/*
 * Copyright (C) 1999-2004 <a href="mailto:mandarax@jbdietrich.com">Jens Dietrich</a>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package org.mandarax.kernel;

import ws.prova.parser.ParsingException;

/**
 * Interface for object owning knowledge (represented as clause sets). The interface
 * defines methods to retrieve this knowledge.
 * @author <A HREF="mailto:mandarax@jbdietrich.com">Jens Dietrich</A>
 * @version 3.3.1 <9 August 2004>
 * @since 1.1
 */
public interface KnowledgeOwner extends java.io.Serializable {

    /**
     * Iterate over all clauses.
     * @return a clause iterator
     * @throws ClauseSetException
     */
    org.mandarax.util.ClauseIterator clauses() throws ClauseSetException;

    /**
     * Get an iterator for clauses. The clause passed represents a query
     * which can be used to restrict the clause set. E.g., if the clause
     * iterator is built from database objects, and some of the variables
     * in the query clause are already replaced by constants, these constants
     * might be used to form a <code>WHERE</code> clause restricting the set of database objects
     * used to establish the clauses. The additional parameter provides a general
     * purpose interface to pass additional information, e.g. to sort the clause
     * set.
     * @return a clause iterator
     * @param query the query clause
     * @param additionalParameter an optional additional parameter
     * @throws ClauseSetException
     */
    org.mandarax.util.ClauseIterator clauses(Clause query, Object additionalParameter)
            throws ClauseSetException, ParsingException;
}
