upstream / includes / trait-up-singleton.php

trait-up-singleton.php in UpStream: a Project Management Plugin for WordPress 2.1.0, at includes/trait-up-singleton.php

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1	<?php
2	/**
3	* Trait that abstracts the Singleton design pattern.
4	*
5	* @package UpStream\Traits
6	*/
7
8	namespace UpStream\Traits;
9
10	// Prevent direct access.
11	if ( ! defined( 'ABSPATH' ) ) {
12	exit;
13	}
14
15	/**
16	* Trait that abstracts the Singleton design pattern.
17	*
18	* @package UpStream
19	* @subpackage Traits
20	* @author UpStream <https://upstreamplugin.com>
21	* @copyright Copyright (c) 2018 UpStream Project Management
22	* @license GPL-3
23	* @since 1.11.0
24	*/
25	trait Singleton {
26
27	/**
28	* The singleton class's instance.
29	*
30	* @var \ReflectionClass
31	*
32	* @since 1.11.0
33	* @access private
34	* @static
35	*/
36	private static $instance = null;
37
38	/**
39	* Retrieve the singleton instance.
40	* If the singleton it's not loaded, it will be initialized first.
41	*
42	* @since 1.11.0
43	* @static
44	*
45	* @return \ReflectionClass
46	*/
47	public static function getInstance() { // phpcs:ignore
48	// Ensure the singleton is loaded.
49	self::instantiate();
50
51	return self::$instance;
52	}
53
54	/**
55	* Initializes the singleton if it's not loaded yet.
56	*
57	* @since 1.11.0
58	* @static
59	* @final
60	*
61	* @uses \ReflectionClass
62	*/
63	final public static function instantiate() {
64	if ( empty( self::$instance ) ) {
65	$reflection = new \ReflectionClass( __CLASS__ );
66	self::$instance = $reflection->newInstanceArgs( func_get_args() );
67	}
68	}
69
70	/**
71	* Prevent the class instance being serialized.
72	*
73	* @since 1.11.0
74	* @final
75	*
76	* @throws \Exception Exception.
77	*/
78	final public function __sleep() {
79	throw new \Exception( 'You cannot serialize a singleton.' );
80	}
81
82	/**
83	* Prevent the class instance being unserialized.
84	*
85	* @since 1.11.0
86	* @final
87	*
88	* @throws \Exception Exception.
89	*/
90	final public function __wakeup() {
91	throw new \Exception( 'You cannot unserialize a singleton.' );
92	}
93
94	/**
95	* Prevent the class instance being cloned.
96	*
97	* @since 1.11.0
98	* @final
99	*/
100	final public function __clone() {
101	// Do nothing.
102	}
103	}
104