Question

I would like to have error codes in my Java project, but they should have variable String descriptions. For example, I might have two BadCharacterCount errors, but I’d like to represent them as two different strings, e.g. “Bad character count: expected 50, got 60” and “Bad character count: expected 40, got 70.” I’d like to be able to recognize both of these cases as BadCharacterCount errors, and ideally have these in an enum of some sort.

There’s a nice discussion of a similar problem here:
Best way to define error codes/strings in Java?

However, they don’t deal with the case of variable error Strings… Any ideas?

Answer 1

I think your two error descriptions:

Bad character count: expected 50, got 60

And:

Bad character count: expected 40, got 70.

Are already the same. The string is:

Bad character count: expected %s, got %s.

Then when you need to construct the error message, just make sure to pass it through String.format:

String.Format(Error.BadCharacterCount, 50, 60)

And

String.Format(Error.BadCharacterCount, 40, 70)