有界类型参数由注释限定 [英] Bounded Type Parameters bounded by an annotation

问题描述

在 Java 中，可以使边界类型参数必须从特定的类或接口扩展，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
    ...
}

无论如何我可以通过注释绑定，以便 T 的值只能是具有特定注释的类吗?

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

从Java 8开始，你可以写

Starting in Java 8, you can write

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

与任何 Java 注释一样，要强制执行语义，您需要使用注释处理器.Checker Framework 是一种为您强制执行语义的注释处理工具:如果您尝试使用缺少 @MyAnno 注释的类型参数实例化 Box 类型.

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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