common.CountdownWatcher.java Source code

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Here is the source code for common.CountdownWatcher.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 common;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeoutException;

import org.apache.log4j.Logger;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.KeeperState;

public class CountdownWatcher implements Watcher {
    protected static final Logger LOG = Logger.getLogger(CountdownWatcher.class);

    private final String name;
    private CountDownLatch clientConnected;
    private KeeperState state;
    private boolean connected;

    public CountdownWatcher(String name) {
        this.name = name;
        reset();
    }

    private synchronized void reset() {
        clientConnected = new CountDownLatch(1);
        state = KeeperState.Disconnected;
        connected = false;
    }

    public synchronized void process(WatchedEvent event) {
        LOG.info("Watcher " + name + " got event " + event);

        state = event.getState();
        if (state == KeeperState.SyncConnected) {
            connected = true;
            clientConnected.countDown();
        } else {
            connected = false;
        }
        notifyAll();
    }

    public synchronized boolean isConnected() {
        return connected;
    }

    public synchronized KeeperState state() {
        return state;
    }

    public synchronized void waitForConnected(long timeout) throws InterruptedException, TimeoutException {
        long expire = System.currentTimeMillis() + timeout;
        long left = timeout;
        while (!connected && left > 0) {
            wait(left);
            left = expire - System.currentTimeMillis();
        }
        if (!connected) {
            throw new TimeoutException("Did not connect");

        }
    }

    public synchronized void waitForDisconnected(long timeout) throws InterruptedException, TimeoutException {
        long expire = System.currentTimeMillis() + timeout;
        long left = timeout;
        while (connected && left > 0) {
            wait(left);
            left = expire - System.currentTimeMillis();
        }
        if (connected) {
            throw new TimeoutException("Did not disconnect");

        }
    }
}