jython-dev — Discussion of developing and enhancing Jython itself(!) (not how to use Jython)

[Jython-dev] (no subject)

[Markus W. <We...@gm...>]

Hello Jythonists,

I tried to use the telnetlib as described in the lib-file 
(telnetlib.py). But module select seems to be untraceable:
(
>>> import telnetlib
Traceback (innermost last):
  File "<console>", line 1, in ?
  File "d:\jython-2.0rc1\Lib\telnetlib.py", line 42, in ?
ImportError: no module named select
)
Any suggestions how to solve this problem ?

Thank you for your help in advance,

regards from Germany

Markus


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[Jython-dev] Mirror possible?

[Mats W. <ma...@la...>]

Is it possible to mirror the last release or two
someplace other than Source Forge?  I can't download
from there unless I get extremely lucky. I don't
know if I have worse paths than anyone else to the
admittedly inadequate sourceforge download server... I
have not been able to download the release candidate file,
which has failed a half-dozen times now.  The average
transfer rate - before things just give up - hovers
around 0.2k/sec, which would put it at a 2.5 hour
download, if it actually completed!  (eventually it
just gives up with no messages)

Mats

Re: [Jython-dev] Problems with weak references?

[Samuele P. <pe...@in...>]

Hi.

[Finn]
>Luckily <wink> it happens fairly often on my 300Mhz win2k & jdk1.3.
>
>The situation where it happens for me, seems to be because
>PyJavaClass(__builtin__) gets booted from the internal tables.
>When that happens, all the assignments done in Py.setBuiltinExceptions()
>is lost. The booting is done during PySystemState.initPackages, which is
>before the default PySystemState instance is create. When that instance
>is created, it will keep the __builtin__ dict alive.
>
>Storing a reference of the PyJavaClass(__builtin__) in Py appears to
>close the hole.
>
>    private static PyJavaClass v;
>
>    public static void setBuiltinExceptions() {
>       v = PyJavaClass.lookup(org.python.core.__builtin__.class);
>        PyObject dict = v.__getattr__("__dict__");
>
>
>Since the the builtin exceptions are stored in PyJavaClass.__dict__,
>these bindings are not recreated when the PyJavaClass(__builtin__) is
>recreated.
>
>I think that could explain it. Do you agree Samuele?
Yes, if an instance of PyJavaClass is kept alive in the non-weak case just by
the internal tables, it could
be garbage collected when weak internal tables are turned on.
The fix seems fine up to the field name v <wink>.
We should check if something similar is happening for other classes too. I
regret not having done such a check before.

[Rich]
> Also, it seems that the PyBeanEventProperty class is has a memory
> leak. Previously I had made a local patch to it, replacing it's
> HashMap's with WeakHasMaps. I verified that garbage collection was
> occurring by means of debugging print statements in the "finalize" method
> of some of my Java base classes. These same statements are never
> executed when using the new weak reference implementation.
>
> I can't see anything wrong with the new code, but it seems
> fairly certain that it isn't working When I switch back to my
> "WeakHashMap" patch I see that they are executed.
>
> Of course, it's difficult to _prove_ anything here, since I don't have
> much control over when garbage collection occurs. But things do look
> a bit suspicious. Has anyone else been trying out the weak reference
> implementation?
Are the adapters that do not get garbage collected (this should work also
without the weak option,
under java2 the adapters table is always implemented as a WeakHashTable)
or the adaptersClasses?

At least for adapters the following example shows that (at least in principle)
they are garbage collected:
Note: itd.py is the module that I used to debug the new internal tables,
you can use it to track the problem (that would be nice <wink>).
(I already tried that before submitting the new table design).
I have experience that also classes (not tried for adaptersClasses) in the main
table get properly discarded.

Jython 2.0beta2 on java1.3.0 (JIT: null)
Type "copyright", "credits" or "license" for more information.
>>> from java import awt,lang
>>> import itd
>>> itd.ac() # lists the "listeners" for which an adapter-class exists and is
hold in the tbl
[]
>>> itd.ad() # lists the adpter instances (truly the for each one the
"listener"
 name is shown)
[]
>>> b=awt.Button() # this alone does not create an adapter
>>> # we force the creation of an adapter
>>> b.actionPerformed
<CompoundCallable with 0 callables>
>>> itd.ac(),itd.ad()
(['java.awt.event.ActionListener'], ['java.awt.event.ActionListener'])
>>> del b
>>> lang.System.gc() # we force gc
>>> itd.ac(),itd.ad() # the adapter should have been gced
(['java.awt.event.ActionListener'], [])
Let me know.

regards, Samuele Pedroni.

<itd.py>
# Copyright 2000 Samuele Pedroni
from java.lang import Class
from org.python.core import PyJavaClass as JC

t=JC.getInternalTables()

def lazy():
 r = []
 t._beginLazyCanonical()
 while 1:
  x=t._next()
  if not x: break
  r.append(x.name)
 return r

def canon():
 r = []
 t._beginCanonical()
 while 1:
  x=t._next()
  if not x: break
  r.append(Class.getName(x))
 return r

def ac():
 r = []
 t._beginOverAdapterClasses()
 while 1:
  x=t._next()
  if not x: break
  r.append(Class.getName(x))
 return r

def ad():
 r = []
 t._beginOverAdapters()
 while 1:
  x=t._next()
  if not x: break
  r.append(Class.getName(x))
 return r

Re: [Jython-dev] Problems with weak references?

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

[Rich]

>I've been playing with the new python.options.internalTablesImpl option.
>I'm noticing some oddities when I set this to "weak".
>
>Every once in a while I get the following error when I start up the
>Jython interpreter:
>
>Jython 2.0rc1 on java1.3.0_01 (JIT: null)
>error importing site
>Traceback (innermost last):
>  File "/home/rseddon/pnp/3rdparty/jython/Lib/site.py", line 68, in ?
>  File "/home/rseddon/pnp/3rdparty/jython/Lib/javaos.py", line 6, in ?
>NameError: OSError
>
>This doesn't happen very often, and I haven't found any way to
>reproduce it consistently.

Luckily <wink> it happens fairly often on my 300Mhz win2k & jdk1.3.

The situation where it happens for me, seems to be because
PyJavaClass(__builtin__) gets booted from the internal tables.
When that happens, all the assignments done in Py.setBuiltinExceptions()
is lost. The booting is done during PySystemState.initPackages, which is
before the default PySystemState instance is create. When that instance
is created, it will keep the __builtin__ dict alive.

Storing a reference of the PyJavaClass(__builtin__) in Py appears to
close the hole.

    private static PyJavaClass v;

    public static void setBuiltinExceptions() {
        v = PyJavaClass.lookup(org.python.core.__builtin__.class);
        PyObject dict = v.__getattr__("__dict__");


Since the the builtin exceptions are stored in PyJavaClass.__dict__,
these bindings are not recreated when the PyJavaClass(__builtin__) is
recreated.

I think that could explain it. Do you agree Samuele?

regards,
finn

[Jython-dev] Problems with weak references?

[<Ric...@i2...>]

Hi,

I've been playing with the new python.options.internalTablesImpl option.
I'm noticing some oddities when I set this to "weak".

Every once in a while I get the following error when I start up the
Jython interpreter:

Jython 2.0rc1 on java1.3.0_01 (JIT: null)
error importing site
Traceback (innermost last):
  File "/home/rseddon/pnp/3rdparty/jython/Lib/site.py", line 68, in ?
  File "/home/rseddon/pnp/3rdparty/jython/Lib/javaos.py", line 6, in ?
NameError: OSError

This doesn't happen very often, and I haven't found any way to
reproduce it consistently.

Is it possible that the table holding this is being garbage collected?
I never see this error when I'm not using the weak table implementation.

Also, it seems that the PyBeanEventProperty class is has a memory
leak. Previously I had made a local patch to it, replacing it's
HashMap's with WeakHasMaps. I verified that garbage collection was
occurring by means of debugging print statements in the "finalize" method
of some of my Java base classes. These same statements are never
executed when using the new weak reference implementation.

I can't see anything wrong with the new code, but it seems
fairly certain that it isn't working When I switch back to my
"WeakHashMap" patch I see that they are executed.

Of course, it's difficult to _prove_ anything here, since I don't have
much control over when garbage collection occurs. But things do look
a bit suspicious. Has anyone else been trying out the weak reference
implementation?

Rich

Re: [Jython-dev] Command history problems in rc1

[charles F s. <yr...@ya...>]

--- Jim Hazen <ji...@my...> wrote:
> Has anyone tried making a very basic AWT (or Swing)
> app out of the jython
> interpreter
> 
> -Jim

Jim,

Check out the \jython..??\Demo\swing\Console.py
program. It was created on my machine when I installed
Jython.  When I run it I get a simple console that
allows using the up arrow and editing past command
lines.

I'm using jython-2.0a1 with jdk1.3 on a Windows ME
machine.

--- chuck ---


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Re: [Jython-dev] Command history problems in rc1

[Jim H. <ji...@my...>]

I'm surprised there isn't better readline support in the JDK.  From poking
around a bit I'm finding the console support in Java to be terrible.

Has anyone tried making a very basic AWT (or Swing) app out of the jython
interpreter?  This way it looks like an interpreter but can use the AWT's
Keyevents, which do support the up arrow.  Having Jython run in a frame with a
textarea should be all that's needed.  It should then be able to read and
append to the text area as usual.

-Jim

> Jim wrote:
>
> "
> I'm new to this list so I'm sorry if this has been answered recently (I
> did a search through the archive and it didn't come up with anything).
>
> Anyway, I'm having a problem with the command history in Jython.  When I
> hit the up arrow, instead of getting my previous commands, I get  ^[OA.
> Command history works correctly in CPython 2.0.  Is this feature
> supported in Jython?
>
> I'm running on JDK 1.3 (Blackdown 1.3.0 FCS).
>
> Any suggestions?
> "

RE: [Jython-dev] Command history problems in rc1

[Adam B. <ada...@gb...>]

Jim wrote:

"
I'm new to this list so I'm sorry if this has been answered recently (I
did a search through the archive and it didn't come up with anything).

Anyway, I'm having a problem with the command history in Jython.  When I
hit the up arrow, instead of getting my previous commands, I get  ^[OA.
Command history works correctly in CPython 2.0.  Is this feature
supported in Jython?

I'm running on JDK 1.3 (Blackdown 1.3.0 FCS).

Any suggestions?
"

This was answered recently on the (gradually more defunct) JPython list,
more info will be in that archive:


> -----Original Message-----
> From:	Robert W. Bill [SMTP:rb...@di...]
> Sent:	Sunday, January 07, 2001 12:47 AM
> To:	Steve Cohen
> Cc:	jpy...@py...
> Subject:	Re: [JPython] jpython interpreter under linux
> 
> On Sat, 6 Jan 2001, Steve Cohen wrote:
> > I am trying to run jpython interactively from a pc at home.  I am used 
> > to running it at work under NT 2000, where it works quite nicely.  At 
> > home, though, I have a PC on which I can run either Windows 98 or Red 
> > Hat LInux 6.2.  Forget Win98, it doesn't have a console worth messing 
> > with, total crap.
> > 
> > Under Linux, there are several console programs.  The default one, 
> > kvt, konsole, the Gnome shell and more.  All have the same problem 
> > with jpython.  Something is causing the interactive jpython program 
> > not to recognize the up and down arrow keys as requests for the 
> > previous/next command in the history.  This does not happen when the 
> > shells are just at system command line mode (shell is bash), nor does 
> > it happen under CPython.  In both of these cases the arrow keys work 
> > as expected.  But when JPython is running, pressing them gets output 
> > like [[A or something similar.
> > 
> > Is there a fix to this?  Or how about a workaround, another way to 
> > access the history functions?
> 
> Hello Steve,
> 
> What enables the up-down arrow history keys is the readline module.  This
> is compiled into your CPython, and all the shells you mention.  Readline
> is not available for JPython so the arrow keys do not work.  It's not a
> matter of JPython looking to the shell for this, because it cannot, as
> CPython cannot, but rather a matter of looking at the compiled-in readline
> 
> which CPython can, but Jython cannot.
> 
> Although what your thinking of is sensible- a shell the wraps the running
> process.  I know Yorick has one, and there may be others, but emacs is a
> great solution for Linux.  If you start emacs and windows, go into shell
> mode, start Jython- *then* you have up-down arrow readline history with
> the Jython intereactive console (and cool editor).
> 
> Regards,
> Robert
> 
> 
> _______________________________________________
> JPython-Interest maillist  -  JPy...@py...
> http://www.python.org/mailman/listinfo/jpython-interest

[Jython-dev] Command history problems in rc1

[Jim H. <ji...@my...>]

I'm new to this list so I'm sorry if this has been answered recently (I
did a search through the archive and it didn't come up with anything).

Anyway, I'm having a problem with the command history in Jython.  When I
hit the up arrow, instead of getting my previous commands, I get  ^[OA.
Command history works correctly in CPython 2.0.  Is this feature
supported in Jython?

I'm running on JDK 1.3 (Blackdown 1.3.0 FCS).

Any suggestions?

Thanks,
Jim

Re: [Jython-dev] ANN: First release candidate of Jython-2.0

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

[I wrote]

>I am happy to announce the first release candidate of Jython 2.0. 

And the CVS is tag and ready. I'm targeting 17-jan-2001 as the release
date of Jython-2.0 final.

regards,
finn

[Jython-dev] ANN: First release candidate of Jython-2.0

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

I am happy to announce the first release candidate 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://jython.sourceforge.net/

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

    http://jython.sourceforge.net/install.html

Jython 2.0 is feature compatible with Python 2.0 and among the 
new features 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"

The changes from beta 2 include:

  New features
   - Experimental support for reloading java packages. Thanks to
     Samuele Pedroni for all his work on the Jython/Java integration.

  Bug fixes.
   - Prevent a NPE when a .jar on the classpath is corrupt. Instead
     a message with the original IOException is printed.


A complete list of changes and differences are available here:

  http://jython.sourceforge.net/NEWS.html

Bugs can be reported to the bug manager on SourceForge:

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

Cheers,
the jython-developers

Re: [Jython-dev] Recommending to join the PSA

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

[Martin v. Loewis]

>On http://jython.sourceforge.net/download.html, item 5 reads
>
># Show you support for Python and Jython by joining the Python
># Software Activity!
>
>While there might be still reasons to join the PSA, I think supporting
>Python and Jython is not one of them. Could you please remove this step?

Done.

regards,
finn

AW: AW: [Jython-dev] Protected Java attributes in Python subclass es

[Schmidmeier, A. <Arn...@si...>]

Hello,
OK, fine with me in general, only one small suggestion, let the static
member throw a=20
runtime-exception, which is called something like =
InvalidInvocationOrder.

Arno

> -----Urspr=FCngliche Nachricht-----
> Von:	bc...@wo... [SMTP:bc...@wo...]
> Gesendet am:	Freitag, 12. Januar 2001 15:42
> An:	jyt...@li...
> Betreff:	Re: AW: [Jython-dev] Protected Java attributes in Python
> subclasses
>=20
> [Finn]
>=20
> > (Perhaps we should consider adding a =
PythonInterpreter.initialize(..)
> > method that just calls one of the PySystemState.initialize=20
> > methods. That
> > way the initialization methods becomes more visible.)
>=20
> [Arno Schmidmeier]
>=20
> >I would suggest to add an additional constructor.
> >PythonInterpreter(Properties,Properties,String [])
>=20
> That might give the impression that you can create a new
> PythonInterpreter which will use the new values. These values can =
only
> be specified once, so I think it is better with a static method on
> PythonInterpreter like this:
>=20
>     /**
>      * Initialize the jython runtime. This method should only be=20
>      * called once, and should be call before any other python =
objects
>      * are created (including the creation of a PythonInterpreter).
>      *
>      * @param preProperties   A set of properties. Typically
>      *                        System.getProperties() is used.
>      * @param postProperties  An other set of properties. Values like
>      *                        python.home, python.path and all other
>      *                        values from the registry files can be
>      *                        added to this property set. =
PostProperties
>      *                        will override system properties and
>      *                        registry properties.
>      * @param argv            Command line argument. These values =
will=20
>      *                        assigned to sys.argv.
>      */
>     public static void initialize(Properties preProperties,=20
>                                   Properties postProperties,
>                                   String[] argv) {
>         PySystemState.initialize(preProperties, postProperties, =
argv);
>     }
>=20
> regards,
> finn
>=20
> _______________________________________________
> Jython-dev mailing list
> Jyt...@li...
> http://lists.sourceforge.net/lists/listinfo/jython-dev

[Jython-dev] java reloading here

[Samuele P. <pe...@in...>]

Hi.

I have committed the first experimental version of some real java classes
reload support.
It correspond roughly to what was indicated as level 0 in one of my previous
mails.

For the moment doc and examples are missing.
I have tested it just a bit.
Clearly there can be bugs and shortcominings (it's an experimental version
really)
but on the other hand it is completely outside of the core.

At least for me it's the ending of a long journey <wink>. Enjoy.

regards, Samuele Pedroni.

PS a) in order to be able to write this in python I had to change a little bit
PyJavaClass and __builtin__.
 I think the changes should be safe. Let me know.
b) news and build.xml should be modified of course.

[Jython-dev] Recommending to join the PSA

[Martin v. L. <ma...@mi...>]

On http://jython.sourceforge.net/download.html, item 5 reads

# Show you support for Python and Jython by joining the Python
# Software Activity!

While there might be still reasons to join the PSA, I think supporting
Python and Jython is not one of them. Could you please remove this step?

Thanks,
Martin

[Jython-dev] docs?

[Samantha A. <sam...@ob...>]

It would be nice if the docs included some dirt simple things about how
to add your own class directories so Jython could see them!  This is
nowhere in the docs nor is it terribly obvious to someone like me who
mainly knows Java. Sorry if this is a dumb question but I am sure I am
not the only one it has frustrated the hell out of.

- samantha

[Jython-dev] classpath command line option

[Harlan H. <ha...@tb...>]

I'm not a fan of using the CLASSPATH environment variable, and more in
favor of using the command line options.  Currently the only way (i know
of) to get more stuff in the classpath for jpython script is to use the
environment variable.  So my suggested fix is to replace the current
jpython script with something like the following.


#!/bin/sh
for arg do 
  if [ $arg = "-cp" ] || [ $arg = "-classpath" ] ; then
    cpisnext=1
  elif [ $cpisnext = 1 ] ; then
    CLASSPATH=$arg
    cpisnext=""
  else 
    arglist="$arglist $arg"
  fi
done

exec java -Dpython.home=/export/home2/packages/JPython-1.1 -classpath
"/export/home2/packages/JPython-1.1/jpython.jar:$CLASSPATH" org.python.util.jpython
$arglist


I'm not an expert shell scripter, so there may be a better way to do this,
maybe with optarg or something.  but the idea is to allow the -cp or
-classpath option, and pass this to the java interpreter very early on.  
could something similar be done for windows?
maybe this feature could make it into a python release?
comments welcome.  thanks for your time.

---
ah... juicyfruit

Re: AW: [Jython-dev] Protected Java attributes in Python subclasses

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

[Finn]

> (Perhaps we should consider adding a PythonInterpreter.initialize(..)
> method that just calls one of the PySystemState.initialize 
> methods. That
> way the initialization methods becomes more visible.)

[Arno Schmidmeier]

>I would suggest to add an additional constructor.
>PythonInterpreter(Properties,Properties,String [])

That might give the impression that you can create a new
PythonInterpreter which will use the new values. These values can only
be specified once, so I think it is better with a static method on
PythonInterpreter like this:

    /**
     * Initialize the jython runtime. This method should only be 
     * called once, and should be call before any other python objects
     * are created (including the creation of a PythonInterpreter).
     *
     * @param preProperties   A set of properties. Typically
     *                        System.getProperties() is used.
     * @param postProperties  An other set of properties. Values like
     *                        python.home, python.path and all other
     *                        values from the registry files can be
     *                        added to this property set. PostProperties
     *                        will override system properties and
     *                        registry properties.
     * @param argv            Command line argument. These values will 
     *                        assigned to sys.argv.
     */
    public static void initialize(Properties preProperties, 
                                  Properties postProperties,
                                  String[] argv) {
        PySystemState.initialize(preProperties, postProperties, argv);
    }

regards,
finn

[Jython-dev] Database Extraction Using Jython (GUI)

[ryzam <ry...@ne...>]

Dear Jython


I'm the fan of Python Programming. I'm also programmer for Java =
Language.
Recently i'm explore to new varian of Python that called Jython formerly =
know as JPython. I think Jython is powerfull language for developing =
Rapid Application Development due of stability of Java and strong in OOP =
class in Python.

I decide to use Jython in my new project. I'm using Jython to extract =
data from Oracle Database running on Unix server .I'm using java Thread =
class when query data from database and also creating Java Internal =
frame using java swing library.Beside that the connectivity to datbase =
using JDBC-ODBC module.=20

*Sorry because english is not my first language.

[Jython-dev] (no subject)

[dustin e. <dus...@ho...>]

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RE: [Jython-dev] (no subject)

[Tim P. <ti...@ho...>]

> I wonder if the JPython has changed to Jython.  Please let me
> know as soon as possible so that I can change our company
> brochure.  Our web site is Exolink.com  We are currently using
> JPython to read XML to convert our database format .  Thank you
> very much.

JPython is a project hosted at CNRI, although it no longer appears to be
under active development.

Jython is a project that spun off of JPython, is hosted at SourceForge, and
is under active development.

So, no, JPython hasn't changed.  If you're using JPython, you should
probably say JPython.  If you switched to Jython, then Jython.

Note that JPython and Jython may (or may not) merge again someday.

[Jython-dev] (no subject)

[Ready F. Y. V. <asp...@ho...>]

I wonder if the JPython has changed to Jython.  Please let me know as soon 
as possible so that I can change our company brochure.  Our web site is 
Exolink.com  We are currently using JPython to read XML to convert our 
database format .  Thank you very much.
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Get your FREE download of MSN Explorer at http://explorer.msn.com

Re: [Jython-dev] Problem with overriding java methods in python subclass

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

[Christian Hudon on how overriden methods doesn't work during the
contructor]

>Now, I'd like to be able to use Jython to do prototyping using that Java
>library, which means I'd like to be able to write Subclass in python...
>Unfortunately, it seems that when the virtual method call createFoo() is
>resolved in the constructor, the lookup mechanism doesn't go all the way
>down to the python subclasses, it stops at the last java class. Is this a
>known bug? 

Yes, I know about it. Now you known about it too <wink>.


http://mail.python.org/pipermail/jpython-interest/2000-September/003871.html

>Is there a way to fix this??

There are still no solution in sight.

regards,
finn

[Jython-dev] ANN: Second beta release of Jython-2.0

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

I am happy to announce the second beta 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://jython.sourceforge.net/

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

    http://jython.sourceforge.net/install.html

Jython 2.0 is feature compatible with Python 2.0 and among the 
new features 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"

The changes from beta 1 include:

  New features
   - Added socket.getfqdn(). Thanks to Brian Zimmer for the patch.

  Bug fixes.
   - Fixed innerclass names with '$' #127200 
   - Fixed a bug where final methods were overriden in proxy #127201.
   - Fixed a bug in exec which allow a fileobject to be passed in.
     Thanks to Brian Zimmer for the patch.

A complete list of changes and differences are available here:

  http://jython.sourceforge.net/NEWS.html

Bugs can be reported to the bug manager on SourceForge:

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

Cheers,
the jython-developers

[Jython-dev] Problem with overriding java methods in python subclass

[Christian H. <ch...@nu...>]

Hi,

we have a Java library that uses the following construct over and over:

public class Superclass {
  private Foo m_foo;  // where Foo is some kind of class.

  public Superclass() {
    m_foo = createFoo();
  }

  protected Foo createFoo() {
    return new Foo(); // Return some default foo...
  }
}

// To configure Superclass differently, derive from it and override
// its create* methods.
public class Subclass extends Superclass {
  protected Foo createFoo() {
    // Return some other kind of Foo...
    return new Superfoo(42);
  }
}

Now, I'd like to be able to use Jython to do prototyping using that Java
library, which means I'd like to be able to write Subclass in python...
Unfortunately, it seems that when the virtual method call createFoo() is
resolved in the constructor, the lookup mechanism doesn't go all the way
down to the python subclasses, it stops at the last java class. Is this a
known bug? Is there a way to fix this?? I'd really like to use jython for
prototyping work, but I can't because of this bug... Making createFoo public
doesn't change anything.

I'm running jython 2.0beta1 with Sun's 1.3.0 JDK, if it matters.

Thanks in advance,

  Christian

PS Attached are two java files and one python file that demonstrate this
bug.