To restate: you have three libraries you want to use:
- One (Jess) is written in Java;
- One (BWAPI) can be accessed from Java by using an existing JNI interface,
- And the third (BWSAL) is currently available only in native code.
Your current plan is to write a JNI wrapper for some or all of BWSAL and write
your application in Java. This makes perfect sense to me.
It might be even easier to use JNA (http://jna.java.net/) instead of writing a
specific wrapper, but that depends on various details. Worth looking at, anyway.
________________________________
From: [email protected] [mailto:[email protected]] On
Behalf Of Hunter McMillen
Sent: Saturday, October 01, 2011 12:52 PM
To: jess-users
Subject: Re: JESS: Call Jess from C++ via JNI
Well I am trying to create an agent to compete in the Starcraft AI competition
for next year, the API that the agents all use is called BWAPI:
http://code.google.com/p/bwapi/, but this is also a standard library that some
of the agents use that would be really useful for for my agent called BWSAL:
http://code.google.com/p/bwsal/. Anyway there is a native interface that
someone created for BWAPI, which I was planning on using in my code, so my plan
was to create a native interface for BWSAL, that way I could do all the Jess
interaction inside of Java, then call associated methods in C++ via JNI. Does
this sound far-fetched?
On Thu, Sep 29, 2011 at 5:10 PM, Socrates Frangis
<[email protected]<mailto:[email protected]>> wrote:
What framework are you using? Curious to see how it is invoking JNI.
"using this I think I can only interact with Jess in my Java program then pass
data from my Java code to C++"
-Unless your framework has an API supporting JESS specifically, i doubt that is
the case. It should be providing a 'simpler' implementation to access your
java classes but that would just eliminate the cryptic path declaration and
still give you an interface to what youre playing with.
Overall opinion, given the chance that your framework may inhibit full controll
of the Rete engine or using JESS (and for the learning experience) i would
recommend sticking with your current implementation. Rule engines require
precise attention to detail and i wouldn't risk the chance of losing fidelity.
On Wed, Sep 28, 2011 at 2:22 PM, Hunter McMillen
<[email protected]<mailto:[email protected]>> wrote:
Sorry to pester you with more questions.
The way I am currently doing things in invoking a JVM from C++ to call Java
code that calls/interacts with Jess code, but it turns out that someone has
actually created a java native interface for the api/framework I am using to
make my agent, using this I think I can only interact with Jess in my Java
program then pass data from my Java code to C++, I was wondering if you thought
this would be a better solution than invoke a JVM from C++
Thanks
Hunter
On Tue, Sep 27, 2011 at 12:03 PM, Friedman-Hill, Ernest
<[email protected]<mailto:[email protected]>> wrote:
This is all perfectly reasonable so far. When you create the JVM you'll need to
tell it where jess.jar is, along with any other jars you use, with the "-cp"
flag or the "java.class.path" property.
Once you have this working, you'll presumably want to connect things a little
more tightly. You can use the JNI API to write the equivalent of your
three-line main() in C++ pretty easily; you'll want to put together a C++
version "executeCommand()" that controls the Rete instance, passes a script
along, executes it, and gets the Value back, decoding it as needed.
________________________________
From: [email protected]<mailto:[email protected]>
[mailto:[email protected]<mailto:[email protected]>] On
Behalf Of Hunter McMillen
Sent: Monday, September 26, 2011 8:51 PM
To: jess-users
Subject: JESS: Call Jess from C++ via JNI
Hello everyone,
I am working on a project where I am using a C++ framework and API to create a
game agent. My agent has to be flexible so it can react to/predict events that
occur inside the game environment, Jess has the kind of flexibility that I need
for my agent to be good, but I am having trouble connecting to Jess from C++
and that is where I was hoping someone could help me out.
What I am doing right now
I have a C++ program that starts a Java Virtual Machine and searches for a Java
class file name "TestJNIJessInvoke"
Inside of "TestJNIJessInvoke.java" I define a simple function in Jess, and try
to call that function then print the result
import jess.*;
public class TestJNIJessInvoke
{
public static void main(String[] args) throws JessException
{
Rete r = new Rete();
r.executeCommand("(deffunction square (?n) (return (* ?n ?n)))");
Value v = r.executeCommand("(square 3)");
System.out.println(v.intValue(r.getGlobalContext()));
}
}
But when I try to compile and link the C++ file with:
cl
-I"C:\Program Files\Java\jdk1.7.0\include"
-I"C:\Program Files\Java\jdk1.7.0\include\win32"
TestJNIJessInvoke.cpp
-link "C:\Program Files\Java\jdk1.7.0\lib\jvm.lib"
I get a class loader exception:
Exception in thread "main" java.lang.NoClassDefFoundError: jess/Rete
at TestJNIJessInvoke.main(TestJNIJessInvoke.java:6)
Caused by: java.lang.ClassNotFoundException: jess.Rete
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
... 1 more
Exception in thread "main" java.lang.NoClassDefFoundError: jess/Rete
at TestJNIJessInvoke.main(TestJNIJessInvoke.java:6)
Caused by: java.lang.ClassNotFoundException: jess.Rete
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
... 1 more
Questions
1) Is there some other directory that I am supposed to be including that has
the .class files for Jess? Right now all I am including is jess.jar
2) Is the general design I have a good idea? or is there a better way to
facilitate communication between Jess and C++?
Thanks,
Hunter McMillen
--
V/R
-Socrates Frangis
-Mathematician & Software Engineer
