responsive-menu / v4.0.0 / inc / traits / trait-singleton.php

trait-singleton.php in Responsive Menu – Mobile Menu & Hamburger Menu Builder 4.7.4, at v4.0.0/inc/traits/trait-singleton.php

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1	<?php
2	/**
3	* Singleton trait which implements Singleton pattern in any class in which this trait is used.
4	*
5	* Using the singleton pattern in WordPress is an easy way to protect against
6	* mistakes caused by creating multiple objects or multiple initialization
7	* of classes which need to be initialized only once.
8	*
9	* With complex plugins, there are many cases where multiple copies of
10	* the plugin would load, and action hooks would load (and trigger) multiple
11	* times.
12	*
13	* If you're planning on using a global variable, then you should implement
14	* this trait. Singletons are a way to safely use globals; they let you
15	* access and set the global from anywhere, without risk of collision.
16	*
17	* If any method in a class needs to be aware of "state", then you should
18	* implement this trait in that class.
19	*
20	* If any method in the class need to "talk" to another or be aware of what
21	* another method has done, then you should implement this trait in that class.
22	*
23	* If you specifically need multiple objects, then use a normal class.
24	*
25	* @package responsive-menu
26	*/
27
28	namespace RMP\Features\Inc\Traits;
29
30	trait Singleton {
31
32	/**
33	* Protected class constructor to prevent direct object creation
34	*
35	* This is meant to be overridden in the classes which implement
36	* this trait. This is ideal for doing stuff that you only want to
37	* do once, such as hooking into actions and filters, etc.
38	*/
39	protected function __construct() {
40	}
41
42	/**
43	* Prevent object cloning
44	*/
45	final protected function __clone() {
46	}
47
48	/**
49	* This method returns new or existing Singleton instance
50	* of the class for which it is called. This method is set
51	* as final intentionally, it is not meant to be overridden.
52	*
53	* @return object Singleton instance of the class.
54	*/
55	final public static function get_instance() {
56
57	/**
58	* Collection of instance.
59	*
60	* @var array
61	*/
62	static $instance = array();
63
64	/**
65	* If this trait is implemented in a class which has multiple
66	* sub-classes then static::$_instance will be overwritten with the most recent
67	* sub-class instance. Thanks to late static binding
68	* we use get_called_class() to grab the called class name, and store
69	* a key=>value pair for each `classname => instance` in self::$_instance
70	* for each sub-class.
71	*/
72	$called_class = get_called_class();
73
74	if ( ! isset( $instance[ $called_class ] ) ) {
75
76	$instance[ $called_class ] = new $called_class();
77
78	/**
79	* Dependent items can use the RMP_features_singleton_init_{$called_class} hook to execute code
80	*/
81	do_action( sprintf( 'rmp_features_singleton_init_%s', $called_class ) );
82
83	}
84
85	return $instance[ $called_class ];
86
87	}
88
89	}
90