ternaryintarithmeticpredicate.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

/*
 * 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.lib.math;


import org.mandarax.kernel.*;

/**
 * Abstract superclass for double arithmetic predicates with three arguments.
 * @author <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</A>
 * @version 3.4 <7 March 05>
 * @since 1.4  (in 1.3 in the renamed package org.mandarax.math)
 */
public abstract class TernaryIntArithmeticPredicate extends org.mandarax.lib.AbstractPredicate {

    private static Class[] structure = { Integer.class, Integer.class,Integer.class };

    /**
     * Evaluate the three values using the predicate.
     * @return true or false
     * @param d1 value 1
     * @param d2 value 2
     * @param d3 value 3
     */
    protected abstract boolean evaluate(int d1, int d2, int d3);

    /**
     * Get the structure of the predicate.
     * @return the structure of the predicate
     */
    public Class[] getStructure() {
        return structure;
    }

    /**
     * Perform the function or predicate using an array of terms as parameters.
     * @return java.lang.Object
     * @param parameter org.mandarax.kernel.Term[]
     * @param session a session object
     * @throws java.lang.UnsupportedOperationException
     * @throws java.lang.IllegalArgumentException
     */
    public Object perform(Term[] parameter,Session session)
            throws IllegalArgumentException, UnsupportedOperationException {
        int d1, d2, d3;

        try {
            d1 = ((Number) (parameter[0].resolve (session))).intValue ();
            d2 = ((Number) (parameter[1].resolve (session))).intValue ();
            d3 = ((Number) (parameter[2].resolve (session))).intValue ();
        } catch(Exception x) {
            throw new IllegalArgumentException ();
        }

        return(evaluate (d1, d2, d3))
              ? Boolean.TRUE
              : Boolean.FALSE;
    }

    /**
     * Convert the object to a string.
     * @return a string
     */
    public String toString() {
        return(getName () == null)
              ? super.toString ()
              : getName ();
    }
}