修饰模式，在运行时将特定的功能绑定在对象上，这就是修饰模式的核心。修饰模式比继承更加灵活，因为后者是在编译时就将特定的功能绑定到类上。 -Modified model, the run-time functions will be bound to a particular object, which is the core of modified models. Modified model more flexible than inheritance, since the latter wi