Package com.qfs.util

Interface ILatch

All Known Implementing Classes:
Latch
public interface ILatch
Simple latch with dynamic increment/decrement.

The latch internal pending count is initialized to 'zero'. The activity associated with the latch can increment the count to register a sub task for instance, and decrement the count to signify the sub task is finished. A Latch to be registered as a quartet type to allow tracing.

Author:
ActiveViam

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    awaitCompletion()
    Wait until the latch is completed: when it is shutdown and the pending count reached zero.
    int
    decrement()
    Decrement the pending count (unregister a unit of activity).
    int
    getPending()
    Returns the pending count.
    int
    increment()
    Increment the pending count (register a unit of activity).
    boolean
    isCompleted()
    Returns true if the latch is completed (shutdown and pending count equal to zero).
    boolean
    isShutdown()
    Returns true if the latch is shutdown.
    void
    setCompletion(ICompletion completion)
    Set the completion method that should run when the latch is complete.
    The completion must be set before the latch is shutdown.
    void
    shutdown()
    Shut down the latch: the latch will not accept any additional increment and can only await its completion.

  • Method Details

    • getPending

      int getPending()
      Returns the pending count.
      Returns:
      the pending count

    • isShutdown

      boolean isShutdown()
      Returns true if the latch is shutdown.
      Returns:
      Whether the latch is shutdown

    • isCompleted

      boolean isCompleted()
      Returns true if the latch is completed (shutdown and pending count equal to zero).
      Returns:
      Whether the latch is completed

    • increment

      int increment()
      Increment the pending count (register a unit of activity).
      Returns:
      the incremented value

    • decrement

      int decrement() throws IllegalStateException
      Decrement the pending count (unregister a unit of activity). If the latch is shut down and this decrement brings the pending count to zero, then the optional completion is executed. If an exception is thrown by the completion, it will propagate through the decrement method.
      Returns:
      the decremented value
      Throws:
      IllegalStateException - if the actual pending count before decrementing is 0

    • awaitCompletion

      void awaitCompletion()
      Wait until the latch is completed: when it is shutdown and the pending count reached zero.

    • setCompletion

      void setCompletion(ICompletion completion)
      Set the completion method that should run when the latch is complete.
      The completion must be set before the latch is shutdown.
      Parameters:
      completion - the completion to set

    • shutdown

      void shutdown() throws IllegalStateException
      Shut down the latch: the latch will not accept any additional increment and can only await its completion. Following a shutdown the latch will be considered complete the pending count reaches zero.

      When the latch will be completed (later or right now) the (optional) completion continuation will be executed.

      If the pending count is already zero when shutdown is called, then the completion is executed immediately, and if the completion throws an exception it is thrown through the shutdown method.

      Throws:
      IllegalStateException - if trying to shutdown a terminated latch