> (like getX throws exceptions until I call setX).
Oh, the wonders of using widespread mutable state! Did you remember to call this other method here before trying to call me??? No?!?! Oh, here's a nasty Exception for you then.
Oh, the wonders of using widespread mutable state! Did you remember to call this other method here before trying to call me??? No?!?! Oh, here's a nasty Exception for you then.
I'm using it for SQL queries. My query returns subset of some column set. It's not practical to define a separate class for every query. So all queries for the given table returns the same class representing all columns in a given table. But if one method returns subset of those columns, other columns contain uninitialized value and should not be read. Any attempt to use uninitialized value is a bug and must be caught as soon as possible.
I'm not sure it's really impractical, at least in my experience. You may not need a separate type for every query, as long as you are willing to have some queries select a few more columns than you actually need right now; and you don't need separate classes, just separate interfaces, which makes the amount of extra code you need smaller.