leftmostselectionpolicy.java

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则

package org.mandarax.reference;

/*
 * 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
 */
import org.mandarax.kernel.Clause;
import org.mandarax.kernel.SelectionPolicy;

/**
 * Simple selection policy - just use the natural order of the
 * negative literals of the goal.
 * @author <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</A>
 * @version 3.4 <7 March 05>
 * @since 1.1
 */
public final class LeftMostSelectionPolicy implements SelectionPolicy {

	/**
	 * Return an array of integers specifying in which order the inference engine
	 * should attempt to unify the literals with the candidate.
	 * @return int[] the indices
	 * @param goal the goal
	 * @param appliedClause the clause that should be used to prove the goal
	 */
	public int[] getOrderedPositions(Clause goal, Clause appliedClause) {
		int   l         = goal.getNegativeLiterals ().size ();
		int[] positions = new int[l];

		for(int i = 0; i < l; i++) {
			positions[i] = i;
		}

		return positions;
	}
}