Package org.apache.hadoop.hbase.zookeeper

Class ZKListener

java.lang.Object

org.apache.hadoop.hbase.zookeeper.ZKListener

Direct Known Subclasses:

ActiveMasterManager, ClientZKSyncer, DeletionListener, DrainingServerTracker, MasterMaintenanceModeTracker, MetaRegionLocationCache, RegionServerTracker, TableHFileArchiveTracker, ZKLeaderManager, ZKNodeTracker, ZKPermissionWatcher, ZKProcedureUtil, ZKSecretWatcher, ZKSplitLogManagerCoordination, ZkSplitLogWorkerCoordination, ZKVisibilityLabelWatcher

@Private
public abstract class ZKListener
extends Object

Base class for internal listeners of ZooKeeper events. The ZKWatcher for a process will execute the appropriate methods of implementations of this class. In order to receive events from the watcher, every listener must register itself via ZKWatcher.registerListener(org.apache.hadoop.hbase.zookeeper.ZKListener). Subclasses need only override those methods in which they are interested. Note that the watcher will be blocked when invoking methods in listeners so they must not be long-running.

Field Summary

Fields

Modifier and Type	Field	Description
protected ZKWatcher	watcher

Constructor Summary

Constructors

Constructor	Description
ZKListener(ZKWatcher watcher)	Construct a ZooKeeper event listener.

Method Summary

Modifier and Type	Method	Description
ZKWatcher	getWatcher()	Returns The watcher associated with this listener
void	nodeChildrenChanged(String path)	Called when an existing node has a child node added or removed.
void	nodeCreated(String path)	Called when a new node has been created.
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 java.lang.Object

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

Field Details

watcher

protected ZKWatcher watcher

Constructor Details

ZKListener

public ZKListener(ZKWatcher watcher)

Construct a ZooKeeper event listener.

Method Details

nodeCreated

public void nodeCreated(String path)

Called when a new node has been created.

Parameters:

path - full path of the new node

nodeDeleted

public void nodeDeleted(String path)

Called when a node has been deleted

Parameters:

path - full path of the deleted node

nodeDataChanged

public void nodeDataChanged(String path)

Called when an existing node has changed data.

Parameters:

path - full path of the updated node

nodeChildrenChanged

public void nodeChildrenChanged(String path)

Called when an existing node has a child node added or removed.

Parameters:

path - full path of the node whose children have changed

getWatcher

public ZKWatcher getWatcher()

Returns The watcher associated with this listener