CODEWITHSUNDEEP
javaoptaplanner
user14915014
user14915014

Reputation: 15

May planning entities be added or removed automatically by Optaplanner?

I am new to Optaplanner. I thought I had understood what planning entities are, as well as planning variables, genuine or some inverse-kind shadow ones. I have started studying the documentation, the examples and old StackOverflow's questions, but some doubts remain.

When trying to make incremental my score calculator, I have found some unexpected methods in the IncrementalScoreCalculator interface. Together with beforeVariableChanged and afterVariableChanged, I find *EntityAdded and *EntityRemoved, which make me suspect that entity objects may be added and removed. Moreover, these methods are implemented in the NQueens documented example, but in the kind of examples I looking at, examples of distributing shifts, resources, time slots, etc., I find that the domain is designed in such a way that planning entities are expected to be modified, but not added or removed.

I don't know if the addition/removal of entity objects is something used somewhere, as in route planning problems which I haven't dove into, and if these additions and removals are explicit or implicit. So, might planning entities be added or removed by Optaplanner without being asked to?

Upvotes: 1

Views: 191

Answers (1)

Geoffrey De Smet
Geoffrey De Smet

Reputation: 27312

No, OptaPlanner out-of-the-box will not add or remove planning entity instances, because the default move selectors only modify planning entities, they don't create or destroy them.

OptaPlanner doesn't have any generic move selectors yet that can do that (and once we do, they won't be on by default).

If you write a custom move (see MoveListFactory and MoveIteratorFactory in docs), then you could choose to add/remove entities in moves, which is why those methods exists, but very few users do that.

Upvotes: 1

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