java.lang.ref

Class ReferenceQueue

java.lang.Object

java.lang.ref.ReferenceQueue

public class ReferenceQueue
extends Object

Reference queues, to which registered reference objects are appended by the garbage collector after the appropriate reachability changes are detected.

Since:

1.2

Version:

1.17 10/31/00

Author:

Mark Reinhold

Constructor Summary

Constructors

Constructor and Description
ReferenceQueue() Constructs a new reference-object queue.

Method Summary

Methods

Modifier and Type	Method and Description
Reference	poll() Polls this queue to see if a reference object is available.
Reference	remove() Removes the next reference object in this queue, blocking until one becomes available.
Reference	remove(long timeout) Removes the next reference object in this queue, blocking until either one becomes available or the given timeout period expires.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReferenceQueue

public ReferenceQueue()

Constructs a new reference-object queue.

Method Detail

poll

public Reference poll()

Polls this queue to see if a reference object is available. If one is available without further delay then it is removed from the queue and returned. Otherwise this method immediately returns null.

Returns:

A reference object, if one was immediately available, otherwise null

remove

public Reference remove(long timeout)
                 throws IllegalArgumentException,
                        InterruptedException

Removes the next reference object in this queue, blocking until either one becomes available or the given timeout period expires.

This method does not offer real-time guarantees: It schedules the timeout as if by invoking the Object.wait(long) method.

Parameters:

timeout - If positive, block for up timeout milliseconds while waiting for a reference to be added to this queue. If zero, block indefinitely.

Returns:

A reference object, if one was available within the specified timeout period, otherwise null

Throws:

IllegalArgumentException - If the value of the timeout argument is negative

InterruptedException - If the timeout wait is interrupted

remove

public Reference remove()
                 throws InterruptedException

Removes the next reference object in this queue, blocking until one becomes available.

Returns:

A reference object, blocking until one becomes available

Throws:

InterruptedException - If the wait is interrupted