Factory工厂模式复习

工厂设计模式 用于创建多种类型的多个实例对象

class Factory{
    //声明静态方法create,根据不同的形状，创建不同的图形类的实例
    public static function create($type,array $size=[]) {
        //检测形状
        switch ($type) {
            //长方形
            case 'rectangle': 
                return new Rectangle($size[0],$size[1]);
            break;
            //三角形
            case 'triangle':
                return new Triangle($size[0],$size[1]);
            break;
        }
    }
}
//声明长方形类
class Rectangle{
    private $width;
    private $height;
    public function __construct($width,$height) {
        $this->height = $height;
        $this->width = $width;
    }
    public function area() {
        return $this->width * $this->height;
    }
}
//声明三角形类
class Triangle{
    private $bottom;  //底边
    private $height;  //边长
    public function __construct($bottom,$height){
        $this->bottom = $bottom;
        $this->height = $height;
    }
    //计算三角形面积:  (底 * 高) / 2
    public function area() {
        return ($this->bottom * $this->height)/2;
    }
}

//使用静态方法来实例化形状类,而不是用传统的new 关键字
//并根据形状类型参数的不同,来实例化不同的类,生成不同的对象
$rectangle = Factory::create('rectangle',[10,30]);
echo '长方形面积是'.$rectangle->area();
echo '<br>';
$triangle = Factory::create('triangle',[10,30]);
echo '三角形面试是'.$triangle->area();