testrecursion1.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 test.org.mandarax.reference;

import java.util.Iterator;
import org.mandarax.kernel.*;
import org.mandarax.lib.math.IntArithmetic;
import org.mandarax.reference.AbstractResolutionInferenceEngine;
import org.mandarax.util.LogicFactorySupport;

/**
 * Test recursion. Uses the factorial example. 
 * In particular, we test whether terms are simplified using semantic evaluation 
 * within the scope of a simple predicate. 
 * @author <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</A>
 * @version 3.4 <7 March 05>
 * @since 3.3
 */
public class TestRecursion1 extends MandaraxTestCase {
	private KnowledgeBase kb = null;
	private InferenceEngine ie = null;
	private Predicate p = null;
	/**
	 * Constructor.
	 * @param testName the name of the test
	 */
	public TestRecursion1(String testName, KnowledgeBase aKnowledgeBase, InferenceEngine anInferenceEngine) {
		super(testName);
        kb = aKnowledgeBase;
        ie = anInferenceEngine;
	}
	/**
	 * Set up the test case.
	 */
	public void setUp() throws Exception {
		super.setUp();
		
		//BasicConfigurator.configure();
		//Logger.getRoot().setLevel(Level.DEBUG);
		
		// init kb
		// the order does matter, but problems can be avoided by setting the appropriate kb comparator,
		// or by adding another prereq to the rule
		LogicFactorySupport lfs = new LogicFactorySupport();
		p = new SimplePredicate("factorial",new Class[]{Integer.class,Integer.class});
		// fact factorial(1,1)
		Fact f = lfs.fact(p,new Integer(1),new Integer(1));
		kb.add(f);
		// rule if factorial(n-1,k) then factorial(n,n*k)
		Rule r = lfs.rule(
				lfs.prereq(
						p,
						lfs.cplx(IntArithmetic.MINUS,lfs.variable("n",Integer.class),new Integer(1)),	
						lfs.variable("k",Integer.class)
				),
				lfs.fact(
						p,
						lfs.variable("n",Integer.class),
						lfs.cplx(IntArithmetic.TIMES,lfs.variable("n",Integer.class),lfs.variable("k",Integer.class))
				)
		);
		kb.add(r);
		
		LOG_TEST.debug("Setup test case " + this);
		LOG_TEST.debug("kb contains:");
		for (Iterator iter = kb.getClauseSets().iterator();iter.hasNext();) {
			LOG_TEST.debug(iter.next().toString());
		}
	}
	/**
	 * Build a query for a certain number.
	 * @param i
	 * @return a query
	 */
	private Query buildQuery(int i) {
		LogicFactorySupport lfs = new LogicFactorySupport();
		// query ? factorial(i,i)
		Query q = lfs.query(
				lfs.fact(p,new Integer(i),lfs.variable("x",Integer.class)),				
				"?factorial(" + i + ")"
		);
		LOG_TEST.debug("Query is : " + q.getFacts()[0]);
		return q;
	}
	/**
	 * Private test method.
	 * @param i a number
	 */
	private void test(int i) throws Exception {
		// this number of steps should be sufficient
		if (ie instanceof AbstractResolutionInferenceEngine) ((AbstractResolutionInferenceEngine)ie).setMaxSteps(100);
		
		Query q = buildQuery(i);
		ResultSet rs = ie.query(q,kb,InferenceEngine.ONE,InferenceEngine.BUBBLE_EXCEPTIONS);
		rs.next();
		int computed = ((Integer)rs.getResult(Integer.class,"x")).intValue();
		int expected = factorial(i);
		rs.close();
		assertTrue(computed==expected);
	}
	/**
	 * Compute the factorial for a certain number.
	 * @param i a number
	 * @return the factorial of this number
	 */
	private int factorial(int i) {
		if (i==0) return 1;
		else return i*factorial(i-1);
	}
	/**
	 * Test method.
	 */
	public void test1() throws Exception {
		test(1);
	}
	/**
	 * Test method.
	 */
	public void test2() throws Exception {
		test(2);
	}
	/**
	 * Test method.
	 */
	public void test3() throws Exception {
		test(3);
	}
	/**
	 * Test method.
	 */
	public void test4() throws Exception {
		test(4);
	}
	/**
	 * Test method.
	 */
	public void test5() throws Exception {
		test(5);
	}
	/**
	 * Test method.
	 */
	public void test6() throws Exception {
		test(10);
	}	
	/**
	 * Test method.
	 */
	public void test7() throws Exception {
		test(30);
	}		
}