=> * * @var array */ private array $listeners = []; /** * Dispatches an event to all registered listeners. * * @param 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. * @param EventArgs|null $eventArgs The event arguments to pass to the event handlers/listeners. * If not supplied, the single empty EventArgs instance is used. */ public function dispatchEvent(string $eventName, EventArgs|null $eventArgs = null): void { if (! isset($this->listeners[$eventName])) { return; } $eventArgs ??= EventArgs::getEmptyInstance(); foreach ($this->listeners[$eventName] as $listener) { $listener->$eventName($eventArgs); } } /** * Gets the listeners of a specific event. * * @param string $event The name of the event. * * @return object[] */ public function getListeners(string $event): array { return $this->listeners[$event] ?? []; } /** * Gets all listeners keyed by event name. * * @return array The event listeners for the specified event, or all event listeners. */ public function getAllListeners(): array { return $this->listeners; } /** * Checks whether an event has any registered listeners. */ public function hasListeners(string $event): bool { return ! empty($this->listeners[$event]); } /** * Adds an event listener that listens on the specified events. * * @param string|string[] $events The event(s) to listen on. * @param object $listener The listener object. */ public function addEventListener(string|array $events, object $listener): void { // Picks the hash code related to that listener $hash = spl_object_hash($listener); foreach ((array) $events as $event) { // Overrides listener if a previous one was associated already // Prevents duplicate listeners on same event (same instance only) $this->listeners[$event][$hash] = $listener; } } /** * Removes an event listener from the specified events. * * @param string|string[] $events */ public function removeEventListener(string|array $events, object $listener): void { // Picks the hash code related to that listener $hash = spl_object_hash($listener); foreach ((array) $events as $event) { unset($this->listeners[$event][$hash]); } } /** * Adds an EventSubscriber. * * The subscriber is asked for all the events it is interested in and added * as a listener for these events. */ public function addEventSubscriber(EventSubscriber $subscriber): void { $this->addEventListener($subscriber->getSubscribedEvents(), $subscriber); } /** * Removes an EventSubscriber. * * The subscriber is asked for all the events it is interested in and removed * as a listener for these events. */ public function removeEventSubscriber(EventSubscriber $subscriber): void { $this->removeEventListener($subscriber->getSubscribedEvents(), $subscriber); } }