api: SolverManager should move from problemId to jobId.

[rsynek]

The SolverManager requires a user to provide a problemId to start solving. Quickstarts meanwhile move to a jobId - a unique identifier generated by the solver process. This inconsistency should be addressed in the SolverManager

Advantages:

• lower entry barrier by not having to provide an identifier
• fewer generics: SolverManager<MySolution> vs. SolverManager<MySolution, Long>

This is a backward-incompatible change and thus it should be introduced no sooner than in Timefold solver 2.0.0.

[Inlustra]

I'm using the problemIds that are calculated in user code (And based on the problems variables), to ensure that I'm not ever running the same problem twice.
My current solution to this is checking the current status for a given problem ID before starting the solving.

With this change I'll need to maintain a list of problemIds to jobIds which reduces the flexibility.

Has this been taken into account? Perhaps my solution is not the best way to manage this?

[triceo]

@Inlustra Thank you for the feedback. This is not to be implemented any time soon, rather a placeholder for some time in the future; which is when we'll actually think it through. Your feedback will be useful when the time comes.

Right now, I wouldn't worry about this issue too much.

[triceo]

After some deliberation, the only change to be made here is to remove the generic type ProblemId from SolverManger, SolverJob etc.

Everything will still be possible as it always was, only the ID will now be just Object.