通过注解界限制类型参数 [英] Bounded Type Parameters bounded by an annotation

问题描述

在Java中，它能够使一个莽汉类型参数已经从特定的类或接口例如

In Java, it is possible to make a bounder type parameter have to extend from a particular class or interface e.g.

public class Box<T extends MyClass> {
    T t
    ...
}

反正是有，我可以通过注解的约束，这样的T值只能是具有特定注解类？

Is there anyway I can bound by an annotation so that values of T can only be classes that have a particular annotation?

推荐答案

在Java的8起，你可以写

Starting in Java 8, you can write

public class Box<T extends @MyAnno MyClass> {
...
}

对于任何Java注释，执行语义，你需要使用注释处理器。该检查框架是一个强制的语义为您注解处理工具：您可以配置它，如果发出错误你曾经尝试实例化箱键入使用缺乏 @MyAnno 注释的类型参数。

As with any Java annotation, to enforce the semantics, you need to use an annotation processor. The Checker Framework is one annotation-processing tool that enforces the semantics for you: you can configure it to issue an error if you ever try to instantiate the Box type using a type argument that lacks the @MyAnno annotation.

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