com.api6.zkclient.watcher.ZKWatcher.java Source code

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Here is the source code for com.api6.zkclient.watcher.ZKWatcher.java

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/**
 *Copyright 2016 zhaojie
 *
 *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.api6.zkclient.watcher;

import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.EventType;
import org.apache.zookeeper.Watcher.Event.KeeperState;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.api6.zkclient.ZKClient;

/**
 * ??
 * @author: zhaojie/zh_jie@163.com.com 
 */
public class ZKWatcher implements Watcher {
    private static final Logger LOG = LoggerFactory.getLogger(ZKWatcher.class);
    private final ZKClient client;
    private final ZKWatcherProcess process;

    public ZKWatcher(ZKClient client) {
        this.client = client;
        this.process = new ZKWatcherProcess(client);
    }

    /**
     * ?
     * @see org.apache.zookeeper.Watcher#process(org.apache.zookeeper.WatchedEvent)
     */
    @Override
    public void process(WatchedEvent event) {
        LOG.debug("ZooKeeper event is arrived [" + event + " ]...");
        EventType eventType = event.getType();
        //?
        boolean stateChanged = event.getPath() == null;
        //
        boolean znodeChanged = event.getPath() != null;

        //???
        boolean nodeChanged = eventType == EventType.NodeDataChanged || eventType == EventType.NodeDeleted
                || eventType == EventType.NodeCreated;

        //???????????
        boolean childChanged = eventType == EventType.NodeDeleted || eventType == EventType.NodeCreated
                || eventType == EventType.NodeChildrenChanged;

        client.acquireEventLock();
        try {
            if (client.getShutdownTrigger()) {
                LOG.debug("client will shutdown,ignore the event [" + eventType + " | " + event.getPath() + "]");
                return;
            }
            if (stateChanged) {//ZooKeeper???
                process.processStateChanged(event);
            }
            if (nodeChanged) {//??????
                process.processNodeChanged(event);
            }
            if (childChanged) {//??????????
                process.processChildChanged(event);
            }
        } finally {
            if (stateChanged) {
                client.getEventLock().getStateChangedCondition().signalAll();
                // ????watch.
                // ????????
                // ????
                if (event.getState() == KeeperState.Expired) {
                    client.getEventLock().getNodeEventCondition().signalAll();
                    client.getEventLock().getNodeOrChildChangedCondition().signalAll();

                    // ????
                    process.processAllNodeAndChildListeners(event);
                }
            }
            if (znodeChanged) {
                client.getEventLock().getNodeEventCondition().signalAll();
            }
            if (nodeChanged || childChanged) {
                client.getEventLock().getNodeOrChildChangedCondition().signalAll();
            }
            client.releaseEventLock();
        }
    }

    /**
     * ??
     * @return void
     */
    public void stop() {
        process.stop();
    }

}