#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.Runtime.Serialization;
using System.Security.Permissions;
#endregion
namespace Spring.Aop.Target{
/// <summary>
/// The <see cref="Spring.Aop.ITargetSource"/> to be used
/// when there is no target object, and behavior is supplied by the
/// advisors.
/// </summary>
/// <remarks>
/// <p>
/// This class is exposed as a singleton.
/// </p>
/// </remarks>
/// <author>Rod Johnson</author>
/// <author>Aleksandar Seovic (.NET)</author>
[Serializable]
public sealed class EmptyTargetSource : ITargetSource, ISerializable
{
/// <summary>
/// The <see cref="Spring.Aop.ITargetSource"/> to be used
/// when there is no target object, and behavior is supplied by the
/// advisors.
/// </summary>
public static readonly ITargetSource Empty = new EmptyTargetSource();
private object _dummyTarget = new object();
/// <summary>
/// Creates a new instance of the
/// <see cref="EmptyTargetSource"/> class.
/// </summary>
/// <remarks>
/// <p>
/// This is a utility class, and as such has no publicly visible constructors.
/// </p>
/// </remarks>
private EmptyTargetSource()
{
}
/// <summary>
/// The <see cref="System.Type"/> of the target object.
/// </summary>
public Type TargetType
{
get { return typeof(object); }
}
/// <summary>
/// Is the target source static?
/// </summary>
/// <remarks>
/// <p>
/// The <see cref="Spring.Aop.Target.EmptyTargetSource.Empty"/>
/// instance is static, and this always returns <see langword="true"/>.
/// </p>
/// </remarks>
/// <value>
/// <see langword="true"/> if the target source is static.
/// </value>
public bool IsStatic
{
get { return true; }
}
/// <summary>
/// Returns the target object.
/// </summary>
/// <returns>The target object.</returns>
/// <exception cref="System.Exception">
/// If unable to obtain the target object.
/// </exception>
public object GetTarget()
{
return _dummyTarget;
}
/// <summary>
/// Releases the target object.
/// </summary>
/// <remarks>
/// <note type="implementnotes">
/// This is a no-op operation in this implementation.
/// </note>
/// </remarks>
/// <param name="target">The target object to release.</param>
public void ReleaseTarget(object target)
{
}
/// <summary>
/// A <see cref="System.String"/> that represents the current
/// <see cref="Spring.Aop.ITargetSource"/>.
/// </summary>
/// <returns>
/// A <see cref="System.String"/> that represents the current
/// <see cref="Spring.Aop.ITargetSource"/>.
/// </returns>
public override string ToString()
{
return "EmptyTargetSource: no target";
}
/// <summary>
/// Populates a <see cref="System.Runtime.Serialization.SerializationInfo"/> with
/// the data needed to serialize the target object.
/// </summary>
/// <param name="info">
/// The <see cref="System.Runtime.Serialization.SerializationInfo"/> to populate
/// with data.
/// </param>
/// <param name="context">
/// The destination (see <see cref="System.Runtime.Serialization.StreamingContext"/>)
/// for this serialization.
/// </param>
[SecurityPermission(SecurityAction.Demand, SerializationFormatter=true)]
public void GetObjectData(SerializationInfo info, StreamingContext context)
{
info.SetType(typeof (EmptyTargetSourceObjectReference));
}
[Serializable]
private sealed class EmptyTargetSourceObjectReference : IObjectReference
{
public object GetRealObject(StreamingContext context)
{
return EmptyTargetSource.Empty;
}
}
}
}
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