org.apache.blur.manager.indexserver.BlurServerShutDown.java Source code

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Here is the source code for org.apache.blur.manager.indexserver.BlurServerShutDown.java

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package org.apache.blur.manager.indexserver;

/**
 * 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.
 */
import org.apache.blur.log.Log;
import org.apache.blur.log.LogFactory;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.Watcher.Event.KeeperState;

public class BlurServerShutDown implements Watcher {

    private static final Log LOG = LogFactory.getLog(BlurServerShutDown.class);

    public interface BlurShutdown {
        void shutdown();
    }

    private BlurShutdown shutdown;
    private ZooKeeper zooKeeper;

    public BlurServerShutDown() {
        Runtime runtime = Runtime.getRuntime();
        runtime.addShutdownHook(new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    LOG.info("Closing zookeeper.");
                    zooKeeper.close();
                } catch (InterruptedException e) {
                    LOG.error("Unknown error while closing zookeeper.", e);
                }
            }
        }));
    }

    public void register(final BlurShutdown shutdown, ZooKeeper zooKeeper) {
        this.shutdown = shutdown;
        this.zooKeeper = zooKeeper;
        zooKeeper.register(new Watcher() {
            @Override
            public void process(WatchedEvent event) {
                KeeperState state = event.getState();
                if (state == KeeperState.Expired) {
                    LOG.fatal("Zookeeper session has [" + state + "] server process shutting down.");
                    shutdown.shutdown();
                }
            }
        });
    }

    @Override
    public void process(WatchedEvent event) {
        register(shutdown, zooKeeper);
    }
}