Java tutorial
/* * 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. */ package org.apache.brooklyn.entity.messaging.zookeeper; import java.io.Closeable; import java.util.concurrent.CountDownLatch; import org.apache.brooklyn.location.paas.PaasLocation; import org.apache.brooklyn.util.exceptions.Exceptions; import org.apache.zookeeper.CreateMode; import org.apache.zookeeper.WatchedEvent; import org.apache.zookeeper.Watcher; import org.apache.zookeeper.ZooDefs; import org.apache.zookeeper.ZooKeeper; import org.apache.zookeeper.data.Stat; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.google.common.net.HostAndPort; /** * Useful methods for writing to and reading from ZooKeeper nodes. */ public class ZooKeeperTestSupport implements Closeable { private static final Logger LOG = LoggerFactory.getLogger(ZooKeeperTestSupport.class); private final ZooKeeper zk; private final CountDownLatch connSignal = new CountDownLatch(1); public ZooKeeperTestSupport(final HostAndPort hostAndPort) throws Exception { final int sessionTimeout = 3000; zk = new ZooKeeper(hostAndPort.toString(), sessionTimeout, new Watcher() { @Override public void process(WatchedEvent event) { if (event.getState() == Event.KeeperState.SyncConnected) { LOG.debug("Connected to ZooKeeper at {}", hostAndPort); connSignal.countDown(); } else { LOG.info("WatchedEvent at {}: {}", hostAndPort, event.getState()); } } }); connSignal.await(); } @Override public void close() { try { zk.close(); } catch (InterruptedException e) { throw Exceptions.propagate(e); } } public String create(String path, byte[] data) throws Exception { return zk.create(path, data, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT); } public Stat update(String path, byte[] data) throws Exception { return zk.setData(path, data, zk.exists(path, true).getVersion()); } public void delete(String path) throws Exception { zk.delete(path, zk.exists(path, true).getVersion()); } public byte[] get(String path) throws Exception { return zk.getData(path, false, zk.exists(path, false)); } }