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optaplannerdrools-planner

Optaplanner : list of planning variables in one planning entity?

I am looking into the example use cases from OptaPlanner. And I could not find any similar example which can solve multiple planning variables in one planning entity. For example, in nurse rostering, each ShiftAssignment(PlanningEntity) for one shift might require multiple assigned Employee(PlanningVariables). In this case, how can we make use of planner and write rules?

Solution

  • Instead of making the OneToMany side a planning variable, make the ManyToOne side a planning variable. If you have a ManyToMany side, introduce a class between (like in relational database design) and acts as a ManyToOne-OneToMany.

    In the nurse rostering example, an example can need 4 nurses on the Shift at ShiftDate 1-JAN for ShiftType Early. In that case, Shift has requiredEmployeeSize 4, and 4 ShiftAssignments are created for that single Shift, each with a different indexInShift. That way, the ShiftAssignment has a planning variable Employee which is a ManyToOne relationship, (even though between Shift and Employee there's a ManyToMany relationship).