name : EventListens.php <?php /** * Hoa * * * @license * * New BSD License * * Copyright © 2007-2017, Hoa community. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * Neither the name of the Hoa nor the names of its contributors may be * used to endorse or promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ namespace Psy\Readline\Hoa; /** * Implementation of a listener. */ trait EventListens { /** * Listener instance of type `Hoa\Event\Listener`. */ protected $_listener = null; /** * Attaches a callable to a listenable component. */ public function on(string $listenerId, $callable): EventListenable { $listener = $this->getListener(); if (null === $listener) { throw new EventException('Cannot attach a callable to the listener %s because '.'it has not been initialized yet.', 0, static::class); } $listener->attach($listenerId, $callable); return $this; } /** * Sets a new listener. */ protected function setListener(EventListener $listener) { $old = $this->_listener; $this->_listener = $listener; return $old; } /** * Returns the listener. */ protected function getListener() { return $this->_listener; } }