关于java上下文的委托示例

Question

什么是Java授权？谁能给我一个恰当的例子？

Answer 1

这是代表团 - 与现实世界完全一样:

public interface Worker() {
  public Result work();
}

public class Secretary() implements Worker {

   public Result work() {
     Result myResult = new Result();
     return myResult;
   }    
}

public class Boss() implements Worker {

   private Secretary secretary;

   public Result work() {
     return secretary.work();
   }   
}

(添加了Worker接口以更接近Delegator模式)

Answer 2

如果您指的是委托模式,维基百科有一个很好的例子,用java编写.

我相信上面这个页面的较长的例子是最好的一个:

interface I {
    void f();
    void g();
}

class A implements I {
    public void f() { System.out.println("A: doing f()"); }
    public void g() { System.out.println("A: doing g()"); }
}

class B implements I {
    public void f() { System.out.println("B: doing f()"); }
    public void g() { System.out.println("B: doing g()"); }
}

class C implements I {
    // delegation
    I i = new A();

    public void f() { i.f(); }
    public void g() { i.g(); }

    // normal attributes
    void toA() { i = new A(); }
    void toB() { i = new B(); }
}


public class Main {
    public static void main(String[] args) {
        C c = new C();
        c.f();     // output: A: doing f()
        c.g();     // output: A: doing g()
        c.toB();
        c.f();     // output: B: doing f()
        c.g();     // output: B: doing g()
    }
}