EventSubscriberInterface.php

<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\EventDispatcher;

/**
 * An EventSubscriber knows itself what events it is interested in.
 * If an EventSubscriber is added to an EventDispatcherInterface, the manager invokes
 * {@link getSubscribedEvents} and registers the subscriber as a listener for all
 * returned events.
 *
 * @author Guilherme Blanco <guilhermeblanco@hotmail.com>
 * @author Jonathan Wage <jonwage@gmail.com>
 * @author Roman Borschel <roman@code-factory.org>
 * @author Bernhard Schussek <bschussek@gmail.com>
 */
interface EventSubscriberInterface
{
    /**
     * Returns an array of event names this subscriber wants to listen to.
     *
     * The array keys are event names and the value can be:
     *
     *  * The method name to call (priority defaults to 0)
     *  * An array composed of the method name to call and the priority
     *  * An array with a "method" key and optional "priority", "before" and "after" ones;
     *    "before" and "after" only apply to subscribers registered as services
     *  * An array of any of the two array forms above, to register several
     *    listeners for the same event
     *
     * For instance:
     *
     *  * ['eventName' => 'methodName']
     *  * ['eventName' => ['methodName', $priority]]
     *  * ['eventName' => ['method' => 'methodName', 'priority' => $priority]]
     *  * ['eventName' => [['methodName1', $priority], ['methodName2']]]
     *  * ['eventName' => [['method' => 'methodName1'], ['method' => 'methodName2', 'priority' => $priority]]]
     *
     * The code must not depend on runtime state as it will only be called at compile time.
     * All logic depending on runtime state must be put into the individual methods handling the events.
     *
     * @return array<string, string|array{0: string, 1?: int}|array{method: string, priority?: int, before?: string|list<string>, after?: string|list<string>}|list<array{0: string, 1?: int}|array{method: string, priority?: int, before?: string|list<string>, after?: string|list<string>}>>
     */
    public static function getSubscribedEvents(): array;
}