com.alibaba.rocketmq.remoting.common.SemaphoreReleaseOnlyOnce Maven / Gradle / Ivy
/**
* Copyright (C) 2010-2013 Alibaba Group Holding Limited
*
* 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 com.alibaba.rocketmq.remoting.common;
import java.util.concurrent.Semaphore;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* 使用布尔原子变量，信号量保证只释放一次
*
* @author shijia.wxr
* @since 2013-7-13
*/
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;
}
}