SemaphoreReleaseOnlyOnce.java

/**
 * $Id: SemaphoreReleaseOnlyOnce.java 1831 2013-05-16 01:39:51Z shijia.wxr $
 */
package com.alibaba.rocketmq.remoting.common;

import java.util.concurrent.Semaphore;
import java.util.concurrent.atomic.AtomicBoolean;


/**
 * ��ֻ֤�ͷ�һ��
 * 
 * @author vintage.wang@gmail.com shijia.wxr@taobao.com
 * 
 */
public class SemaphoreReleaseOnlyOnce {
    private final AtomicBoolean released = new AtomicBoolean(false);
    private final Semaphore semaphore;


    public SemaphoreReleaseOnlyOnce(Semaphore semaphore) {
        this.semaphore = semaphore;
    }


    public void release() {
        if (this.semaphore != null) {
            if (this.released.compareAndSet(false, true)) {
                this.semaphore.release();
            }
        }
    }


    public Semaphore getSemaphore() {
        return semaphore;
    }
}