Decouple configuration of IObjectsFactory from BytecodeProvider

doc/reference/modules/configuration.xml

@@ -441,14 +441,6 @@ var session = sessions.OpenSession(conn);
             at runtime. All are optional and have reasonable default values.
         </para>
 
-        <para>
-            Some properties are system-level properties. They can only be set manually by setting static properties of
-            <literal>NHibernate.Cfg.Environment</literal> class or be defined in the
-            <literal>&lt;hibernate-configuration&gt;</literal> section of the application
-            configuration file. These properties cannot be set using <literal>Configuration.SetProperties</literal> or
-            the <literal>hibernate.cfg.xml</literal> configuration file.
-        </para>
-
         <table frame="topbot" id="configuration-optional-properties" revision="3">
             <title>NHibernate Configuration Properties</title>
             <tgroup cols="2">
@@ -514,53 +506,6 @@ var session = sessions.OpenSession(conn);
                             </para>
                         </entry>
                     </row>
-                    <row>
-                        <entry>
-                            <literal>use_reflection_optimizer</literal>
-                        </entry>
-                        <entry>
-                            Enables use of a runtime-generated class to set or get properties of an entity
-                            or component instead of using runtime reflection. This is a system-level property.
-                            The use of the reflection optimizer inflicts a certain startup cost on the
-                            application but should lead to better performance in the long run.
-                            Defaults to <literal>true</literal>.
-                            <para>
-                                You can not set this property in <literal>hibernate.cfg.xml</literal>, but only
-                                in <literal>&lt;hibernate-configuration&gt;</literal> section of the application
-                                configuration file or by code by setting
-                                <literal>NHibernate.Cfg.Environment.UseReflectionOptimizer</literal>
-                                before creating any <literal>NHibernate.Cfg.Configuration</literal> instance.
-                            </para>
-                            <para>
-                                <emphasis role="strong">eg.</emphasis> 
-                                <literal>true</literal> | <literal>false</literal>
-                            </para>
-                        </entry>
-                    </row>
-                    <row>
-                        <entry>
-                            <literal>bytecode.provider</literal>
-                        </entry>
-                        <entry>
-                            Specifies the bytecode provider to use to optimize the use of reflection in NHibernate.
-                            This is a system-level property.
-                            Use <literal>null</literal> to disable the optimization completely, <literal>lcg</literal>
-                            to use built-in lightweight code generation, or the class name of a custom
-                            <literal>IBytecodeProvider</literal> implementation. Defaults to <literal>lcg</literal>.
-                            <para>
-                                You can not set this property in <literal>hibernate.cfg.xml</literal>, but only
-                                in <literal>&lt;hibernate-configuration&gt;</literal> section of the application
-                                configuration file or by code by setting
-                                <literal>NHibernate.Cfg.Environment.BytecodeProvider</literal>
-                                before creating any <literal>NHibernate.Cfg.Configuration</literal> instance.
-                            </para>
-                            <para>
-                                <emphasis role="strong">eg.</emphasis>
-                                <literal>null</literal> | <literal>lcg</literal> |
-                                <literal>classname.of.BytecodeProvider, assembly</literal>
-                            </para>
-                        </entry>
-                    </row>
                     <row>
                         <entry>
                             <literal>cache.use_second_level_cache</literal>
@@ -1467,6 +1412,95 @@ in the parameter binding.</programlisting>
 
         </sect2>
 
+        <sect2 id="configuration-optional-systemlevel">
+            <title>System level optional properties</title>
+
+            <para>
+                Some properties are system-level properties. They can only be set manually by setting static
+                properties of <literal>NHibernate.Cfg.Environment</literal> class or be defined in the
+                <literal>&lt;hibernate-configuration&gt;</literal> section of the application configuration
+                file, as direct sub-elements. These properties can neither be set using
+                <literal>Configuration.SetProperties</literal> or the <literal>hibernate.cfg.xml</literal>
+                configuration file, nor be set as <literal>&lt;session-factory&gt;</literal> properties.
+            </para>
+
+            <table frame="topbot" id="configuration-systemlevel-properties">
+                <title>NHibernate system level properties</title>
+                <tgroup cols="2">
+                    <colspec colname="c1" colwidth="1*"/>
+                    <colspec colname="c2" colwidth="1*"/>
+                    <thead>
+                        <row>
+                            <entry>Property name</entry>
+                            <entry>Purpose</entry>
+                        </row>
+                    </thead>
+                    <tbody>
+                        <row>
+                            <entry>
+                                <literal>bytecode-provider</literal>
+                            </entry>
+                            <entry>
+                                <para>
+                                    Specifies the bytecode provider to use to optimize the use of reflection in NHibernate.
+                                    Use <literal>null</literal> to disable the optimization completely, <literal>lcg</literal>
+                                    to use built-in lightweight code generation, or the assembly qualified class name of a custom
+                                    <literal>IBytecodeProvider</literal> implementation. Defaults to <literal>lcg</literal>.
+                                </para>
+                                <programlisting><![CDATA[<bytecode-provider
+    type="lcg|null|className" />]]></programlisting>
+                                <para>
+                                    You can also set this property by code by setting
+                                    <literal>NHibernate.Cfg.Environment.BytecodeProvider</literal>
+                                    before creating any <literal>NHibernate.Cfg.Configuration</literal> instance.
+                                </para>
+                            </entry>
+                        </row>
+                        <row>
+                            <entry>
+                                <literal>objects-factory</literal>
+                            </entry>
+                            <entry>
+                                <para>
+                                    Specifies a custom objects factory to use for instantiating NHibernate dependencies.
+                                    Use the assembly qualified class name of a custom <literal>IObjectsFactory</literal>
+                                    implementation.
+                                </para>
+                                <programlisting><![CDATA[<bytecode-provider
+    type="className" />]]></programlisting>
+                                <para>
+                                    You can also set this property by code by setting
+                                    <literal>NHibernate.Cfg.Environment.ObjectsFactory</literal>
+                                    before creating any <literal>NHibernate.Cfg.Configuration</literal> instance.
+                                </para>
+                            </entry>
+                        </row>
+                        <row>
+                            <entry>
+                                <literal>reflection-optimizer</literal>
+                            </entry>
+                            <entry>
+                                <para>
+                                    Enables use of a runtime-generated class to set or get properties of an entity
+                                    or component instead of using runtime reflection. The use of the reflection
+                                    optimizer inflicts a certain startup cost on the application but should lead to
+                                    better performance in the long run. Defaults to <literal>true</literal>.
+                                </para>
+                                <programlisting><![CDATA[<reflection-optimizer
+    use="true|false"/>]]></programlisting>
+                                <para>
+                                    You can also set this property by code by setting
+                                    <literal>NHibernate.Cfg.Environment.UseReflectionOptimizer</literal>
+                                    before creating any <literal>NHibernate.Cfg.Configuration</literal> instance.
+                                </para>
+                            </entry>
+                        </row>
+                    </tbody>
+                </tgroup>
+            </table>
+
+        </sect2>
+
     </sect1>
 
     <sect1 id="configuration-logging">

src/NHibernate.Test/CfgTest/ConfigurationSchemaFixture.cs

@@ -57,6 +57,30 @@ public void IgnoreSystemOutOfAppConfig()
 			Assert.AreEqual(hc.UseReflectionOptimizer, newhc.UseReflectionOptimizer);
 		}
 
+		[Test]
+		public void ObjectsFactory()
+		{
+			Assume.That(TestsContext.ExecutingWithVsTest, Is.False);
+
+			var xml =
+				@"<?xml version='1.0' encoding='utf-8' ?>
+<hibernate-configuration xmlns='urn:nhibernate-configuration-2.2'>
+		<objects-factory type='test'/>
+		<session-factory>
+		</session-factory>
+</hibernate-configuration>";
+
+			HibernateConfiguration hc;
+			using (var xtr = new XmlTextReader(xml, XmlNodeType.Document, null))
+			{
+				hc = new HibernateConfiguration(xtr);
+				Assert.That(hc.ObjectsFactoryType, Is.Null);
+			}
+
+			hc = HibernateConfiguration.FromAppConfig(xml);
+			Assert.That(hc.ObjectsFactoryType, Is.EqualTo("test"));
+		}
+
 		[Test]
 		public void EmptyFactoryNotAllowed()
 		{

src/NHibernate.Test/CfgTest/CustomObjectsFactoryTest.cs

@@ -0,0 +1,66 @@
+using System;
+using System.Collections.Generic;
+using NHibernate.Bytecode;
+using NUnit.Framework;
+using Environment = NHibernate.Cfg.Environment;
+
+namespace NHibernate.Test.CfgTest
+{
+	[TestFixture]
+	public class CustomObjectsFactoryTest
+	{
+		private class MyObjectsFactory : IObjectsFactory
+		{
+			public object CreateInstance(System.Type type)
+			{
+				throw new NotImplementedException();
+			}
+
+			public object CreateInstance(System.Type type, bool nonPublic)
+			{
+				throw new NotImplementedException();
+			}
+
+			public object CreateInstance(System.Type type, params object[] ctorArgs)
+			{
+				throw new NotImplementedException();
+			}
+		}
+		private class InvalidObjectsFactory
+		{
+		}
+		private class InvalidNoCtorObjectsFactory : MyObjectsFactory
+		{
+			public InvalidNoCtorObjectsFactory(string pizza) {}
+		}
+
+		[Test]
+		public void WhenNoShortCutUsedThenCanBuildObjectsFactory()
+		{
+			var properties = new Dictionary<string, string> { { Environment.PropertyBytecodeProvider, typeof(MyObjectsFactory).AssemblyQualifiedName } };
+			Assert.That(() => Environment.BuildObjectsFactory(properties), Throws.Nothing);
+		}
+
+		[Test]
+		public void WhenNoShortCutUsedThenCanBuildInstanceOfConfiguredObjectsFactory()
+		{
+			var properties = new Dictionary<string, string> { { Environment.PropertyObjectsFactory, typeof(MyObjectsFactory).AssemblyQualifiedName } };
+			Assert.That(Environment.BuildObjectsFactory(properties), Is.InstanceOf<MyObjectsFactory>());
+		}
+
+		[Test]
+		public void WhenInvalidThenThrow()
+		{
+			var properties = new Dictionary<string, string> { { Environment.PropertyObjectsFactory, typeof(InvalidObjectsFactory).AssemblyQualifiedName } };
+			Assert.That(() => Environment.BuildObjectsFactory(properties), Throws.TypeOf<HibernateObjectsFactoryException>());
+		}
+
+		[Test]
+		public void WhenNoDefaultCtorThenThrow()
+		{
+			var properties = new Dictionary<string, string> { { Environment.PropertyObjectsFactory, typeof(InvalidNoCtorObjectsFactory).AssemblyQualifiedName } };
+			Assert.That(() => Environment.BuildObjectsFactory(properties), Throws.TypeOf<HibernateObjectsFactoryException>()
+																				   .And.InnerException.Message.Contains("constructor was not found"));
+		}
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH1547/Fixture.cs

@@ -132,7 +132,7 @@ public partial class DriverForSubstitutedCommand : IDriver
 
 		public DriverForSubstitutedCommand()
 		{
-			_driverImplementation = (IDriver) Cfg.Environment.BytecodeProvider.ObjectsFactory.CreateInstance(DriverClass);
+			_driverImplementation = (IDriver) Cfg.Environment.ObjectsFactory.CreateInstance(DriverClass);
 		}
 
 		DbCommand IDriver.GenerateCommand(CommandType type, SqlString sqlString, SqlType[] parameterTypes)

src/NHibernate.Test/TypesTest/AbstractDateTimeTypeFixture.cs

@@ -533,7 +533,7 @@ public class ClientDriverWithParamsStats : IDriver
 
 		public ClientDriverWithParamsStats()
 		{
-			_driverImplementation = (IDriver) Cfg.Environment.BytecodeProvider.ObjectsFactory.CreateInstance(DriverClass);
+			_driverImplementation = (IDriver) Cfg.Environment.ObjectsFactory.CreateInstance(DriverClass);
 		}
 
 		private static void Inc<T>(T type, IDictionary<T, int> dic)

src/NHibernate/Async/Tool/hbm2ddl/SchemaExport.cs

@@ -187,7 +187,7 @@ private async Task ExecuteInitializedAsync(Action<string> scriptAction, bool exe
 			cancellationToken.ThrowIfCancellationRequested();
 			if (dialect.SupportsSqlBatches)
 			{
-				var objFactory = Environment.BytecodeProvider.ObjectsFactory;
+				var objFactory = Environment.ObjectsFactory;
 				ScriptSplitter splitter = (ScriptSplitter)objFactory.CreateInstance(typeof(ScriptSplitter), sql);
 
 				foreach (string stmt in splitter)

src/NHibernate/Async/Tool/hbm2ddl/SchemaUpdate.cs

@@ -78,7 +78,7 @@ public partial class SchemaUpdate
 						{
 							cfg.SetNamingStrategy(
 								(INamingStrategy)
-								Environment.BytecodeProvider.ObjectsFactory.CreateInstance(ReflectHelper.ClassForName(args[i].Substring(9))));
+								Environment.ObjectsFactory.CreateInstance(ReflectHelper.ClassForName(args[i].Substring(9))));
 						}
 					}
 					else

src/NHibernate/Async/Tool/hbm2ddl/SchemaValidator.cs

@@ -48,7 +48,7 @@ public partial class SchemaValidator
 						{
 							cfg.SetNamingStrategy(
 								(INamingStrategy)
-								Cfg.Environment.BytecodeProvider.ObjectsFactory.CreateInstance(ReflectHelper.ClassForName(args[i].Substring(9))));
+								Cfg.Environment.ObjectsFactory.CreateInstance(ReflectHelper.ClassForName(args[i].Substring(9))));
 						}
 					}
 					else

src/NHibernate/Bytecode/AbstractBytecodeProvider.cs

@@ -6,7 +6,6 @@ namespace NHibernate.Bytecode
 {
 	public abstract class AbstractBytecodeProvider : IBytecodeProvider, IInjectableProxyFactoryFactory, IInjectableCollectionTypeFactoryClass
 	{
-		private readonly IObjectsFactory objectsFactory = new ActivatorObjectsFactory();
 		protected System.Type proxyFactoryFactory;
 		private ICollectionTypeFactory collectionTypeFactory;
 		private System.Type collectionTypeFactoryClass = typeof(Type.DefaultCollectionTypeFactory);
@@ -21,7 +20,7 @@ public virtual IProxyFactoryFactory ProxyFactoryFactory
 				{
 					try
 					{
-						return (IProxyFactoryFactory) ObjectsFactory.CreateInstance(proxyFactoryFactory);
+						return (IProxyFactoryFactory) Cfg.Environment.ObjectsFactory.CreateInstance(proxyFactoryFactory);
 					}
 					catch (Exception e)
 					{
@@ -35,10 +34,9 @@ public virtual IProxyFactoryFactory ProxyFactoryFactory
 
 		public abstract IReflectionOptimizer GetReflectionOptimizer(System.Type clazz, IGetter[] getters, ISetter[] setters);
 
-		public virtual IObjectsFactory ObjectsFactory
-		{
-			get { return objectsFactory; }
-		}
+		// Since 5.2
+		[Obsolete("Please use NHibernate.Cfg.Environment.ObjectsFactory instead")]
+		public virtual IObjectsFactory ObjectsFactory => Cfg.Environment.ObjectsFactory;
 
 		public virtual ICollectionTypeFactory CollectionTypeFactory
 		{
@@ -49,7 +47,7 @@ public virtual ICollectionTypeFactory CollectionTypeFactory
 					try
 					{
 						collectionTypeFactory =
-							(ICollectionTypeFactory) ObjectsFactory.CreateInstance(collectionTypeFactoryClass);
+							(ICollectionTypeFactory) Cfg.Environment.ObjectsFactory.CreateInstance(collectionTypeFactoryClass);
 					}
 					catch (Exception e)
 					{

src/NHibernate/Bytecode/HibernateObjectsFactoryException.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Runtime.Serialization;
+
+namespace NHibernate.Bytecode
+{
+	/// <summary>
+	/// Thrown if NHibernate can't instantiate the <see cref="IObjectsFactory"/> type.
+	/// </summary>
+	[Serializable]
+	public class HibernateObjectsFactoryException : HibernateException
+	{
+		public HibernateObjectsFactoryException() {}
+		public HibernateObjectsFactoryException(string message) : base(message) {}
+		public HibernateObjectsFactoryException(string message, Exception inner) : base(message, inner) {}
+
+		protected HibernateObjectsFactoryException(SerializationInfo info, StreamingContext context) : base(info, context) {}
+	}
+}

src/NHibernate/Bytecode/IBytecodeProvider.cs

@@ -1,3 +1,4 @@
+using System;
 using NHibernate.Properties;
 
 namespace NHibernate.Bytecode
@@ -26,6 +27,8 @@ public interface IBytecodeProvider
 		/// <remarks>
 		/// For entities <see cref="IReflectionOptimizer"/> and its implementations.
 		/// </remarks>
+		// Since 5.2
+		[Obsolete("Please use NHibernate.Cfg.Environment.ObjectsFactory instead")]
 		IObjectsFactory ObjectsFactory { get; }
 
 		/// <summary>

src/NHibernate/Cfg/Configuration.cs

@@ -1902,7 +1902,7 @@ public void SetListeners(ListenerType type, string[] listenerClasses)
 				{
 					try
 					{
-						listeners[i] = Environment.BytecodeProvider.ObjectsFactory.CreateInstance(ReflectHelper.ClassForName(listenerClasses[i]));
+						listeners[i] = Environment.ObjectsFactory.CreateInstance(ReflectHelper.ClassForName(listenerClasses[i]));
 					}
 					catch (Exception e)
 					{