PHP设计模式 单例模式与工厂模式

//设计模式
//1、单例
//类的计划生育
//1、让该类在外界无法造对象
//2、让外界可以造一个对象，做一个静态方法返回对象
//3、在类里面通过静态变量控制 只有一个

class Cat{
    public $name;

    private function __construct()
    {
    }

    static $temp;
    static function new_ob(){
        if(empty(self::$temp)){
            self::$temp = new Cat();
        }
        return self::$temp;
    }

    function speak(){
        return"喵喵喵喵喵";
    }
}

$mao = Cat::new_ob();
$mao2 = Cat::new_ob();

$mao->name = "abc";
echo $mao2->name;



//$mao;
//if(empty($mao)){
//    $mao = new Cat();
//}
//
//$xxx = $mao;



//工厂模式
//class Jsq
//{
//    public $a;
//    public $b;
//
//    public function jiafa(){
//        return $this->a + $this->b;
//    }
//}

abstract class Jsq{
    public $a;
    public $b;
    function yunsuan(){

    }
}

class Jiafa extends Jsq{
    function yunsuan(){
        return $this->a + $this->b;
    }
}
class Jianfa extends Jsq{
    function yunsuan(){
        return $this->a - $this->b;
    }
}
//$j1 = new jiafa();
//$j1->a = 1;
//$j1->b = 2;
//$j1->yunsuan();

class Factory{
    static function creat($x){
        switch ($x){
            case "+":
                return new Jiafa();
                break;
            case "-":                return new Jianfa();                break;        }    }}$jf = Factory::creat("+");$jf->a = 1;$jf->b = 2;echo $jf->yunsuan();