public void signal(){
  Thread t=ownerAccess.getAndSet(this,null);
  if (t != null) {
    LockSupport.unpark(t);
  }
}

public void signal ( ) { Thread t = ownerAccess . getAndSet ( this , null ) ; if ( t != null ) { LockSupport . unpark ( t ) ; } }
signal the owner that the barrier is ready . this has no effect if the signalbarrer is unowned .
