工厂类中有一个创建对象的方法,根据传入参数的不同来生成不同的对象

class Operation extends Model
{

    private   $numberA;
    private   $numberB;

    public function getResult(){

        $result = 0;

        return $result;

    }

    public  function getNumberA(){

        return $this->numberA;
    }
    public  function  setNumberA($numberA){

        $this->numberA = $numberA;

    }

    public  function getNumberB(){

        return $this->numberB;
    }
    public  function  setNumberB($numberB){

        $this->numberB = $numberB;

    }

}

class OperationAdd extends  Operation
{

    public  function  getResult()
    {
       $result =  0 ;

       $result = $this->numberA + $this->numberB;

       return $result;

    }

}

class OperationSub extends  Operation
{

    public  function  getResult()
    {
       $result = 0;

       $result = $this->numberA - $this->numberB;

       return $result;
    }

}

class OperationMul extends  Operation
{
    public  function getResult(){

        $result = 0;

        $result = $this->numberA  *  $this->numberB;

        return $result;

    }

}

class OperationDiv extends  Operation
{

public  function  getResult(){

    $result =  0;
    if ($this->numberA == 0){

        throw new HttpException("除数不能为0");
    }

    $result = $this->numberA  /  $this->numberB;

    return $result;
}

}

class Factory extends Model
{

     private  $type;

     public  function __construct($type,array $config = [])
     {
         $this->type = $type;
         parent::__construct($config);
     }

    public  function createOperate(){

switch ($this->type){
    case "+":

        return new OperationAdd();

        break;

    case "-":

        return new OperationSub();

        break;

    case  "*":

        return new OperationMul();
        break;

    case  "/":

        return new OperationDiv();
        break;

}

     }

}

$factory  = new Factory("+");

$operation = $factory->createOperate();

$operation->numberA = 2;

$operation->numberB = 1;

$result = $operation->getResult();

echo $result;