Field Detail

• valueAndFlags

  private final AtomicLong valueAndFlags

  Contains the number of outstanding operations, as well as flags. Initially, the number of operations is 1. Each beginOp increments, and endOp decrements it. beginOp does not proceed when it sees the draining flag. When stop is called, it atomically decrements the number of operations (the initial 1) and sets the draining flag. If stop did the decrement to zero, that means there are no more operations outstanding, so stop is done. Otherwise, stop blocks, and the endOp that decrements the count to 0 unblocks it.

• DRAINING_FLAG

  private static final long DRAINING_FLAG

  See Also:

  Constant Field Values

• FLAG_BIT_COUNT

  private static final int FLAG_BIT_COUNT

  See Also:

  Constant Field Values

Constructor Detail

• DrainBarrier

  public DrainBarrier()

Method Detail

• beginOp

  public boolean beginOp()

  Tries to start an operation.

  Returns:

  false iff the stop is in progress, and the operation cannot be started.

• endOp

  public void endOp()

  Ends the operation. Unblocks the blocked caller of stop, if necessary.

• stopAndDrainOps

  public void stopAndDrainOps()
                       throws InterruptedException

  Blocks new operations from starting, waits for the current ones to drain. If someone already called it, returns immediately, which is currently unavoidable as most of the users stop and close things right and left, and hope for the best. stopAndWaitForOpsOnce asserts instead.

  Throws:

  InterruptedException - the wait for operations has been interrupted.

• stopAndDrainOpsOnce

  public void stopAndDrainOpsOnce()
                           throws InterruptedException

  Blocks new operations from starting, waits for the current ones to drain. Can only be called once.

  Throws:

  InterruptedException - the wait for operations has been interrupted.

• stopAndDrainOps

  private void stopAndDrainOps(boolean ignoreRepeatedCalls)
                        throws InterruptedException

  Parameters:

  ignoreRepeatedCalls - If this is true and somebody already called stop, this method will return immediately if true; if this is false and somebody already called stop, it will assert.

  Throws:

  InterruptedException

• isDraining

  private static final boolean isDraining(long valueAndFlags)

• getValue

  private static final long getValue(long valueAndFlags)

• inc

  private static final long inc(long valueAndFlags)

• dec

  private static final long dec(long valueAndFlags)