计算器——简单工厂模式

1.目录结构

目录结构.png

2.工厂模式解析

待补充

3.计算基类

class BaseOperator
{
    private $num_1    =  null;
    private $num_2    =  null;

    public function setFirstNum($num)
    {
        $this->num_1   =  $num;
    }

    public function setSecondNum($num)
    {
        $this->num_2   =  $num;
    }

    public function getFirstNum()
    {
        return $this->num_1;
    }

    public function getSecondNum()
    {
        return $this->num_2;
    }
}

4.计算接口类

interface InterfaceOperator
{
    function doOperate();
}

5.计算类

include_once './BaseOperator.php';
include_once './InterfaceOperator.php';

class ActionAdd extends BaseOperator implements InterfaceOperator
{
    // 加法
    public function doOperate()
    {
        $result   =  null;
        $num_1    =  parent::getFirstNum();
        $num_2    =  parent::getSecondNum();
        $result   =  $num_1 + $num_2;
        return $result;
    }
}

class ActionSub extends BaseOperator implements InterfaceOperator
{
    // 减法
    public function doOperate()
    {
        $result    =  null;
        $num_1     =  parent::getFirstNum();
        $num_2     =  parent::getSecondNum();
        $result    =  $num_1 - $num_2;
        return $result;
    }
}

class ActionDiv extends BaseOperator implements InterfaceOperator
{
    // 除法
    public function doOperate()
    {
        $result    =  null;
        $num_1     =  parent::getFirstNum();
        $num_2     =  parent::getSecondNum();
        if ($num_2 == 0) {
            throw new \Exception('Number invalid', '2202');
        }
        $result    =  $num_1 / $num_2;
        return $result;
    }
}

class ActionMul extends BaseOperator implements InterfaceOperator
{
    // 乘法
    public function doOperate()
    {
        $result    =  null;
        $num_1     =  parent::getFirstNum();
        $num_2     =  parent::getSecondNum();
        $result    =  $num_1 * $num_2;
        return $result;
    }
}

6.计算工厂类

include_once './FunctionOperator.php';

class FactoryOperator
{

    /**
     * @param $operation
     * @return ActionAdd|ActionDiv|ActionMul|ActionSub
     * @throws Exception
     */
    public static function factory($operation)
    {
        switch($operation)
        {
            case "+":
                $operator    =  new ActionAdd();
                break;
            case "-":
                $operator    =  new ActionSub();
                break;
            case "*":
                $operator    =  new ActionMul();
                break;
            case "/":
                $operator    =  new ActionDiv();
                break;
            default:
                throw new \Exception('Operation invalid', '2202');
                break;
        }
        return $operator;
    }
}

6.模拟

include_once './FactoryOperator.php';
try {
    $operator    =  FactoryOperator::factory('*');
    $operator->setFirstNum(4);
    $operator->setSecondNum(2);
    $result      =  $operator->doOperate();
    echo "Result is $result";
} catch (\Exception $e) {
    echo $e->getTraceAsString();
}

效果.png

7.感想

通过分层达到了解耦的目的。感觉越高级的东西就有越多的分层，在分层的道路上越走越远。
工厂类的左右是实例化一个对象，也仅仅是实例化一个对象。其他属性不要在工厂类里面进行设置，而是在实例化之后进行设置（setFirstNum...）。