包含其他注释的注释成员? [英] Annotation member which holds other annotations?

问题描述

我想创建一个自定义注释(使用 Java)，它会接受其他注释作为参数，例如:

I want to create a custom annotation (using Java) which would accept other annotations as parameter, something like:

public @interface ExclusiveOr {
    Annotation[] value();
}

但这会导致编译器错误注释成员的类型无效".

But this causes compiler error "invalid type for annotation member".

Object[] 也不起作用.

Object[] also doesn't work.

有没有办法做我想做的事?

Is there a way to do what I want?

推荐答案

我本人在此提出针对给定问题的解决方法:

I myself hereby propose a workaround for the given problem:

好吧，我想让它成为可能:

Well, what I wanted to make possible was something like that:

@Contract({
    @ExclusiveOr({
        @IsType(IAtomicType.class),
        @Or({
            @IsType(IListType.class),
            @IsType(ISetType.class)
        })
    })
})

建议的解决方法:

通过以下方式定义一个带有无参数构造函数的类(稍后将由您自己的注解处理器调用):

Define a class with parameter-less constructor (which will be called by your own annotation processor later) in following way:

final class MyContract extends Contract{
    // parameter-less ctor will be handeled by annotation processor
    public MyContract(){
        super(
            new ExclusiveOr(
                new IsType(IAtomicType.class),
                new Or(
                    new IsType(IListType.class),
                    new IsType(ISetType.class)
                )
            )
        );
    }
}

用法:

@Contract(MyContract.class)
class MyClass{
    // ...
}

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