Java EmptyWatcher类代码示例

import org.apache.hadoop.hbase.zookeeper.EmptyWatcher; //导入依赖的package包/类
@Override public Void call() throws Exception {
  ZooKeeper zooKeeper = null;
  try {
    zooKeeper = new ZooKeeper(host, timeout, EmptyWatcher.instance);
    Stat exists = zooKeeper.exists(znode, false);
    StopWatch stopwatch = new StopWatch();
    stopwatch.start();
    zooKeeper.getData(znode, false, exists);
    stopwatch.stop();
    sink.publishReadTiming(znode, host, stopwatch.getTime());
  } catch (KeeperException | InterruptedException e) {
    sink.publishReadFailure(znode, host);
  } finally {
    if (zooKeeper != null) {
      zooKeeper.close();
    }
  }
  return null;
}
 

import org.apache.hadoop.hbase.zookeeper.EmptyWatcher; //导入依赖的package包/类
/**
 * Expire a ZooKeeper session as recommended in ZooKeeper documentation
 * http://wiki.apache.org/hadoop/ZooKeeper/FAQ#A4
 * There are issues when doing this:
 * [1] http://www.mail-archive.com/[email protected]/msg01942.html
 * [2] https://issues.apache.org/jira/browse/ZOOKEEPER-1105
 *
 * @param nodeZK - the ZK watcher to expire
 * @param checkStatus - true to check if we can create an HTable with the
 *                    current configuration.
 */
public void expireSession(ZooKeeperWatcher nodeZK, boolean checkStatus)
  throws Exception {
  Configuration c = new Configuration(this.conf);
  String quorumServers = ZKConfig.getZKQuorumServersString(c);
  ZooKeeper zk = nodeZK.getRecoverableZooKeeper().getZooKeeper();
  byte[] password = zk.getSessionPasswd();
  long sessionID = zk.getSessionId();

  // Expiry seems to be asynchronous (see comment from P. Hunt in [1]),
  //  so we create a first watcher to be sure that the
  //  event was sent. We expect that if our watcher receives the event
  //  other watchers on the same machine will get is as well.
  // When we ask to close the connection, ZK does not close it before
  //  we receive all the events, so don't have to capture the event, just
  //  closing the connection should be enough.
  ZooKeeper monitor = new ZooKeeper(quorumServers,
    1000, new org.apache.zookeeper.Watcher(){
    @Override
    public void process(WatchedEvent watchedEvent) {
      LOG.info("Monitor ZKW received event="+watchedEvent);
    }
  } , sessionID, password);

  // Making it expire
  ZooKeeper newZK = new ZooKeeper(quorumServers,
      1000, EmptyWatcher.instance, sessionID, password);

  //ensure that we have connection to the server before closing down, otherwise
  //the close session event will be eaten out before we start CONNECTING state
  long start = System.currentTimeMillis();
  while (newZK.getState() != States.CONNECTED
       && System.currentTimeMillis() - start < 1000) {
     Thread.sleep(1);
  }
  newZK.close();
  LOG.info("ZK Closed Session 0x" + Long.toHexString(sessionID));

  // Now closing & waiting to be sure that the clients get it.
  monitor.close();

  if (checkStatus) {
    new HTable(new Configuration(conf), TableName.META_TABLE_NAME).close();
  }
}
 

import org.apache.hadoop.hbase.zookeeper.EmptyWatcher; //导入依赖的package包/类
/**
 * Expire a ZooKeeper session as recommended in ZooKeeper documentation
 * http://hbase.apache.org/book.html#trouble.zookeeper
 * There are issues when doing this:
 * [1] http://www.mail-archive.com/[email protected]/msg01942.html
 * [2] https://issues.apache.org/jira/browse/ZOOKEEPER-1105
 *
 * @param nodeZK - the ZK watcher to expire
 * @param checkStatus - true to check if we can create a Table with the
 *                    current configuration.
 */
public void expireSession(ZKWatcher nodeZK, boolean checkStatus)
  throws Exception {
  Configuration c = new Configuration(this.conf);
  String quorumServers = ZKConfig.getZKQuorumServersString(c);
  ZooKeeper zk = nodeZK.getRecoverableZooKeeper().getZooKeeper();
  byte[] password = zk.getSessionPasswd();
  long sessionID = zk.getSessionId();

  // Expiry seems to be asynchronous (see comment from P. Hunt in [1]),
  //  so we create a first watcher to be sure that the
  //  event was sent. We expect that if our watcher receives the event
  //  other watchers on the same machine will get is as well.
  // When we ask to close the connection, ZK does not close it before
  //  we receive all the events, so don't have to capture the event, just
  //  closing the connection should be enough.
  ZooKeeper monitor = new ZooKeeper(quorumServers,
    1000, new org.apache.zookeeper.Watcher(){
    @Override
    public void process(WatchedEvent watchedEvent) {
      LOG.info("Monitor ZKW received event="+watchedEvent);
    }
  } , sessionID, password);

  // Making it expire
  ZooKeeper newZK = new ZooKeeper(quorumServers,
      1000, EmptyWatcher.instance, sessionID, password);

  //ensure that we have connection to the server before closing down, otherwise
  //the close session event will be eaten out before we start CONNECTING state
  long start = System.currentTimeMillis();
  while (newZK.getState() != States.CONNECTED
       && System.currentTimeMillis() - start < 1000) {
     Thread.sleep(1);
  }
  newZK.close();
  LOG.info("ZK Closed Session 0x" + Long.toHexString(sessionID));

  // Now closing & waiting to be sure that the clients get it.
  monitor.close();

  if (checkStatus) {
    getConnection().getTable(TableName.META_TABLE_NAME).close();
  }
}
 

import org.apache.hadoop.hbase.zookeeper.EmptyWatcher; //导入依赖的package包/类
/**
 * Expire a ZooKeeper session as recommended in ZooKeeper documentation
 * http://wiki.apache.org/hadoop/ZooKeeper/FAQ#A4
 * There are issues when doing this:
 * [1] http://www.mail-archive.com/[email protected]/msg01942.html
 * [2] https://issues.apache.org/jira/browse/ZOOKEEPER-1105
 *
 * @param nodeZK - the ZK watcher to expire
 * @param checkStatus - true to check if we can create an HTable with the
 *                    current configuration.
 */
public void expireSession(ZooKeeperWatcher nodeZK, boolean checkStatus)
  throws Exception {
  Configuration c = new Configuration(this.conf);
  String quorumServers = ZKConfig.getZKQuorumServersString(c);
  ZooKeeper zk = nodeZK.getRecoverableZooKeeper().getZooKeeper();
  byte[] password = zk.getSessionPasswd();
  long sessionID = zk.getSessionId();

  // Expiry seems to be asynchronous (see comment from P. Hunt in [1]),
  //  so we create a first watcher to be sure that the
  //  event was sent. We expect that if our watcher receives the event
  //  other watchers on the same machine will get is as well.
  // When we ask to close the connection, ZK does not close it before
  //  we receive all the events, so don't have to capture the event, just
  //  closing the connection should be enough.
  ZooKeeper monitor = new ZooKeeper(quorumServers,
    1000, new org.apache.zookeeper.Watcher(){
    @Override
    public void process(WatchedEvent watchedEvent) {
      LOG.info("Monitor ZKW received event="+watchedEvent);
    }
  } , sessionID, password);

  // Making it expire
  ZooKeeper newZK = new ZooKeeper(quorumServers,
      1000, EmptyWatcher.instance, sessionID, password);

  //ensure that we have connection to the server before closing down, otherwise
  //the close session event will be eaten out before we start CONNECTING state
  long start = System.currentTimeMillis();
  while (newZK.getState() != States.CONNECTED
       && System.currentTimeMillis() - start < 1000) {
     Thread.sleep(1);
  }
  newZK.close();
  LOG.info("ZK Closed Session 0x" + Long.toHexString(sessionID));

  // Now closing & waiting to be sure that the clients get it.
  monitor.close();

  if (checkStatus) {
    new HTable(new Configuration(conf), HConstants.META_TABLE_NAME).close();
  }
}