/*
 * Copyright 2002-2018 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
 *
 *      https://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;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;

Implementation of the TargetSource interface that holds a given object. This is the default implementation of the TargetSource interface, as used by the Spring AOP framework. There is usually no need to create objects of this class in application code. 
This class is serializable. However, the actual serializability of a
SingletonTargetSource will depend on whether the target is serializable.
Author:
Rod Johnson, Juergen Hoeller
See Also:
AdvisedSupport.setTarget(Object)/**
 * Implementation of the {@link org.springframework.aop.TargetSource} interface
 * that holds a given object. This is the default implementation of the TargetSource
 * interface, as used by the Spring AOP framework. There is usually no need to
 * create objects of this class in application code.
 *
 * <p>This class is serializable. However, the actual serializability of a
 * SingletonTargetSource will depend on whether the target is serializable.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @see org.springframework.aop.framework.AdvisedSupport#setTarget(Object)
 */
public class SingletonTargetSource implements TargetSource, Serializable {

	
use serialVersionUID from Spring 1.2 for interoperability. /** use serialVersionUID from Spring 1.2 for interoperability. */
	private static final long serialVersionUID = 9031246629662423738L;


	
Target cached and invoked using reflection. /** Target cached and invoked using reflection. */
	private final Object target;


	
Create a new SingletonTargetSource for the given target.
Params:
target – the target object/**
	 * Create a new SingletonTargetSource for the given target.
	 * @param target the target object
	 */
	public SingletonTargetSource(Object target) {
		Assert.notNull(target, "Target object must not be null");
		this.target = target;
	}


	@Override
	public Class<?> getTargetClass() {
		return this.target.getClass();
	}

	@Override
	public Object getTarget() {
		return this.target;
	}

	@Override
	public void releaseTarget(Object target) {
		// nothing to do
	}

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

	
SingletonTargetSource uses the hash code of the target object.
/**
	 * SingletonTargetSource uses the hash code of the target object.
	 */
	@Override
	public int hashCode() {
		return this.target.hashCode();
	}

	@Override
	public String toString() {
		return "SingletonTargetSource for target object [" + ObjectUtils.identityToString(this.target) + "]";
	}

}