public class ReferenceQueue<T>
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

  Constructors 

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

• Method Summary

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

  Methods declared in class java.lang.Object

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

• Constructor Details

  • ReferenceQueue

    public ReferenceQueue()

    Constructs a new reference-object queue.

• Method Details

  • 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

    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 to 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

    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