设计模式之原型模式

Posted 2022-02-11 wawjandcsws

原型模式：用原型实例指定创建对象的种类，并通过拷贝这些原型创建新的对象。

浅拷贝：被拷贝对象的所有变量都含有与原对象相同的值，而且对其他对象的引用仍然是指向原来的对象，即浅拷贝只负责当前对象实例，对引用的对象不做拷贝。

深拷贝：被拷贝对象的所有的变量都含有与原来对象相同的值，除了那些引用其他对象的变量，那些引用其他对象的变量将指向一个被拷贝的新对象，而不再是原来那些被引用的对象。即深拷贝把要拷贝的对象所引用的对象也拷贝了一次。而这种对被引用到的对象拷贝叫做间接拷贝。

序列化深拷贝：利用序列化来做深拷贝，把对象写到流里的过程是序列化的过程，这一过程称为“冷冻”或“腌咸菜”，反序列化对象的过程叫做“解冻”或“回鲜”。

案例：

\Libs\Prototype.php

1 <?php
2 namespace Libs;
3 
4 interface Prototype
5 
6     public function shallowCopy();
7     public function deepCopy();
8 

\Libs\ConcretePrototype.php

 1 <?php
 2 namespace Libs;
 3 
 4 class ConcretePrototype implements Prototype
 5 
 6     private $_name;
 7     public function __construct($name)
 8     
 9         $this->_name = $name;
10     
11     
12     public function setName($name)
13     
14         $this->_name = $name;
15     
16     public function getName()
17     
18         return $this->_name;
19     
20     /**
21      * 浅拷贝
22      * */
23     public function shallowCopy()
24     
25         
26         return clone $this;
27         
28     
29     /**
30      * 深拷贝
31      * */
32     public function deepCopy()
33     
34         $serialize_obj = serialize($this);
35         $clone_obj = unserialize($serialize_obj);
36         return $clone_obj;
37     
38 

 

\Libs\UsePrototype.php

 1 <?php
 2 namespace Libs;
 3 
 4 class Demo
 5 
 6     public $string;
 7 
 8 class UsePrototype
 9 
10     public function shallow()
11     
12         $demo = new Demo();
13         $demo->string = "susan";
14         $object_shallow_first = new ConcretePrototype($demo);
15         $object_shallow_second = $object_shallow_first->shallowCopy();
16         
17         var_dump($object_shallow_first->getName());
18         echo ‘<br/>‘;
19         var_dump($object_shallow_second->getName());
20         echo ‘<br/>‘;
21         
22         $demo->string = "sacha";
23         var_dump($object_shallow_first->getName());
24         echo ‘<br/>‘;
25         var_dump($object_shallow_second->getName());
26         echo ‘<br/>‘;
27         
28     
29     
30     public function deep()
31     
32         $demo = new Demo();
33         $demo->string = "Siri";
34         $object_deep_first = new ConcretePrototype($demo);
35         $object_deep_second = $object_deep_first->deepCopy();
36     
37         var_dump($object_deep_first->getName());
38         echo ‘<br/>‘;
39         var_dump($object_deep_second->getName());
40         echo ‘<br/>‘;
41     
42         $demo->string = "Demo";
43         var_dump($object_deep_first->getName());
44         echo ‘<br/>‘;
45         var_dump($object_deep_second->getName());
46         echo ‘<br/>‘;
47     
48     
49     
50 

 

调用：

1 $up = new \Libs\UsePrototype;
2 $up->shallow();
3 echo ‘<hr>‘;
4 $up->deep();

 

结果：

1 object(Libs\Demo)#2 (1)  ["string"]=> string(5) "susan"  
2 object(Libs\Demo)#2 (1)  ["string"]=> string(5) "susan"  
3 object(Libs\Demo)#2 (1)  ["string"]=> string(5) "sacha"  
4 object(Libs\Demo)#2 (1)  ["string"]=> string(5) "sacha"  
5  
6 object(Libs\Demo)#4 (1)  ["string"]=> string(4) "Siri"  
7 object(Libs\Demo)#5 (1)  ["string"]=> string(4) "Siri"  
8 object(Libs\Demo)#4 (1)  ["string"]=> string(4) "Demo"  
9 object(Libs\Demo)#5 (1)  ["string"]=> string(4) "Siri"