| Interface Summary | 
| DequeueInterceptor | The dequeue executable interface describes operations that
 are executed before and after elements are pulled from a
 queue. | 
| EnqueuePredicate | Enqueue predicates allow users to specify a method that
 will 'screen' elements being enqueued onto a sink, either
 accepting or rejecting them. | 
| EventHandler | An EventHandlertakes care of processing specific events in
 an event-based architecture. | 
| Message | A Source implements the side of an event queue where queue elements are
 dequeued operations only. | 
| PreparedEnqueue | A PreparedEnqueueis an object returned from aprepareEnqueuemethod that allows you to either
 commit or abort the enqueue operation. | 
| Queue | A Source implements the side of an event queue where QueueElements are
 dequeued operations only. | 
| Signal | A Signal is a specific type of queue element that denotes a Control code for
 the Queue system. | 
| Sink | A Sink implements the end of a finite-length event queue where
 elements are enqueued. | 
| Source | A Source implements the side of an event queue where QueueElements are
 dequeued operations only. |