Package org.apache.curator.framework.recipes.barriers

Class DistributedDoubleBarrier

java.lang.Object

org.apache.curator.framework.recipes.barriers.DistributedDoubleBarrier

public class DistributedDoubleBarrier
extends Object

A double barrier as described in the ZK recipes. Quoting the recipe:

Double barriers enable clients to synchronize the beginning and the end of a computation. When enough processes have joined the barrier, processes start their computation and leave the barrier once they have finished.

Constructor Summary

Constructors

Constructor	Description
DistributedDoubleBarrier(CuratorFramework client, String barrierPath, int memberQty)	Creates the barrier abstraction.

Method Summary

Modifier and Type	Method	Description
void	enter()	Enter the barrier and block until all members have entered
boolean	enter(long maxWait, TimeUnit unit)	Enter the barrier and block until all members have entered or the timeout has elapsed
protected List<String>	getChildrenForEntering()
void	leave()	Leave the barrier and block until all members have left
boolean	leave(long maxWait, TimeUnit unit)	Leave the barrier and block until all members have left or the timeout has elapsed

Methods inherited from class java.lang.Object

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

Constructor Details

DistributedDoubleBarrier

public DistributedDoubleBarrier(CuratorFramework client,
 String barrierPath,
 int memberQty)

Creates the barrier abstraction. memberQty is the number of members in the barrier. When enter() is called, it blocks until all members have entered. When leave() is called, it blocks until all members have left.

Parameters:

client - the client

barrierPath - path to use

memberQty - the number of members in the barrier. NOTE: more than memberQty can enter the barrier. memberQty is a threshold, not a limit

Method Details

enter

public void enter()
           throws Exception

Enter the barrier and block until all members have entered

Throws:

Exception - interruptions, errors, etc.

enter

public boolean enter(long maxWait,
 TimeUnit unit)
              throws Exception

Enter the barrier and block until all members have entered or the timeout has elapsed

Parameters:

maxWait - max time to block

unit - time unit

Returns:

true if the entry was successful, false if the timeout elapsed first

Throws:

Exception - interruptions, errors, etc.

leave

public void leave()
           throws Exception

Leave the barrier and block until all members have left

Throws:

Exception - interruptions, errors, etc.

leave

public boolean leave(long maxWait,
 TimeUnit unit)
              throws Exception

Leave the barrier and block until all members have left or the timeout has elapsed

Parameters:

maxWait - max time to block

unit - time unit

Returns:

true if leaving was successful, false if the timeout elapsed first

Throws:

Exception - interruptions, errors, etc.

getChildrenForEntering

protected List<String> getChildrenForEntering()
                                       throws Exception

Throws:

Exception