JavaTM 2 Platform
Std. Ed. v1.4.1

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

Constructor Summary
ReferenceQueue()
          Constructs a new reference-object queue.
 
Method Summary
 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

JavaTM 2 Platform
Std. Ed. v1.4.1

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.