1: <?php
 2: /*
 3:  * Copyright (c) 2015 @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  2.2.0
27:  */
28: namespace Peach\Http\Header;
29: 
30: use Peach\Http\HeaderField;
31: 
32: /**
33:  * 存在しない HeaderField をあらわします. (Null Object パターン)
34:  * 
35:  * この HeaderField の getName() および format() は空文字列を返します..
36:  */
37: class NoField implements HeaderField
38: {
39:     /**
40:      * このクラスを直接インスタンス化することはできません.
41:      */
42:     private function __construct() {}
43:     
44:     /**
45:      * 空文字列を返します.
46:      * 
47:      * @return string 空文字列
48:      */
49:     public function format()
50:     {
51:         return "";
52:     }
53:     
54:     /**
55:      * 空文字列を返します.
56:      * 
57:      * @return string 空文字列
58:      */
59:     public function getName()
60:     {
61:         return "";
62:     }
63:     
64:     /**
65:      * このフィールドは値を持たないため null を返します.
66:      * @return null
67:      */
68:     public function getValue()
69:     {
70:         return null;
71:     }
72:     
73:     /**
74:      * このクラスの唯一のインスタンスを返します.
75:      * @return NoField 唯一の NoField インスタンス
76:      * @codeCoverageIgnore
77:      */
78:     public static function getInstance()
79:     {
80:         static $instance = null;
81:         if ($instance === null) {
82:             $instance = new self();
83:         }
84:         return $instance;
85:     }
86: 
87: }
88: