Every week, a hospital needs to create a nurse roster. That roster needs to continue from last week's roster, without changing the past. Also, nurses want to know their free days weeks in advance. This is known as the problem of continuous planning . Here's a video how Drools Planner deals with it.







This implementation is based on immovable planning entities , which works just as well for other use cases (such as vehicle routing, course scheduling, task scheduling, ...).

Immovable planning entities

Drools Planner 5.5.0.Beta1 will directly support immovable planning entities in the new selector framework, making it much easier to do continuous planning:



To make some planning entities immovable, simply add an entity SelectionFilter that returns true if an entity is movable and false if it is immovable:

public
 
class
 
MovableShiftAssignmentSelectionFilter
 
implements
 
SelectionFilter
<
ShiftAssignment
>
 
{


    
public
 
boolean
 accept
(
ScoreDirector
 scoreDirector
,
 
ShiftAssignment
 shiftAssignment
)
 
{

        
ShiftDate
 shiftDate 
=
 shiftAssignment
.
getShift
().
getShiftDate
();

        
NurseRoster
 nurseRoster 
=
 
(
NurseRoster
)
 scoreDirector
.
getWorkingSolution
();

        
return
 nurseRoster
.
getNurseRosterInfo
().
isInPlanningWindow
(
shiftDate
);

    
}


}

And configure it like this:

@
PlanningEntity
(
movableEntitySelectionFilter 
=
 
MovableShiftAssignmentSelectionFilter
.
class
)

public
 
class
 
ShiftAssignment
 
{

    
...

}