001package net.sf.cpsolver.exam.criteria; 002 003import java.util.Map; 004import java.util.Set; 005 006import net.sf.cpsolver.exam.model.Exam; 007import net.sf.cpsolver.exam.model.ExamPeriod; 008import net.sf.cpsolver.exam.model.ExamPlacement; 009import net.sf.cpsolver.exam.model.ExamStudent; 010import net.sf.cpsolver.ifs.solver.Solver; 011import net.sf.cpsolver.ifs.util.DataProperties; 012 013/** 014 * Number of back-to-back student conflicts. I.e., number of cases when 015 * an exam is attended by a student that attends some other exam at 016 * the previous {@link ExamPeriod#prev()} or following 017 * {@link ExamPeriod#next()} period. If 018 * {@link StudentBackToBackConflicts#isDayBreakBackToBack()} is false, back-to-back conflicts 019 * are only considered between consecutive periods that are of the same day. 020 * <br><br> 021 * Back-to-back student conflict weight can be set by problem property 022 * Exams.BackToBackConflictWeight, or in the input xml file, 023 * property backToBackConflictWeight. 024 * 025 * 026 * <br> 027 * 028 * @version ExamTT 1.2 (Examination Timetabling)<br> 029 * Copyright (C) 2008 - 2012 Tomáš Müller<br> 030 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br> 031 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br> 032 * <br> 033 * This library is free software; you can redistribute it and/or modify 034 * it under the terms of the GNU Lesser General Public License as 035 * published by the Free Software Foundation; either version 3 of the 036 * License, or (at your option) any later version. <br> 037 * <br> 038 * This library is distributed in the hope that it will be useful, but 039 * WITHOUT ANY WARRANTY; without even the implied warranty of 040 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 041 * Lesser General Public License for more details. <br> 042 * <br> 043 * You should have received a copy of the GNU Lesser General Public 044 * License along with this library; if not see 045 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>. 046 */ 047public class StudentBackToBackConflicts extends ExamCriterion { 048 private boolean iDayBreakBackToBack = false; 049 050 @Override 051 public boolean init(Solver<Exam, ExamPlacement> solver) { 052 boolean ret = super.init(solver); 053 iDayBreakBackToBack = solver.getProperties().getPropertyBoolean("Exams.IsDayBreakBackToBack", iDayBreakBackToBack); 054 return ret; 055 } 056 057 @Override 058 public String getWeightName() { 059 return "Exams.BackToBackConflictWeight"; 060 } 061 062 @Override 063 public String getXmlWeightName() { 064 return "backToBackConflictWeight"; 065 } 066 067 @Override 068 public double getWeightDefault(DataProperties config) { 069 return 10.0; 070 } 071 072 /** 073 * True when back-to-back student conflict is to be encountered when a 074 * student is enrolled into an exam that is on the last period of one day 075 * and another exam that is on the first period of the consecutive day. It 076 * can be set by problem property Exams.IsDayBreakBackToBack, or in the 077 * input xml file, property isDayBreakBackToBack) 078 */ 079 public boolean isDayBreakBackToBack() { 080 return iDayBreakBackToBack; 081 } 082 083 /** 084 * True when back-to-back student conflict is to be encountered when a 085 * student is enrolled into an exam that is on the last period of one day 086 * and another exam that is on the first period of the consecutive day. It 087 * can be set by problem property Exams.IsDayBreakBackToBack, or in the 088 * input xml file, property isDayBreakBackToBack) 089 * 090 */ 091 public void setDayBreakBackToBack(boolean dayBreakBackToBack) { 092 iDayBreakBackToBack = dayBreakBackToBack; 093 } 094 095 @Override 096 public void getXmlParameters(Map<String, String> params) { 097 params.put(getXmlWeightName(), String.valueOf(getWeight())); 098 params.put("isDayBreakBackToBack", isDayBreakBackToBack() ? "true" : "false"); 099 } 100 101 @Override 102 public void setXmlParameters(Map<String, String> params) { 103 try { 104 setWeight(Double.valueOf(params.get(getXmlWeightName()))); 105 } catch (NumberFormatException e) {} catch (NullPointerException e) {} 106 try { 107 setDayBreakBackToBack("true".equals(params.get("isDayBreakBackToBack"))); 108 } catch (NumberFormatException e) {} catch (NullPointerException e) {} 109 } 110 111 @Override 112 public double getValue(ExamPlacement value, Set<ExamPlacement> conflicts) { 113 Exam exam = value.variable(); 114 int penalty = 0; 115 for (ExamStudent s : exam.getStudents()) { 116 if (value.getPeriod().prev() != null) { 117 if (isDayBreakBackToBack() || value.getPeriod().prev().getDay() == value.getPeriod().getDay()) { 118 Set<Exam> exams = s.getExams(value.getPeriod().prev()); 119 int nrExams = exams.size() + (exams.contains(exam) ? -1 : 0); 120 penalty += nrExams; 121 } 122 } 123 if (value.getPeriod().next() != null) { 124 if (isDayBreakBackToBack() || value.getPeriod().next().getDay() == value.getPeriod().getDay()) { 125 Set<Exam> exams = s.getExams(value.getPeriod().next()); 126 int nrExams = exams.size() + (exams.contains(exam) ? -1 : 0); 127 penalty += nrExams; 128 } 129 } 130 } 131 return penalty; 132 } 133 134 @Override 135 public String getName() { 136 return "Back-To-Back Conflicts"; 137 } 138 139 @Override 140 public void getInfo(Map<String, String> info) { 141 if (getValue() != 0.0) 142 info.put(getName(), sDoubleFormat.format(getValue())); 143 } 144 145 @Override 146 public String toString() { 147 return "BTB:" + sDoubleFormat.format(getValue()); 148 } 149}