| /** |
| * 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.camel.component.zookeeper; |
| |
| import java.util.concurrent.CountDownLatch; |
| |
| import org.apache.camel.RuntimeCamelException; |
| import org.apache.camel.util.ObjectHelper; |
| import org.apache.zookeeper.WatchedEvent; |
| import org.apache.zookeeper.Watcher; |
| import org.apache.zookeeper.Watcher.Event.KeeperState; |
| import org.apache.zookeeper.ZooKeeper; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * <code>ConnectionHolder</code> watches for Connection based events from |
| * {@link ZooKeeper} and can be used to block until a connection has been |
| * established. |
| */ |
| public class ConnectionHolder implements Watcher { |
| private static final Logger LOG = LoggerFactory.getLogger(ConnectionHolder.class); |
| |
| private CountDownLatch connectionLatch = new CountDownLatch(1); |
| |
| private ZooKeeperConfiguration configuration; |
| |
| private ZooKeeper zookeeper; |
| |
| public ConnectionHolder(ZooKeeperConfiguration configuration) { |
| this.configuration = configuration; |
| } |
| |
| public ZooKeeper getZooKeeper() { |
| if (zookeeper != null) { |
| return zookeeper; |
| } |
| if (configuration.getConnectString() == null) { |
| throw new RuntimeCamelException("Cannot create ZooKeeper connection as connection string is null. Have servers been configured?"); |
| } |
| try { |
| zookeeper = new ZooKeeper(configuration.getConnectString(), configuration.getTimeout(), this); |
| } catch (Exception e) { |
| throw ObjectHelper.wrapRuntimeCamelException(e); |
| } |
| awaitConnection(); |
| return zookeeper; |
| } |
| |
| public boolean isConnected() { |
| return connectionLatch.getCount() == 0; |
| } |
| |
| public void awaitConnection() { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("Awaiting Connection event from Zookeeper cluster {}", configuration.getConnectString()); |
| } |
| try { |
| connectionLatch.await(); |
| } catch (InterruptedException e) { |
| throw ObjectHelper.wrapRuntimeCamelException(e); |
| } |
| } |
| |
| public void process(WatchedEvent event) { |
| if (event.getState() == KeeperState.SyncConnected) { |
| connectionLatch.countDown(); |
| } |
| connectionLatch.countDown(); |
| } |
| |
| public void closeConnection() { |
| try { |
| if (zookeeper != null) { |
| zookeeper.close(); |
| zookeeper = null; |
| } |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("Shutting down connection to Zookeeper cluster {}", configuration.getConnectString()); |
| } |
| } catch (InterruptedException e) { |
| LOG.warn("Error closing zookeeper connection " + configuration.getConnectString() + ". This exception will be ignored.", e); |
| } |
| } |
| } |