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     * Implementations manage collections for rules.
029     * Rules itself shall not maintain collections of 
030     * facts and objects, but use CollectionManager.
031     * 
032     * @author Pavel Vlasov
033     * @version ${Revision}
034     */
035    public interface CollectionManager extends Negatable {
036            
037            /**
038             * Retrieves collection from the manager.
039             * If a collection for this name doesn't exist it 
040             * should be created.
041             * @param ruleName Name of the rule this collection belongs to.
042             * @param collectionName Name of the collection withing the rule.
043             * @return Collection, never null.
044             * @param lock Collection monitor for synchronization.
045             */
046            Collection get(String ruleName, String collectionName, Object lock);
047            
048    
049            /**
050             * Clears all collections.
051             */
052            void clear();   
053    }