创建型设计模式 - 原型 Prototype
作者：菜皮日记
- 2023-09-08 北京
本文字数：1201 字
阅读完需：约 4 分钟
简介
原型模式支持按照一个对象为模板，创建出另一个一模一样的对象。
简单说就是把 A 对象的属性，都赋值到 B 上，注意必须是深拷贝，即 clone 后的 AB 关联的对象是不同的对象。
角色
抽象原型类
定义 clone 方法
具体实现类
实现 clone 方法
类图
类图
代码
class Prototype{ public $primitive; public $component; public $circularReference;
public function __clone() { $this->component = clone $this->component;
$this->circularReference = clone $this->circularReference; $this->circularReference->prototype = $this; }}
class ComponentWithBackReference{ public $prototype;
public function __construct(Prototype $prototype) { $this->prototype = $prototype; }}
function clientCode(){ $p1 = new Prototype(); $p1->primitive = 245; $p1->component = new \DateTime(); $p1->circularReference = new ComponentWithBackReference($p1);
$p2 = clone $p1; if ($p1->primitive === $p2->primitive) { echo "Primitive field values have been carried over to a clone. Yay!\n"; } else { echo "Primitive field values have not been copied. Booo!\n"; } if ($p1->component === $p2->component) { echo "Simple component has not been cloned. Booo!\n"; } else { echo "Simple component has been cloned. Yay!\n"; }
if ($p1->circularReference === $p2->circularReference) { echo "Component with back reference has not been cloned. Booo!\n"; } else { echo "Component with back reference has been cloned. Yay!\n"; }
if ($p1->circularReference->prototype === $p2->circularReference->prototype) { echo "Component with back reference is linked to original object. Booo!\n"; } else { echo "Component with back reference is linked to the clone. Yay!\n"; }}
clientCode();
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output:
Primitive field values have been carried over to a clone. Yay!Simple component has been cloned. Yay!Component with back reference has been cloned. Yay!Component with back reference is linked to the clone. Yay!
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