jython-users — Discussion of and questions about using Jython

[Jython-users] os.shutil.copytree and os.execv not implemented in jython (2.0)?

[Joseph S. B. I. <jo...@ba...>]

Hi,

I'm trying to replace some installation shell scripts with jython scripts,
but I'm getting stuck fairly early on. In particular, I need to implement a
copy of files from one directory to another, but os.shutil.copytree appears
to be unimplemented, as does os.execv (my fallback).

Am I just doing something wrong, or are these functions really missing? And
if so, how would you solve the problem of needing to copy a tree of files?

Thanks much,

- Joe

Re: [Jython-users] cyphon

[<bc...@wo...>]

[Ype on the pairing of Jython and CPython through JNI]

>You might ask Finn Buck to distribute the source as an experimental
>Jython module.

It would have to an *outstandingly* useful module before I will even
consider adding JNI code to the core Jython distribution. Neither jnios
nor jTkinter can ever fulfill the requirement for inclusion.

OTOH if some basic support or hooks in jython could make the integration
easier or more complete, it is certainly worth considering.

regards,
finn

Re: [Jython-users] cyphon

[Ype K. <yk...@xs...>]

Jack,
you wrote:

(snip)

>I'm between jobs at the moment and to keep my brain busy, I've
>prototyped 'cyphon', a jython module that allows you to call *native*
>python modules. To give you a use case:
>
>   Jython 2.0alpha2 on java1.2 (JIT: NONE)
>   Type "copyright", "credits" or "license" for more information.
>   >>> import cyphon
>   >>> string = cyphon.string
>   >>> print string.find('abcde','d')
>   3
>
>or more usefully:
>
>   Jython 2.0alpha2 on java1.2 (JIT: NONE)
>   Type "copyright", "credits" or "license" for more information.
>   >>> import cyphon
>   >>> cyphon.os.getenv('PATH')
>   'DEBUG;C:\\JYTHON'
>
>cyphon achieves this by using JNI to embed python in jython:
>   import cyphon           # dynamically loads python.dll
>   string = cyphon.string  # calls PyImport_ImportModule("string")

Sounds like you have doing the opposite of the java for python
jpe project.
python.dll: would this port to Unix? That is: is most of it
written in python? Did you perform reflection on the types
to get from jython to C?

>
>Now, cyphon would be really useful for using python extension modules
>like MetaKit or wxPython (to name a couple of extensions that I have an
>interest in).  The complications I forsee are:
>   - inheriting from native python classes
>   - passing callback jython functions to native python functions
>but I'm sure that these can be resolved.

Some of this has probably been solved (or is being solved) in jpe.
I have not seen the source for jpe yet. Thinking of it, cyphon
might make an interesting alternative to jpe.

>Anyway, having proved to myself that I can get this far, I've lost
>motivation to complete it.  If there's a demand for cyphon, I may polish
>it up a bit or if anyone can tell me the most convenient way to publish
>it, let me know.  (it's only a few source files)

I'm certainly interested in using it under Unix, but that will take
work. Would anyone have an idea how much?

You might ask Finn Buck to distribute the source as an experimental
Jython module.

Regards,
Ype

Re: [Jython-users] Jython-2.0 released

[<bc...@wo...>]

On Thu, 18 Jan 2001 17:27:39 -0500, you wrote:

>How can you access Python classes / modules directly from Java? 

A python class can implement a java interface or java class by listing
the java interface as a base class. Instances of such a python class can
be passed to java code as a parameter and used as any other java class.

In addition, the command "jythonc" can be be used to create a java class
from a python module. Such a java class be used from a java program as a
normal java class. Including in a "new" statement.

regards.
finn

Re: [Jython-users] Re: ANN: Jython-2.0 released

[<bc...@wo...>]

On Fri, 19 Jan 2001 05:14:08 +0100, you wrote:

>I just downloaded Jython2.0, and tried it out on some of my CPython
>files. I got in trouble with something that looks OK to me, and that
>works fine in CPython. I've simulated it in interactive mode:
>
>Jython 2.0 on java1.1.4 (JIT: null)
>Type "copyright", "credits" or "license" for more information.
>>>> import re
>>>> print re.split(r"\s*=\s*","X = 10")
>Traceback (innermost last):
>  File "<console>", line 1, in ?
>  File "C:\WINNT\Java\jython-2.0\Lib\sre.py", line 56, in split
>  File "C:\WINNT\Java\jython-2.0\Lib\sre.py", line 151, in _split
>java.lang.ArrayIndexOutOfBoundsException
>
>Is this a bug, or does Jython use another RE syntax?

The Jython RE syntax is exactly the same as CPython2.0. What you have
encountered is a bug in the Microsoft JVM. 

To workaround the bug, you can either:

- Install some other JVM. I use javasoft SDK myself.
    http://www.javasoft.com/j2se/

- Enable the apache ORO matcher. You enable the ORO matcher by
  adding this line to your <jython.home>/registry file:
    python.modules.builtin = re

By rewriting the code a little bit, I have avoided the MS bug, so the
problem will not exist in the next release of jython.

regards,
finn

Re: [Jython-users] urllib.urlretrieve(): runtime exception

[<bc...@wo...>]

[Ben Hutchison]

>Im getting an AttributeError in the httplib.py standard library when
>using urlretrieve():
>
>Traceback (innermost last):
>  File "FutureSourceSpider.py", line 86, in ?
>  File "c:\software\jython\Lib\urllib.py", line 68, in urlretrieve
>  File "c:\software\jython\Lib\urllib.py", line 198, in retrieve
>  File "c:\software\jython\Lib\urllib.py", line 169, in open
>  File "c:\software\jython\Lib\urllib.py", line 273, in open_http
>  File "c:\software\jython\Lib\httplib.py", line 430, in putrequest
>AttributeError: __getitem__
>
>The line throwing the error in inside an exception handler:
>        try:
>            self.send(str)
>        except socket.error, v:
>            # trap 'Broken pipe' if we're allowed to automatically
>reconnect
>>>>>   if v[0] != 32 or not self.auto_open: <<<<<
>                raise
>            # try one more time (the socket was closed; this will
>reopen)
>            self.send(str)
>
>I instrumented this code and determined that it executes when there is a
>timeout setting up a socket connection. This timeout condition is for my
>purpoises, transient and non-fatal.
>The underlying message: java.net.NoRouteToHostException: Operation timed
>out: no further information
>
>Possibly because this section rarely executes, a bug has gone
>undiscovered?
>
>I dont fully understand what would cause the AttributeError on the line
>above, can someone explain?

In CPython, the exception would have been a subclass of Exception, which
defines a __getitem__ method. Index 0 would then contain the error
number and index 1 an textual description. So the httplib will most
likely work on CPython.

OTOH, the java exception is just passed back from the jython socket
module. This exception can not be indexed as a list, therefore we get
the AttributeError: __getitem__. There is also no error number in a java
exception.

I'm not yet sure what the right long term solution is. Either httplib
could test that the exception is a sequence before doing any indexing.
Or the socket module could catch the java.net exception and reraise it
as a SocketException.

Can anyone tell when the resend condition should occur under jython?

regards,
finn

[Jython-users] Re: [JPython] Searchable mailing list archives

[Frederic L. <f.l...@al...>]

Ben Hutchison wrote:
> 
> I want to be able to do keyword searching on the older JPython/Jython
> list archives.  http://mail.python.org/pipermail/jpython-interest
> http://lists.sourceforge.net/archives//jython-users/
> 

You can have access to the JPython mailing list with egroups.com
In my website, I made a J(p)ython column, and I provide a web page
with a search functionnality... Sorry it's in French, but hope this
helps...

http://flrt.free.fr/html/jpython/liste.html


-- 
Frédéric Laurent 
http://flrt.free.fr

[Jython-users] jython and VisualAge for Java

[Peter M <po...@ly...>]

Does anybody use jython with VisualAge for Java? 

I got it working to the point that no error messages come up when I try to import a 
.class file, but when I try to access a method, it is not recognized (NameError:...) 

Cheers 
pm 


Get your small business started at Lycos Small Business at http://www.lycos.com/business/mail.html

[Jython-users] Using jython with VisualAge for Java

[Ken S. <K.S...@bo...>]

Does anybody use jython with VisualAge for Java?

I got it working to the point that no error messages come up when I try
to import a .class file, but when I try to access a method, it is not
recognized (NameError:...)

Cheers
pm

[Jython-users] Re: [wxPython] cyphon

[Brendan J S. <bre...@ct...>]

Jack Andrews wrote:

> Anyway, having proved to myself that I can get this far, I've lost
> motivation to complete it.  If there's a demand for cyphon, I may polish
> it up a bit or if anyone can tell me the most convenient way to publish
> it, let me know.  (it's only a few source files)

Put it on sourceforge as an opensource project.  Anyone interested can 
be added as a developer or even a maintainer.
Brendan Simon.

Re: [Jython-users] Re: ANN: Jython-2.0 released

[Venkatesh P. R. <rvp...@ci...>]

Hi,

I tried the same example with jython 2.0 (jre/jdk 1.3.0 on a linux box) and it
works fine.  Can it be something to do with the underlying jvm?  Guessing.

 - Venkatesh

[Jython-users] Re: ANN: Jython-2.0 released

[Jan D. <jan...@fr...>]

Finn Bock wrote:
> 
> I am happy to announce the release of Jython 2.0.
> 

I just downloaded Jython2.0, and tried it out on some of my CPython
files. I got in trouble with something that looks OK to me, and that
works fine in CPython. I've simulated it in interactive mode:

Jython 2.0 on java1.1.4 (JIT: null)
Type "copyright", "credits" or "license" for more information.
>>> import re
>>> print re.split("=","X=10")
['X', '10']
>>> print re.split(r"\s=\s","X = 10")
['X', '10']
>>> print re.split(r"\s+=\s+","X = 10")
['X', '10']
>>> print re.split(r"\s*=\s*","X = 10")
Traceback (innermost last):
  File "<console>", line 1, in ?
  File "C:\WINNT\Java\jython-2.0\Lib\sre.py", line 56, in split
  File "C:\WINNT\Java\jython-2.0\Lib\sre.py", line 151, in _split
java.lang.ArrayIndexOutOfBoundsException

Is this a bug, or does Jython use another RE syntax?

Regards,
Jan

[Jython-users] urllib.urlretrieve(): runtime exception

[Ben H. <be...@in...>]

Im getting an AttributeError in the httplib.py standard library when
using urlretrieve():

Traceback (innermost last):
  File "FutureSourceSpider.py", line 86, in ?
  File "c:\software\jython\Lib\urllib.py", line 68, in urlretrieve
  File "c:\software\jython\Lib\urllib.py", line 198, in retrieve
  File "c:\software\jython\Lib\urllib.py", line 169, in open
  File "c:\software\jython\Lib\urllib.py", line 273, in open_http
  File "c:\software\jython\Lib\httplib.py", line 430, in putrequest
AttributeError: __getitem__

The line throwing the error in inside an exception handler:
        try:
            self.send(str)
        except socket.error, v:
            # trap 'Broken pipe' if we're allowed to automatically
reconnect
>>>>   if v[0] != 32 or not self.auto_open: <<<<<
                raise
            # try one more time (the socket was closed; this will
reopen)
            self.send(str)

I instrumented this code and determined that it executes when there is a
timeout setting up a socket connection. This timeout condition is for my
purpoises, transient and non-fatal.
The underlying message: java.net.NoRouteToHostException: Operation timed
out: no further information

Possibly because this section rarely executes, a bug has gone
undiscovered?

I dont fully understand what would cause the AttributeError on the line
above, can someone explain?

--
Ben Hutchison
Software Engineer-Market Predictor
Webmind Australia
http://www.webmind.com/productspredictor.html

[Jython-users] cyphon

[Jack A. <ef...@bi...>]

Hi,

I remember a mail to a jpython list last year asking if you could call
python modules from jpython.  For the case where the python module was
written in python, then you need to port from python to jython. But if
the python module is an "extension module" -- ie. is written in C (or
has a C interface), then it's pretty hard.

I'm between jobs at the moment and to keep my brain busy, I've
prototyped 'cyphon', a jython module that allows you to call *native*
python modules. To give you a use case:

  Jython 2.0alpha2 on java1.2 (JIT: NONE)
  Type "copyright", "credits" or "license" for more information.
  >>> import cyphon
  >>> string = cyphon.string
  >>> print string.find('abcde','d')
  3

or more usefully:

  Jython 2.0alpha2 on java1.2 (JIT: NONE)
  Type "copyright", "credits" or "license" for more information.
  >>> import cyphon
  >>> cyphon.os.getenv('PATH')
  'DEBUG;C:\\JYTHON'

cyphon achieves this by using JNI to embed python in jython:
  import cyphon           # dynamically loads python.dll
  string = cyphon.string  # calls PyImport_ImportModule("string")
  
Now, cyphon would be really useful for using python extension modules
like MetaKit or wxPython (to name a couple of extensions that I have an
interest in).  The complications I forsee are:
  - inheriting from native python classes
  - passing callback jython functions to native python functions
but I'm sure that these can be resolved.  

Anyway, having proved to myself that I can get this far, I've lost
motivation to complete it.  If there's a demand for cyphon, I may polish
it up a bit or if anyone can tell me the most convenient way to publish
it, let me know.  (it's only a few source files)



Jack.

Re: [Jython-users] Jython-2.0 released

[D-Man <ds...@ri...>]

Jython is very cool!  Thanks Finn.

I have used it already to find some errors in my Java code ;-) (the
interactiveness is invaluable).

On Thu, Jan 18, 2001 at 10:12:20AM +0000, Finn Bock wrote:
| Java beans, and can subclass Java classes in Python and vice
| versa.  Like Python, and unlike Java, Jython can also be

How can you access Python classes / modules directly from Java?  It
would be very cool if I could use Jython while not changing any of the
Java my coworkers are using.  (ie.  They wouldn't even have to know I
was using jython except for including the jar file in the classpath)

Thanks,
-D

Re: [Jython-users] Jython-2.0 released

[<ba...@di...>]

On behalf of the Pythonlabs team, I want to extend my congratulations
to Finn Bock on the release of Jython 2.0 final.  This is a wonderful
milestone in the life of JPython and Jython.

Some of you are probably aware that I haven't been actively involved
in Jython development for many months.  With the Pythonlabs turmoil in
2000, I found that trying to lead two open source projects (Mailman
and Jython) while still contributing to CPython's development was
simply too much.  I ran out of cycles and something had to give.

Handing over the reins of Jython project leadership to Finn was
actually quite an easy decision.  He has been a valued contributor to
the project for a long time, and I knew that he would serve Jython
well.  The Jython 2.0 release reinforces the wisdom of that decision!
:)

Jython is and continues to be a very important part of the Python
world.  The Pythonlabs team encourages and salutes Finn's work on
Jython and will continue to work with him on various issues such as
language development, CPython compatibility, and legal issues.

I leave Jython in good hands -- thanks Finn Bock, Samuele Pedroni, and
all the other Jython developers.

-Barry

Barry A. Warsaw
PythonLabs at Digital Creations
ba...@di...

[Jython-users] Jython-2.0 released

[<bc...@wo...>]

I am happy to announce the release of Jython 2.0. 

Jython is a Java implementation of the Python programming
language.  It allows users to compile Python source code to
Java byte codes, and run the resulting bytecodes on any Java
Virtual Machine.  It is a very seamless and smooth
integration with Java:  from Python you have complete access
to all Java libraries, can build applets, can integrate with
Java beans, and can subclass Java classes in Python and vice
versa.  Like Python, and unlike Java, Jython can also be
used interactively:  just type some Jython code at the
prompt and see the results immediately.

A java installer is available for download at the Jython website:

    http://www.jython.org/

Installation is started by running the installer class. Further 
information and tips on installation is available at:

    http://www.jython.org/install.html

Jython 2.0 is feature compatible with Python 2.0 and among the 
new feature are:

  - Augmented assignment, e.g. x += 1
  - List comprehensions, e.g. [x**2 for x in range(10)]
  - Extended import statement, e.g. import Module as Name
  - Extended print statement, e.g. print >> file, "Hello"


A complete list of changes and differences are available here:

  http://www.jython.org/NEWS.html

Bugs can be reported to the bug manager on SourceForge:

  http://sourceforge.net/bugs/?group_id=12867

Cheers,
the jython-developers 

[Jython-users] Re: [JPython] Searchable mailing list archives

[Frederic L. <f.l...@al...>]

Ben Hutchison wrote:
> 
> I want to be able to do keyword searching on the older JPython/Jython
> list archives.  http://mail.python.org/pipermail/jpython-interest
> http://lists.sourceforge.net/archives//jython-users/
> 

You can have access to the JPython mailing list with egroups.com
In my website, I made a J(p)ython column, and I provide a web page
with a search functionnality... Sorry it's in French, but hope this
helps...

http://flrt.free.fr/html/jpython/liste.html


-- 
Frédéric Laurent 
http://flrt.free.fr

[Jython-users] Re: [JPython] Searchable mailing list archives (Found)

[Ben H. <be...@in...>]

FYI, I have found a searchable archive for the JPython, (but not Jython)
list, that is very current:
http://mailarchive.activestate.com/browse/JPython

It is possible to do keyword searching of mail content, which is archives
back to the start of 2000.

However, with JPyhon devel proceeding under the new name Jython, that
archive will become incomplete and out of date rapidly. I think it would be
desirable to append Jython list traffic to this archive.

Ben

Ben Hutchison wrote:

> I want to be able to do keyword searching on the older JPython/Jython
> list archives.  http://mail.python.org/pipermail/jpython-interest
> http://lists.sourceforge.net/archives//jython-users/
>
> The knowledge contained in these archives has solved many a problem I
> have faced, avoiding the need to post questions to the list. This is
> especially true because of the lack of reference documentation for
> Jython. However, searching both new old archives is manual and
> difficult, because there is no server-side text search facility.
>
> I have seen sites which host lists which provide text searching
> facilities over the archives. An example is the advanced java archive at
> egroups.com (http://www.egroups.com/messages/advanced-java).
>
> Is there way to add this capability to JPython/Jython, either by
> enhancing the existing site at sourceforge, or by mirroring the mail
> archives elsewhere?
>
> Regards
> Ben
>
> --
> Ben Hutchison
> Software Engineer-Market Predictor
> Webmind Australia
> http://www.webmind.com/productspredictor.html
>
> _______________________________________________
> JPython-Interest maillist  -  JPy...@py...
> http://mail.python.org/mailman/listinfo/jpython-interest

--
Ben Hutchison
Software Engineer-Market Predictor
Webmind Australia
http://www.webmind.com/productspredictor.html

[Jython-users] Re: [JPython] Searchable mailing list archives

[Steven M. C. <sca...@sa...>]

	Well, it's neither pretty, nor quick, nor resource-friendly, but a
temporary solution would be for you to download the full raw archive
(http://mail.python.org/pipermail/jpython-interest.mbox/jpython-interest.mbox)
and import that file into your favorite email program.

	Netscape for linux allows me to treat this file as a folder, and I can
use its search tool to locate specifc messages within the archive.

	Having such functionality built into a webpage interface would of
course be highly preferable though.

Ben Hutchison wrote:
> 
> I want to be able to do keyword searching on the older JPython/Jython
> list archives.  http://mail.python.org/pipermail/jpython-interest
> http://lists.sourceforge.net/archives//jython-users/
> 
> The knowledge contained in these archives has solved many a problem I
> have faced, avoiding the need to post questions to the list. This is
> especially true because of the lack of reference documentation for
> Jython. However, searching both new old archives is manual and
> difficult, because there is no server-side text search facility.
> 
> I have seen sites which host lists which provide text searching
> facilities over the archives. An example is the advanced java archive at
> egroups.com (http://www.egroups.com/messages/advanced-java).
> 
> Is there way to add this capability to JPython/Jython, either by
> enhancing the existing site at sourceforge, or by mirroring the mail
> archives elsewhere?
> 
> Regards
> Ben
> 
> --
> Ben Hutchison
> Software Engineer-Market Predictor
> Webmind Australia
> http://www.webmind.com/productspredictor.html
> 
> _______________________________________________
> JPython-Interest maillist  -  JPy...@py...
> http://mail.python.org/mailman/listinfo/jpython-interest

-- 
Steve Castellotti
Systems Programmer
School of Arts and Sciences, University of Pennsylvania

[Jython-users] Searchable mailing list archives

[Ben H. <be...@in...>]

I want to be able to do keyword searching on the older JPython/Jython
list archives.  http://mail.python.org/pipermail/jpython-interest
http://lists.sourceforge.net/archives//jython-users/

The knowledge contained in these archives has solved many a problem I
have faced, avoiding the need to post questions to the list. This is
especially true because of the lack of reference documentation for
Jython. However, searching both new old archives is manual and
difficult, because there is no server-side text search facility.

I have seen sites which host lists which provide text searching
facilities over the archives. An example is the advanced java archive at
egroups.com (http://www.egroups.com/messages/advanced-java).

Is there way to add this capability to JPython/Jython, either by
enhancing the existing site at sourceforge, or by mirroring the mail
archives elsewhere?

Regards
Ben

--
Ben Hutchison
Software Engineer-Market Predictor
Webmind Australia
http://www.webmind.com/productspredictor.html

Re: [Jython-users] Jini

[Jaap S. <j....@hc...>]

charles cosse wrote:

> Hi, yup, i'm about to. So far all i did was import some Jini stuff into
> the interpreter, but as that was effortless, it's the way i'll be
> doing Jini work for the most part.  Good to know there's someone
> else interested in the same.
> Charles Cosse
> 
> Jaap Spies wrote:
> 
> 
>> Hi,
>> 
>> Is there anybody out there who is using J(P)ython to write
>> JINI-applications??
>> 
>> Jaap Spies
>> 
>> Keep Peace in Mind
>> 
>> _______________________________________________
>> Jython-users mailing list
>> Jyt...@li...
>> http://lists.sourceforge.net/lists/listinfo/jython-users
> 
> 
> 
> _______________________________________________
> Jython-users mailing list
> Jyt...@li...
> http://lists.sourceforge.net/lists/listinfo/jython-users

Great,

Let's keep posted.

Jaap

Re: [Jython-users] subclassing problems

[<bc...@wo...>]

[Erlend V Bøe]

>I'm having some problems with the following situation:
>
>I have a Java class that I extend in Jython.
>When I try to use this Jython class from Java, I get an exception similar to 
>the following: "TypeError: instance already instantiated for 
>problem.JavaClass"
>
>What am I doing wrong?

You need a python constructor in your PyClass, and when using jythonc,
the constructor must *not* call the superclass ctor. Something along the
lines of:

import problem

_jythonc = 1

class PyClass(problem.JavaClass):
    def __init__(self, s=None):
        if not _jythonc:
            problem.JavaClass.__init__(self, s)

    def myMethod(self):
        "@sig void myMethod()"
        print "python method myMethod called"

if __name__ == "__main__":
    _jythonc = 0
    x = PyClass("hi from python")
    x.myMethod()




In the generated PyClass.java, we have code like:

public class PyClass extends problem.JavaClass 
    implements org.python.core.PyProxy
{
    public PyClass(java.lang.String arg0) {
        super(arg0);
        Py.initProxy(this, ... new Object[] {arg0}, ...);
    }
}

i.e, the JavaClass ctor is called before any python code gets to
execute. Without the __init__() method, jython will automaticly call the
JavaClass ctor (again) and the exception "instance already instantiated"
is thrown.

regards,
finn

Re: [Jython-users] How do i override a static Java method in Jython ?

[D. J. H. <Dj....@ce...>]

In Java, static methods are /not/ virtual.  Overriding will not work the
way you expect if called through a base class method -- the derived static
method can only be called from derived code. =20

I don't have the exact language spec entry at-hand, but I hit this same
exact problem about a year ago (not with Jython, tho).

=09=09=09-=3D- D. J.


On Mon, 15 Jan 2001, Erlend V [iso-8859-1] B=F8e wrote:

> Hi all!
>=20
> I'm trying to look into using Jython with JUnit
>=20
> in my Class that extends junit.framework.TestCase, i have
>=20
>  def suite():
>         "@sig public static junit.framework.Test suite()"
>         print "suite called"
>         return junit.framework.TestSuite("test.SimpleTest")
>=20
>=20
> If I dont specify the "@sig", the static suite method is not overridden, =
and=20
> if I add the @sig, I get the problem shown below.
>=20
> How can a Jython program override a static method?
>=20
> Erlend
> ------
> [evb@evb unittest]$ jythonc -p test SimpleTest.py
> processing SimpleTest
>=20
> Required packages:
>   junit.swingui
>   junit.framework
> =20
> Creating adapters:
> =20
> Creating .java files:
>   SimpleTest module
>     SimpleTest extends junit.framework.TestCase
> =20
> Compiling .java to .class...
> Compiling with args: ['/usr/local/ibmjdk1.3/bin/javac', '-classpath',=20
> '/usr/local/jython-2.0b2/jython.jar:.::/usr/local/ant/ant/lib/ant.jar:/us=
r/local/JacORB1_1/classes:/usr/local/JacORB1_1/lib/idl.jar:/usr/local/JacOR=
B1_1/lib/jacorb.jar:/usr/local/jython-2.0b2/jython.jar:/usr/local/junit3.4/=
junit.jar:./jpywork::/usr/local/jython-2.0b2/Tools/jythonc:/home/evb/work/p=
ython/unittest/.:/usr/local/jython-2.0b2/Lib',=20
> './jpywork/test/SimpleTest.java']
> 1  ./jpywork/test/SimpleTest.java:158: non-static variable this cannot be=
=20
> referenced from a static context
>         PyObject inst =3D Py.jgetattr(this, "suite");
>                                     ^
> Note: ./jpywork/test/SimpleTest.java uses or overrides a deprecated API.
> Note: Recompile with -deprecation for details.
> 1 error
> =20
> ERROR DURING JAVA COMPILATION... EXITING
>=20
> _______________________________________________
> Jython-users mailing list
> Jyt...@li...
> http://lists.sourceforge.net/lists/listinfo/jython-users
>=20

[Jython-users] subclassing problems

[Erlend V <eb...@im...>]

hi,

I'm having some problems with the following situation:

I have a Java class that I extend in Jython.
When I try to use this Jython class from Java, I get an exception similar to 
the following: "TypeError: instance already instantiated for 
problem.JavaClass"

What am I doing wrong?

Erlend
-----

Here is the console output and test programs:

[evb@evb unittest]$ jythonc -p problem problem/PyClass.py 
.... stuff deleted......

[evb@evb unittest]$ java problem.UsesPyClass
JavaClass called with 'hi from Java'
Exception in thread "main" Java Traceback:
 
        at java.lang.Throwable.<init>(Throwable.java:84)
        at java.lang.Exception.<init>(Exception.java:35)
        at java.lang.RuntimeException.<init>(RuntimeException.java:39)
        at org.python.core.PyException.<init>(PyException.java:44)
        at org.python.core.PyException.<init>(PyException.java:56)
        at org.python.core.Py.TypeError(Py.java:120)
        at 
org.python.core.PyReflectedConstructor.__call__(PyReflectedConstructor.java:88)
        at 
org.python.core.PyReflectedConstructor.__call__(PyReflectedConstructor.java:72)
        at org.python.core.PyInstance.__init__(PyInstance.java:167)
        at org.python.core.Py.initProxy(Py.java:746)
        at problem.PyClass.<init>(PyClass.java:100)
        at problem.UsesPyClass.main(UsesPyClass.java:6)
Traceback (innermost last):
  (no code object) at line 0
TypeError: instance already instantiated for problem.JavaClass

The Java class that the jython class extends: 
------
package problem;

public class JavaClass{

  public JavaClass(String name) {
    System.out.println("JavaClass called with '" + name + "'");
  }
}
-----
The Jython class that extends this java class:
-----
import problem

class PyClass(problem.JavaClass):
    def myMethod(self):
        "@sig void myMethod()"
        print "python method myMethod called"

if __name__ == "__main__":
    x = PyClass("hi from python")
    x.myMethod()
-----
The Java class that uses the PyClass : 
-----
package problem;

public class UsesPyClass {

  public static void main(String[] args) {
    PyClass py = new PyClass("hi from Java");
    py.myMethod();
  }
}