|
| 1 | +..index:: |
| 2 | + single: EventDispatcher; Debug |
| 3 | + single: EventDispatcher; Traceable |
| 4 | + |
| 5 | +The Traceable Event Dispatcher |
| 6 | +============================== |
| 7 | + |
| 8 | +The:class:`Symfony\\Component\\HttpKernel\\Debug\\TraceableEventDispatcher` |
| 9 | +is an event dispatcher that wraps any other event dispatcher and can then |
| 10 | +be used to determine which event listeners have been called by the dispatcher. |
| 11 | +Pass the event dispatcher to be wrapped and an instance of the |
| 12 | +:class:`Symfony\\Component\\Stopwatch\\Stopwatch` to its constructor:: |
| 13 | + |
| 14 | + use Symfony\Component\HttpKernel\Debug\TraceableEventDispatcher; |
| 15 | + use Symfony\Component\Stopwatch\Stopwatch; |
| 16 | + |
| 17 | + // the event dispatcher to debug |
| 18 | + $eventDispatcher = ...; |
| 19 | + |
| 20 | + $traceableEventDispatcher = new TraceableEventDispatcher($eventDispatcher, new Stopwatch()); |
| 21 | + |
| 22 | +Now, the ``TraceableEventDispatcher`` can be used like any other event dispatcher |
| 23 | +to register event listeners and dispatch events:: |
| 24 | + |
| 25 | + // ... |
| 26 | + |
| 27 | + // register an event listener |
| 28 | + $eventListener = ...; |
| 29 | + $priority = ...; |
| 30 | + $traceableEventDispatcher->addListener('the-event-name', $eventListener, $priority); |
| 31 | + |
| 32 | + // dispatch an event |
| 33 | + $event = ...; |
| 34 | + $traceableEventDispatcher->dispatch('the-event-name', $event); |
| 35 | + |
| 36 | +After your application has been processed, you can use the |
| 37 | +:method:`Symfony\\Component\\EventDispatcher\\Debug\\TraceableEventDispatcherInterface::getCalledListeners` |
| 38 | +method to retrieve an array of event listeners that have been called in your |
| 39 | +application. Similarly, the |
| 40 | +:method:`Symfony\\Component\\EventDispatcher\\Debug\\TraceableEventDispatcherInterface::getNotCalledListeners` |
| 41 | +method returns an array of event listeners that have not been called:: |
| 42 | + |
| 43 | + // ... |
| 44 | + |
| 45 | + $calledListeners = $traceableEventDispatcher->getCalledListeners(); |
| 46 | + $notCalledListeners = $traceableEventDispatcher->getNotCalledListeners(); |