com.bigdata.zookeeper
Class ZNodeDeletedWatcher

java.lang.Object
  com.bigdata.zookeeper.AbstractZNodeConditionWatcher
      com.bigdata.zookeeper.ZNodeDeletedWatcher

All Implemented Interfaces:

org.apache.zookeeper.Watcher

public class ZNodeDeletedWatcher
extends AbstractZNodeConditionWatcher

An instance of this class may be used to watch for the delete of a single znode.

Version:

$Id$

Author:

Bryan Thompson

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.zookeeper.Watcher

org.apache.zookeeper.Watcher.Event

Field Summary

Fields inherited from class com.bigdata.zookeeper.AbstractZNodeConditionWatcher

log, zookeeper, zpath

Constructor Summary

protected

ZNodeDeletedWatcher(org.apache.zookeeper.ZooKeeper zookeeper, String zpath)

Method Summary

static boolean	awaitDelete(org.apache.zookeeper.ZooKeeper zookeeper, String zpath, long timeout, TimeUnit unit) If the znode identified by the path exists, then wait up to the timeout for the znode to be deleted.
protected void	clearWatch() Clear any watches.
protected boolean	isConditionSatisfied() Implementation must check the state of the znode using the AbstractZNodeConditionWatcher.zpath and determine if the conditions are satisfied always resetting the watch(es) as a side-effect.
protected boolean	isConditionSatisfied(org.apache.zookeeper.WatchedEvent event) Implementation must inspect the event and determine if the conditions are satisfied.

Methods inherited from class com.bigdata.zookeeper.AbstractZNodeConditionWatcher

_resumeWatch, awaitCondition, awaitCondition, isCancelled, process, success, toString, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

ZNodeDeletedWatcher

protected ZNodeDeletedWatcher(org.apache.zookeeper.ZooKeeper zookeeper,
                              String zpath)

Method Detail

awaitDelete

public static boolean awaitDelete(org.apache.zookeeper.ZooKeeper zookeeper,
                                  String zpath,
                                  long timeout,
                                  TimeUnit unit)
                           throws InterruptedException

If the znode identified by the path exists, then wait up to the timeout for the znode to be deleted.

Parameters:

zookeeper -

zpath -

timeout -

unit -

Returns:

false if the waiting time detectably elapsed before return from the method, else true.

Throws:

org.apache.zookeeper.KeeperException

InterruptedException

isConditionSatisfied

protected boolean isConditionSatisfied(org.apache.zookeeper.WatchedEvent event)
                                throws org.apache.zookeeper.KeeperException,
                                       InterruptedException

Description copied from class: AbstractZNodeConditionWatcher

Implementation must inspect the event and determine if the conditions are satisfied.

Specified by:

isConditionSatisfied in class AbstractZNodeConditionWatcher

Parameters:

event - The WatchedEvent

Returns:

true if the event satisfied the condition.

Throws:

org.apache.zookeeper.KeeperException

InterruptedException

isConditionSatisfied

protected boolean isConditionSatisfied()
                                throws org.apache.zookeeper.KeeperException,
                                       InterruptedException

Description copied from class: AbstractZNodeConditionWatcher

Implementation must check the state of the znode using the AbstractZNodeConditionWatcher.zpath and determine if the conditions are satisfied always resetting the watch(es) as a side-effect.

This is used to handle the initial case, where we need to know whether or not the condition is satisfied before waiting for an event.

Specified by:

isConditionSatisfied in class AbstractZNodeConditionWatcher

Returns:

Throws:

org.apache.zookeeper.KeeperException

InterruptedException

clearWatch

protected void clearWatch()
                   throws org.apache.zookeeper.KeeperException,
                          InterruptedException

Description copied from class: AbstractZNodeConditionWatcher

Clear any watches.

Specified by:

clearWatch in class AbstractZNodeConditionWatcher

Throws:

org.apache.zookeeper.KeeperException

InterruptedException