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Class loader problem

9 messages

Hemanth kumar

Class loader problem

Reply Threaded

(This post was updated on )

hi,
Im working on a sample test project.
In that im dynamically creating a class ( fact) and compiling it.

here is my test project
--------------------------------------------------------------------------------------
mainJavaclass

public void runRule()
{
try{

System.out.println("Initializing Fact....");

URL[] urls = new URL[]{ new URL("file://"+path) };
ClassLoader loader = new URLClassLoader(urls);
Class clazz = loader.loadClass("test.Message");
//Class.forName("test.Message", false, ucl);
Object factObj = clazz.newInstance();
String ruleFile = "test/Sample.drl";

Method method = clazz.getMethod("setMessage", new Class[]{String.class});
Method method1 = clazz.getMethod("getMessage");
//System.out.println("facts loaded\n");

method.invoke(factObj, new Object[]{"Hello"});

System.out.println("initializing packageBuilder");

PackageBuilderConfiguration config = new PackageBuilderConfiguration();
config.setClassLoader(loader);

KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(config);

System.out.println("finding Rule");
kbuilder.add(ResourceFactory.newClassPathResource("test/Sample.drl"),ResourceType.DRL);

if (kbuilder.hasErrors())
throw new RuntimeException("Unable to compile rules. " +
kbuilder.getErrors().toString());

KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(new RuleBaseConfiguration(loader));

kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());

StatelessKnowledgeSession session = kbase.newStatelessKnowledgeSession();

System.out.println("running rule....... \n");
session.execute(factObj);

System.out.println("\nend...\n");
System.out.println(method1.invoke(factObj).toString());
}
catch (Throwable t) {
t.printStackTrace();
}

}

----------------------------------------------------------------------
Fact

package test;
public class Message{
private String message;
public String getMessage(){
return this.message;
}

public void setMessage(String message) {
this.message = message;
}

}

------------------------------------------------------------------------
sample rule

package test
import test.Message;

rule "Your First Rule"
dialect "mvel"
when
m:Message(message != "Good Bye" )
then
System.out.println("First Rule fired "+m.message );
modify(m){ message = "Good Bye"};
end
-----------------------------------------------------------------
console.PNG

what happens is when i was running the project inside eclipse IDE it works fine but when i hosted in tomcat and calling from outside ide the rule is not getting fired.
I think the dyanamically loaded class is not recognised by the rule engine.

suggest me any ideas or post an working example

Hemanth

Swapnil Raverkar

Re: Class loader problem

Reply Threaded

Are you inserting the instance of the dynamically loaded class into the KnowledgeBase?
i.e. session.insert(dynamicInstance);

If not the rule won't get fired.

Cheers,

Swapnil

2009/11/3 Hemanth kumar <[hidden email]>

hi,
Im working on a sample test project.
In that im dynamically creating a class ( fact) and compiling it.

here is my test project
--------------------------------------------------------------------------------------
mainJavaclass

public void runRule()
{
try {
System.out.println("\nRunning rule\n");

// go !

URL[] urls = new URL[]{ new
URL("file://"+path) };

URLClassLoader ucl = new
URLClassLoader(urls);
Class<?> clazz =
ucl.loadClass("test.Message");
Object classObj = clazz.newInstance();

Method method =
clazz.getDeclaredMethod("setMessage", new Class[]{String.class});

//System.out.println("facts loaded\n");

method.invoke(classObj, new
Object[]{"Hello"});

log.info("==== Calling Rule Runner ======");

Collection facts = new ArrayList();
facts.add(classObj);

// Load and fire our rules files against the
data
new
RuleRunner().runStatelessRules(RULES_FILES, null, facts, null, null,
logger);

}
catch (Throwable t) {
t.printStackTrace();
}

}

----------------------------------------------------------------------
Fact

package test;
public class Message{
private String message;
public String getMessage(){
return this.message;
}

public void setMessage(String message) {
this.message = message;
}

}

------------------------------------------------------------------------
sample rule

package test
import test.Message;

rule "Your First Rule"
dialect "mvel"
when
m:Message(message != "Good Bye" )
then
System.out.println("First Rule fired "+m.message );
modify(m){ message = "Good Bye"};
end
-----------------------------------------------------------------
http://old.nabble.com/file/p26160051/console.PNG console.PNG

what happens is when i was running the project inside eclipse IDE it works
fine but when i hosted in tomcat and calling from outside ide the rule is
not getting fired.
I think the dyanamically loaded class is not recognised by the rule engine.

suggest me any ideas or post an working example

Hemanth
--
View this message in context: http://old.nabble.com/Class-loader-problem-tp26160051p26160051.html
Sent from the drools - user mailing list archive at Nabble.com.

_______________________________________________
rules-users mailing list
[hidden email]
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Hemanth kumar

Re: Class loader problem

Reply Threaded

swapnil thanx for the reply,
this is my modified code

try{

            System.out.println("Initializing Fact....");

            URL[] urls = new URL[]{ new URL("file://"+path) };
             ClassLoader loader = new URLClassLoader(urls);
             Class clazz = loader.loadClass("test.Message");
                              //Class.forName("test.Message", false, ucl);
             Object factObj = clazz.newInstance();
             String ruleFile = "test/Sample.drl";

             Method method = clazz.getMethod("setMessage", new Class[]{String.class});
             Method method1 = clazz.getMethod("getMessage");
             //System.out.println("facts loaded\n");

             method.invoke(factObj, new Object[]{"Hello"});

             System.out.println("initializing packageBuilder");

             PackageBuilderConfiguration config = new PackageBuilderConfiguration();
             config.setClassLoader(loader);

            KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(config);

            System.out.println("finding Rule");
            kbuilder.add(ResourceFactory.newClassPathResource("test/Sample.drl"),ResourceType.DRL);

            if (kbuilder.hasErrors())
                throw new RuntimeException("Unable to compile rules. " +
                            kbuilder.getErrors().toString());


            KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(new RuleBaseConfiguration(loader));

            kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());

            StatelessKnowledgeSession session = kbase.newStatelessKnowledgeSession();

            System.out.println("running rule....... \n");
             session.execute(factObj);

             System.out.println("\nend...\n");
             System.out.println(method1.invoke(factObj).toString());
        }
        catch (Throwable t) {
            t.printStackTrace();
        }

thanx and regards
Hemanth

2009/11/3 Swapnil Raverkar <[hidden email]>

Are you inserting the instance of the dynamically loaded class into the KnowledgeBase?
i.e. session.insert(dynamicInstance);

If not the rule won't get fired.

Cheers,

Swapnil

2009/11/3 Hemanth kumar <[hidden email]>

hi,
Im working on a sample test project.
In that im dynamically creating a class ( fact) and compiling it.

here is my test project
--------------------------------------------------------------------------------------
mainJavaclass

public void runRule()
{
try {
System.out.println("\nRunning rule\n");

// go !

URL[] urls = new URL[]{ new
URL("file://"+path) };

URLClassLoader ucl = new
URLClassLoader(urls);
Class<?> clazz =
ucl.loadClass("test.Message");
Object classObj = clazz.newInstance();

Method method =
clazz.getDeclaredMethod("setMessage", new Class[]{String.class});

//System.out.println("facts loaded\n");

method.invoke(classObj, new
Object[]{"Hello"});

log.info("==== Calling Rule Runner ======");

Collection facts = new ArrayList();
facts.add(classObj);

// Load and fire our rules files against the
data
new
RuleRunner().runStatelessRules(RULES_FILES, null, facts, null, null,
logger);

}
catch (Throwable t) {
t.printStackTrace();
}

}

----------------------------------------------------------------------
Fact

package test;
public class Message{
private String message;
public String getMessage(){
return this.message;
}

public void setMessage(String message) {
this.message = message;
}

}

------------------------------------------------------------------------
sample rule

package test
import test.Message;

rule "Your First Rule"
dialect "mvel"
when
m:Message(message != "Good Bye" )
then
System.out.println("First Rule fired "+m.message );
modify(m){ message = "Good Bye"};
end
-----------------------------------------------------------------
http://old.nabble.com/file/p26160051/console.PNG console.PNG

what happens is when i was running the project inside eclipse IDE it works
fine but when i hosted in tomcat and calling from outside ide the rule is
not getting fired.
I think the dyanamically loaded class is not recognised by the rule engine.

suggest me any ideas or post an working example

Hemanth
--
View this message in context: http://old.nabble.com/Class-loader-problem-tp26160051p26160051.html
Sent from the drools - user mailing list archive at Nabble.com.

_______________________________________________
rules-users mailing list
[hidden email]
https://lists.jboss.org/mailman/listinfo/rules-users

_______________________________________________
rules-users mailing list
[hidden email]
https://lists.jboss.org/mailman/listinfo/rules-users

--
regards
Hemanth kumar

_______________________________________________
rules-users mailing list
[hidden email]
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Sachint

Re: Class loader problem

Reply Threaded

In reply to this post by Hemanth kumar

Hi Hemant,

In eclipse we have configured drools runtime environment which contains the required jars, i assume you have provided them to tomcat.

Regards,
Sachin

Hemanth kumar wrote:

hi,
Im working on a sample test project.
In that im dynamically creating a class ( fact) and compiling it.

here is my test project
--------------------------------------------------------------------------------------
mainJavaclass

public void runRule()
{
try{

System.out.println("Initializing Fact....");

URL[] urls = new URL[]{ new URL("file://"+path) };
ClassLoader loader = new URLClassLoader(urls);
Class clazz = loader.loadClass("test.Message");
//Class.forName("test.Message", false, ucl);
Object factObj = clazz.newInstance();
String ruleFile = "test/Sample.drl";

Method method = clazz.getMethod("setMessage", new Class[]{String.class});
Method method1 = clazz.getMethod("getMessage");
//System.out.println("facts loaded\n");

method.invoke(factObj, new Object[]{"Hello"});

System.out.println("initializing packageBuilder");

PackageBuilderConfiguration config = new PackageBuilderConfiguration();
config.setClassLoader(loader);

KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(config);

System.out.println("finding Rule");
kbuilder.add(ResourceFactory.newClassPathResource("test/Sample.drl"),ResourceType.DRL);

if (kbuilder.hasErrors())
throw new RuntimeException("Unable to compile rules. " +
kbuilder.getErrors().toString());

KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(new RuleBaseConfiguration(loader));

kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());

StatelessKnowledgeSession session = kbase.newStatelessKnowledgeSession();

System.out.println("running rule....... \n");
session.execute(factObj);

System.out.println("\nend...\n");
System.out.println(method1.invoke(factObj).toString());
}
catch (Throwable t) {
t.printStackTrace();
}

}

----------------------------------------------------------------------
Fact

package test;
public class Message{
private String message;
public String getMessage(){
return this.message;
}

public void setMessage(String message) {
this.message = message;
}

}

------------------------------------------------------------------------
sample rule

package test
import test.Message;

rule "Your First Rule"
dialect "mvel"
when
m:Message(message != "Good Bye" )
then
System.out.println("First Rule fired "+m.message );
modify(m){ message = "Good Bye"};
end
-----------------------------------------------------------------
console.PNG

what happens is when i was running the project inside eclipse IDE it works fine but when i hosted in tomcat and calling from outside ide the rule is not getting fired.
I think the dyanamically loaded class is not recognised by the rule engine.

suggest me any ideas or post an working example

Hemanth

Hemanth kumar

Re: Class loader problem

Reply Threaded

In reply to this post by Swapnil Raverkar

swapnil thanx for the reply,
this is my modified code

try{

System.out.println("Initializing Fact....");

URL[] urls = new URL[]{ new URL("file://"+path) };
ClassLoader loader = new URLClassLoader(urls);
Class clazz = loader.loadClass("test.Message");
//Class.forName("test.Message", false, ucl);
Object factObj = clazz.newInstance();
String ruleFile = "test/Sample.drl";

Method method = clazz.getMethod("setMessage", new Class[]{String.class});
Method method1 = clazz.getMethod("getMessage");

//System.out.println("facts loaded\n");

method.invoke(factObj, new Object[]{"Hello"});

System.out.println("initializing packageBuilder");

PackageBuilderConfiguration config = new PackageBuilderConfiguration();
config.setClassLoader(loader);

KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder(config);

System.out.println("finding Rule");
kbuilder.add(ResourceFactory.newClassPathResource("test/Sample.drl"),ResourceType.DRL);

if (kbuilder.hasErrors())
throw new RuntimeException("Unable to compile rules. " +
kbuilder.getErrors().toString());

KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(new RuleBaseConfiguration(loader));

kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());

StatelessKnowledgeSession session = kbase.newStatelessKnowledgeSession();

System.out.println("running rule....... \n");
session.execute(factObj);

System.out.println("\nend...\n");
System.out.println(method1.invoke(factObj).toString());

}
catch (Throwable t) {
t.printStackTrace();
}

------------------------------------------------------------
Added the following JARS in WEB-INF\lib

antlr-runtime-3.1.1.jar
core-3.4.2.v_883_R34x.jar
drools-api-5.0.1.jar
drools-core-5.0.1.jar
drools-decisiontables-5.0.1.jar
mvel2-2.0.10.jar
drools-compiler-5.0.1.jar
xstream-1.3.1.jar

thanx and regards
Hemanth

Swapnil Raverkar

Re: Class loader problem

Reply Threaded

URL[] urls = new URL[]{ new URL("file://"+path)

Are you using relative or absolute paths for classLoaders?

Did you check that the paths are valid when you deploy your application in Tomcat container?

Cheers,

Swapnil

2009/11/4 Hemanth kumar <[hidden email]>

swapnil thanx for the reply,
this is my modified code

try{

System.out.println("Initializing Fact....");

URL[] urls = new URL[]{ new URL("file://"+path) };

ClassLoader loader = new URLClassLoader(urls);
Class clazz = loader.loadClass("test.Message");

//Class.forName("test.Message", false, ucl);
Object factObj = clazz.newInstance();
String ruleFile = "test/Sample.drl";

Method method = clazz.getMethod("setMessage", new
Class[]{String.class});

Method method1 = clazz.getMethod("getMessage");

//System.out.println("facts loaded\n");

method.invoke(factObj, new Object[]{"Hello"});

System.out.println("initializing packageBuilder");

PackageBuilderConfiguration config = new
PackageBuilderConfiguration();
config.setClassLoader(loader);

KnowledgeBuilder kbuilder =
KnowledgeBuilderFactory.newKnowledgeBuilder(config);

System.out.println("finding Rule");

kbuilder.add(ResourceFactory.newClassPathResource("test/Sample.drl"),ResourceType.DRL);

if (kbuilder.hasErrors())
throw new RuntimeException("Unable to compile rules. " +
kbuilder.getErrors().toString());

KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(new
RuleBaseConfiguration(loader));

kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());

StatelessKnowledgeSession session =
kbase.newStatelessKnowledgeSession();

System.out.println("running rule....... \n");
session.execute(factObj);

System.out.println("\nend...\n");
System.out.println(method1.invoke(factObj).toString());

}

catch (Throwable t) {
t.printStackTrace();
}

------------------------------------------------------------

Added the following JARS in WEB-INF\lib

antlr-runtime-3.1.1.jar
core-3.4.2.v_883_R34x.jar
drools-api-5.0.1.jar
drools-core-5.0.1.jar
drools-decisiontables-5.0.1.jar
mvel2-2.0.10.jar
drools-compiler-5.0.1.jar
xstream-1.3.1.jar

thanx and regards
Hemanth
--
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Sent from the drools - user mailing list archive at Nabble.com.

_______________________________________________
rules-users mailing list
[hidden email]
https://lists.jboss.org/mailman/listinfo/rules-users

_______________________________________________
rules-users mailing list
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Hemanth kumar

Re: Class loader problem

Reply Threaded

Hi swapnil thanx for the reply
I think there is no error in url path.for a week i was not active in my project.
Im sending my sample project

Here is my sample application
---------------------------------------------------------------------
main java class
ruleTest.txt

sample rule

Sample.drl

tomcat console

console1.PNG

Added following jars in tomcat/lib
( actual path : C:\Program Files\Apache Software Foundation\Tomcat 6.0\webapps\JStudio\WEB-INF\lib)

antlr-runtime-3.1.1.jar
core-3.4.2.v_883_R34x.jar
drools-api-5.0.1.jar
drools-compiler-5.0.1.jar
drools-core-5.0.1.jar
drools-jsr94-5.0.1.jar
drools-decisiontables-5.0.1.jar
mvel2-2.0.14.jar
xstream-1.3.1.jar

suggest me any ideas

leo_gomes

Re: Class loader problem

Reply Threaded

Hi Hemanth,

If you're looking for dynamic creation of Facts, you should have a look here:

http://downloads.jboss.com/drools/docs/5.0.1.26597.FINAL/drools-expert/html_single/index.html#d0e3350

HTH,
Leo.

On Mon, Nov 9, 2009 at 8:37 AM, Hemanth kumar <[hidden email]> wrote:

>
> Hi swapnil thanx for the reply
> I think there is no error in url path.for a week i was not active in my
> project.
> Im sending my sample project
>
> Here is my sample application
> ---------------------------------------------------------------------
> main java class
> http://old.nabble.com/file/p26262304/ruleTest.txt ruleTest.txt
>
> sample rule
>
> http://old.nabble.com/file/p26262304/Sample.drl Sample.drl
>
> tomcat console
>
> http://old.nabble.com/file/p26262304/console1.PNG console1.PNG
>
>
> Added following jars in tomcat/lib
> ( actual path : C:\Program Files\Apache Software Foundation\Tomcat
> 6.0\webapps\JStudio\WEB-INF\lib)
>
> antlr-runtime-3.1.1.jar
> core-3.4.2.v_883_R34x.jar
> drools-api-5.0.1.jar
> drools-compiler-5.0.1.jar
> drools-core-5.0.1.jar
> drools-jsr94-5.0.1.jar
> drools-decisiontables-5.0.1.jar
> mvel2-2.0.14.jar
> xstream-1.3.1.jar
>
> suggest me any ideas
> --
> View this message in context: http://old.nabble.com/Class-loader-problem-tp26160051p26262304.html
> Sent from the drools - user mailing list archive at Nabble.com.
>
> _______________________________________________
> rules-users mailing list
> [hidden email]
> https://lists.jboss.org/mailman/listinfo/rules-users
>

_______________________________________________
rules-users mailing list
[hidden email]
https://lists.jboss.org/mailman/listinfo/rules-users

isterin

Re: Class loader problem

Reply Threaded

In reply to this post by Hemanth kumar

Hemanth, I had a similar issue, here is a blog post...

http://www.ilyasterin.com/blog/2009/10/java-multiple-class-loaders-issue.html

Hope this helps.

On Tue, Nov 3, 2009 at 5:27 AM, Hemanth kumar <[hidden email]> wrote:

>
> hi,
> Im working on a sample test project.
> In that im dynamically creating a class ( fact) and compiling it.
>
> here is my test project
> --------------------------------------------------------------------------------------
> mainJavaclass
>
>
> public void runRule()
> {
> try {
> System.out.println("\nRunning rule\n");
>
> // go !
>
> URL[] urls = new URL[]{ new
> URL("file://"+path) };
>
> URLClassLoader ucl = new
> URLClassLoader(urls);
> Class<?> clazz =
> ucl.loadClass("test.Message");
> Object classObj = clazz.newInstance();
>
>
> Method method =
> clazz.getDeclaredMethod("setMessage", new Class[]{String.class});
>
> //System.out.println("facts loaded\n");
>
> method.invoke(classObj, new
> Object[]{"Hello"});
>
>
> log.info("==== Calling Rule Runner ======");
>
> Collection facts = new ArrayList();
> facts.add(classObj);
>
>
> // Load and fire our rules files against the
> data
> new
> RuleRunner().runStatelessRules(RULES_FILES, null, facts, null, null,
> logger);
>
> }
> catch (Throwable t) {
> t.printStackTrace();
> }
>
> }
>
> ----------------------------------------------------------------------
> Fact
>
> package test;
> public class Message{
> private String message;
> public String getMessage(){
> return this.message;
> }
>
> public void setMessage(String message) {
> this.message = message;
> }
>
> }
>
>
> ------------------------------------------------------------------------
> sample rule
>
> package test
> import test.Message;
>
> rule "Your First Rule"
> dialect "mvel"
> when
> m:Message(message != "Good Bye" )
> then
> System.out.println("First Rule fired "+m.message );
> modify(m){ message = "Good Bye"};
> end
> -----------------------------------------------------------------
> http://old.nabble.com/file/p26160051/console.PNG console.PNG
>
> what happens is when i was running the project inside eclipse IDE it works
> fine but when i hosted in tomcat and calling from outside ide the rule is
> not getting fired.
> I think the dyanamically loaded class is not recognised by the rule engine.
>
> suggest me any ideas or post an working example
>
> Hemanth
> --
> View this message in context: http://old.nabble.com/Class-loader-problem-tp26160051p26160051.html
> Sent from the drools - user mailing list archive at Nabble.com.
>
> _______________________________________________
> rules-users mailing list
> [hidden email]
> https://lists.jboss.org/mailman/listinfo/rules-users
>

_______________________________________________
rules-users mailing list
[hidden email]
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