org.apache.solr.cloud.ShardLeaderWatcher.java Source code

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Here is the source code for org.apache.solr.cloud.ShardLeaderWatcher.java

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package org.apache.solr.cloud;

/**
 * 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.solr.common.cloud.SolrZkClient;
import org.apache.solr.common.cloud.ZkCoreNodeProps;
import org.apache.solr.common.cloud.ZkNodeProps;
import org.apache.solr.common.cloud.ZkStateReader;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.KeeperException.Code;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A watcher for shard leader.
 */
public class ShardLeaderWatcher implements Watcher {
    private static Logger logger = LoggerFactory.getLogger(ShardLeaderWatcher.class);

    static interface ShardLeaderListener {
        void announceLeader(String collection, String shardId, ZkCoreNodeProps props);
    }

    private final String shard;
    private final String collection;
    private final String path;
    private final SolrZkClient zkClient;
    private volatile boolean closed = false;
    private final ShardLeaderListener listener;

    public ShardLeaderWatcher(String shard, String collection, SolrZkClient zkClient, ShardLeaderListener listener)
            throws KeeperException, InterruptedException {
        this.shard = shard;
        this.collection = collection;
        this.path = ZkStateReader.getShardLeadersPath(collection, shard);
        this.zkClient = zkClient;
        this.listener = listener;
        processLeaderChange();
    }

    private void processLeaderChange() throws KeeperException, InterruptedException {
        if (closed)
            return;
        try {
            byte[] data = zkClient.getData(path, this, null, true);
            if (data != null) {
                final ZkCoreNodeProps leaderProps = new ZkCoreNodeProps(ZkNodeProps.load(data));
                listener.announceLeader(collection, shard, leaderProps);
            }
        } catch (KeeperException ke) {
            //check if we lost connection or the node was gone
            if (ke.code() != Code.CONNECTIONLOSS && ke.code() != Code.SESSIONEXPIRED && ke.code() != Code.NONODE) {
                throw ke;
            }
        }
    }

    @Override
    public void process(WatchedEvent event) {
        try {
            processLeaderChange();
        } catch (KeeperException e) {
            logger.warn("Shard leader watch triggered but Solr cannot talk to zk.");
        } catch (InterruptedException e) {
            Thread.interrupted();
            logger.warn("Shard leader watch triggered but Solr cannot talk to zk.");
        }
    }

    public void close() {
        closed = true;
    }

}