apache-zest - Qi4J 关注部分实现

Question

有可能以这样的方式结束:

    ServiceChild (class) extends (or only partial implements) Service and overrides sayHello
    Service (interface) implements hello,goodbye

    Hello (has a mixin HelloMixin) has method sayHello
    Goodbye (has a mixin GoodbyeMixin) has method sayGoodbye

我已经尝试使用 ServiceChild 中的关注方法执行上述操作

    public class ServiceChild extends ConcernOf<Service> implements Hello 
 {

    @Override
    public String sayHello() {
     return "Rulle Pharfar";
    }
 }

但是使用这种方法只有 Hello 实现被 java 检测到，而不是来自 Service 类的其余内容。那么还有其他可行的方法吗？

Answer 1

我不确定我是否理解您正在尝试做的事情，但是应该更多地将关注视为对它所关注的类的原始实现的包装。正如文档所述:

关注点是一个无状态片段，在调用之间共享，充当对 Mixin 调用的拦截器。

通常会这样做:

//Given interface MyStuff
@Mixins( MyStuff.Mixin.class )
@Concerns( MyStuffConcern.class )
public interface MyStuff
{
    public void doStuff();

    abstract class Mixin implements MyStuff
    {
       public void doStuff()
       {
          System.out.println( "Doing original stuff." );
       }
    }
}

public class MyStuffConcern extends ConcernOf<MyStuff>
   implements MyStuff
{
   public void doStuff()
   {
     // if I want to do anything before going down the call chain I'll do it here
     System.out.println( "Doing stuff before original." );

     // calling the next concern or actual implementation
     next.doStuff();

     // anything to do after calling down the call chain - here is the place for it
     System.out.println( "Doing stuff after original." );
   }
}

但是，如果您对接口(interface)有顾虑，您还应该实现所述接口(interface):

public abstract class ServiceChild extends ConcernOf<Service> implements Service
{
   public String sayHello()
   {
       return "Rulle Pharfar";
   }
}

希望这对您有所帮助。