pt.ua.concurrent

Class Barrier

java.lang.Object

pt.ua.concurrent.CObject

pt.ua.concurrent.Barrier

All Implemented Interfaces:

InterruptibleAwaitingThreads, SyncCV

Direct Known Subclasses:

ExternalBarrier, InternalBarrier

public abstract class Barrier
extends CObject

A thread barrier abstract class.

Invariant:

numberWaitingThreads() >= 0

This class follows DbC(tm) methodology (Wikipedia). Where possible, contracts are implement with native's Java assert.

Version:

0.5, October 2013, 0.6, December 2015

Author:

Miguel Oliveira e Silva (mos@ua.pt)

Constructor Summary

Constructors

Constructor and Description
Barrier() Constructs a new barrier registering waiting threads.
Barrier(boolean registerAwaitingThreads) Constructs a new barrier.

Method Summary

Modifier and Type	Method and Description
abstract void	await() Caller will wait until the thread barrier is released, situation in which all waiting threads are awakened.
abstract long	awaitCount() Caller will wait until the thread barrier is released, situation in which all waiting threads are awakened.
long	count() Number of times the barrier was released (to be more precise: the remainder of the integer division for 2^63)
abstract int	numberWaitingThreads() Number of threads currently waiting on the barrier.

Methods inherited from class pt.ua.concurrent.CObject

await, await, broadcast, interruptWaitingThreads, lockIsMine, registerAwaitingThreads, signal, syncronizedLockIsMine

Methods inherited from class java.lang.Object

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

Constructor Detail

Barrier

public Barrier()

Constructs a new barrier registering waiting threads.

Barrier

public Barrier(boolean registerAwaitingThreads)

Constructs a new barrier.

Parameters:

registerAwaitingThreads - if true, threads are registered when waiting

Method Detail

numberWaitingThreads

public abstract int numberWaitingThreads()

Number of threads currently waiting on the barrier.

Returns:

number of threads

await

public abstract void await()
                    throws ThreadInterruptedException

Caller will wait until the thread barrier is released, situation in which all waiting threads are awakened.

Postcondition:

count() == old(count())+ 1

Specified by:

await in interface SyncCV

Overrides:

await in class CObject

Throws:

ThreadInterruptedException

awaitCount

public abstract long awaitCount()
                         throws ThreadInterruptedException

Caller will wait until the thread barrier is released, situation in which all waiting threads are awakened.

Postcondition:

count() == old(count())+ 1

Returns:

the current barrier count

Throws:

ThreadInterruptedException

count

public long count()

Number of times the barrier was released (to be more precise: the remainder of the integer division for 2^63)

Returns:

the current barrier count