装饰模式

装饰模式:动态地给一个对象添加一些额外的职责,就增加功能来说,装饰模式比生成子类更为灵活。

abstract class Component
{

    public  abstract  function Operation();

}

class ConcreteComponent  extends Component
{
    public  function Operation()
    {
        echo '具体对象的操作<br>';
    }

}

 abstract class Decorator extends Component
{

    protected  $component;

    public  function  setComponent($component){

        $this->component = $component;
    }

     public  function Operation()
    {
        if($this->component != null){

            $this->component->Operation();
        }
    }

 }

class ConcreteDecoratorA extends Decorator
{
    private  $addedState;

    public  function  Operation()
    {
        parent::Operation(); // TODO: Change the autogenerated stub
        $this->addedState = "New State";
        echo "具体装饰对象A的操作<br>";
    }


}

class ConcreteDecoratorB extends  Decorator
{

    public  function Operation()
    {
        parent::Operation(); // TODO: Change the autogenerated stub

        $this->addedBehavior();

        echo "具体装饰对象B的操作<br>";
    }

    private  function  addedBehavior(){


    }

}

$c  = new ConcreteComponent();

$d1 = new ConcreteDecoratorA();

$d2 = new ConcreteDecoratorB();

$d1->setComponent($c);

$d2->setComponent($d1);

$d2->Operation();

Component是定义一个对象接口,可以给这些对象动态地添加职责,ConcreteComponent是定义了一个具体的对象,也可以给这个对象添加一些职责。Decorator,装饰抽象类,继承了Component,从外类来扩展Component类的功能
但对于Component来说,是无需知道Decorator的存在的。对于ConcreteDecorator就是具体的装饰对象,起到给Component添加职责的功能
装饰模式是利用setComponent来对对象进行包装的,这样每个装饰对象的实现就和如何使用这个对象分离了,每个装饰对象只关心自己的功能,不需要关心如何被添加到对象链当中

如果只有一个ConcreteComponent类而没有抽象的Component类,那么Decorator类可以是ConcreteComponent的一个子类。如果只有一个ConcreteDecorator类,那么就没有必要建立一个单独的Decorator类,可以把Decorator和ConcreteDecorator的责任合并成一个类.

#相当于ConcreteComponent
class Person
{

    private $name;

    public function __construct($name)
    {
        $this->name = $name;
    }


    public   function  Show(){

        echo '装扮的'.$this->name.'<br>';

    }


}

//Decorator
class Finery extends Person
{

    public function __construct()
    {
        parent::__construct('');
    }

    private  $component;

    public  function setComponent($component){

        $this->component = $component;

    }

    public  function  Show()
    {
        if ($this->component != null){

            $this->component->Show();
        }

    }


}

class TShirts extends Finery
{
    public  function Show()
    {
        echo '大T恤<br>';
        parent::Show(); // TODO: Change the autogenerated stub
    }

}

class Sneakers extends Finery
{

    public  function  Show()
    {
        echo '拖鞋<br>';
        parent::Show(); // TODO: Change the autogenerated stub
    }

}

class BigTrouser extends Finery
{
    public  function Show()
    {
        echo '垮裤<br>';
        parent::Show(); // TODO: Change the autogenerated stub
    }

}

$paul = new Person('paulversion');

echo '第一种装扮<br>';

 $sneaker  = new Sneakers();

 $trouser  = new BigTrouser();

 $shirts   = new TShirts();

 $sneaker->setComponent($paul);
 $trouser->setComponent($sneaker);
 $shirts->setComponent($trouser);

 $shirts->Show();

装饰模式是为已有功能动态地添加更多功能的一种方式.装饰模式把每个要装饰的功能放在单独的类中,并让这个类包装它所要装饰的对象,因此当需要执行特殊行为时,客户代码就可以在运行时根据需要有选择地,按顺序地使用装饰功能包装对象.