Package com.linkedin.venice.helix

Class CachedResourceZkStateListener

java.lang.Object

com.linkedin.venice.helix.CachedResourceZkStateListener

All Implemented Interfaces:

org.apache.helix.zookeeper.zkclient.IZkStateListener

public class CachedResourceZkStateListener
extends Object
implements org.apache.helix.zookeeper.zkclient.IZkStateListener

Listener used to monitor zk connection state change and refresh venice resource once zk connection is reconnected.

ZK does not guarantee the delivery of notifications. After ZK client disconnect from one ZK server, it will try to connect to another server. After client is connected again, ZK client will register all of watcher again to the new server. But all of events happen during disconnecting are unknown in client's view. So venice should refresh some resources to sync up local cache with ZK.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_RETRY_LOAD_ATTEMPTS
static final long	DEFAULT_RETRY_LOAD_INTERVAL_IN_MS

Constructor Summary

Constructors

Constructor	Description
CachedResourceZkStateListener(VeniceResource resource)
CachedResourceZkStateListener(VeniceResource resource, int retryLoadAttempts, long retryLoadIntervalInMs)

Method Summary

Modifier and Type	Method	Description
void	handleNewSession(String s)
void	handleSessionEstablishmentError(Throwable error)
void	handleStateChanged(org.apache.zookeeper.Watcher.Event.KeeperState state)	Once the state of zk connection is changed, this function will be called.
protected boolean	isDisconnected()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.helix.zookeeper.zkclient.IZkStateListener

handleStateChanged

Field Details

DEFAULT_RETRY_LOAD_ATTEMPTS

public static final int DEFAULT_RETRY_LOAD_ATTEMPTS

See Also:

• Constant Field Values

DEFAULT_RETRY_LOAD_INTERVAL_IN_MS

public static final long DEFAULT_RETRY_LOAD_INTERVAL_IN_MS

Constructor Details

CachedResourceZkStateListener

public CachedResourceZkStateListener(VeniceResource resource)

CachedResourceZkStateListener

public CachedResourceZkStateListener(VeniceResource resource,
 int retryLoadAttempts,
 long retryLoadIntervalInMs)

Method Details

handleStateChanged

public void handleStateChanged(org.apache.zookeeper.Watcher.Event.KeeperState state)
                        throws Exception

Once the state of zk connection is changed, this function will be called. So it could not be called twice for the same state change.

Specified by:

handleStateChanged in interface org.apache.helix.zookeeper.zkclient.IZkStateListener

Throws:

Exception

handleNewSession

public void handleNewSession(String s)
                      throws Exception

Specified by:

handleNewSession in interface org.apache.helix.zookeeper.zkclient.IZkStateListener

Throws:

Exception

handleSessionEstablishmentError

public void handleSessionEstablishmentError(Throwable error)
                                     throws Exception

Specified by:

handleSessionEstablishmentError in interface org.apache.helix.zookeeper.zkclient.IZkStateListener

Throws:

Exception

isDisconnected

protected boolean isDisconnected()