#region License
/*
* Copyright 2002-2005 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#endregion
#region Imports
using System;
using System.Globalization;
using System.Reflection;
using Common.Logging;
using Spring.Core;
using Spring.Core.TypeResolution;
using Spring.Util;
#endregion
namespace Spring.Objects.Factory.Support{
/// <summary>
/// Simple object instantiation strategy for use in
/// <see cref="Spring.Objects.Factory.IObjectFactory"/> implementations.
/// </summary>
/// <remarks>
/// <p>
/// Does not support method injection, although it provides hooks for subclasses
/// to override to add method injection support, for example by overriding methods.
/// </p>
/// </remarks>
/// <author>Rod Johnson</author>
/// <author>Rick Evans (.NET)</author>
/// <seealso cref="Spring.Objects.Factory.Support.MethodInjectingInstantiationStrategy"/>
[Serializable]
public class SimpleInstantiationStrategy : IInstantiationStrategy
{
/// <summary>
/// The shared <see cref="Common.Logging.ILog"/> instance for this class (and derived classes).
/// </summary>
protected static readonly ILog log =
LogManager.GetLogger(typeof(SimpleInstantiationStrategy));
/// <summary>
/// Instantiate an instance of the object described by the supplied
/// <paramref name="definition"/> from the supplied <paramref name="factory"/>.
/// </summary>
/// <param name="definition">
/// The definition of the object that is to be instantiated.
/// </param>
/// <param name="name">
/// The name associated with the object definition. The name can be the null
/// or zero length string if we're autowiring an object that doesn't belong
/// to the supplied <paramref name="factory"/>.
/// </param>
/// <param name="factory">
/// The owning <see cref="Spring.Objects.Factory.IObjectFactory"/>
/// </param>
/// <returns>
/// An instance of the object described by the supplied
/// <paramref name="definition"/> from the supplied <paramref name="factory"/>.
/// </returns>
public virtual object Instantiate(
RootObjectDefinition definition, string name, IObjectFactory factory)
{
AssertUtils.ArgumentNotNull(definition, "definition");
AssertUtils.ArgumentNotNull(factory, "factory");
if (log.IsTraceEnabled) log.Trace(string.Format("instantiating object '{0}'", name));
if (definition.HasMethodOverrides)
{
return InstantiateWithMethodInjection(definition, name, factory);
}
else
{
Type objectType = definition.HasObjectType
? definition.ObjectType
: TypeResolutionUtils.ResolveType(definition.ObjectTypeName);
ConstructorInfo constructor = GetZeroArgConstructorInfo(objectType);
return ObjectUtils.InstantiateType(constructor, ObjectUtils.EmptyObjects);
}
}
/// <summary>
/// Gets the zero arg ConstructorInfo object, if the type offers such functionality.
/// </summary>
/// <param name="type">The type.</param>
/// <returns>Zero argument ConstructorInfo</returns>
/// <exception cref="FatalReflectionException">
/// If the type does not have a zero-arg constructor.
/// </exception>
private ConstructorInfo GetZeroArgConstructorInfo(Type type)
{
const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
BindingFlags.Instance | BindingFlags.DeclaredOnly;
ConstructorInfo constructor = type.GetConstructor(flags, null, Type.EmptyTypes, null);
if (constructor == null)
{
throw new FatalReflectionException(string.Format(
CultureInfo.InvariantCulture, "Cannot instantiate a class that does not have a no-argument constructor [{0}].", type));
}
return constructor;
}
/// <summary>
/// Instantiate an instance of the object described by the supplied
/// <paramref name="definition"/> from the supplied <paramref name="factory"/>.
/// </summary>
/// <param name="definition">
/// The definition of the object that is to be instantiated.
/// </param>
/// <param name="name">
/// The name associated with the object definition. The name can be the null
/// or zero length string if we're autowiring an object that doesn't belong
/// to the supplied <paramref name="factory"/>.
/// </param>
/// <param name="factory">
/// The owning <see cref="Spring.Objects.Factory.IObjectFactory"/>
/// </param>
/// <param name="constructor">
/// The <see cref="System.Reflection.ConstructorInfo"/> to be used to instantiate
/// the object.
/// </param>
/// <param name="arguments">
/// Any arguments to the supplied <paramref name="constructor"/>. May be null.
/// </param>
/// <returns>
/// An instance of the object described by the supplied
/// <paramref name="definition"/> from the supplied <paramref name="factory"/>.
/// </returns>
public virtual object Instantiate(
RootObjectDefinition definition, string name, IObjectFactory factory,
ConstructorInfo constructor, object[] arguments)
{
if (definition.HasMethodOverrides)
{
return InstantiateWithMethodInjection(definition, name, factory, constructor, arguments);
}
else
{
return ObjectUtils.InstantiateType(constructor, arguments);
}
}
/// <summary>
/// Instantiate an instance of the object described by the supplied
/// <paramref name="definition"/> from the supplied <paramref name="factory"/>.
/// </summary>
/// <param name="definition">
/// The definition of the object that is to be instantiated.
/// </param>
/// <param name="name">
/// The name associated with the object definition. The name can be the null
/// or zero length string if we're autowiring an object that doesn't belong
/// to the supplied <paramref name="factory"/>.
/// </param>
/// <param name="factory">
/// The owning <see cref="Spring.Objects.Factory.IObjectFactory"/>
/// </param>
/// <param name="factoryMethod">
/// The <see cref="System.Reflection.MethodInfo"/> to be used to get the object.
/// </param>
/// <param name="arguments">
/// Any arguments to the supplied <paramref name="factoryMethod"/>. May be null.
/// </param>
/// <returns>
/// An instance of the object described by the supplied
/// <paramref name="definition"/> from the supplied <paramref name="factory"/>.
/// </returns>
public virtual object Instantiate(
RootObjectDefinition definition, string name, IObjectFactory factory,
MethodInfo factoryMethod, object[] arguments)
{
object instance = null;
object target = null;
if (StringUtils.HasText(definition.FactoryObjectName))
{
target = factory[definition.FactoryObjectName];
}
try
{
// the target will be null if using a static factory method
instance = factoryMethod.Invoke(target, arguments);
}
catch (TargetInvocationException ex)
{
string msg = string.Format(
CultureInfo.InvariantCulture,
"Factory method '{0}' threw an Exception.", factoryMethod);
#region Instrumentation
if (log.IsWarnEnabled)
{
log.Warn(msg, ex.InnerException);
}
#endregion
throw new ObjectDefinitionStoreException(msg, ex.InnerException);
}
catch (Exception ex)
{
throw new ObjectDefinitionStoreException(string.Format(
CultureInfo.InvariantCulture,
"Factory method '{0}' threw an Exception.", factoryMethod), ex);
}
return instance;
}
/// <summary>
/// Instantiate an instance of the object described by the supplied
/// <paramref name="definition"/> from the supplied <paramref name="factory"/>,
/// injecting methods as appropriate.
/// </summary>
/// <remarks>
/// <p>
/// The default implementation of this method is to throw a
/// <see cref="System.InvalidOperationException"/>.
/// </p>
/// <p>
/// Derived classes can override this method if they can instantiate an object
/// with the Method Injection specified in the supplied
/// <paramref name="definition"/>. Instantiation should use a no-arg constructor.
/// </p>
/// </remarks>
/// <param name="definition">
/// The definition of the object that is to be instantiated.
/// </param>
/// <param name="objectName">
/// The name associated with the object definition. The name can be a
/// <see lang="null"/> or zero length string if we're autowiring an object that
/// doesn't belong to the supplied <paramref name="factory"/>.
/// </param>
/// <param name="factory">
/// The owning <see cref="Spring.Objects.Factory.IObjectFactory"/>
/// </param>
/// <returns>
/// An instance of the object described by the supplied
/// <paramref name="definition"/> from the supplied <paramref name="factory"/>.
/// </returns>
protected virtual object InstantiateWithMethodInjection(
RootObjectDefinition definition, string objectName, IObjectFactory factory)
{
throw new InvalidOperationException("Method Injection not supported in SimpleInstantiationStrategy");
}
/// <summary>
/// Instantiate an instance of the object described by the supplied
/// <paramref name="definition"/> from the supplied <paramref name="factory"/>,
/// injecting methods as appropriate.
/// </summary>
/// <remarks>
/// <p>
/// The default implementation of this method is to throw a
/// <see cref="System.InvalidOperationException"/>.
/// </p>
/// <p>
/// Derived classes can override this method if they can instantiate an object
/// with the Method Injection specified in the supplied
/// <paramref name="definition"/>. Instantiation should use the supplied
/// <paramref name="constructor"/> and attendant <paramref name="arguments"/>.
/// </p>
/// </remarks>
/// <param name="definition">
/// The definition of the object that is to be instantiated.
/// </param>
/// <param name="objectName">
/// The name associated with the object definition. The name can be the null
/// or zero length string if we're autowiring an object that doesn't belong
/// to the supplied <paramref name="factory"/>.
/// </param>
/// <param name="factory">
/// The owning <see cref="Spring.Objects.Factory.IObjectFactory"/>
/// </param>
/// <param name="constructor">
/// The <see cref="System.Reflection.ConstructorInfo"/> to be used to instantiate
/// the object.
/// </param>
/// <param name="arguments">
/// Any arguments to the supplied <paramref name="constructor"/>. May be null.
/// </param>
/// <returns>
/// An instance of the object described by the supplied
/// <paramref name="definition"/> from the supplied <paramref name="factory"/>.
/// </returns>
protected virtual object InstantiateWithMethodInjection(
RootObjectDefinition definition, string objectName, IObjectFactory factory,
ConstructorInfo constructor, object[] arguments)
{
throw new InvalidOperationException("Method Injection not supported in SimpleInstantiationStrategy");
}
}
}
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