[设计模式]head first 设计模式之PHP实现 第三章 装饰者模式

 <?phpabstract class Beverage { public $description;function getDescription(){return $this->description;} abstract function cost();}//这是调味料的接口（抽象装饰）abstract class CondimentDecorator extends Beverage { }//一种饮料 (被装饰者)class Espresso extends Beverage {public function __construct(){$this->description = 'This is Espresso';}public function cost(){return 1.99;}}//另一种饮料(被装饰者)class HouseBlend extends Beverage {public function __construct(){$this->description = 'This is HouseBlend';}public function cost(){return 3.00;}}//以下是调味料(装饰者)class Moca extends CondimentDecorator {public $beverage; //实例变量 public function __construct(Beverage $beverage){$this->beverage = $beverage;}public function getDescription(){return $this->beverage->getDescription().'+Mocha';}public function cost(){return .20+$this->beverage->cost() ;}}$a = new HouseBlend();echo '<br />HouseBlend 详情：<br />';echo '简介：'.$a->getDescription();echo '<br />价格：'.$a->cost();echo '<br />我要加些调味料：Moca <br />';$m = new Moca($a);echo '简介：'.$k = $m->getDescription();echo '<br />价格：'.$m->cost();//var_dump($m);$b = new Espresso();echo '<br />Espresso 详情：<br />';echo '简介：'.$b->getDescription();echo '<br />价格：'.$b->cost();echo '<br />我要加些调味料：Moca <br />';$m = new Moca($b);echo '简介：'.$k = $m->getDescription();echo '<br />价格：'.$m->cost();//var_dump($m); 

要好好理解这个模式，以后写框架肯定大派用场