001    /*
002     * hammurapi-rules @mesopotamia.version@
003     * Hammurapi rules engine. 
004     * Copyright (C) 2005  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;
024    
025    import java.util.Collection;
026    
027    /**
028     * This interface is a facade for object dispatchers.
029     * Rule containers shall implement this interface.
030     * @author Pavel Vlasov
031     * @revision $Revision$
032     */
033    public interface KnowledgeBase {
034            
035            /**
036             * Interface for dispatching commands to knowledge bases.
037             * @author Pavel
038             */
039            public interface KnowledgeBaseCommand {
040    
041                    /**
042                     * Knowledge base invokes this method when 
043                     * instance of command is dispatched to it.
044                     * @param knowledgeBase
045                     */
046                    void execute(KnowledgeBase knowledgeBase);
047            }
048            
049            /**
050             * Adds object to the knowledge base.
051             * @param obj
052             */
053            void add(Object obj);
054            
055            /**
056             * Removes object from the knowledge base
057             * and all conclusions based on this object.
058             * @param obj
059             */
060            void remove(Object obj);
061            
062            /**
063             * Executes rules
064             */
065            void executeRules();
066    
067            /**
068             * @return Collection of rule instances in the knowledge base.
069             */
070            Collection getRules();
071            
072            /**
073             * Resets rules state (if any).
074             */
075            void reset();
076    
077    }