com.jkoolcloud.tnt4j.stream.jmx.vm.ZKConnection Maven / Gradle / Ivy
/*
* Copyright 2014-2023 JKOOL, LLC.
*
* 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.jkoolcloud.tnt4j.stream.jmx.vm;
import java.io.Closeable;
import java.io.IOException;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
/**
* ZooKeeper connection wrapper-helper class.
*
* @version $Revision: 1 $
*/
public class ZKConnection implements Closeable {
private static final int DEFAULT_CONN_TIMEOUT = (int) TimeUnit.SECONDS.toMillis(5);
// ZooKeeper instance to access ZooKeeper ensemble
private ZooKeeper zk;
/**
* Connects to ZooKeeper ensemble. Waits until connection establishment is confirmed over watcher.
*
* @param connStr
* ZooKeeper ensemble connection definition string
* @return zookeeper instance
*
* @throws java.io.IOException
* if I/O exception occurs while initializing ZooKeeper connection
* @throws InterruptedException
* if the current thread is interrupted while waiting
*
* @see #connect(String, int)
*/
public ZooKeeper connect(String connStr) throws IOException, InterruptedException {
return connect(connStr, DEFAULT_CONN_TIMEOUT);
}
/**
* Connects to ZooKeeper ensemble. Waits until connection establishment is confirmed over watcher.
*
* @param connStr
* ZooKeeper ensemble connection definition string
* @param timeout
* connection timeout
* @return zookeeper instance
*
* @throws java.io.IOException
* if I/O exception occurs while initializing ZooKeeper connection
* @throws InterruptedException
* if the current thread is interrupted while waiting
*/
public ZooKeeper connect(String connStr, int timeout) throws IOException, InterruptedException {
CountDownLatch connectedSignal = new CountDownLatch(1);
zk = new ZooKeeper(connStr, timeout, new Watcher() {
@Override
public void process(WatchedEvent we) {
if (we.getState() == Event.KeeperState.SyncConnected) {
connectedSignal.countDown();
}
}
});
connectedSignal.await();
return zk;
}
/**
* Checks if connection to {@link org.apache.zookeeper.ZooKeeper} ensemble was performed.
*
* @return {@code true} if {@link org.apache.zookeeper.ZooKeeper} instance is not {@code null}, {@code false} -
* otherwise
*/
public boolean isConnected() {
return zk != null;
}
/**
* Returns {@link org.apache.zookeeper.ZooKeeper} instance connection was established to.
*
* @return zookeeper instance
*/
public ZooKeeper zk() {
return zk;
}
/**
* Disconnects from ZooKeeper ensemble.
*/
@Override
public void close() {
if (isConnected()) {
try {
zk.close();
} catch (InterruptedException exc) {
}
}
}
}