bool hasListeners(string $eventName = null) Checks whether an event has any registered listeners. Parameters string $eventName The name of the event Return Value bool true if the specified event has any listeners, false otherwise

array getListeners(string $eventName = null) Gets the listeners of a specific event or all listeners sorted by descending priority. Parameters string $eventName The name of the event Return Value array The event listeners for the specified event, or all event listeners by event name

int|null getListenerPriority(string $eventName, callable $listener) Gets the listener priority for a specific event. Returns null if the event or the listener does not exist. Parameters string $eventName The name of the event callable $listener The listener Return Value int|null The event listener priority

array getCalledListeners() Gets the called listeners. Return Value array An array of called listeners

addSubscriber(EventSubscriberInterface $subscriber) Adds an event subscriber. The subscriber is asked for all the events he is interested in and added as a listener for these events. Parameters EventSubscriberInterface $subscriber The subscriber.

addListener(string $eventName, callable $listener, int $priority) Adds an event listener that listens on the specified events. Parameters string $eventName The event to listen on callable $listener The listener int $priority The higher this value, the earlier an event listener will be triggered in the chain (defaults to 0)

Event dispatch(string $eventName, Event $event = null) Dispatches an event to all registered listeners. Parameters string $eventName The name of the event to dispatch. The name of the event is the name of the method that is invoked on listeners. Event $event The event to pass to the event handlers/listeners. If not supplied, an empty Event instance is created. Return Value Event

class TraceableEventDispatcher extends TraceableEventDispatcher Collects some data about event listeners. This event dispatcher delegates the dispatching to another one. Methods __construct(EventDispatcherInterface $dispatcher, Stopwatch $stopwatch, LoggerInterface $logger = null) Constructor. from TraceableEventDispatcher addListener(string $eventName, callable $listener, int $priority) Adds an event listener that listens on the specified events. from TraceableEventDispatcher ad

class TraceableEventDispatcher implements TraceableEventDispatcherInterface Collects some data about event listeners. This event dispatcher delegates the dispatching to another one. Methods __construct(EventDispatcherInterface $dispatcher, Stopwatch $stopwatch, LoggerInterface $logger = null) Constructor. addListener(string $eventName, callable $listener, int $priority) Adds an event listener that listens on the specified events. addSubscriber(EventSubscriberInterface $subscrib

array getArguments(Request $request, callable $controller) deprecated deprecated This method is deprecated as of 3.1 and will be removed in 4.0. Returns the arguments to pass to the controller. Parameters Request $request A Request instance callable $controller A PHP callable Return Value array An array of arguments to pass to the controller Exceptions RuntimeException When value for argument given is not provided