【设计模式】装饰器模式

发表于 更新于 分类于 阅读次数： Disqus：

结构性模式: 装饰模式 decorator

动态地给一个对象添加一些额外的职责, 就增加功能来说, 装饰器模式相比生成子类更灵活

不改变原有的功能, 不对原有的功能加限制, 不需要原有功能对新功能提供任何帮助, 仅在原有功能上添加新的功能

  • 给老系统进行升级扩展
  • 不一定都是对同一个方法进行装饰，其实装饰者应该更多的用于对对象的装饰，对对象进行扩展, 增加功能方法, 削弱/减少功能方法
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interface HouseBuilderInterface {
    public function beautify();
}

class HouseBuilder implements HouseBuilderInterface {
    public function beautify()
    {
        echo "粉刷完成\t";
    }
}

abstract class HouseBuilderDecorator implements HouseBuilderInterface {
    protected $houseBuilder;
    public function __construct(HouseBuilderInterface $houseBuilder) {
        $this->houseBuilder = $houseBuilder;
    }
}

class HouseBuilderDecoratorFloor extends HouseBuilderDecorator {
    public function beautify()
    {
        $this->houseBuilder->beautify();
        echo "铺完地板啦\t";
    }
}

class HouseBuilderDecoratorClean extends HouseBuilderDecorator {
    public function beautify()
    {
        $this->houseBuilder->beautify();
        echo "打扫好啦\t";
    }
}

$houseBuilder = new HouseBuilder();
$houseBuilder->beautify();
echo PHP_EOL;
$houseBuilder = new HouseBuilderDecoratorFloor($houseBuilder);
$houseBuilder->beautify();
echo PHP_EOL;
$houseBuilder = new HouseBuilderDecoratorClean($houseBuilder);
$houseBuilder->beautify();
echo PHP_EOL;

$houseBuilder = new HouseBuilder();
$houseBuilder = new HouseBuilderDecoratorFloor($houseBuilder);
$houseBuilder = new HouseBuilderDecoratorClean($houseBuilder);
$houseBuilder->beautify();
echo PHP_EOL;