqualTo(3));
+
+				// verify that all instances are loaded from the right table
+				Assert.That(session.Query<Entity>("Entity1").Count(x => x.Name.Contains("Mapping1")), Is.EqualTo(4));
+				Assert.That(session.Query<Entity>("Entity2").Count(x => x.Name.Contains("Mapping2")), Is.EqualTo(3));
+
+				// a query for Entity returns instances of both mappings 
+				// Remark: session.Query<Entity>().Count() doesn't work because only the count of the first mapping (4) is returned
+				Assert.That(session.Query<Entity>().ToList().Count, Is.EqualTo(7));
+			}
+		}
+	}
+}

src/NHibernate.Test/NHSpecificTest/NH2218/Mappings.hbm.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernate.Test" namespace="NHibernate.Test.NHSpecificTest.NH0000">
+
+	<class name="Entity" entity-name="Entity1">
+		<id name="Id" generator="guid.comb" />
+		<property name="Name" />
+	</class>
+	<class name="Entity" entity-name="Entity2">
+		<id name="Id" generator="guid.comb" />
+		<property name="Name" />
+	</class>
+
+</hibernate-mapping>

src/NHibernate.Test/NHibernate.Test.csproj

@@ -723,6 +723,7 @@
     <Compile Include="NHSpecificTest\BagWithLazyExtraAndFilter\Fixture.cs" />
     <Compile Include="Linq\ByMethod\DistinctTests.cs" />
     <Compile Include="Component\Basic\ComponentWithUniqueConstraintTests.cs" />
+    <Compile Include="NHSpecificTest\NH2218\Fixture.cs" />
     <Compile Include="NHSpecificTest\NH2931\Fixture.cs" />
     <Compile Include="NHSpecificTest\NH2931\Mappings.cs" />
     <Compile Include="NHSpecificTest\NH2931\Models.cs" />
@@ -3164,6 +3165,7 @@
     <EmbeddedResource Include="NHSpecificTest\NH1291AnonExample\Mappings.hbm.xml" />
   </ItemGroup>
   <ItemGroup>
+    <EmbeddedResource Include="NHSpecificTest\NH2218\Mappings.hbm.xml" />
     <EmbeddedResource Include="NHSpecificTest\NH3046\Mappings.hbm.xml" />
     <EmbeddedResource Include="NHSpecificTest\NH3518\Mappings.hbm.xml" />
     <EmbeddedResource Include="NHSpecificTest\NH3609\Mappings.hbm.xml" />

src/NHibernate/Linq/LinqExtensionMethods.cs

@@ -16,14 +16,24 @@ public static IQueryable<T> Query<T>(this ISession session)
 			return new NhQueryable<T>(session.GetSessionImplementation());
 		}
 
+		public static IQueryable<T> Query<T>(this ISession session, string entityName)
+		{
+			return new NhQueryable<T>(session.GetSessionImplementation(), entityName);
+		}
+
 		public static IQueryable<T> Query<T>(this IStatelessSession session)
 		{
 			return new NhQueryable<T>(session.GetSessionImplementation());
 		}
 
+		public static IQueryable<T> Query<T>(this IStatelessSession session, string entityName)
+		{
+			return new NhQueryable<T>(session.GetSessionImplementation(), entityName);
+		}
+
 		public static IQueryable<T> Cacheable<T>(this IQueryable<T> query)
 		{
-			var method = ReflectionHelper.GetMethodDefinition(() => Cacheable<object>(null)).MakeGenericMethod(typeof (T));
+			var method = ReflectionHelper.GetMethodDefinition(() => Cacheable<object>(null)).MakeGenericMethod(typeof(T));
 
 			var callExpression = Expression.Call(method, query.Expression);
 
@@ -32,7 +42,7 @@ public static IQueryable<T> Cacheable<T>(this IQueryable<T> query)
 
 		public static IQueryable<T> CacheMode<T>(this IQueryable<T> query, CacheMode cacheMode)
 		{
-			var method = ReflectionHelper.GetMethodDefinition(() => CacheMode<object>(null, NHibernate.CacheMode.Normal)).MakeGenericMethod(typeof (T));
+			var method = ReflectionHelper.GetMethodDefinition(() => CacheMode<object>(null, NHibernate.CacheMode.Normal)).MakeGenericMethod(typeof(T));
 
 			var callExpression = Expression.Call(method, query.Expression, Expression.Constant(cacheMode));
 
@@ -41,7 +51,7 @@ public static IQueryable<T> CacheMode<T>(this IQueryable<T> query, CacheMode cac
 
 		public static IQueryable<T> CacheRegion<T>(this IQueryable<T> query, string region)
 		{
-			var method = ReflectionHelper.GetMethodDefinition(() => CacheRegion<object>(null, null)).MakeGenericMethod(typeof (T));
+			var method = ReflectionHelper.GetMethodDefinition(() => CacheRegion<object>(null, null)).MakeGenericMethod(typeof(T));
 
 			var callExpression = Expression.Call(method, query.Expression, Expression.Constant(region));
 

src/NHibernate/Linq/NhQueryable.cs

@@ -6,21 +6,51 @@
 
 namespace NHibernate.Linq
 {
-    /// <summary>
-    /// Provides the main entry point to a LINQ query.
-    /// </summary>
-    public class NhQueryable<T> : QueryableBase<T>
-    {
-        // This constructor is called by our users, create a new IQueryExecutor.
-        public NhQueryable(ISessionImplementor session)
-            : base(QueryProviderFactory.CreateQueryProvider(session))
-        {
-        }
-
-        // This constructor is called indirectly by LINQ's query methods, just pass to base.
-        public NhQueryable(IQueryProvider provider, Expression expression)
-            : base(provider, expression)
-        {
-        }
-    }
-}
+	/// <summary>
+	/// Interface to access the entity name of a NhQueryable instance.
+	/// </summary>
+	interface IEntityNameProvider
+	{
+		string EntityName { get; }
+	}
+
+	/// <summary>
+	/// Provides the main entry point to a LINQ query.
+	/// </summary>
+	public class NhQueryable<T> : QueryableBase<T>, IEntityNameProvider
+	{
+		// This constructor is called by our users, create a new IQueryExecutor.
+		public NhQueryable(ISessionImplementor session)
+			: this(session, typeof(T).FullName)
+		{
+		}
+
+		// This constructor is called by our users, create a new IQueryExecutor.
+		public NhQueryable(ISessionImplementor session, string entityName)
+			: base(QueryProviderFactory.CreateQueryProvider(session))
+		{
+			EntityName = entityName;
+		}
+
+
+		// This constructor is called indirectly by LINQ's query methods, just pass to base.
+		public NhQueryable(IQueryProvider provider, Expression expression)
+			: this(provider, expression, typeof(T).FullName)
+		{
+		}
+
+		// This constructor is called indirectly by LINQ's query methods, just pass to base.
+		public NhQueryable(IQueryProvider provider, Expression expression, string entityName)
+			: base(provider, expression)
+		{
+			EntityName = entityName;
+		}
+
+		public string EntityName { get; private set; }
+
+		public override string ToString()
+		{
+			return "NHibernate.Linq.NhQueryable`1[" + EntityName + "]";
+		}
+	}
+}

src/NHibernate/Linq/Visitors/HqlGeneratorExpressionTreeVisitor.cs

@@ -387,11 +387,10 @@ protected HqlTreeNode VisitConstantExpression(ConstantExpression expression)
 		{
 			if (expression.Value != null)
 			{
-				System.Type t = expression.Value.GetType();
-
-				if (t.IsGenericType && t.GetGenericTypeDefinition() == typeof (NhQueryable<>))
+				IEntityNameProvider entityName = expression.Value as IEntityNameProvider;
+				if (entityName != null)
 				{
-					return _hqlTreeBuilder.Ident(t.GetGenericArguments()[0].FullName);
+					return _hqlTreeBuilder.Ident(entityName.EntityName);
 				}
 			}