com.vmware.bdd.aop.lock.ClusterEntityConcurentWriteLockAdvice.java Source code

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Here is the source code for com.vmware.bdd.aop.lock.ClusterEntityConcurentWriteLockAdvice.java

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/***************************************************************************
 * Copyright (c) 2012-2013 VMware, Inc. All Rights Reserved.
 * 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.vmware.bdd.aop.lock;

import org.apache.log4j.Logger;
import org.aspectj.lang.ProceedingJoinPoint;

/**
 * @author Jarred Li
 * @since 0.8
 * @version 0.8
 * 
 */
public class ClusterEntityConcurentWriteLockAdvice {

    private static final Logger logger = Logger.getLogger(ClusterEntityConcurentWriteLockAdvice.class);

    private void lockConcurrentWrite(String clusterName) {
        LockFactory.getClusterLock(clusterName).readLock().lock();
        logger.debug("Cluster" + clusterName + " competitive write is locked.");
    }

    private void unlockConcurrentWrite(String clusterName) {
        LockFactory.getClusterLock(clusterName).readLock().unlock();
        logger.debug("Cluster" + clusterName + " competitive write is unlocked.");
    }

    public Object lock(ProceedingJoinPoint pjp) throws Throwable {
        Object[] objs = pjp.getArgs();
        String clusterName = (String) objs[0];
        logger.info("Lock competitive write for cluster " + clusterName);
        boolean locked = false;
        try {
            lockConcurrentWrite((String) clusterName);
            locked = true;
            return pjp.proceed();
        } finally {
            if (locked) {
                unlockConcurrentWrite(clusterName);
                logger.info("Unlock competitive write for cluster " + clusterName);
            }
        }
    }
}