Rules Engine Working Memory in JBoss-Cache

[kieran]

I am placing the working memory of the drools open-source rules engine (http://drools.org/ using fishmonger example) into JBoss-Cache. I am using TreeCacheAOP, and am having problems with a single method call. I am driving this from Beanshell (adapted from runShellDemo):

The problem line of code is:
workingMemory.assertObject( cart );

which is responsible for storing an additional fact into the working memory.

The exception I receive is:
target exception: Sourced file:c:\jboss-cache\drools.bsh : Method Invocation workingMemory.assertObject: at Line 33 : in file: c:\jboss-cache\drools.bsh : workingMemory .assertObject ( cart )

Appreciate any assistance. I am new to JBoss-Cache.

drools.bsh

//
// Beanshell script to run the aop tree cache demo
//
import org.jboss.cache.PropertyConfigurator;
import org.jboss.cache.aop.TreeCacheAop;

import org.drools.RuleBase;
import org.drools.WorkingMemory;
import org.drools.rule.RuleSet;
import org.drools.io.RuleBaseBuilder;
import org.drools.examples.fishmonger.FishMonger;
import org.drools.examples.fishmonger.CartItem;
import org.drools.examples.fishmonger.ShoppingCart;

import java.io.IOException;
import java.net.URL;
import java.util.List;
import java.util.Iterator;

show(); // verbose mode

tree = new TreeCacheAop();
config = new PropertyConfigurator();
config.configure(tree, "META-INF/replSync-service.xml");

url = FishMonger.class.getResource( "fishmonger.drl" );
ruleBase = RuleBaseBuilder.buildFromUrl( url );
workingMemory = ruleBase.newWorkingMemory();

cart = new ShoppingCart();
item = new CartItem( "tropical fish",12.99 );
cart.addItem( item );
//workingMemory.assertObject( cart );
workingMemory.fireAllRules();

tree.start(); // kick start tree cache

tree.putObject("rules", workingMemory); // add aop sanctioned object

// tree.stop(); // will stop the cache

[belaban]

Might be a problem of bsh: Can you create a standalone Java program from your bsh (should be simple) and try again ?

And did you include all classes you want to be instrumentable in jboss-aop.xml ? You can use wildcards, e.g. org.drools.*

Bela

[ben.wang]

Like Bela suggested, please try it in Java program first. One thing I don't like bsh is the debugging capability is poor.

Thanks,

-Ben

[kieran]

Bela / Ben,

At your suggestion, I took the following two steps:
1. Added POJOs contained within drools rules engine packages into jboss-aop.xml
2. Wrote a program (attached) to exercise the cache

This was successful. Thanks.

**** source code ****

import org.jboss.cache.aop.TreeCacheAop;
import org.jboss.cache.PropertyConfigurator;

import org.drools.RuleBase;
import org.drools.WorkingMemory;
import org.drools.io.RuleBaseBuilder;
import org.drools.examples.fishmonger.FishMonger;
import org.drools.examples.fishmonger.CartItem;
import org.drools.examples.fishmonger.ShoppingCart;
import org.drools.DroolsException;
import org.drools.AssertionException;

import java.io.IOException;
import java.net.URL;

/**
* @author kieran
*
* TODO To change the template for this generated type comment go to Window -
* Preferences - Java - Code Style - Code Templates
*/
public class DroolsTester implements Runnable {
static TreeCacheAop _cache;

public DroolsTester(TreeCacheAop cache) {
_cache = cache;
}

public static void main(String[] args) {
try {
_cache = new TreeCacheAop();
PropertyConfigurator config = new PropertyConfigurator();
config.configure(_cache, "META-INF/replSync-service.xml");
_cache.start(); // kick start tree cache
} catch (Exception e) {
e.printStackTrace();
}
DroolsTester tester1 = new DroolsTester(_cache);
DroolsTester tester2 = new DroolsTester(_cache);

Thread t1 = new Thread(tester1);
Thread t2 = new Thread(tester2);
t1.start();
t2.start();
try {
t1.join();
t2.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
}

public void run() {
RuleBase ruleBase = null;
WorkingMemory workingMemory = null;
ShoppingCart cart = null;

try {
synchronized (_cache) {
URL url = FishMonger.class.getResource("fishmonger.drl");
ruleBase = RuleBaseBuilder.buildFromUrl(url);
workingMemory = (WorkingMemory) _cache
.getObject("/workingMemory/rules");
cart = (ShoppingCart) _cache.getObject("/shoppingCart/cart");
}
if (workingMemory == null) {
workingMemory = ruleBase.newWorkingMemory();
cart = new ShoppingCart();
_cache.putObject("/workingMemory/rules", workingMemory);
_cache.putObject("/shoppingCart/cart", cart);

try {
cart.addItem(new CartItem("tropical fish", 12.99));
cart.addItem(new CartItem("tropical fish", 12.99));
cart.addItem(new CartItem("tropical fish", 12.99));
cart.addItem(new CartItem("tropical fish", 12.99));
cart.addItem(new CartItem("tropical fish", 12.99));
cart.addItem(new CartItem("tropical fish", 12.99));
cart.addItem(new CartItem("tropical fish", 12.99));
cart.addItem(new CartItem("tropical fish food", 8.00));
System.out
.println("----------------------------------------");
System.out.println(" PRE");
System.out
.println("----------------------------------------");
System.out.println(cart);
System.out
.println("----------------------------------------");
// Now, simply assert them into the working memory and let
// the logic engine do the rest.
workingMemory.assertObject(cart);

} catch (AssertionException e) {
e.printStackTrace();
}
} else {
try {
// now fire the rules engine...
workingMemory.fireAllRules();
System.out
.println("----------------------------------------");
System.out.println(" POST");
System.out
.println("----------------------------------------");
System.out.println(cart);
System.out
.println("----------------------------------------");
_cache.stop(); // will stop the cache
} catch (AssertionException e) {
e.printStackTrace();
}
}
} catch (DroolsException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
}

[belaban]

So which one caused the problem:
- missing drools from jboss-aop.xml (my guess) or
- using a Java program.

I assume you can just cut&paste your program back into bsh, and it should work now.

Bela