com.atlassian.utt.concurrency

Class Sync

java.lang.Object

com.atlassian.utt.concurrency.Sync

public class Sync
extends Object

A simple synchronization point for coordinating two or more test threads.

This is just a CyclicBarrier, but with timeouts and exceptions built in that are more suitable for writing tests.

This establishes that everything before the sync() in every associated thread happens-before everything after it. Two of them in a row therefore usually signifies one thread handing control over to another, then waiting to receive control back again. This can be used instead of a series of barriers to repeatedly exchange control between two or more threads. For example, these two threads would print the numbers 1 through 5 in order:

     // in thread 1
     System.out.println(1);
     sync.sync();   // Sync A: thread1 => thread2
     sync.sync();   // Sync B: thread1 <= thread2
     System.out.println(3);
     sync.sync();   // Sync C: thread1 => thread2
     sync.sync();   // Sync D: thread1 <= thread2
     System.out.println(5);

     // in thread 2
     sync.sync();   // Sync A: thread1 => thread2
     System.out.println(2);
     sync.sync();   // Sync B: thread1 <= thread2
     sync.sync();   // Sync C: thread1 => thread2
     System.out.println(4);
     sync.sync();   // Sync D: thread1 <= thread2
 

You can also create a Sync with more than two parties for coordinating the flow of control among even more threads, but a series of barriers would probably be easier to understand for that.

Since:

v0.0.1

Constructor Summary

Constructors

Constructor and Description
Sync() Creates a thread synchronization point to coordinate 2 threads.
Sync(int parties) Creates a thread synchronization point to coordinate the given number of threads.

Method Summary

Modifier and Type	Method and Description
void	sync() Synchronizes the threads using Barrier.getDefaultTimeout() as the timeout.
void	sync(long millis) Synchronizes the threads using the specified timeout in milliseconds.
void	sync(long timeout, TimeUnit units) Synchronizes the threads using the specified timeout.

Methods inherited from class java.lang.Object

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

Constructor Detail

Sync

public Sync()

Creates a thread synchronization point to coordinate 2 threads.

Sync

public Sync(int parties)

Creates a thread synchronization point to coordinate the given number of threads.

Parameters:

parties - the number of threads that must reach the synchronization point to satisfy the barrier

Method Detail

sync

public void sync()

Synchronizes the threads using Barrier.getDefaultTimeout() as the timeout.

sync

public void sync(long millis)

Synchronizes the threads using the specified timeout in milliseconds.

Parameters:

millis - the timeout, in milliseconds

sync

public void sync(long timeout,
                 TimeUnit units)

Synchronizes the threads using the specified timeout.

Parameters:

timeout - the timeout

units - the unit of time in which the timeout is specified