package org.apache.helix.util;
/*
* 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 java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.helix.manager.zk.ZNRecordSerializer;
import org.apache.helix.manager.zk.ZkClient;
import org.apache.zookeeper.ZooKeeper.States;
public class ZKClientPool
{
static final Map<String, ZkClient> _zkClientMap = new ConcurrentHashMap<String, ZkClient>();
static final int DEFAULT_SESSION_TIMEOUT = 30 * 1000;
public static ZkClient getZkClient(String zkServer)
{
// happy path that we cache the zkclient and it's still connected
if (_zkClientMap.containsKey(zkServer))
{
ZkClient zkClient = _zkClientMap.get(zkServer);
if (zkClient.getConnection().getZookeeperState() == States.CONNECTED)
{
return zkClient;
}
}
synchronized (_zkClientMap)
{
// if we cache a stale zkclient, purge it
if (_zkClientMap.containsKey(zkServer))
{
ZkClient zkClient = _zkClientMap.get(zkServer);
if (zkClient.getConnection().getZookeeperState() != States.CONNECTED)
{
_zkClientMap.remove(zkServer);
}
}
// get a new zkclient
if (!_zkClientMap.containsKey(zkServer))
{
ZkClient zkClient = new ZkClient(zkServer, DEFAULT_SESSION_TIMEOUT,
ZkClient.DEFAULT_CONNECTION_TIMEOUT, new ZNRecordSerializer());
_zkClientMap.put(zkServer, zkClient);
}
return _zkClientMap.get(zkServer);
}
}
public static void reset()
{
_zkClientMap.clear();
}
}