abstractautofactiterator.java

来自「Mandarax是一个规则引擎的纯Java实现。它支持多类型的事实和基于反映的规」· Java 代码 · 共 57 行

/*
 * Copyright (C) 1999-2004 <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">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.*;

/**
 * Abstract clause iterator used by auto facts.
 * @author <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</A>
 * @version 3.4 <7 March 05>
 * @since 1.2
 */
abstract class AbstractAutoFactIterator extends AbstractClauseIterator {

	protected AutoFacts autofacts = null;

	/**
	 * Constructor.
	 * @param af the client object
	 */
	public AbstractAutoFactIterator(AutoFacts af) {
		autofacts = af;
	}

	/**
	 * Perform a fact (e.g., resolve functions and predicates).
	 * Return true if the predicate (JPredicate) returns true!
	 * @param f the fact
	 * @param session a session
	 * @return the result of performing the fact
	 */
	protected boolean perform(Fact f,Session session) {
		try {
			return ((Boolean) f.resolve(session)).booleanValue();
		}
		catch (Throwable t) {
			return false;
		}
	}

}