php - 使用 Doctrine ORM 实现状态模式

Question

我有一个使用状态模式的类。这是一个简单的例子

/**
 * @Enitity
 **/
class Door
{
  protected $id;
  protected $state;
  public function __construct($id, DoorState $state)
  public function setState(DoorState $state)
  {
    $this->state = $state;
  }
  public function close()
  {
    $this->setState($this->state->close())
  }
  ...
}

interface DoorState
{
  public function close;
  public function open;
  public function lock;
  public function unlock;
}

class DoorAction implements DoorState
{
  public function close()
  {
     throw new DoorError();
  }
  ...
}

然后是几个定义状态中适当 Action 的类

class OpenedDoor extends DoorAction
{
  public function close()
  {
      return new ClosedDoor();
  }
}

所以我会有一些像

$door = new Door('1', new OpenedDoor());
DoctrineDoorRepository::save($door);
$door->close();
DoctrineDoorRepository::save($door);

我将如何在 Doctrine 中实现映射以便我可以坚持它？
我被卡在 $state 属性(property)上。我想保存整个基于 DoorAction 的对象，但我是否必须映射 DoorAction 父类(super class)或每个单独的子类？

我看过使用 Embeddable 来实现它或 SuperMapping但每个人都会遇到问题。

Answer 1

Doctrine2 DBAL 在文档中有一个特性，允许 ENUM的
https://www.doctrine-project.org/projects/doctrine-orm/en/current/cookbook/mysql-enums.html#mysql-enums
当我们取解决方案 2:定义类型 作为基础，可以创建自己的类型，例如名为 doorstatetype或类似的表示打开/关闭状态。例如像这样:

<?php
namespace Acme\Model\Door;

use Doctrine\DBAL\Types\Type;
use Doctrine\DBAL\Platforms\AbstractPlatform;

class DoorStateType extends Type
{
    const ENUM_DOORSTATE = 'enumdoorstate';
    const STATE_OPEN = 'open';
    const STATE_CLOSED = 'closed';

    public function getSQLDeclaration(array $fieldDeclaration, AbstractPlatform $platform)
    {
        return "ENUM('" . self::STATE_OPEN . "', '" . self::STATE_CLOSED . "') COMMENT '(DC2Type:" . ENUM_DOORSTATE  . ")'";
    }

    public function convertToPHPValue($value, AbstractPlatform $platform)
    {
        return $value;
    }

    public function convertToDatabaseValue($value, AbstractPlatform $platform)
    {
        if (!in_array($value, array(self::STATE_OPEN, self::STATE_CLOSED))) {
            throw new \InvalidArgumentException("Invalid state");
        }
    
        return $value;
    }

    public function getName()
    {
        return self::ENUM_DOORSTATE;
    }
}

然后像这样使用它:

<?php

namespace Acme\Model\Door;

/** @Entity */
class Door
{
    /** @Column(type="enumdoorstate") */
    private $state;

    public function open()
    {
        if (!DoorStateType::STATE_OPEN === $this->state) {
            throw new \LogicException('Cannot open an already open door');
        }

        $this->state = DoorStateType::STATE_OPEN;
    }

    public function close()
    {
        if (!DoorStateType::STATE_CLOSED === $this->state) {
            throw new \LogicException('Cannot close an already closed door');
        }

        $this->state = DoorStateType::STATE_CLOSED;
    }
}

这允许搜索状态:

$openDoors = $repository->findBy(array('state' => DoorStateType::STATE_OPEN));

你基本上可以拥有 convertToPHPValue方法创建允许某些逻辑的所需状态的对象，例如检查打开的门是否可以锁定或类似。
在状态必须是包含逻辑的类的情况下，您可以像这样实现它:
首先我们定义一个可以继承的正常状态:

<?php
namespace Acme\Model\Door;

abstract class DoorState
{
    // Those methods define default behaviour for when something isn't possible
    public function open()
    {
        throw new \LogicException('Cannot open door');
    }

    public function close()
    {
        throw new \LogicException('Cannot close door');
    }


    abstract public function getStateName();
}

然后是 OpenState:

<?php
namespace Acme\Model\Door;

class OpenState extends DoorState
{
    const STATE = 'open';
    
    public function close()
    {
        return new ClosedState();
    }

    public function getStateName()
    {
        return self::STATE;
    }

    // More logic
}

最后是 ClosedState:

<?php
namespace Acme\Model\Door;

class ClosedState extends DoorState
{
    const STATE = 'closed';
    
    public function open()
    {
        return new OpenState();
    }

    public function getStateName()
    {
        return self::STATE;
    }

    // More logic
}

然后，为了持久性，我们可以简单地使用不同的转换方法:

<?php
namespace Acme\Model\Door;

use Doctrine\DBAL\Types\Type;
use Doctrine\DBAL\Platforms\AbstractPlatform;

class DoorStateType extends Type
{
    // SQL declarations etc.

    public function convertToPHPValue($value, AbstractPlatform $platform)
    {
        if ($value === OpenState::STATE) {
            return new OpenState();
        }

        if ($value === ClosedState::STATE) {
            return new ClosedState();
        }

        throw new \Exception(sprintf('Unknown state "%s", expected one of "%s"', $value, implode('", "', [OpenState::STATE, ClosedState::STATE])));
    }

    public function convertToDatabaseValue($value, AbstractPlatform $platform)
    {
        return $value->getStateName();
    }
}