/**
* 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 com.github.zkclient;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.List;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper.States;
import org.apache.zookeeper.data.Stat;
import com.github.zkclient.exception.ZkException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class ZkConnection {
private static final Logger LOG = LoggerFactory.getLogger(ZkConnection.class);
private ZooKeeper _zk = null;
private final Lock _zookeeperLock = new ReentrantLock();
private final String _servers;
private final int _sessionTimeOut;
private static final Method method;
static {
Method[] methods = ZooKeeper.class.getDeclaredMethods();
Method m = null;
for (Method method : methods) {
if (method.getName().equals("multi")) {
m = method;
break;
}
}
method = m;
}
/**
* build a zookeeper connection
* @param zkServers zookeeper connection string
* @param sessionTimeOut session timeout in milliseconds
*/
public ZkConnection(String zkServers, int sessionTimeOut) {
_servers = zkServers;
_sessionTimeOut = sessionTimeOut;
}
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();
}
}
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();
}
}
public String create(String path, byte[] data, CreateMode mode) throws KeeperException, InterruptedException {
return _zk.create(path, data, Ids.OPEN_ACL_UNSAFE, mode);
}
public void delete(String path) throws InterruptedException, KeeperException {
_zk.delete(path, -1);
}
public boolean exists(String path, boolean watch) throws KeeperException, InterruptedException {
return _zk.exists(path, watch) != null;
}
public List<String> getChildren(final String path, final boolean watch) throws KeeperException, InterruptedException {
return _zk.getChildren(path, watch);
}
public byte[] readData(String path, Stat stat, boolean watch) throws KeeperException, InterruptedException {
return _zk.getData(path, watch, stat);
}
/**
* wrapper for 3.3.x/3.4.x
*
* @param ops multi operations
* @return OpResult list
*/
@SuppressWarnings("unchecked")
public List<?> multi(Iterable<?> ops) {
if (method == null) throw new UnsupportedOperationException("multi operation must use zookeeper 3.4+");
try {
return (List<?>) method.invoke(_zk, ops);
} catch (IllegalArgumentException e) {
throw new UnsupportedOperationException("ops must be 'org.apache.zookeeper.Op'");
} catch (IllegalAccessException e) {
throw new UnsupportedOperationException(e);
} catch (InvocationTargetException e) {
throw new RuntimeException(e);
}
}
public Stat writeData(String path, byte[] data, int version) throws KeeperException, InterruptedException {
return _zk.setData(path, data, version);
}
public States getZookeeperState() {
return _zk != null ? _zk.getState() : null;
}
public long getCreateTime(String path) throws KeeperException, InterruptedException {
Stat stat = _zk.exists(path, false);
if (stat != null) {
return stat.getCtime();
}
return -1;
}
public String getServers() {
return _servers;
}
public ZooKeeper getZooKeeper() {
return _zk;
}
}