org.apache.zookeeper.server.quorum

Class LearnerSyncThrottler

java.lang.Object

org.apache.zookeeper.server.quorum.LearnerSyncThrottler

public class LearnerSyncThrottler
extends Object

Utility class to limit the number of concurrent syncs from a leader to observers and followers or from a follower to observers. LearnerHandler objects should call beginSync(boolean) before sending a sync and endSync() after finishing, successfully or not.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LearnerSyncThrottler.SyncType

Constructor Summary

Constructors

Constructor and Description
LearnerSyncThrottler(int maxConcurrentSyncs, LearnerSyncThrottler.SyncType syncType) Constructs a new instance limiting the concurrent number of syncs to maxConcurrentSyncs.

Method Summary

Modifier and Type	Method and Description
protected void	beginSync(boolean essential) Indicates that a new sync is about to be sent.
void	endSync() Indicates that a sync has been completed.
int	getSyncInProgress()
void	setMaxConcurrentSyncs(int maxConcurrentSyncs)

Methods inherited from class java.lang.Object

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

Constructor Detail

LearnerSyncThrottler

public LearnerSyncThrottler(int maxConcurrentSyncs,
                            LearnerSyncThrottler.SyncType syncType)
                     throws IllegalArgumentException

Constructs a new instance limiting the concurrent number of syncs to maxConcurrentSyncs.

Parameters:

maxConcurrentSyncs - maximum concurrent number of syncs

syncType - either a snapshot sync or a txn-based diff sync

Throws:

IllegalArgumentException - when maxConcurrentSyncs is less than 1

Method Detail

beginSync

protected void beginSync(boolean essential)
                  throws SyncThrottleException,
                         InterruptedException

Indicates that a new sync is about to be sent.

Parameters:

essential - if true, do not throw an exception even if throttling limit is reached

Throws:

SyncThrottleException - if throttling limit has been exceeded and essential == false, even after waiting for the timeout period, if any

InterruptedException - if thread is interrupted while trying to start a sync; cannot happen if timeout is zero

endSync

public void endSync()

Indicates that a sync has been completed.

setMaxConcurrentSyncs

public void setMaxConcurrentSyncs(int maxConcurrentSyncs)

getSyncInProgress

public int getSyncInProgress()