what is Singleton in PHP
what is Singleton in PHP
What is Singleton? explain with PHP example
In SIngleton design pattern
Only a single object will be created and i.e available all across the application.
Singleton Pattern ensures that a class has only one instance and provides a global point to access it. It ensures that only one object is available all across the application in a controlled state. Singleton pattern provides a way to access its only object which can be accessed directly without the need to instantiate the object of the class.
xxxxxxxxxx// General singleton class.class Singleton { // Hold the class instance. private static $instance = null; // The constructor is private // to prevent initiation with outer code. private function __construct() { // The expensive process (e.g.,db connection) goes here. } // The object is created from within the class itself // only if the class has no instance. public static function getInstance() { if (self::$instance == null) { self::$instance = new Singleton(); } return self::$instance; }}// sesond example:<?php class database { public static $connection; private function __construct(){ echo "connection created"; } public function connect(){ if(!isset(self::$connection)){ self::$connection = new database(); } return self::$connection; } } $db = database::connect(); //$db2 = database::connect(); //will not work if we try to initiate object again.?>Source: Grepper
Closely Related Answers
xxxxxxxxxx<?php/*singleton design pattern should haveprivate static variableprivate constructor methodpublic static method return class single instance */class clsSingleTon{ private static $conn=null; private function __construct() { print "Instance Created \n"; } public static function setConn() { if(self::$conn == null) { self::$conn = new static(); }else{ print "Instance Already Created \n"; } return self::$conn; }}$obj = clsSingleTon::setConn();//$obj = clsSingleTon::setConn(); //if we create second Instance then it will say already created ?>Source: onecompiler.com
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