package org.drools.examples.helloworld;
/*
* $Id: HelloWorldNative.java,v 1.9 2005/12/30 05:38:32 michaelneale Exp $
*
* Copyright 2004 (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 bob@werken.com.
*
* 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.DroolsException;
import org.drools.RuleBase;
import org.drools.WorkingMemory;
import org.drools.event.DebugWorkingMemoryEventListener;
import org.drools.io.ReteDumper;
import org.drools.reteoo.HelloWorldBuilder;
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.Tuple;
/**
* This simple Hello World example demonstrates how to build a native RuleSet
* without using one of the many Semantic Modules. It is an ideal examples to
* learn what is happening under the hood. It is accompanied by
* HelloWorldBuilder which is a simplified Rete builder to illustrate what
* happens in org.drools.reteoo.Builder
*/
public class HelloWorldNative
{
public static void main(String[] args) throws DroolsException
{
Rule helloRule = new Rule( "Hello World" );
Rule goodbyeRule = new Rule( "Goodbye Cruel World" );
Rule debugRule = new Rule( "Debug" );
/*
* Reuse the Java semantics ObjectType so Drools can identify String and
* Object
*/
ClassObjectType StringType = new ClassObjectType( String.class );
ClassObjectType ObjectType = new ClassObjectType( Object.class );
/*
* Build the declaration and specify it as a parameter of the hello Rule
*/
final Declaration helloDeclaration = helloRule.addParameterDeclaration( "hello",
StringType );
/*
* Build the declaration and specify it as a parameter of the goodbye
* Rule
*/
final Declaration goodbyeDeclaration = goodbyeRule.addParameterDeclaration( "goodbye",
StringType );
/*
* Build the declaration and specify it as a parameter of the debug Rule
*/
final Declaration debugDeclaration = debugRule.addParameterDeclaration( "object",
ObjectType );
/*
* Build and Add the Condition to the hello Rule
*/
Condition conditionHello = new Condition( )
{
public boolean isAllowed(Tuple tuple)
{
String hello = (String) tuple.get( helloDeclaration );
if ( hello == null ) return false;
if ( hello.equals( "Hello" ) ) return true;
return false;
}
public Declaration[] getRequiredTupleMembers()
{
return new Declaration[]{helloDeclaration};
}
};
helloRule.addCondition( conditionHello );
/*
* Build and Add the Condition to the goodbye Rule
*/
Condition conditionGoodbye = new Condition( )
{
public boolean isAllowed(Tuple tuple)
{
String goodbye = (String) tuple.get( goodbyeDeclaration );
if ( goodbye == null ) return false;
if ( goodbye.equals( "Goodbye" ) ) return true;
return false;
}
public Declaration[] getRequiredTupleMembers()
{
return new Declaration[]{goodbyeDeclaration};
}
};
goodbyeRule.addCondition( conditionGoodbye );
// No condition to build and add to the debug Rule
/*
* Build and Add the Consequence to the hello Rule
*/
Consequence helloConsequence = new Consequence( )
{
public void invoke(Tuple tuple)
{
String hello = (String) tuple.get( helloDeclaration );
System.out.println( hello + " World" );
}
};
helloRule.setConsequence( helloConsequence );
/*
* Build and Add the Consequence to the goodbye Rule
*/
Consequence goodbyeConsequence = new Consequence( )
{
public void invoke(Tuple tuple)
{
String goodbye = (String) tuple.get( goodbyeDeclaration );
System.out.println( goodbye + " Cruel World" );
}
};
goodbyeRule.setConsequence( goodbyeConsequence );
/*
* Build and Add the Consequence to the debug Rule
*/
Consequence debugConsequence = new Consequence( )
{
public void invoke(Tuple tuple)
{
Object object = tuple.get( debugDeclaration );
System.out.println( "Asserted object: " + object );
}
};
debugRule.setConsequence( debugConsequence );
RuleSet ruleSet = new RuleSet( "Hello World Example" );
ruleSet.addRule( helloRule );
ruleSet.addRule( goodbyeRule );
ruleSet.addRule( debugRule );
HelloWorldBuilder builder = new HelloWorldBuilder( ruleSet );
RuleBase ruleBase = builder.buildRuleBase( );
System.out.println( "DUMP RETE" );
System.out.println( "---------" );
ReteDumper dumper = new ReteDumper( ruleBase );
dumper.dumpRete( System.out );
System.out.println( "FIRE RULES(Hello)" );
System.out.println( "----------" );
WorkingMemory workingMemory = ruleBase.newWorkingMemory( );
workingMemory.addEventListener( new DebugWorkingMemoryEventListener( ) );
workingMemory.assertObject( "Hello" );
workingMemory.fireAllRules( );
System.out.println( "\n" );
System.out.println( "FIRE RULES(GoodBye)" );
System.out.println( "----------" );
workingMemory = ruleBase.newWorkingMemory( );
workingMemory.addEventListener( new DebugWorkingMemoryEventListener( ) );
workingMemory.assertObject( "Goodbye" );
workingMemory.fireAllRules( );
}
}