/**
* Copyright (C) 2012 LinkedIn Inc <opensource@linkedin.com>
*
* 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.linkedin.helix.util;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.zookeeper.ZooKeeper.States;
import com.linkedin.helix.manager.zk.ZNRecordSerializer;
import com.linkedin.helix.manager.zk.ZkClient;
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();
}
}