状态模式（State）

向右看齐 2022-05-15 14:21 212阅读 0赞

*  [3.9.1. 目的][3.9.1.]
 *  [3.9.2. UML 类图][3.9.2. UML]
 *  [3.9.3. 代码][3.9.3.]
 *  [3.9.4. 测试][3.9.4.]

## 3.9.1. 目的 ##

状态模式可以基于一个对象的同种事务而封装出不同的行为。它提供一种简洁的方式使得对象在运行时可以改变自身行为，而不必借助单一庞大的条件判断语句。

## 3.9.2. UML 类图 ##

![file][]

## 3.9.3. 代码 ##

你可以在  [GitHub][] 上找到这些代码

ContextOrder.php

<?php
    
    namespace DesignPatterns\Behavioral\State;
    
    class ContextOrder extends StateOrder
    {
        public function getState():StateOrder
        {
            return static::$state;
        }
    
        public function setState(StateOrder $state)
        {
            static::$state = $state;
        }
    
        public function done()
        {
            static::$state->done();
        }
    
        public function getStatus(): string
        {
            return static::$state->getStatus();
        }
    }

StateOrder.php

<?php
    
    namespace DesignPatterns\Behavioral\State;
    
    abstract class StateOrder
    {
        /**
         * @var array
         */
        private $details;
    
        /**
         * @var StateOrder $state
         */
        protected static $state;
    
        /**
         * @return mixed
         */
        abstract protected function done();
    
        protected function setStatus(string $status)
        {
            $this->details['status'] = $status;
            $this->details['updatedTime'] = time();
        }
    
        protected function getStatus(): string
        {
            return $this->details['status'];
        }
    }

ShippingOrder.php

<?php
    
    namespace DesignPatterns\Behavioral\State;
    
    class ShippingOrder extends StateOrder
    {
        public function __construct()
        {
            $this->setStatus('shipping');
        }
    
        protected function done()
        {
            $this->setStatus('completed');
        }
    }

CreateOrder.php

<?php
    
    namespace DesignPatterns\Behavioral\State;
    
    class CreateOrder extends StateOrder
    {
        public function __construct()
        {
            $this->setStatus('created');
        }
    
        protected function done()
        {
            static::$state = new ShippingOrder();
        }
    }

## 3.9.4. 测试 ##

Tests/StateTest.php

<?php
    
    namespace DesignPatterns\Behavioral\State\Tests;
    
    use DesignPatterns\Behavioral\State\ContextOrder;
    use DesignPatterns\Behavioral\State\CreateOrder;
    use PHPUnit\Framework\TestCase;
    
    class StateTest extends TestCase
    {
        public function testCanShipCreatedOrder()
        {
            $order = new CreateOrder();
            $contextOrder = new ContextOrder();
            $contextOrder->setState($order);
            $contextOrder->done();
    
            $this->assertEquals('shipping', $contextOrder->getStatus());
        }
    
        public function testCanCompleteShippedOrder()
        {
            $order = new CreateOrder();
            $contextOrder = new ContextOrder();
            $contextOrder->setState($order);
            $contextOrder->done();
            $contextOrder->done();
    
            $this->assertEquals('completed', $contextOrder->getStatus());
        }
    }

参考文献：

[http://bbs.yii-china.com/doc/detail?id=390][http_bbs.yii-china.com_doc_detail_id_390]

[3.9.1.]: http://bbs.yii-china.com/doc/detail?id=390#1
[3.9.2. UML]: http://bbs.yii-china.com/doc/detail?id=390#2
[3.9.3.]: http://bbs.yii-china.com/doc/detail?id=390#3
[3.9.4.]: http://bbs.yii-china.com/doc/detail?id=390#4
[file]: https://lccdn.phphub.org/uploads/images/201803/19/1/rkjnhCggA4.png
[GitHub]: https://github.com/domnikl/DesignPatternsPHP/tree/master/Behavioral/State
[http_bbs.yii-china.com_doc_detail_id_390]: http://bbs.yii-china.com/doc/detail?id=390