/**
* Check assignments of the given exams
*
* @param first assignment of the first exam
* @param second assignment of the second exam
* @return true, if the constraint is satisfied
*/
public boolean check(ExamPlacement first, ExamPlacement second) {
switch (getType()) {
case sDistPrecedence:
return first.getPeriod().getIndex() < second.getPeriod().getIndex();
case sDistPrecedenceRev:
return first.getPeriod().getIndex() > second.getPeriod().getIndex();
case sDistSamePeriod:
return first.getPeriod().getIndex() == second.getPeriod().getIndex();
case sDistDifferentPeriod:
return first.getPeriod().getIndex() != second.getPeriod().getIndex();
case sDistSameRoom:
return first.getRoomPlacements().containsAll(second.getRoomPlacements())
|| second.getRoomPlacements().containsAll(first.getRoomPlacements());
case sDistDifferentRoom:
for (Iterator<ExamRoomPlacement> i = first.getRoomPlacements().iterator(); i.hasNext(); )
if (second.getRoomPlacements().contains(i.next())) return false;
return true;
default:
return false;
}
}
/**
* Return true if this is hard constraint or this is a soft constraint without any violation
*
* @param p exam assignment to be made
*/
public boolean isSatisfied(ExamPlacement p) {
if (isHard()) return true;
switch (getType()) {
case sDistPrecedence:
ExamPeriod last = null;
for (Exam exam : variables()) {
ExamPlacement placement =
(p != null && exam.equals(p.variable()) ? p : exam.getAssignment());
if (placement == null) continue;
if (last == null || last.getIndex() < placement.getPeriod().getIndex())
last = placement.getPeriod();
else return false;
}
return true;
case sDistPrecedenceRev:
last = null;
for (Exam exam : variables()) {
ExamPlacement placement =
(p != null && exam.equals(p.variable()) ? p : exam.getAssignment());
if (placement == null) continue;
if (last == null || last.getIndex() > placement.getPeriod().getIndex())
last = placement.getPeriod();
else return false;
}
return true;
case sDistSamePeriod:
ExamPeriod period = null;
for (Exam exam : variables()) {
ExamPlacement placement =
(p != null && exam.equals(p.variable()) ? p : exam.getAssignment());
if (placement == null) continue;
if (period == null) period = placement.getPeriod();
else if (period.getIndex() != placement.getPeriod().getIndex()) return false;
}
return true;
case sDistDifferentPeriod:
HashSet<ExamPeriod> periods = new HashSet<ExamPeriod>();
for (Exam exam : variables()) {
ExamPlacement placement =
(p != null && exam.equals(p.variable()) ? p : exam.getAssignment());
if (placement == null) continue;
if (!periods.add(placement.getPeriod())) return false;
}
return true;
case sDistSameRoom:
Set<ExamRoomPlacement> rooms = null;
for (Exam exam : variables()) {
ExamPlacement placement =
(p != null && exam.equals(p.variable()) ? p : exam.getAssignment());
if (placement == null) continue;
if (rooms == null) rooms = placement.getRoomPlacements();
else if (!rooms.containsAll(placement.getRoomPlacements())
|| !placement.getRoomPlacements().containsAll(rooms)) return false;
}
return true;
case sDistDifferentRoom:
HashSet<ExamRoomPlacement> allRooms = new HashSet<ExamRoomPlacement>();
for (Exam exam : variables()) {
ExamPlacement placement =
(p != null && exam.equals(p.variable()) ? p : exam.getAssignment());
if (placement == null) continue;
for (ExamRoomPlacement room : placement.getRoomPlacements()) {
if (!allRooms.add(room)) return false;
}
}
return true;
default:
return false;
}
}
