1: <?php
 2: 
 3: /*
 4:  * This file is part of the Symfony package.
 5:  *
 6:  * (c) Fabien Potencier <fabien@symfony.com>
 7:  *
 8:  * For the full copyright and license information, please view the LICENSE
 9:  * file that was distributed with this source code.
10:  */
11: 
12: namespace Symfony\Component\EventDispatcher;
13: 
14: /**
15:  * The EventDispatcherInterface is the central point of Symfony's event listener system.
16:  * Listeners are registered on the manager and events are dispatched through the
17:  * manager.
18:  *
19:  * @author Bernhard Schussek <bschussek@gmail.com>
20:  *
21:  * @api
22:  */
23: interface EventDispatcherInterface
24: {
25:     /**
26:      * Dispatches an event to all registered listeners.
27:      *
28:      * @param string $eventName The name of the event to dispatch. The name of
29:      *                          the event is the name of the method that is
30:      *                          invoked on listeners.
31:      * @param Event  $event     The event to pass to the event handlers/listeners.
32:      *                          If not supplied, an empty Event instance is created.
33:      *
34:      * @return Event
35:      *
36:      * @api
37:      */
38:     public function dispatch($eventName, Event $event = null);
39: 
40:     /**
41:      * Adds an event listener that listens on the specified events.
42:      *
43:      * @param string   $eventName The event to listen on
44:      * @param callable $listener  The listener
45:      * @param int      $priority  The higher this value, the earlier an event
46:      *                            listener will be triggered in the chain (defaults to 0)
47:      *
48:      * @api
49:      */
50:     public function addListener($eventName, $listener, $priority = 0);
51: 
52:     /**
53:      * Adds an event subscriber.
54:      *
55:      * The subscriber is asked for all the events he is
56:      * interested in and added as a listener for these events.
57:      *
58:      * @param EventSubscriberInterface $subscriber The subscriber.
59:      *
60:      * @api
61:      */
62:     public function addSubscriber(EventSubscriberInterface $subscriber);
63: 
64:     /**
65:      * Removes an event listener from the specified events.
66:      *
67:      * @param string   $eventName The event to remove a listener from
68:      * @param callable $listener  The listener to remove
69:      */
70:     public function removeListener($eventName, $listener);
71: 
72:     /**
73:      * Removes an event subscriber.
74:      *
75:      * @param EventSubscriberInterface $subscriber The subscriber
76:      */
77:     public function removeSubscriber(EventSubscriberInterface $subscriber);
78: 
79:     /**
80:      * Gets the listeners of a specific event or all listeners.
81:      *
82:      * @param string $eventName The name of the event
83:      *
84:      * @return array The event listeners for the specified event, or all event listeners by event name
85:      */
86:     public function getListeners($eventName = null);
87: 
88:     /**
89:      * Checks whether an event has any registered listeners.
90:      *
91:      * @param string $eventName The name of the event
92:      *
93:      * @return bool true if the specified event has any listeners, false otherwise
94:      */
95:     public function hasListeners($eventName = null);
96: }
97: