工厂模式之简单计算器的实现

<?php
abstract class  operation{
	public $num1;
	public $num2;	

	public function setNum1($num1){
		$this->num1 = $num1;
	}

	public function setNum2($num2){
		$this->num2 = $num2;
	}

	public function getResult(){
		return null;
	}
}

class add extends operation{
	public function getResult(){
		return $this->num1+$this->num2;
	}
}

class mul extends operation{
	public function getResult(){
		return $this->num1*$this->num2;
	}
}


class Factory{
	public static function setOpratory($type){
		switch($type){
			case '+':
				return new add();
				break;
			case '*':
				return new mul();
				break;
			default:
				return null;
				break;
		}
	}
}

$cal = Factory::setOpratory('*');
$cal->setNum1(4);
$cal->setNum2(2);
$result = $cal->getResult();