org.springframework.aop.target.EmptyTargetSource Maven / Gradle / Ivy
/*
* 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.
*/
package org.springframework.aop.target;
import java.io.Serializable;
import org.springframework.aop.TargetSource;
/**
* Canonical TargetSource when there's no target,
* and behavior is supplied by interfaces and advisors.
*
* @author Rod Johnson
*/
public class EmptyTargetSource implements TargetSource, Serializable {
public static final EmptyTargetSource INSTANCE = new EmptyTargetSource();
/**
* Enforce Singleton.
*/
private EmptyTargetSource() {
}
public Class getTargetClass() {
return null;
}
public boolean isStatic() {
return true;
}
public Object getTarget() {
return null;
}
public void releaseTarget(Object target) {
}
/**
* Required to support serialization.
* Replaces with canonical instance on deserialization,
* protecting the Singleton pattern.
* Alternative to overriding equals.
*/
private Object readResolve() {
return INSTANCE;
}
public String toString() {
return "EmptyTargetSource: no target";
}
}