1: <?php
 2: /*
 3:  * Copyright (c) 2014 @trashtoy
 4:  * https://github.com/trashtoy/
 5:  * 
 6:  * Permission is hereby granted, free of charge, to any person obtaining a copy of
 7:  * this software and associated documentation files (the "Software"), to deal in
 8:  * the Software without restriction, including without limitation the rights to use,
 9:  * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
10:  * Software, and to permit persons to whom the Software is furnished to do so,
11:  * subject to the following conditions:
12:  * 
13:  * The above copyright notice and this permission notice shall be included in all
14:  * copies or substantial portions of the Software.
15:  * 
16:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17:  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
18:  * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
19:  * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
20:  * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21:  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22:  */
23: /**
24:  * PHP class file.
25:  * @auhtor trashtoy
26:  * @since  2.0.0
27:  */
28: namespace Peach\Markup;
29: 
30: /**
31:  * 「何もない」ことをあらわす Component です. (Null Object パターン)
32:  *
33:  * この Component は以下の特徴を持ちます.
34:  * 
35:  * - コンテナに append しても何も追加されない
36:  * - Context に処理させても何も行われない (ただし DebugContext を除く)
37:  */
38: class None implements Component
39: {
40:     /**
41:      * このクラスはインスタンス化できません.
42:      */
43:     private function __construct() {}
44:     
45:     /**
46:      * このクラスの唯一のインスタンスを返します.
47:      * @return None
48:      * @codeCoverageIgnore
49:      */
50:     public static function getInstance()
51:     {
52:         static $instance = null;
53:         if ($instance === null) {
54:             $instance = new self();
55:         }
56:         
57:         return $instance;
58:     }
59:     
60:     /**
61:      * 指定された Context にこのノードを処理させます.
62:      * {@link Context::handleNone()} を呼び出します.
63:      * @param Context $context
64:      */
65:     public function accept(Context $context)
66:     {
67:         $context->handleNone($this);
68:     }
69:     
70:     /**
71:      * 空の NodeList を返します.
72:      * 
73:      * @return Component 空の NodeList
74:      */
75:     public function getAppendee()
76:     {
77:         return new NodeList();
78:     }
79: }
80: