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}