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.