Inheritance disadvantage Unlike method invocation, inheritance violates encapsulation. Since you don't know the super class implementation which may involve some unpredictable calling between different methods of super class. And it is difficult to maintain the subclass when there is a change of the sup...
18.Favor composition over inheritance 19.Design and document for inheritance or else prohibit it 20.Prefer interfaces to abstract classes 21.Design interfaces for posterity 22.Use interfaces only to define types 23.Prefer class hierarchies to tagged classes 24.Fav...
Item 18: Favor composition over inheritance 继承并不适合于所有场合。在同一个包中使用继承是安全的,对专为扩展而设计的类使用继承也是安全的。但对普通的具体类做跨包的继承是危险的。 继承的危险在于它破坏了封装。因为子类的功能是否正确依赖于超类的实现细节。 下面例子说明了这个问题,它统计一个HashSet自创...
Item 16: Favor composition over inheritance 继承其实会破坏封encapsulation。在同一个package内用inheritance是安全的,但是在不同的package间用inheritance就很惨了,注这里的inheritance只是指extends class而不包括implement(extends) interface。比如基类的实现者是类库作者,然后client继承了它,然后子类的行为可能是依赖于某...
并没有什么比较让人满意的方法来拓展一个可实例化的类并且加上一个值成员,在这里有一个比较好的方法,在后面会提到这一点”Favor composition over inheritance“(继承上进行组合)而不是用ColorPoint继承于Point,而是直接给ColorPoint一个private的Point成员和一个public的view方法,该方法返回这个相同位置的point作为这个...
about class design, whether using inheritance or composition. Tips on designing methods show you how to create understandable, maintainable, and robust classes that can be easily reused by others on your team. Sections on mapping C code (like structures, unions, and enumerated types) onto Java ...
实现继承(implementation inheritance), 接口继承(interface inheritance) 组合(composition), 转发方法(forwarding method) 包装类(wrapper class)-->Decorator模式 十七,要么为继承而设计并提供文档说明,要么就禁止继承 十八,接口优于抽象类 抽象类允许包含某些方法的实现;接口不允许。
An example where this is a problem is JavaTimestampclass which extendsDateand violates the symmetry part. If both are intermixed in a Collection, they can create erratic behavior. The solution is prefer composition over inheritance. java.net.URLrelies on IP address of the hosts associated with ...
Item 18: Favor composition over inheritance(优先选择复合而不是继承) Item 19: Design and document for inheritance or else prohibit it(继承要设计良好并且具有文档,否则禁止使用) Item 20: Prefer interfaces to abstract classes(接口优于抽象类) Item 21: Design interfaces for posterity(为后代设计接口) It...
Item 16: Favor composition over inheritance (P81) InstrumentedHashSet implemented with inheritance (P84) InstrumentedHashSet implemented with composition Item 17: Design and document for inheritance or else prohibit it Item 18: Prefer interfaces to abstract classes (P95) A skeletal implementation example...