Copyright 2010 the original author or authors.
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.
/**
 * Copyright 2010 the original author or authors.
 *
 * 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 org.I0Itec.zkclient;

import java.io.IOException;
import java.util.AbstractMap.SimpleEntry;
import java.util.List;
import java.util.Map;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

import org.I0Itec.zkclient.exception.ZkException;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.Op;
import org.apache.zookeeper.OpResult;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.ZooKeeper.States;
import org.apache.zookeeper.data.ACL;
import org.apache.zookeeper.data.Stat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ZkConnection implements IZkConnection {

    private static final Logger LOG = LoggerFactory.getLogger(ZkConnection.class);

    
It is recommended to use quite large sessions timeouts for ZooKeeper. /** It is recommended to use quite large sessions timeouts for ZooKeeper. */
    private static final int DEFAULT_SESSION_TIMEOUT = 30000;

    private ZooKeeper _zk = null;
    private final Lock _zookeeperLock = new ReentrantLock();

    private final String _servers;
    private final int _sessionTimeOut;

    public ZkConnection(String zkServers) {
        this(zkServers, DEFAULT_SESSION_TIMEOUT);
    }

    public ZkConnection(String zkServers, int sessionTimeOut) {
        _servers = zkServers;
        _sessionTimeOut = sessionTimeOut;
    }

    @Override
    public void connect(Watcher watcher) {
        _zookeeperLock.lock();
        try {
            if (_zk != null) {
                throw new IllegalStateException("zk client has already been started");
            }
            try {
                LOG.debug("Creating new ZookKeeper instance to connect to " + _servers + ".");
                _zk = new ZooKeeper(_servers, _sessionTimeOut, watcher);
            } catch (IOException e) {
                throw new ZkException("Unable to connect to " + _servers, e);
            }
        } finally {
            _zookeeperLock.unlock();
        }
    }

    @Override
    public void close() throws InterruptedException {
        _zookeeperLock.lock();
        try {
            if (_zk != null) {
                LOG.debug("Closing ZooKeeper connected to " + _servers);
                _zk.close();
                _zk = null;
            }
        } finally {
            _zookeeperLock.unlock();
        }
    }

    @Override
    public String create(String path, byte[] data, CreateMode mode) throws KeeperException, InterruptedException {
        return _zk.create(path, data, Ids.OPEN_ACL_UNSAFE, mode);
    }

    @Override
    public String create(String path, byte[] data, List<ACL> acl, CreateMode mode) throws KeeperException, InterruptedException {
        return _zk.create(path, data, acl, mode);
    }

    @Override
    public void delete(String path) throws InterruptedException, KeeperException {
        _zk.delete(path, -1);
    }

    @Override
    public void delete(String path, int version) throws InterruptedException, KeeperException {
        _zk.delete(path, version);
    }

    @Override
    public boolean exists(String path, boolean watch) throws KeeperException, InterruptedException {
        return _zk.exists(path, watch) != null;
    }

    @Override
    public List<String> getChildren(final String path, final boolean watch) throws KeeperException, InterruptedException {
        return _zk.getChildren(path, watch);
    }

    @Override
    public byte[] readData(String path, Stat stat, boolean watch) throws KeeperException, InterruptedException {
        return _zk.getData(path, watch, stat);
    }

    public void writeData(String path, byte[] data) throws KeeperException, InterruptedException {
        writeData(path, data, -1);
    }

    @Override
    public void writeData(String path, byte[] data, int version) throws KeeperException, InterruptedException {
        _zk.setData(path, data, version);
    }

    @Override
    public Stat writeDataReturnStat(String path, byte[] data, int version) throws KeeperException, InterruptedException {
        return _zk.setData(path, data, version);
    }

    @Override
    public States getZookeeperState() {
        return _zk != null ? _zk.getState() : null;
    }

    public ZooKeeper getZookeeper() {
        return _zk;
    }

    @Override
    public long getCreateTime(String path) throws KeeperException, InterruptedException {
        Stat stat = _zk.exists(path, false);
        if (stat != null) {
            return stat.getCtime();
        }
        return -1;
    }

    @Override
    public String getServers() {
        return _servers;
    }

    @Override
    public List<OpResult> multi(Iterable<Op> ops) throws KeeperException, InterruptedException {
        return _zk.multi(ops);
    }

    @Override
    public void addAuthInfo(String scheme, byte[] auth) {
        _zk.addAuthInfo(scheme, auth);
    }

    @Override
    public void setAcl(String path, List<ACL> acl, int version) throws KeeperException, InterruptedException {
        _zk.setACL(path, acl, version);
    }

    @Override
    public Map.Entry<List<ACL>, Stat> getAcl(String path) throws KeeperException, InterruptedException {
        Stat stat = new Stat();
        List<ACL> acl = _zk.getACL(path, stat);
        return new SimpleEntry(acl, stat);
    }

}