设计模式之(三、装饰模式Decorator)

设计模式之三、装饰模式Decorator适合范围：动态地给一个对象添加一些额外的职责。书中的实例：以人为对象，对其做的各种装饰性的行为，如穿衣；裤子；鞋子；等等行为。装饰模式的结构图如下： C++实现的关键代码如下：1、抽象类:CComponentCComponent.h//纯虚函数virtual void Operation() = 0;2、具体对象类：CConcreteComponent.cppvoid CConcreteComponent::Operation(){}3、装饰父类：CDecorator.cppvoid CDecorator::Operation(){    if(m_com != NULL)    {        m_com->Operation();     } }void CDecorator::SetDecorator(CComponent *com){    m_com = com;}CDecorator.hprotected:CComponent *m_com;4、子类：实现装饰行为 CDecoratorA.cppvoid CDecoratorA::Operation(){    m_com->Operation();    //实现子类自己的行为    OperationA();}void CDecoratorA::OperationA(){    cout<<"穿上衣服"< }5、子类:实现装饰行为 CDecoratorB.cppvoid CDecoratorB::Operation(){    m_com->Operation();    //实现子类自己的行为    OperationB();}void CDecorator::OperationB(){    cout<<"穿上裙子"< }...6、客户端代码 main.cppCConcreteComponent *con = new CConcreteComponent();CDecoratorA *ca = new CDecoratorA();CDecoratorB *cb = new CDecoratorB();ca->SetDecorator(con);cb->SetDecorator(ca);cb->Operation();

 

//释放内存

if(con != NULL)

{

   delete con;

}

 

if(ca != NULL)

{

   delete ca;

}

 

if(cb != NULL)

{

   delete cb;

}