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PHP设计模式之装饰者模式代码实例_PHP

时间:2021-07-01 10:21:17 帮助过:20人阅读

定义:

装饰者模式就是不修改原类代码和继承的情况下动态扩展类的功能。传统的编程模式都是子类继承父类实现方法重载,使用装饰器模式,只需添加一个新的装饰器对象,更加灵活,避免类数量和层次过多。

角色:

Component(被装饰对象基类)
ConcreteComponent(具体被装饰对象)
Decorator(装饰者基类)
ContreteDecorator(具体的装饰者类)

示例代码:

//被装饰者基类
interface Component
{
  public function operation();
}
 
//装饰者基类
abstract class Decorator implements Component
{
  protected $component;
 
  public function __construct(Component $component)
  {
    $this->component = $component;
  }
 
  public function operation()
  {
    $this->component->operation();
  }
}
 
//具体装饰者类
class ConcreteComponent implements Component
{
  public function operation()
  {
    echo 'do operation'.PHP_EOL;
  }
}
 
//具体装饰类A
class ConcreteDecoratorA extends Decorator {
  public function __construct(Component $component) {
    parent::__construct($component);
 
  }
 
  public function operation() {
    parent::operation();
    $this->addedOperationA();  // 新增加的操作
  }
 
  public function addedOperationA() {
    echo 'Add Operation A '.PHP_EOL;
  }
}
 
//具体装饰类B
class ConcreteDecoratorB extends Decorator {
  public function __construct(Component $component) {
    parent::__construct($component);
 
  }
 
  public function operation() {
    parent::operation();
    $this->addedOperationB();
  }
 
  public function addedOperationB() {
    echo 'Add Operation B '.PHP_EOL;
  }
}
 
 
class Client {
 
  public static function main() {
    /*
    do operation
    Add Operation A
    */
    $decoratorA = new ConcreteDecoratorA(new ConcreteComponent());
    $decoratorA->operation();
 
 
    /*
    do operation
    Add Operation A 
    Add Operation B 
    */
    $decoratorB = new ConcreteDecoratorB($decoratorA);
    $decoratorB->operation();
  }
 
}
 
Client::main();

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