PHP design mode single-instance mode

directly on the code;

<?PHPclasssinglecase{//declaring private variables  Private $name; //declaring static variables   Public Static $interest; //declaring private constructors to prevent external instantiation  Private function__construct () {//code ...  }  //External Call entry (static method)   Public Static functionenterance () {//determine if a $interest has a value    if(!self::$interest) Self::$interest=Newsinglecase (); //returns the current object    returnSelf::$interest; }  //single-mode test method to determine if internal methods can be successfully invoked   Public functionSetName ($n)  {    $this->name =$n; }   Public functiongetname () {return $this-name; }}//call the static method directly from the backdoor$a= Singlecase::enterance ();//passing values to the SetName function$a->setname ("singleton mode is complete."));Echo $a-getname ();$b= Singlecase::enterance ();if($a==$b) {  Echo"</br> is the same instance";} Else {  Echo"Not the same instance";}

Why use static member properties to store instances?

因为只有第一次实例化的时候才赋值、以后都直接给出静态实例。

PHP design mode single-instance mode