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.distributedlog;
  
  import static org.junit.Assert.assertTrue;
  
  import com.google.common.base.Stopwatch;
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.TimeUnit;
  import org.apache.zookeeper.KeeperException;
  import org.apache.zookeeper.WatchedEvent;
  import org.apache.zookeeper.Watcher;
  import org.apache.zookeeper.ZooKeeper;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  
  /**
   * Utilities of {@link org.apache.distributedlog.ZooKeeperClient}.
   */
  public class ZooKeeperClientUtils {
  
      private static final Logger logger = LoggerFactory.getLogger(ZooKeeperClientUtils.class);
  
      /**
       * Expire given zookeeper client's session.
       *
       * @param zkc
       *          zookeeper client
       * @param zkServers
       *          zookeeper servers
       * @param timeout
       *          timeout
       * @throws Exception
       */
      public static void expireSession(ZooKeeperClient zkc, String zkServers, int timeout)
              throws Exception {
          final CountDownLatch expireLatch = new CountDownLatch(1);
          final CountDownLatch latch = new CountDownLatch(1);
          ZooKeeper oldZk = zkc.get();
          oldZk.exists("/", new Watcher() {
              @Override
              public void process(WatchedEvent event) {
                  logger.debug("Receive event : {}", event);
                  if (event.getType() == Event.EventType.None
                          && event.getState() == Event.KeeperState.Expired) {
                      expireLatch.countDown();
                  }
              }
          });
          ZooKeeper newZk = new ZooKeeper(zkServers, timeout, new Watcher() {
              @Override
              public void process(WatchedEvent event) {
                  if (Event.EventType.None == event.getType()
                          && Event.KeeperState.SyncConnected == event.getState()) {
                      latch.countDown();
                  }
              }
          }, oldZk.getSessionId(), oldZk.getSessionPasswd());
          if (!latch.await(timeout, TimeUnit.MILLISECONDS)) {
              throw KeeperException.create(KeeperException.Code.CONNECTIONLOSS);
          }
          newZk.close();
  
          boolean done = false;
          Stopwatch expireWait = Stopwatch.createStarted();
          while (!done && expireWait.elapsed(TimeUnit.MILLISECONDS) < timeout * 2) {
              try {
                  zkc.get().exists("/", false);
                  done = true;
              } catch (KeeperException ke) {
                  done = (ke.code() == KeeperException.Code.SESSIONEXPIRED);
              }
          }
  
          assertTrue("Client should receive session expired event.",
                     expireLatch.await(timeout, TimeUnit.MILLISECONDS));
      }
  }
  