singletontargetsource.java

spring的源代码

/*
 * Copyright 2002-2004 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 org.springframework.aop.TargetSource;

/**
 * Implementation of the TargetSource interface that 
 * holds a local object. This is the default implementation of TargetSource
 * used by the AOP framework. There is no need to create objects of this
 * class in application code.
 * @author Rod Johnson
 * @version $Id: SingletonTargetSource.java,v 1.5 2004/03/18 02:46:13 trisberg Exp $
 */
public final class SingletonTargetSource implements TargetSource {

	/** Target cached and invoked using reflection */	
	private Object target;
	
	public SingletonTargetSource(Object target) {
		this.target = target;
	}
	
	public Class getTargetClass() {
		return target.getClass();
	}
	
	public Object getTarget() {
		return this.target;
	}
	
	public void releaseTarget(Object o) {
	}
	
	public String toString() {
		return "Singleton target source (not dynamic): target=[" + target + "]";
	}
	

	/**
	 * @see org.springframework.aop.TargetSource#isStatic()
	 */
	public boolean isStatic() {
		return true;
	}

	/**
	 * Two invoker interceptors are equal if they have the same target or if the targets
	 * or the targets are equal.
	 */
	public boolean equals(Object other) {
		if (this == other)
			return true;
		if (!(other instanceof SingletonTargetSource))
			return false;
		SingletonTargetSource b = (SingletonTargetSource) other;
		if (this.target == null)
			return b.target == null;
		return this.target.equals(b.target);
	}
}