package org.mandarax.kernel;

/*
 * 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
 */


/**
 * Interface for prerequisites used in the bodies of rules.
 * @see org.mandarax.kernel.Rule
 * @see org.mandarax.kernel.LogicFactory
 * @author <A HREF="mailto:mandarax@jbdietrich.com">Jens Dietrich</A>
 * @version 3.3.1 <9 August 2004>
 * @since 2.0
 * [Prova] Re-integration modifications
 * @author <A HREF="mailto:a.kozlenkov@city.ac.uk">Alex Kozlenkov</A>
 * @version 3.3.1 <9 August 2004>
 */
public interface Prerequisite extends Fact {

	/**
	 * Set the negated (as failure) flag.
	 * @param value true or false
	 */
	void setNegatedAF(boolean value);

	/**
	 *
	 * @return Object
	 */
	public Object getExtra();

	/**
	 *
	 * @param _cutPredicate Object
	 */
	public void setExtra( Object _cutPredicate );
	}
