Optaplanner-约束流groupBy

Question

我试图解决一个调度问题，它围绕着以下安排：

是否可以使用join()和groupby()实现约束？我尝试过以下路线：

    private Constraint doNotOverbookEquipment(ConstraintFactory factory) {
        return factory.from(ShiftAssignment.class)
                // join shift assignments with the shifts they are assignments of
                .join(Shift.class, equal(ShiftAssignment::getShiftId, Shift::getId))
                // join with ALL pieces of equipment
                .join(Equipment.class)
                .groupBy([Shift and Equipment, summing the equipment-usage for each ShiftAssignment])
                .filter([equipment usage greater than a constant])
                .penalizeConfigurable("do not overbook Equipment");

我认为filter()应该没有问题，但不确定如何获得这个groupby()来实现我想要的。这里是否需要TriconStraintCollector？还是有一个不同的、更好的整体方法？

作为参考，ShiftAssignment类可以很容易地拥有如下所示的方法：

public LinkedHashSet<Equipment, Integer> getEquipmentUsage()

Answer 1

我认为您的groupby()应该如下所示：

.groupBy(
    (shiftAssignment, shift, equipment) -> shift,
    (shiftAssignment, shift, equipment) -> equipment,
    ConstraintCollectors.sum((shiftAssignment, shift, equipment) ->
        shiftAssignment.getUsage(shift, equipment)
)

在本例中，要求和的实际逻辑应该在ShiftAssignment.getUsage（...）或您选择在其中使用的任何其他方法中实现。