原型模式

设计模式

定义

• 原型模式（Prototype Pattern）是用于创建重复的对象，同时又能保证性能。这种类型的设计模式属于创建型模式，它提供了一种创建对象的最佳方式。
• 用于创建重复的对象,使用克隆技术来复制实例化的对象,新对象是复制原型实例创造来的
• 使用克隆对象来减少new对象的开销
• 原型: 是被克隆的那一个

这种模式是实现了一个原型接口，该接口用于创建当前对象的克隆。当直接创建对象的代价比较大时，则采用这种模式。例如，一个对象需要在一个高代价的数据库操作之后被创建。我们可以缓存该对象，在下一个请求时返回它的克隆，在需要的时候更新数据库，以此来减少数据库调用。

实现原理

• 克隆不会调用构造函数
• 使用克隆来创建新的对象的时候,并不能触发类的构造函数
• 避免构造函数的强依赖

浅复制

• 原型被改变了,克隆出来的对象也会被改变

1.创建一个键盘类

<?php
/**
 * 键盘类
 *
 * @author     Luffy (lufei@swoole.com)
 * @date       2019/10/24
 * @copyright  Swoole, Inc.
 * @package    sy-records/design-patterns
 */
namespace Luffy\DesignPatterns\Prototype;
class Keyboard
{
    /**
     * 键盘名称
     *
     * @var
     */
    public $name;
}

2.创建一个浅复制类

<?php
/**
 * 浅复制
 *
 * @author    Luffy (lufei@swoole.com)
 * @date      2019/10/24
 * @copyright Swoole, Inc.
 * @package   sy-records/design-patterns
 */
namespace Luffy\DesignPatterns\Prototype;
class ShallowCopy
{
    private $keyboard;
    public function __construct()
    {
        echo '亲爱的大哥'.PHP_EOL;
    }
    public function setKeyboard($keyboard)
    {
        $this->keyboard = $keyboard;
    }
    public function get()
    {
        echo '我想要个'.$this->keyboard->name. '的键盘' .PHP_EOL;
    }
}

3.创建客户端实现类

<?php
/**
 * User:çlufei
 * Date: 2019/10/24
 * Email: lufei@swoole.com.
 */
require  __DIR__ . '/../vendor/autoload.php';
use Luffy\DesignPatterns\Prototype\ShallowCopy;
use Luffy\DesignPatterns\Prototype\Keyboard;
use Luffy\DesignPatterns\Prototype\DeepCopy;
class Client
{
    /**
     * 浅复制
     */
    public static function shallowCopy()
    {
        $shallowCopy = new ShallowCopy();
        $keyboard = new Keyboard();
        $keyboard->name = "ikbc";
        $shallowCopy->setKeyboard($keyboard);
        $shallowCopy->get();
        echo "-----\n";
        // clone不会调用构造函数
        $cloneShallow = clone $shallowCopy;
        $cloneShallow->get();
    }
    public static function shallowCopy2()
    {
        $shallowCopy = new ShallowCopy();
        $keyboard = new Keyboard();
        $keyboard->name = "ikbc";
        $shallowCopy->setKeyboard($keyboard);
        $shallowCopy->get();
        echo "-----\n";
        // clone不会调用构造函数
        $cloneShallow = clone $shallowCopy;
        $cloneShallow->get();
        echo "=====\n";
        $keyboard->name = "hhkb";
        $shallowCopy->get();
        $cloneShallow->get();
    }
    public static function deepCopy()
    {
        $keyboard = new Keyboard();
        $keyboard->name = "ikbc";
        $deepCopy = new DeepCopy();
        $deepCopy->setKeyboard($keyboard);
        $deepCopy->get();
        echo "-----\n";
        $cloneDeep = clone $deepCopy;
        $cloneDeep->get();
        echo "=====\n";
        $keyboard->name = "hhkb";
        $deepCopy->get();
        $cloneDeep->get();
    }
}
Client::shallowCopy();
echo "***************".PHP_EOL;
Client::shallowCopy2();
echo "***************".PHP_EOL;
Client::deepCopy();

深复制

• 实现了克隆的接口

1.创建一个键盘类

<?php
/**
 * 键盘类
 *
 * @author     Luffy (lufei@swoole.com)
 * @date       2019/10/24
 * @copyright  Swoole, Inc.
 * @package    sy-records/design-patterns
 */
namespace Luffy\DesignPatterns\Prototype;
class Keyboard
{
    /**
     * 键盘名称
     *
     * @var
     */
    public $name;
}

2.创建克隆接口

<?php
/**
 * 原型模式
 *
 * @author    Luffy (lufei@swoole.com)
 * @date      2019/10/24
 * @copyright Swoole, Inc.
 * @package   sy-records/design-patterns
 */
namespace Luffy\DesignPatterns\Prototype;
interface Prototype
{
    public function __clone();
}

3.创建一个深复制实现克隆接口

<?php
/**
 * 深复制
 *
 * @author    Luffy (lufei@swoole.com)
 * @date      2019/10/25
 * @copyright Swoole, Inc.
 * @package   sy-records/design-patterns
 */
namespace Luffy\DesignPatterns\Prototype;
class DeepCopy implements Prototype
{
    private $keyboard;
    public function __construct()
    {
        echo '美丽的姐姐'.PHP_EOL;
    }
    public function setKeyboard($keyboard)
    {
        $this->keyboard = $keyboard;
    }
    public function get()
    {
        echo '我想要个'.$this->keyboard->name. '的键盘' .PHP_EOL;
    }
    public function __clone()
    {
        $this->keyboard = clone $this->keyboard;
    }
}

4.创建客户端实现类

<?php
/**
 * User:çlufei
 * Date: 2019/10/24
 * Email: lufei@swoole.com.
 */
require  __DIR__ . '/../vendor/autoload.php';
use Luffy\DesignPatterns\Prototype\ShallowCopy;
use Luffy\DesignPatterns\Prototype\Keyboard;
use Luffy\DesignPatterns\Prototype\DeepCopy;
class Client
{
    /**
     * 浅复制
     */
    public static function shallowCopy()
    {
        $shallowCopy = new ShallowCopy();
        $keyboard = new Keyboard();
        $keyboard->name = "ikbc";
        $shallowCopy->setKeyboard($keyboard);
        $shallowCopy->get();
        echo "-----\n";
        // clone不会调用构造函数
        $cloneShallow = clone $shallowCopy;
        $cloneShallow->get();
    }
    public static function shallowCopy2()
    {
        $shallowCopy = new ShallowCopy();
        $keyboard = new Keyboard();
        $keyboard->name = "ikbc";
        $shallowCopy->setKeyboard($keyboard);
        $shallowCopy->get();
        echo "-----\n";
        // clone不会调用构造函数
        $cloneShallow = clone $shallowCopy;
        $cloneShallow->get();
        echo "=====\n";
        $keyboard->name = "hhkb";
        $shallowCopy->get();
        $cloneShallow->get();
    }
    public static function deepCopy()
    {
        $keyboard = new Keyboard();
        $keyboard->name = "ikbc";
        $deepCopy = new DeepCopy();
        $deepCopy->setKeyboard($keyboard);
        $deepCopy->get();
        echo "-----\n";
        $cloneDeep = clone $deepCopy;
        $cloneDeep->get();
        echo "=====\n";
        $keyboard->name = "hhkb";
        $deepCopy->get();
        $cloneDeep->get();
    }
}
Client::shallowCopy();
echo "***************".PHP_EOL;
Client::shallowCopy2();
echo "***************".PHP_EOL;
Client::deepCopy();

参考资料:
swoole微课堂
GitHub
https://www.runoob.com/