Should I make a constants class for my annotations?

Question

Which is better?

1. @SuppressWarnings("unchecked")
2. @SuppressWarnings(AnnotationConstants.UNCHECKED)

Where AnnotationConstants is a typical constants class...

public final class AnnotationConstants {
    private AnnotationConstants() { }

    public static final String UNCHECKED = "unchecked";

    ...
}

I know that there are a lot of general arguments for and against constants classes--and that's exactly what I'm not interested in. I want to know if a constants class specifically for annotations is a good idea or a bad idea.

Answer 1

For @SuppressWarning and the likes, I don't think so. I prefer writing the constants directly, and have the compiler check them if possible. Eclipse does a nice job at that.

Answer 2

For this specific example I'd stick with literals. After all, you're trying to suppress warnings - if you use the wrong literal, the warning won't be suppressed, which will draw your attention to the problem.

Answer 3

I'd say a little bit of both, please.

In Spring, you could say something like @Scope(Scopes.SESSION) or @Scope(Scopes.REQUEST), which attaches a specific kind of behavior to the annotation so I'd say always use a constants class, which is good for traceability.

If you're just supressing warnings, there's little likelyhood that you want to really trace this, so just go with the literal.

Answer 4

I'd agree with Holsam for SuppressWarnings - use the strings

If you're writing your own annotation, I'd recommend usng enums where possible for things that could be represented as a set of constants