<?php
declare(strict_types=1);
namespace Doctrine\Common;
use function spl_object_hash;
/**
* The EventManager is the central point of Doctrine's event listener system.
* Listeners are registered on the manager and events are dispatched through the
* manager.
*/
class EventManager
{
/**
* Map of registered listeners.
* <event> => <listeners>
*
* @var array<string, object[]>
*/
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<string, object[]> 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);
}
}