PHP设计模式之状态模式(State)代码实例大全(29)
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。
UML图
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();
}
}
测试
- Tests/StateTest.php
<?php
namespace DesignPatterns\Behavioral\State\Tests;
use DesignPatterns\Behavioral\State\ContextOrder;
use DesignPatterns\Behavioral\State\CreateOrder;
use DesignPatterns\Behavioral\State\ShippingOrder;
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 ShippingOrder();
$contextOrder = new ContextOrder();
$contextOrder->setState($order);
$contextOrder->done();
$this->assertEquals('completed', $contextOrder->getStatus());
}
}
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