Running a Gosu program from within Java
Jeff Klein
I am dabbling with gw.lang.reflect.ReflectUtil from open source Gosu version 0.9-3 in an attempt to reflectively instantiate a Gosu class, and invoke a method on it. However, I’m getting the following error when I try to run it.
Exception in thread "main" java.lang.RuntimeException: Current module must not be null.
at gw.internal.gosu.parser.TypeLoaderAccess.returnFirstNonNullByName(TypeLoaderAccess.java:1152)
at gw.internal.gosu.parser.TypeLoaderAccess.getTypeByFullNameIfValid(TypeLoaderAccess.java:572)
at gw.internal.gosu.parser.TypeLoaderAccess.getTypeByFullNameIfValid(TypeLoaderAccess.java:539)
at gw.internal.gosu.parser.TypeLoaderAccess.getIntrinsicTypeByFullName(TypeLoaderAccess.java:519)
at gw.internal.gosu.parser.TypeSystemImpl.getByFullName(TypeSystemImpl.java:224)
at gw.lang.reflect.TypeSystem.getByFullName(TypeSystem.java:145)
at gw.lang.reflect.ReflectUtil.construct(ReflectUtil.java:19)
at gw.lang.reflect.ReflectUtil.constructGosuClassInstance(ReflectUtil.java:39)
at InvokeGosuHello.main(InvokeGosuHello.java:14)
Here’s a very simple test case:
Gosu side: (GosuHello.gs)
class GosuHello {
function helloWorld() {
print("Hello from Gosu!")
}
}
Java side: (InvokeGosuHello.java)
import gw.lang.reflect.ReflectUtil;
import gw.lang.reflect.gs.IGosuObject;
public class InvokeGosuHello {
public static void main(String[] args) {
IGosuObject gosuObj = ReflectUtil.constructGosuClassInstance("GosuHello");
ReflectUtil.invokeMethod(gosuObj, "helloWorld", null);
}
}
Any thoughts would be appreciated.
Thanks,
Jeff Klein
Vyktur with a Y
I think you're going to need to put that .gs file in a package and reference it with the whole path.
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Vyktur with a Y
--
Alan Keefer
and then execute the .gsp file using Gosu. If you want to use Java as
the driver, you have to call Gosu.init() before referencing any Gosu
types or executing any code.
-Alan
On Wed, Feb 15, 2012 at 12:31 PM, Vyktur with a Y
Brian Chang
Brian Chang
Jeff Klein
Thanks to everyone for your replies. I scoped my .gs file to a package (org.jeffklein.gosu), and added Gosu.init(). I am now able to instantiate the Gosu class, but I’m getting an NPE when it tries to invoke the method. Seems like I’m getting close!
Exception in thread "main" java.lang.NullPointerException
org.jeffklein.gosu.GosuHello@136a1a1
at gw.lang.reflect.ReflectUtil.extractRuntimeTypes(ReflectUtil.java:222)
at gw.lang.reflect.ReflectUtil.invokeMethod(ReflectUtil.java:107)
at org.jeffklein.gosu.InvokeGosuHello.main(InvokeGosuHello.java:13)
The java source now looks like:
package org.jeffklein.gosu;
import gw.lang.Gosu;
import gw.lang.reflect.ReflectUtil;
import gw.lang.reflect.gs.IGosuObject;
public class InvokeGosuHello {
public static void main(String[] args) {
Gosu.init();
IGosuObject gosuObj = ReflectUtil.constructGosuClassInstance("org.jeffklein.gosu.GosuHello");
System.out.println(gosuObj);
ReflectUtil.invokeMethod(gosuObj, "helloWorld", null);
Jeff Klein
Thank you for the pointer to the Goson project Brian. My project is indeed a maven project, and I am pulling in my Gosu dependencies from an internal repo (only because I didn’t know about the public repo @gosu-lang.org). I’ve changed my repository setting in my pom to match that in the Goson project pom:
<repositories>
<repository>
<id>gosu-lang.org-releases</id>
<name>Official Gosu website (releases)</name>
<url>http://gosu-lang.org/repositories/m2/releases</url>
</repository>
</repositories>
There are much more current versions of my gosu dependencies on the public site. Thank you again for the tip!!
Jeff
From: gosu...@googlegroups.com [mailto:gosu...@googlegroups.com] On Behalf Of Brian Chang
Sent: Wednesday, February 15, 2012 1:16 PM
To: gosu...@googlegroups.com
Jeff Klein
Thanks to everyone for your replies. I scoped my .gs file to a package (org.jeffklein.gosu), and added Gosu.init(). I am now able to instantiate the Gosu class, but I’m getting an NPE when it tries to invoke the method.
Exception in thread "main" java.lang.NullPointerException
org.jeffklein.gosu.GosuHello@136a1a1
at gw.lang.reflect.ReflectUtil.extractRuntimeTypes(ReflectUtil.java:222)
at gw.lang.reflect.ReflectUtil.invokeMethod(ReflectUtil.java:107)
at org.jeffklein.gosu.InvokeGosuHello.main(InvokeGosuHello.java:13)
The java source now looks like:
package org.jeffklein.gosu;
import gw.lang.Gosu;
import gw.lang.reflect.ReflectUtil;
import gw.lang.reflect.gs.IGosuObject;
public class InvokeGosuHello {
public static void main(String[] args) {
Gosu.init();
IGosuObject gosuObj = ReflectUtil.constructGosuClassInstance("org.jeffklein.gosu.GosuHello");
System.out.println(gosuObj);
ReflectUtil.invokeMethod(gosuObj, "helloWorld", null);
}
}
From: gosu...@googlegroups.com [mailto:gosu...@googlegroups.com] On Behalf Of Brian Chang
Sent: Wednesday, February 15, 2012 1:16 PM
To: gosu...@googlegroups.com
Subject: Re: [gosu-lang:718] Running a Gosu program from within Java
BTW, Jeff, since you're a Maven guy, I think you'll be delighted to learn that it's very convenient to do your stuff in a Maven-structured project and pull the Gosu dependencies. See https://github.com/gosu-lang/Goson for a barebones example.
Carson Gross
Carson
Jeff Klein
Hi Carson,
I am developing in IntelliJ Ultimate. I haven’t installed the Gosu plugin yet for that reason. I have been meaning to install a community edition of IJ so that I can try it out, but alas I haven’t gotten around to it yet.
Just FYI, the NPE was my bad. I was using the 3-arg version of invokeMethod(), and passing a null list of method arguments. Changing to the 2-arg version took care of the problem, and I can invoke Gosu from Java- Very cool! Again, thanks to everyone for your replies.
Cheers,
Jeff
Brian Chang
Carson Gross
Carson