Solution #1 - Java6 compatible introducing an enum for response type

[cstrap]

With the enum type we'll return to java6, maybe it could be a project constraint using java6 instead other java version.
I don't like switch/case, but it seems pretty readable than if/else.

[arialdomartini]

@giancosta86, you were the one who made the switch to Java 7, you decide ;)

[giancosta86]

Generally speaking, I'm always in favor of upgrading to the very latest stable version of Java, but it's true that a version constraint might exist in a production environment - it's up to us all to choose whether to apply such constraint or not in this case. ^__^
As for the enum, it seems a nice way of using the elegance of the switch statement without breaking the interface of the service...
The idea of having a translation layer to decouple the domain from the service seems nice and fosters Protected Variations, but should such responsibility be given to the class itself? Perhaps, we might introduce another class performing the translation...