001 package net.sf.cpsolver.coursett.preference;
002
003 import net.sf.cpsolver.coursett.Constants;
004
005 /**
006 * Preference combination. <br>
007 * <br>
008 * A preference can be:
009 * <ul>
010 * <li>R .. required
011 * <li>P .. prohibited
012 * <li>number .. soft preference (smaller value is better)
013 * </ul>
014 *
015 * @version CourseTT 1.2 (University Course Timetabling)<br>
016 * Copyright (C) 2006 - 2010 Tomas Muller<br>
017 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
018 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
019 * <br>
020 * This library is free software; you can redistribute it and/or modify
021 * it under the terms of the GNU Lesser General Public License as
022 * published by the Free Software Foundation; either version 3 of the
023 * License, or (at your option) any later version. <br>
024 * <br>
025 * This library is distributed in the hope that it will be useful, but
026 * WITHOUT ANY WARRANTY; without even the implied warranty of
027 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
028 * Lesser General Public License for more details. <br>
029 * <br>
030 * You should have received a copy of the GNU Lesser General Public
031 * License along with this library; if not see
032 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
033 */
034 public abstract class PreferenceCombination {
035 boolean iIsRequired = false;
036 boolean iIsProhibited = false;
037
038 /** Add preference a preference */
039 public void addPreferenceProlog(String prologPref) {
040 addPreferenceInt(Constants.preference2preferenceLevel(prologPref));
041 }
042
043 /** Returns combined preference from the given preferences */
044 public void addPreferenceInt(int intPref) {
045 String prologPref = Constants.preferenceLevel2preference(intPref);
046 if (Constants.sPreferenceRequired.equals(prologPref))
047 iIsRequired = true;
048 if (Constants.sPreferenceProhibited.equals(prologPref))
049 iIsProhibited = true;
050 }
051
052 public boolean isRequired() {
053 return iIsRequired && !iIsProhibited;
054 }
055
056 public boolean isProhibited() {
057 return iIsProhibited;
058 }
059
060 public abstract int getPreferenceInt();
061
062 public String getPreferenceProlog() {
063 if (iIsProhibited)
064 return Constants.sPreferenceProhibited;
065 if (iIsRequired)
066 return Constants.sPreferenceRequired;
067 return Constants.preferenceLevel2preference(getPreferenceInt());
068 }
069
070 public static PreferenceCombination getDefault() {
071 return new SumPreferenceCombination();
072 }
073 }