Package com.yahoo.concurrent

Class EventBarrier

  • public class EventBarrier
extends java.lang.Object
    Reference implementation of the 'Incremental Minimal Event Barrier' algorithm. An event in this context is defined to be something that happens during a time interval. An event barrier is a time interval for which events may start before or end after, but not both. The problem solved by the algorithm is to determine the minimal event barrier starting at a given time. In other words; wait for the currently active events to complete. The most natural use of this algorithm would be to make a thread wait for events happening in other threads to complete.
    Author:
    Haavard Pettersen, Simon Thoresen Hult

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static interface  EventBarrier.BarrierWaiter
      Declares the interface required to wait for the detection of a minimal event barrier.

    • Constructor Summary

      Constructors 
      Constructor Description
      EventBarrier()
      At creation there are no active events and no pending barriers.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void completeEvent​(int token)
      Signal the completion of an event.
      boolean startBarrier​(EventBarrier.BarrierWaiter handler)
      Initiate the detection of the minimal event barrier starting now.
      int startEvent()
      Signal the start of an event.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • EventBarrier

        public EventBarrier()
        At creation there are no active events and no pending barriers.

    • Method Detail

      • startEvent

        public int startEvent()
        Signal the start of an event. The value returned from this method must later be passed to the completeEvent method when signaling the completion of the event.
        Returns:
        Opaque token identifying the started event.

      • completeEvent

        public void completeEvent​(int token)
        Signal the completion of an event. The value passed to this method must be the same as the return value previously obtained from the startEvent method. This method will signal the completion of all pending barriers that were completed by the completion of this event.
        Parameters:
        token - Opaque token identifying the completed event.

      • startBarrier

        public boolean startBarrier​(EventBarrier.BarrierWaiter handler)
        Initiate the detection of the minimal event barrier starting now. If this method returns false it means that no events were currently active and the minimal event barrier was infinitely small. If this method returns false the handler will not be notified of the completion of the barrier. If this method returns true it means that the started barrier is pending and that the handler passed to this method will be notified of its completion at a later time.
        Parameters:
        handler - Handler notified of the completion of the barrier.
        Returns:
        True if a barrier was started, false if no events were active.