java - 使用组合

Question

我正在尝试使用自定义类来使用组合重写其父类(super class)中的方法。下面是我尝试的代码，在“Bar”类中什么对象调用方法 doSomethingElse() ？这不是我的代码，并链接到问题 - Using composition over inheritance when overriding

所有实例化都在子类中进行。

class Child extents Parent(){

public Child(){
   super();
   addButtons():
}
 addButtons(){
   <custom code here>
}

}


class Parent(){
 addButtons(){
   add(button1);
}
}

<小时/>

interface SomeMethods {
  void doSomething();
  void doSomethingElse();
}

class Foo implements SomeMethod {
  public void doSomething() { // implementation }
  public void doSomethingElse() { // implementation }
}

class Bar implements SomeMethod {
   private final Foo foo = new Foo();

   public void doSomething() { foo.doSomething(); }
   public void doSomethingElse() { // do something else! }
}

Answer 1

你已经很接近了，只需使用 Bar 类执行此操作即可

class Bar extends Foo {
   // note Bar is still of type SomeMethods because it extends a class of that type.
   public void doSomething() {
      super.doSomething();
      //add more code here if you want to do some more stuff, note you don't need to define this function if you don't need to do anything else.
   }
   public void doSomethingElse() {
      //don't call super, and do whatever you like
   }
}