/*
 * 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.util;


import org.mandarax.kernel.Clause;
import org.mandarax.kernel.ClauseSetException;
import ws.prova.parser.ParsingException;

/**
 * Iterator for clauses. The iterator provides a simple mean for
 * iterating but avoiding casting as it is the case when using
 * the <code>java.util.Enumeration</code> or <code>java.util.Iterator</code>
 * interface. But both interfaces are also supported (i.e., extended).
 * @author <A HREF="mailto:mandarax@jbdietrich.com">Jens Dietrich</A>
 * @version 3.3.1 <9 August 2004>
 * @since 1.0
 */
public interface ClauseIterator extends java.util.Enumeration, java.util.Iterator {

    /**
     * Indicates whether there are more clauses.
     * @return true if there are more clauses, false otherwise
     * @throws ClauseSetException
     */
    boolean hasMoreClauses() throws ClauseSetException, ParsingException;

    /**
     * Get the next clause.
     * @return the next clause
     * @throws ClauseSetException
     */
    Clause nextClause() throws ClauseSetException;
    /**
     * Close the iterator and release all resources.
     * New in 2.0 - the main motivation is to have a method
     * to release jdbc connections and other external resources.
     */
    void close();
}
