001    /*
002     * hammurapi-rules-tutorial @mesopotamia.version@
003     * Hammurapi rules tutorial. 
004     * Copyright (C) 2006  Hammurapi Group
005     *
006     * This program is free software; you can redistribute it and/or
007     * modify it under the terms of the GNU Lesser General Public
008     * License as published by the Free Software Foundation; either
009     * version 2 of the License, or (at your option) any later version.
010     *
011     * This program is distributed in the hope that it will be useful,
012     * but WITHOUT ANY WARRANTY; without even the implied warranty of
013     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014     * Lesser General Public License for more details.
015     *
016     * You should have received a copy of the GNU Lesser General Public
017     * License along with this library; if not, write to the Free Software
018     * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
019     *
020     * URL: http://http://www.hammurapi.biz
021     * e-Mail: support@hammurapi.biz
022     */
023    package biz.hammurapi.rules.tutorial.rules;
024    
025    import biz.hammurapi.rules.Rule;
026    import biz.hammurapi.rules.tutorial.conclusions.Father;
027    import biz.hammurapi.rules.tutorial.conclusions.Mother;
028    import biz.hammurapi.rules.tutorial.conclusions.Parent;
029    
030    public class ParentRules extends Rule { 
031                    
032            public ParentRules() {
033                    setMethodFactTypes(Parent.class, new Class[] { Father.class, Mother.class });
034            }
035            
036            /**
037             * Male parent is father, female parent is mother.
038             * @param parent
039             * @return Brother or Sister.
040             */
041            public Parent infer(Parent parent) {    
042                    
043                    if (parent.getSubject().isMale()) {
044                            if (!(parent instanceof Father)) {
045                                    return new  Father(parent.getSubject(), parent.getObject());
046                            }                       
047                    } else {
048                            if (!(parent instanceof Mother)) {
049                                    return new Mother(parent.getSubject(), parent.getObject());
050                            }                       
051                    }
052                    return null;
053            }
054    }