com.continuuity.weave.internal.zookeeper.KillZKSession.java Source code

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Here is the source code for com.continuuity.weave.internal.zookeeper.KillZKSession.java

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/*
 * Copyright 2012-2013 Continuuity,Inc.
 *
 * 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.continuuity.weave.internal.zookeeper;

import com.google.common.base.Preconditions;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;

import java.io.IOException;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

/**
 * Utility class for killing ZK client to simulate failures during testing.
 */
public final class KillZKSession {

    /**
     * Utility classes should have a public constructor or a default constructor
     * hence made it private.
     */
    private KillZKSession() {
    }

    /**
     * Kills a Zookeeper client to simulate failure scenarious during testing.
     * Callee will provide the amount of time to wait before it's considered failure
     * to kill a client.
     *
     * @param client that needs to be killed.
     * @param connectionString of Quorum
     * @param maxMs time in millisecond specifying the max time to kill a client.
     * @throws IOException When there is IO error
     * @throws InterruptedException When call has been interrupted.
     */
    public static void kill(ZooKeeper client, String connectionString, int maxMs)
            throws IOException, InterruptedException {
        final CountDownLatch latch = new CountDownLatch(1);
        ZooKeeper zk = new ZooKeeper(connectionString, maxMs, new Watcher() {
            @Override
            public void process(WatchedEvent event) {
                if (event.getState() == Event.KeeperState.SyncConnected) {
                    latch.countDown();
                }
            }
        }, client.getSessionId(), client.getSessionPasswd());

        try {
            Preconditions.checkState(latch.await(maxMs, TimeUnit.MILLISECONDS), "Fail to kill ZK connection.");
        } finally {
            zk.close();
        }
    }
}