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    }