At this point, I am laying down a framework of sorts for GMs to be able to implement battle layouts and methodology, whether these are provided by others or whether the GM is designing a custom layout or methodology. Since I'm aiming to keep this all open-source, I am hoping for a decent amount of code sharing -- from those who understand implementation, to those who are looking for a pre-set solution. My framework should allow for this.
To begin, the framework starts with a few abstract Java classes that must be subclassed to provide the implementation; first, the ABattleSystem class provides the basics but must be subclassed to provide the specifics. Next, I have abstract classes ABattleSystemLayout and ABattleSystemMethod to provide some of the specifics of layout/presentation and turn-based methodology.
It does not need to be so difficult to implement a battle system; although I will have to decide first on which layout and methodology will be the "defaults". The different layouts (front, side, top-down, isometric) each have their benefits and weaknesses, followers and detractors; and the methodolody can be just as difficult to determine. More may be added as necessary; but I'm hoping this will be a good start, for when the engine is ready for a test-play. Beyond this, I'm open to further comments and questions.
If you are looking for example battle systems to test the parameters of what your system can be customized to, and that you could provide as usable free samples with your system, I can give you descriptions of two or three such systems. PM me if you want to discuss this further. :)