PHP设计模式之装饰者模式代码实例
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 interfaceComponent { publicfunctionoperation(); } //装饰者基类 abstractclassDecoratorimplementsComponent { protected$component; publicfunction__construct(Component$component) { $this->component=$component; } publicfunctionoperation() { $this->component->operation(); } } //具体装饰者类 classConcreteComponentimplementsComponent { publicfunctionoperation() { echo'dooperation'.PHP_EOL; } } //具体装饰类A classConcreteDecoratorAextendsDecorator{ publicfunction__construct(Component$component){ parent::__construct($component); } publicfunctionoperation(){ parent::operation(); $this->addedOperationA();//新增加的操作 } publicfunctionaddedOperationA(){ echo'AddOperationA'.PHP_EOL; } } //具体装饰类B classConcreteDecoratorBextendsDecorator{ publicfunction__construct(Component$component){ parent::__construct($component); } publicfunctionoperation(){ parent::operation(); $this->addedOperationB(); } publicfunctionaddedOperationB(){ echo'AddOperationB'.PHP_EOL; } } classClient{ publicstaticfunctionmain(){ /* dooperation AddOperationA */ $decoratorA=newConcreteDecoratorA(newConcreteComponent()); $decoratorA->operation(); /* dooperation AddOperationA AddOperationB */ $decoratorB=newConcreteDecoratorB($decoratorA); $decoratorB->operation(); } } Client::main();