org.cpsolver.exam.model.ExamStudent Maven / Gradle / Ivy
package org.cpsolver.exam.model;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.cpsolver.ifs.assignment.Assignment;
import org.cpsolver.ifs.model.Constraint;
/**
* A student.
*
*
* @author Tomas Muller
* @version ExamTT 1.3 (Examination Timetabling)
* Copyright (C) 2008 - 2014 Tomas Muller
* [email protected]
* http://muller.unitime.org
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 3 of the
* License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not see
* http://www.gnu.org/licenses/.
*/
public class ExamStudent extends Constraint {
private boolean iAllowDirectConflicts = true;
private List iOwners = new ArrayList();
private boolean[] iAvailable = null;
/**
* Constructor
*
* @param model
* examination timetabling model
* @param id
* student unique id
*/
public ExamStudent(ExamModel model, long id) {
super();
iAllowDirectConflicts = model.getProperties().getPropertyBoolean("Student.AllowDirectConflicts", iAllowDirectConflicts);
iId = id;
setModel(model);
}
/**
* True if direct student conflicts are allowed for this student
* @return direct conflicts are allowed
*/
public boolean isAllowDirectConflicts() {
return iAllowDirectConflicts;
}
/**
* Set whether direct student conflicts are allowed for this student
* @param allowDirectConflicts direct conflicts are allowed
*/
public void setAllowDirectConflicts(boolean allowDirectConflicts) {
iAllowDirectConflicts = allowDirectConflicts;
}
/**
* True if the given two exams can have a direct student conflict with this
* student, i.e., they can be placed at the same period.
*
* @param ex1
* an exam
* @param ex2
* an exam
* @return {@link ExamStudent#isAllowDirectConflicts()} and
* {@link Exam#isAllowDirectConflicts()} for both exams
*/
public boolean canConflict(Exam ex1, Exam ex2) {
return isAllowDirectConflicts() && ex1.isAllowDirectConflicts() && ex2.isAllowDirectConflicts();
}
/**
* Exam(s) enrolled by the student that are scheduled in the given period
* @param assignment current assignment
* @param period given period
* @return set of exams that this student is enrolled into and that are placed in the given period
*/
public Set getExams(Assignment assignment, ExamPeriod period) {
Set exams = ((ExamModel)getModel()).getStudentsOfPeriod(assignment, period).get(this);
return (exams != null ? exams : new HashSet());
// return getContext(assignment).getExams(period.getIndex());
}
/**
* Exam(s) enrolled by the student that are scheduled in the given day
* @param assignment current assignment
* @param period given period
* @return set of exams that this student is enrolled into and that are placed in the day of the given period
*/
public Set getExamsADay(Assignment assignment, ExamPeriod period) {
Set exams = ((ExamModel)getModel()).getStudentsOfDay(assignment, period).get(this);
return (exams != null ? exams : new HashSet());
// return getContext(assignment).getExamsOfDay(period.getDay());
}
/**
* Exam(s) enrolled by the student that are scheduled in the given day
* @param assignment current assignment
* @param day given day
* @return set of exams that this student is enrolled into and that are placed in the given day
*/
public Set getExamsADay(Assignment assignment, int day) {
Set exams = ((ExamModel)getModel()).getStudentsOfDay(assignment, day).get(this);
return (exams != null ? exams : new HashSet());
// return getContext(assignment).getExamsOfDay(day);
}
/**
* Compute conflicts between the given assignment of an exam and all the
* current assignments (of this student). Only not-allowed conflicts (see
* {@link ExamStudent#canConflict(Exam, Exam)} are considered.
*/
@Override
public void computeConflicts(Assignment assignment, ExamPlacement p, Set conflicts) {
Exam ex = p.variable();
Set exams = ((ExamModel)getModel()).getStudentsOfPeriod(assignment, p.getPeriod()).get(this);
if (exams != null)
for (Exam exam : exams) {
if (!canConflict(ex, exam))
conflicts.add(assignment.getValue(exam));
}
}
/**
* Check whether there is a conflict between the given assignment of an exam
* and all the current assignments (of this student). Only not-allowed
* conflicts (see {@link ExamStudent#canConflict(Exam, Exam)} are
* considered.
*/
@Override
public boolean inConflict(Assignment assignment, ExamPlacement p) {
Exam ex = p.variable();
Set exams = ((ExamModel)getModel()).getStudentsOfPeriod(assignment, p.getPeriod()).get(this);
if (exams != null)
for (Exam exam : exams) {
if (!canConflict(ex, exam))
return true;
}
return false;
}
/**
* True if the given exams can conflict (see
* {@link ExamStudent#canConflict(Exam, Exam)}), or if they are placed at
* different periods.
*/
@Override
public boolean isConsistent(ExamPlacement p1, ExamPlacement p2) {
return (p1.getPeriod() != p2.getPeriod() || canConflict(p1.variable(), p2.variable()));
}
/**
* Compare two student for equality
*/
@Override
public boolean equals(Object o) {
if (o == null || !(o instanceof ExamStudent))
return false;
ExamStudent s = (ExamStudent) o;
return getId() == s.getId();
}
/**
* Hash code
*/
@Override
public int hashCode() {
return (int) (getId() ^ (getId() >>> 32));
}
/**
* Student unique id
*/
@Override
public String toString() {
return String.valueOf(getId());
}
/**
* Compare two students (by student ids)
*/
@Override
public int compareTo(Constraint o) {
return toString().compareTo(o.toString());
}
/**
* Constraint is hard if {@link ExamStudent#isAllowDirectConflicts()} is
* false.
*/
@Override
public boolean isHard() {
return !isAllowDirectConflicts();
}
/**
* Courses and/or sections that this student is enrolled to
*
* @return list of {@link ExamOwner}
*/
public List getOwners() {
return iOwners;
}
/**
* True if the student is available (for examination timetabling) during the
* given period
*
* @param period
* a period
* @return true if a student can attend an exam at the given period, false
* if otherwise
*/
public boolean isAvailable(ExamPeriod period) {
return (iAvailable == null ? true : iAvailable[period.getIndex()]);
}
/**
* Set whether the student is available (for examination timetabling) during
* the given period
*
* @param period
* a period
* @param available
* true if a student can attend an exam at the given period,
* false if otherwise
*/
public void setAvailable(int period, boolean available) {
if (iAvailable == null) {
iAvailable = new boolean[((ExamModel)getModel()).getNrPeriods()];
for (int i = 0; i < iAvailable.length; i++)
iAvailable[i] = true;
}
iAvailable[period] = available;
}
/*
@Override
public Context createAssignmentContext(Assignment assignment) {
return new Context(assignment);
}
public class Context implements AssignmentConstraintContext {
private Set[] iTable;
private Set[] iDayTable;
@SuppressWarnings("unchecked")
public Context(Assignment assignment) {
ExamModel model = (ExamModel)getModel();
iTable = new Set[model.getNrPeriods()];
for (int i = 0; i < iTable.length; i++)
iTable[i] = new HashSet();
iDayTable = new Set[model.getNrDays()];
for (int i = 0; i < iDayTable.length; i++)
iDayTable[i] = new HashSet();
for (Exam exam: variables()) {
ExamPlacement placement = assignment.getValue(exam);
if (placement != null)
assigned(assignment, placement);
}
}
@Override
public void assigned(Assignment assignment, ExamPlacement placement) {
iTable[placement.getPeriod().getIndex()].add(placement.variable());
iDayTable[placement.getPeriod().getDay()].add(placement.variable());
}
@Override
public void unassigned(Assignment assignment, ExamPlacement placement) {
iTable[placement.getPeriod().getIndex()].remove(placement.variable());
iDayTable[placement.getPeriod().getDay()].remove(placement.variable());
}
public Set getExams(int period) { return iTable[period]; }
public Set getExamsOfDay(int day) { return iDayTable[day]; }
}
*/
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