Custom shadow variables are not updating when visit change to one chain(vehicle) to another while planning - optaplanner

Question

We have a scenario like delivery the new order and pickup the old order from same visit. For this scenario we have added pickCapacity and deliveryCapacity and also calculating accumulated capacity(weightUsedAtEndOfVisit) at end of visit in ArrivalTimeUpdatingVariableListener class.
This is working fine, But some times weightUsedAtEndOfVisit values are not getting updated in previous chain when visit change one chain to another.
TimeWindowedVisit
#PlanningEntity
public class TimeWindowedVisit{
protected Long dropWeight;
protected Long pickupWeight;
private Long weightUsedAtEndOfVisit;
#CustomShadowVariable(variableListenerRef = #PlanningVariableReference(variableName = "arrivalTime"))
public Long getWeightUsedAtEndOfVisit() {
return weightUsedAtEndOfVisit;
}
public void setWeightUsedAtEndOfVisit(Long weightUsedAtEndOfVisit) {
this.weightUsedAtEndOfVisit = weightUsedAtEndOfVisit;
}
}
ArrivalTimeUpdatingVariableListener
public class ArrivalTimeUpdatingVariableListener implements VariableListener<TimeWindowedPlanningVisit> {
#Override
public void afterEntityAdded(ScoreDirector scoreDirector, TimeWindowedPlanningVisit planningVisit) {
updateUsedCapacityAtVisit(scoreDirector, planningVisit);
}
#Override
public void afterVariableChanged(ScoreDirector scoreDirector, TimeWindowedPlanningVisit planningVisit) {
updateUsedCapacityAtVisit(scoreDirector, planningVisit);
}
...
protected void updateUsedCapacityAtVisit(ScoreDirector<?> scoreDirector, TimeWindowedPlanningVisit sourcePlanningVisit) {
TimeWindowedPlanningVisit shadowPlanningVisit;
if (sourcePlanningVisit.getPreviousStandstill() != null) {
shadowPlanningVisit = sourcePlanningVisit;
while (shadowPlanningVisit != null) {
if (shadowPlanningVisit.getPreviousStandstill() instanceof TimeWindowedPlanningVisit) {
shadowPlanningVisit = (TimeWindowedPlanningVisit) shadowPlanningVisit.getPreviousStandstill();
} else {
break;
}
}
//calculate the first stop in the chain, will be needed to get a running capacity total at each stop
//we broadcast the running total so that we can determine if we ever exceed vehicle capacity
TimeWindowedPlanningVisit firstVisit = shadowPlanningVisit;
// begin at the first stop and evaluate all of the stops to see what capacity we will be leaving the depot with
// the capacity will be a sum of all the items that need to be dropped (delivered) at the location.
long runningCapacity = 0;
while (shadowPlanningVisit != null) {
if (shadowPlanningVisit.isWarehousePickup()) {
runningCapacity += shadowPlanningVisit.getDropWeight();
}
shadowPlanningVisit = shadowPlanningVisit.getNextPlanningVisit();
}
shadowPlanningVisit = firstVisit;
// now that we know the full capcity we will be leaving the depot with, calculate the capacity at each
// stop, accounting for capacity being dropped (delivered) and picked up (returned) along the way
while (shadowPlanningVisit != null) {
runningCapacity -= shadowPlanningVisit.getDropWeight();
runningCapacity += shadowPlanningVisit.getPickupWeight();
if (!Objects.equals(runningCapacity, shadowPlanningVisit.getWeightUsedAtEndOfVisit())) {
scoreDirector.beforeVariableChanged(shadowPlanningVisit, "weightUsedAtEndOfVisit");
shadowPlanningVisit.setWeightUsedAtEndOfVisit(runningCapacity);
scoreDirector.afterVariableChanged(shadowPlanningVisit, "weightUsedAtEndOfVisit");
}
shadowPlanningVisit = shadowPlanningVisit.getNextPlanningVisit();
}
}
}
}
Constraint Class
protected Constraint vehicleCapacityStopLevel(ConstraintFactory factory) {
System.out.println("vehicleCapacityStopLevel...");
return factory.from(TimeWindowedPlanningVisit.class)
.filter(visit -> visit.getWeightUsedAtEndOfVisit() > visit.getVehicle().getWeight())
.penalizeLong("vehicle capacity exceeded at stop",
BendableLongScore.ofHard(2, 1, 0, 1),
visit -> visit.getWeightUsedAtEndOfVisit() - visit.getVehicle().getWeight());
}

Answer 1

Your #CustomShadowVariable should have a sources field, and not a variableListenerRef value. The latter is to piggy-back on another custom shadow variable's variable listener.
This is also an issue in optaplanner, because a variableListenerRef should fail fast if it doesn't lead to a custom shadow variable. We'll confirm and fix that.