edu.rice.hj.runtime.util

Class ModCountDownLatch

java.lang.Object

edu.rice.hj.runtime.util.ModCountDownLatch

public class ModCountDownLatch
extends Object

Extension of JCU CountDownLatch to allow for increments (so as to support finish).

Author:

Raj Barik, Vivek Sarkar

Constructor Summary

Constructors

Constructor and Description
ModCountDownLatch(int count) Constructs a CountDownLatch initialized with the given count.

Method Summary

Modifier and Type	Method and Description
void	await() Causes the current thread to wait until the latch has counted down to zero, unless the thread is interrupted.
boolean	await(long timeout, TimeUnit unit) Causes the current thread to wait until the latch has counted down to zero, unless the thread is interrupted, or the specified waiting time elapses.
void	countDown() Decrements the count of the latch, releasing all waiting threads if the count reaches zero.
long	getCount() Returns the current count.
String	toString() Returns a string identifying this latch, as well as its state.
void	updateCount() Updates the counter of the synch variable dynamically Update only if the counter value is > 0

Methods inherited from class java.lang.Object

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

Constructor Detail

ModCountDownLatch

public ModCountDownLatch(int count)

Constructs a CountDownLatch initialized with the given count.

Parameters:

count - the number of times countDown() must be invoked before threads can pass through await().

Throws:

IllegalArgumentException - if count is less than zero.

Method Detail

await

public void await()
           throws InterruptedException

Causes the current thread to wait until the latch has counted down to zero, unless the thread is interrupted.

If the current count is zero then this method returns immediately.

If the current count is greater than zero then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of two things happen:

• The count reaches zero due to invocations of the countDown() method; or
• Some other thread interrupts the current thread.

If the current thread:

• has its interrupted status set on entry to this method; or
• is interrupted while waiting,

then InterruptedException is thrown and the current thread's interrupted status is cleared.

Throws:

InterruptedException - if the current thread is interrupted while waiting.

await

public boolean await(long timeout,
                     TimeUnit unit)
              throws InterruptedException

Causes the current thread to wait until the latch has counted down to zero, unless the thread is interrupted, or the specified waiting time elapses.

If the current count is zero then this method returns immediately with the value true.

If the current count is greater than zero then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of three things happen:

• The count reaches zero due to invocations of the countDown() method; or
• Some other thread interrupts the current thread; or
• The specified waiting time elapses.

If the count reaches zero then the method returns with the value true.

If the current thread:

• has its interrupted status set on entry to this method; or
• is interrupted while waiting,

then InterruptedException is thrown and the current thread's interrupted status is cleared.

If the specified waiting time elapses then the value false is returned. If the time is less than or equal to zero, the method will not wait at all.

Parameters:

timeout - the maximum time to wait

unit - the time unit of the timeout argument.

Returns:

true if the count reached zero and false if the waiting time elapsed before the count reached zero.

Throws:

InterruptedException - if the current thread is interrupted while waiting.

countDown

public void countDown()

Decrements the count of the latch, releasing all waiting threads if the count reaches zero.

If the current count is greater than zero then it is decremented. If the new count is zero then all waiting threads are re-enabled for thread scheduling purposes.

If the current count equals zero then nothing happens.

updateCount

public void updateCount()

Updates the counter of the synch variable dynamically Update only if the counter value is > 0

getCount

public long getCount()

Returns the current count.

This method is typically used for debugging and testing purposes.

Returns:

the current count.

toString

public String toString()

Returns a string identifying this latch, as well as its state. The state, in brackets, includes the String "Count =" followed by the current count.

Overrides:

toString in class Object

Returns:

a string identifying this latch, as well as its state