Question

I’m developping several java packages that are then distributed as jar files.
Due to some new requirements, I now have to program several new features in jython; these will probably cover quite a bit of code distributed over a lot of separate jython files.

I would like to continue with the distribution of a single jar file per package. I bit of search provided me with two approaches which are unfortunately both not very good:

1) jythonc: I’m using jython 2.5.1, so jythonc is no longer part of the distribution. Besides, I don’t like the restriction this would place on my jython code.

2) Package everything together with the jython.jar file. Unfortunately, this is not possible; all of the people using my code package already have a jython.jar file in their environment (and many of them use different versions). In other words, my package must be distributed without the python core; instead I can rely on it being found in the classpath at the target system.

Now the question remains, is there another way of packaging all my java and jython code within one jar while keeping the jython.jar file untouched?

Answer 1

I finally found a solution for my problem. Maybe this is also of interest for someone else.
Just as a reminder, this is meant for a mixed java/jython package with java on top that will then be delivered to a customer, NOT for a self-contained application.

1) All jython sources are put in a separate folder on the top level within the jar file using the tool “jar” (or any other zip tool); I used the folder “Lib”.

2) Access to the jython code from java is done using an object factory class modeled as a singleton (similar to the one described here); access to java from jython works straightforward with just the full package name.

3) In the constructor of the object factory I use

String jarPath = myObjectFactory.class.getProtectionDomain().getCodeSource().getLocation()
.getPath();

to determine the location of the jar file from within the code.

4) I add the “Lib” folder within the jar file to the jython module lookup path using

PySystemState newState = new PySystemState();
newState.path.insert(0,Py.newString(jarPath + java.io.File.separator + "Lib")); Py.setSystemState(newState);

As long as the jython.jar file is included in the classpath, this will work.