AspectJ - 实现给定接口的类的静态类型间声明 [英] AspectJ - Static inter-type declaration on classes implementing a given interface

问题描述

我想知道是否有可能(以及如何...)进行静态类型间声明，该声明适用于实现给定接口的所有类.

I would like to know if it is possible (and how if it is...) to make a static inter-type declaration that works on all classes that implements a given interface.

在我的用例中，我有一个空接口:

In my use case, I have an empty interface:

public interface Delegate {}

和两个实现它的类:

public class DelegateA implements Delegate {...}
public class DelegateB implements Delegate {...}

我想要一个方面在 DelegateA 和 DelegateB 上声明一个静态成员......以及将实现我的接口的所有未来类！

And I want an aspect to declare a static member on DelegateA and DelegateB... and all the future classes that will implements my interface !

我该怎么做?如果只是可能...

How should I do it ? If it's only possible...

推荐答案

您确定要这样做吗?无论如何，这是我为您的问题提供的最佳解决方案:

Are you sure that you want to do that? In any case, here is my best solution for your problem:

public aspect MyAspect pertypewithin(Delegate+){
    public int oneFieldPerClass;
}

这将为 Delegate 的每个子类型实例化一个方面.您可以通过以下方式访问该字段:

This will instantiate an aspect for each subtype of Delegate. You can access the field in the following ways:

MyAspect.aspectOf(DelegateA.class).oneFieldPerClass = 1;
MyAspect.aspectOf(DelegateB.class).oneFieldPerClass = 2;

Delegate d = new DelegateA(); 
MyAspect.aspectOf(d.getClass()).onFieldPerClass = 3;

以下主题也可能有帮助:

The following thread might be helpful as well:

AspectJ - 创建全局 Logger 字段使用类型间声明

HTH、DSP

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