001package org.cpsolver.studentsct.heuristics.studentord; 002 003import org.cpsolver.ifs.util.DataProperties; 004import org.cpsolver.studentsct.model.CourseRequest; 005import org.cpsolver.studentsct.model.Request; 006import org.cpsolver.studentsct.model.Student; 007 008/** 009 * Return the given set of students in an order of average course request 010 * time stamp {@link CourseRequest#getTimeStamp()}. If the time stamp 011 * is the same (or not set), fall back to the number of choices 012 * (student with fewer choices first). 013 * 014 * @version StudentSct 1.3 (Student Sectioning)<br> 015 * Copyright (C) 2007 - 2019 Tomáš Müller<br> 016 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br> 017 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br> 018 * <br> 019 * This library is free software; you can redistribute it and/or modify 020 * it under the terms of the GNU Lesser General Public License as 021 * published by the Free Software Foundation; either version 3 of the 022 * License, or (at your option) any later version. <br> 023 * <br> 024 * This library is distributed in the hope that it will be useful, but 025 * WITHOUT ANY WARRANTY; without even the implied warranty of 026 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 027 * Lesser General Public License for more details. <br> 028 * <br> 029 * You should have received a copy of the GNU Lesser General Public 030 * License along with this library; if not see 031 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>. 032 */ 033public class StudentByRequestDate extends StudentChoiceOrder { 034 035 public StudentByRequestDate(DataProperties config) { 036 super(config); 037 } 038 039 public Long getRequestDate(Student s) { 040 long total = 0, cnt = 0; 041 for (Request r: s.getRequests()) { 042 if (r instanceof CourseRequest) { 043 CourseRequest cr = (CourseRequest)r; 044 if (cr.getTimeStamp() != null) { 045 total += cr.getTimeStamp(); 046 cnt ++; 047 } 048 } 049 } 050 if (cnt > 0) 051 return total / cnt; 052 return Long.MAX_VALUE; 053 } 054 055 @Override 056 public int compare(Student s1, Student s2) { 057 int cmp = getRequestDate(s1).compareTo(getRequestDate(s2)); 058 if (cmp != 0) return (isReverse() ? -1 : 1) * cmp; 059 return - super.compare(s1, s2); 060 } 061}