    001package org.cpsolver.coursett.preference;
    002
    003import org.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 1.3 (University Course Timetabling)<br>
    016 *          Copyright (C) 2006 - 2014 Tomáš Müller<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 */
    034public abstract class PreferenceCombination {
    035    boolean iIsRequired = false;
    036    boolean iIsProhibited = false;
    037
    038    /** Add preference a preference
    039     * @param prologPref prolog preference (R for required, P for prohibited, -2 strongly preferred, ... 2 strongly discouraged)
    040     **/
    041    public void addPreferenceProlog(String prologPref) {
    042        addPreferenceInt(Constants.preference2preferenceLevel(prologPref));
    043    }
    044
    045    /** Returns combined preference from the given preferences
    046     * @param intPref preference
    047     **/
    048    public void addPreferenceInt(int intPref) {
    049        String prologPref = Constants.preferenceLevel2preference(intPref);
    050        if (Constants.sPreferenceRequired.equals(prologPref))
    051            iIsRequired = true;
    052        if (Constants.sPreferenceProhibited.equals(prologPref))
    053            iIsProhibited = true;
    054    }
    055
    056    public boolean isRequired() {
    057        return iIsRequired && !iIsProhibited;
    058    }
    059
    060    public boolean isProhibited() {
    061        return iIsProhibited;
    062    }
    063
    064    public abstract int getPreferenceInt();
    065
    066    public String getPreferenceProlog() {
    067        if (iIsProhibited)
    068            return Constants.sPreferenceProhibited;
    069        if (iIsRequired)
    070            return Constants.sPreferenceRequired;
    071        return Constants.preferenceLevel2preference(getPreferenceInt());
    072    }
    073
    074    public static PreferenceCombination getDefault() {
    075        return new SumPreferenceCombination();
    076    }
    077}