1<?php 2/* 3 * $Id: Null.php 7490 2010-03-29 19:53:27Z jwage $ 4 * 5 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 6 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 7 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 8 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 9 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 10 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 11 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 12 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 13 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 14 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 15 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 16 * 17 * This software consists of voluntary contributions made by many individuals 18 * and is licensed under the LGPL. For more information, see 19 * <http://www.doctrine-project.org>. 20 */ 21 22/** 23 * Doctrine_Null 24 * 25 * Simple empty class representing a null value 26 * used for extra fast null value testing with isset() rather than array_key_exists() 27 * 28 * @package Doctrine 29 * @subpackage Null 30 * @license http://www.opensource.org/licenses/lgpl-license.php LGPL 31 * @link www.doctrine-project.org 32 * @since 1.0 33 * @version $Revision: 7490 $ 34 * @author Konsta Vesterinen <kvesteri@cc.hut.fi> 35 */ 36final class Doctrine_Null 37{ 38 public function exists() 39 { 40 return false; 41 } 42 43 public function __toString() 44 { 45 return ''; 46 } 47}