设计模式(一创建型模式)

单例模式: 作用范围内一个类只有一个它的实例

/**单例模式
 * 类里设计方法, 返回类的唯一实例
 */
class a{
    public $name ;
    private static $instance ;
    public function __construct($name){
        $this->name = $name ;
        echo "实例化";
    }
    public static function getInstances($name){
        if(!self::$instance){
            self::$instance = new a($name);
            return self::$instance ;
        }
        else return self::$instance ;
    }
}

$b =  a::getInstances(1);
echo $b->name ;
$b->getInstances(2);
echo $b->name ;

抽象工厂模式: 包括抽象工厂, 具体工厂 ; 抽象产品, 具体产品 . 将行为和事物本身分离 ; 将实例化操作再封装

/*抽象工厂模式*/
interface factory{
    function getOperator();
}


class addFactory implements factory{
    function getOperator(){
        return new addOperator();
    }
}

class subFactory implements factory{
    function getOperator(){
        return new subOperator();
    }
}

class operator{
    protected $num1 , $num2 ;
    function setNum($num1 , $num2){
        $this->num1 = $num1;
        $this->num2 = $num2;
    }
    function getResult(){
        echo null; 
    }
}

class addOperator extends operator
{
    function getResult()
    {
        echo ($this->num1 + $this->num2);
    }
}

class subOperator extends operator
{
    function getResult()
    {
        echo ($this->num1 - $this->num2);
    }
}



class client
{
    static function main()
    {
        $factory = new addFactory();
        $operator = $factory->getOperator();
        $operator->setNum(1,2);
        $operator->getResult();

        $factory = new subFactory();
        $operator = $factory->getOperator();
        $operator->setNum(1,2);
        $operator->getResult();
    }
}

client::main();

image.png

demo参考 : https://blog.csdn.net/clevercode/article/details/53044679