fibonaccinative.java

rule engine drools-2.0-beta-18

package org.drools.examples.fibonacci;

/*
 * $Id: FibonacciNative.java,v 1.6 2004/11/17 16:29:37 dbarnett Exp $
 *
 * Copyright 2001-2003 (C) The Werken Company. All Rights Reserved.
 *
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided that the
 * following conditions are met:
 *
 * 1. Redistributions of source code must retain copyright statements and
 * notices. Redistributions must also contain a copy of this document.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. The name "drools" must not be used to endorse or promote products derived
 * from this Software without prior written permission of The Werken Company.
 * For written permission, please contact [e-mail].
 *
 * 4. Products derived from this Software may not be called "drools" nor may
 * "drools" appear in their names without prior written permission of The Werken
 * Company. "drools" is a trademark of The Werken Company.
 *
 * 5. Due credit should be given to The Werken Company. (http://werken.com/)
 *
 * THIS SOFTWARE IS PROVIDED BY THE WERKEN COMPANY AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE WERKEN COMPANY OR ITS CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 */

import org.drools.FactException;
import org.drools.RuleBase;
import org.drools.RuleBaseBuilder;
import org.drools.WorkingMemory;
import org.drools.reteoo.Dumper;
import org.drools.rule.Declaration;
import org.drools.rule.Rule;
import org.drools.rule.RuleSet;
import org.drools.semantics.base.ClassObjectType;
import org.drools.spi.Condition;
import org.drools.spi.Consequence;
import org.drools.spi.ConsequenceException;
import org.drools.spi.Tuple;

/**
 * This Fibonacci example demonstrates how to build a native RuleSet without
 * using one of the many Semantic Modules.
 */

public class FibonacciNative
{
    public static void main(String[] args) throws Exception
    {
        // <rule-set name="fibonacci" ...>
        RuleSet ruleSet = new RuleSet( "fibonacci" );

        // <rule name="Bootstrap 1" salience="20">
        final Rule bootstrap1Rule = new Rule( "Bootstrap 1" );
        bootstrap1Rule.setSalience( 20 );

        // Reuse the Java semantics ObjectType
        // so Drools can identify the Fibonacci class
        final ClassObjectType fibonacciType = new ClassObjectType( Fibonacci.class );

        // Build the declaration and specify it as a parameter of the Bootstrap1
        // Rule
        // <parameter identifier="f">
        //   <class>org.drools.examples.fibonacci.Fibonacci</class>
        // </parameter>
        final Declaration fDeclaration = bootstrap1Rule.addParameterDeclaration( "f", fibonacciType );

        // Build and Add the Condition to the Bootstrap1 Rule
        // <java:condition>f.getSequence() == 1</java:condition>
        final Condition conditionBootstrap1A = new Condition( )
        {
            public boolean isAllowed(Tuple tuple)
            {
                Fibonacci f = ( Fibonacci ) tuple.get( fDeclaration );
                return f.getSequence( ) == 1;
            }

            public Declaration[] getRequiredTupleMembers()
            {
                return new Declaration[]{fDeclaration};
            }

            public String toString()
            {
                return "f.getSequence() == 1";
            }
        };
        bootstrap1Rule.addCondition( conditionBootstrap1A );

        // <java:condition>f.getValue() == -1</java:condition>
        final Condition conditionBootstrap1B = new Condition( )
        {
            public boolean isAllowed(Tuple tuple)
            {
                Fibonacci f = ( Fibonacci ) tuple.get( fDeclaration );
                return f.getValue( ) == -1;
            }

            public Declaration[] getRequiredTupleMembers()
            {
                return new Declaration[]{fDeclaration};
            }

            public String toString()
            {
                return "f.getValue() == -1";
            }
        };
        bootstrap1Rule.addCondition( conditionBootstrap1B );

        // Build and Add the Consequence to the Bootstrap1 Rule
        // <java:consequence>
        //   f.setValue( 1 );
        //   System.err.println( f.getSequence() + " == " + f.getValue() );
        //   drools.modifyObject( f );
        // </java:consequence>
        final Consequence bootstrapConsequence = new Consequence( )
        {
            public void invoke(Tuple tuple, WorkingMemory workingMemory) throws ConsequenceException
            {
                Fibonacci f = ( Fibonacci ) tuple.get( fDeclaration );
                f.setValue( 1 );
                System.err.println( f.getSequence( ) + " == " + f.getValue( ) );

                try
                {
                    workingMemory.modifyObject( tuple.getFactHandleForObject( f ), f );
                }
                catch ( FactException e )
                {
                    throw new ConsequenceException( e );
                }
            }
        };
        bootstrap1Rule.setConsequence( bootstrapConsequence );
        ruleSet.addRule( bootstrap1Rule );

        // <rule name="Bootstrap 2">
        final Rule bootstrap2Rule = new Rule( "Bootstrap 2" );

        // Specify the declaration as a parameter of the Bootstrap2 Rule
        // <parameter identifier="f">
        //   <class>org.drools.examples.fibonacci.Fibonacci</class>
        // </parameter>
        final Declaration fDeclaration2 = bootstrap2Rule.addParameterDeclaration( "f", fibonacciType  );

        // Build and Add the Conditions to the Bootstrap1 Rule
        // <java:condition>f.getSequence() == 2</java:condition>
        final Condition conditionBootstrap2A = new Condition( )
        {
            public boolean isAllowed(Tuple tuple)
            {
                Fibonacci f = ( Fibonacci ) tuple.get( fDeclaration2 );
                return f.getSequence( ) == 2;
            }

            public Declaration[] getRequiredTupleMembers()
            {
                return new Declaration[]{fDeclaration2};
            }

            public String toString()
            {
                return "f.getSequence() == 2";
            }
        };
        bootstrap2Rule.addCondition( conditionBootstrap2A );

        // <java:condition>f.getValue() == -1</java:condition>
        final Condition conditionBootstrap2B = new Condition( )
        {
            public boolean isAllowed(Tuple tuple)
            {
                Fibonacci f = ( Fibonacci ) tuple.get( fDeclaration2 );
                return f.getValue( ) == -1;
            }

            public Declaration[] getRequiredTupleMembers()
            {
                return new Declaration[]{fDeclaration2};
            }

            public String toString()
            {
                return "f.getValue() == -1";
            }
        };
        bootstrap2Rule.addCondition( conditionBootstrap2B );

        // Build and Add the Consequence to the Bootstrap2 Rule
        // <java:consequence>
        //   f.setValue( 1 );
        //   System.err.println( f.getSequence() + " == " + f.getValue() );
        //   drools.modifyObject( f );
        // </java:consequence>
        final Consequence bootstrapConsequence2 = new Consequence( )
        {
            public void invoke(Tuple tuple, WorkingMemory workingMemory) throws ConsequenceException
            {
                Fibonacci f = ( Fibonacci ) tuple.get( fDeclaration2 );
                f.setValue( 1 );
                System.err.println( f.getSequence( ) + " == " + f.getValue( ) );

                try
                {
                    workingMemory.modifyObject( tuple.getFactHandleForObject( f ), f );
                }
                catch ( FactException e )
                {
                    throw new ConsequenceException( e );
                }
            }
        };
        bootstrap2Rule.setConsequence( bootstrapConsequence2 );
        ruleSet.addRule( bootstrap2Rule );

        // <rule name="Recurse" salience="10">
        final Rule recurseRule = new Rule( "Recurse" );