content: /*
   * 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.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 RuntimeCamelException.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) {
              Thread.currentThread().interrupt();
              throw RuntimeCamelException.wrapRuntimeCamelException(e);
          }
      }
  
      @Override
      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 {}. This exception will be ignored.",
                      configuration.getConnectString(), e);
              Thread.currentThread().interrupt();
          }
      }
  }
  