9.8嵌套接口

接口可以嵌套在类或其他接口中

//: interfaces/nesting/NestingInterfaces.java
package com.zx.chapter09.shipqi;
class A {
  interface B {
    void f();
  }
  public class BImp implements B {
    public void f() {}
  }
  private class BImp2 implements B {
    public void f() {}
  }
  public interface C {
    void f();
  }
  class CImp implements C {
    public void f() {}
  }    
  private class CImp2 implements C {
    public void f() {}
  }
  private interface D {
    void f();
  }
  private class DImp implements D {
    public void f() {}
  }
  public class DImp2 implements D {
    public void f() {}
  }
  public D getD() { return new DImp2(); }
  private D dRef;
  public void receiveD(D d) {
    dRef = d;
    dRef.f();
  }
}    
interface E {
  interface G {
    void f();
  }
  public interface H {
    void f();
  }
  void g();
}
public class NestingInterfaces {
  public class BImp implements A.B {
    public void f() {
    }
  }
  class CImp implements A.C {
    public void f() {
    }
  }
  class EImp implements E {
    public void g() {
    }
  }
  class EGImp implements E.G {
    public void f() {
    }
  }
  class EImp2 implements E {
    public void g() {
    }
    class EG implements E.G {
      public void f() {
      }
    }
  }
  public static void main(String[] args) {
    A a = new A();
    A a2 = new A();
    a2.receiveD(a.getD());
  }
}

在类中嵌套的接口可以用private修饰，但是在接口中嵌套的接口则必须public 修饰