java.lang.ref

Class ReferenceQueue<T>


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

    • Method Summary

      Modifier and Type Method and 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.

    • Constructor Detail

      • ReferenceQueue

        public ReferenceQueue()
        Constructs a new reference-object queue.

    • Method Detail

      • poll

        public Reference<? extends T> 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<? extends T> 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 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

        public Reference<? extends T> 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