org.apache.hadoop.hbase.zookeeper

Class DeletionListener

java.lang.Object

org.apache.hadoop.hbase.zookeeper.ZKListener

org.apache.hadoop.hbase.zookeeper.DeletionListener

@InterfaceAudience.Private
public class DeletionListener
extends ZKListener

A ZooKeeper watcher meant to detect deletions of ZNodes.

Field Summary

Fields

Modifier and Type	Field and Description
private CountDownLatch	deletedLatch
private Throwable	exception
private static org.slf4j.Logger	LOG
private String	pathToWatch

Fields inherited from class org.apache.hadoop.hbase.zookeeper.ZKListener

watcher

Constructor Summary

Constructors

Constructor and Description
DeletionListener(ZKWatcher zkWatcher, String pathToWatch, CountDownLatch deletedLatch) Create a new instance of the deletion watcher.

Method Summary

Modifier and Type	Method and Description
Throwable	getException() Get the last exception which has occurred when re-setting the watch.
boolean	hasException() Check if an exception has occurred when re-setting the watch.
void	nodeDataChanged(String path) Called when an existing node has changed data.
void	nodeDeleted(String path) Called when a node has been deleted

Methods inherited from class org.apache.hadoop.hbase.zookeeper.ZKListener

getWatcher, nodeChildrenChanged, nodeCreated

Methods inherited from class java.lang.Object

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

Field Detail

LOG

private static final org.slf4j.Logger LOG

pathToWatch

private final String pathToWatch

deletedLatch

private final CountDownLatch deletedLatch

exception

private volatile Throwable exception

Constructor Detail

DeletionListener

public DeletionListener(ZKWatcher zkWatcher,
                        String pathToWatch,
                        CountDownLatch deletedLatch)

Create a new instance of the deletion watcher.

Parameters:

zkWatcher - ZookeeperWatcher instance

pathToWatch - (Fully qualified) ZNode path that we are waiting to be deleted.

deletedLatch - Count down on this latch when deletion has occurred.

Method Detail

hasException

public boolean hasException()

Check if an exception has occurred when re-setting the watch.

Returns:

True if we were unable to re-set a watch on a ZNode due to an exception.

getException

public Throwable getException()

Get the last exception which has occurred when re-setting the watch. Use hasException() to check whether or not an exception has occurred.

Returns:

The last exception observed when re-setting the watch.

nodeDataChanged

public void nodeDataChanged(String path)

Description copied from class: ZKListener

Called when an existing node has changed data.

Overrides:

nodeDataChanged in class ZKListener

Parameters:

path - full path of the updated node

nodeDeleted

public void nodeDeleted(String path)

Description copied from class: ZKListener

Called when a node has been deleted

Overrides:

nodeDeleted in class ZKListener

Parameters:

path - full path of the deleted node