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

[Jython-dev] Freeplay project

[James H. <ja...@ex...>]

Hi,

Could you please add this project to to your Jython users list?

www.free-schooling.org

The Freeplay project is developing a free course authoring tool which 
can be used to create lessons which are more like adventure games than 
school lessons. Jython is used as the scripting language.



Many thanks,
James


--------------------
James Holmes

Re: [Jython-dev] Why do python classes show up in Java under weird names?

[Kenny L. <ken...@po...>]

On Friday, May 4, 2001, at 11:05 AM, Finn Bock wrote:

> Please keep in mind that getting the class name right is just one part
> of the problem. The proxy classes are loaded by a custom classloader
> (some instance of BytecodeLoader). By default, I doubt that the
> Class.forName() call used by the framework will find the classes loaded
> by the BytecodeLoaders. If it is jython that loads the framework, I can
> ways of ensuring that the framework can find the proxyclasses.

Thanks for the answers, Finn. Yes, you're right. Further experimentation 
reveals that the class.forName call uses the "standard" class loader, 
whichever that one is. Here's the backtrace.

java.lang.ClassNotFoundException: org.python.proxies.Main$Main$1
	at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:297)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:286)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:253)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:120)

The documentation is sketchy on this front, but there seems to be no way 
to replace this standard class loader, nor is there a way to tell it 
that the class is already loaded in the system. (I assume it has been 
loaded into the system, because the code from this class has alredy been 
run. I'm not sure if this is true since I don't know how the Jython 
internals work.) If this is correct, Java is pretty broken. Even though 
a class has already been loaded in the system, there's no way to tell 
other parts of the system!

-Kenny

Re: [Jython-dev] Why do python classes show up in Java under weird names?

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

On Wed, 2 May 2001 14:55:07 -0700, you wrote:

>Hi All.
>
>I want to use jython as a an interpreted replacement for Java classes in 
>my development cycle. However, the framework I'm using expects to find 
>classes using Class.forName(), and python classes show up in Java with 
>funny package names.
>
>Is there a guide for how jython interfaces python classes into Java? 

No.

>Is there a good reason that python classes need to show up with the funny 
>package names? 

Yes.

1) To avoid naming conflicts. The same class can exists in multiple
python modules. The same class name can even be used multiple times
within the same module.
2) To allow a reverse mapping of the proxy class name back to the module
and classname where the class is defined. This is used when reading a
serialized object stream with the PythonObjectInputStream class.

>If not, can someone give me a pointer as to where to fix 
>up the code so that python classes show up in Java as with the same name?

Part of the name is created in PyClass.init() just before the call to
MakeProxies.makeProxy(). The rest of the name is created in the
makeProxy() method.

A real solution to this problem could maybe be to define the proxyname
somewhere in the python class:

    import java
    class A(java.lang.Object):
        __proxyname__ = "my.package.FooBar"

The special __proxyname__ attribute must then be defined when the class
statement is executed. The value will be available in PyClass.init()
method in the dict parameter. Such a manually renamed proxy class can
never be de-serialized using java serialization.

Please keep in mind that getting the class name right is just one part
of the problem. The proxy classes are loaded by a custom classloader
(some instance of BytecodeLoader). By default, I doubt that the
Class.forName() call used by the framework will find the classes loaded
by the BytecodeLoaders. If it is jython that loads the framework, I can
ways of ensuring that the framework can find the proxyclasses.

regards,
finn

Re: [Jython-dev] distrib/licensing

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

[Randy Heiland]

>I'd like to know if it is possible (legally) to distribute Jython on a CD.

It is. As long as you comply with the licenses that cover the various
parts of Jython. You will have read the licenses yourself in order to
decide whether you can live with the very few restrictions that they put
in place.

The licenses in question are:

- JPython-1.1 license (cover the original sources)
- Apache license (cover the ORO matcher code)
- Python-2.0 license (cover most of the python modules in Lib)
- BSD license (cover the changes made to JPython-1.1 sources)

regards,
fin

Re: [Jython-dev] Problem with method overrides in latest CVS jython?

[Rich S. <rse...@ya...>]

Hi Brian,

If I understand your test program correctly, it should work when I run it for 
PyTestA class, and fail for PyTestB. 

In my case it works for both, clone() is there.

What JDK version are you running? We've had some problems here before with 
Java not accessing protected methods properly. FWIW, I'm running JDK 1.3.1 
RC2 on Linux.

It is odd that you got a KeyError for my test program. I get a segfault 
(which may or may not be caused by a stack overflow). However, the same 
scenario in my real-world application definately causes an infinite 
recursion, I can see it in the stack trace. This is why I am suspecting a 
stack overflow for the test program as well.

Here's my output:

~/jython-2.1a1 > ./jython test.py
./jython: line 7:  8029 Segmentation fault      
/usr/local/jdk1.3.1/jre/bin/java -Dpython.home=/home/rseddon/jython-2.1a1 
-classpath "/home/rseddon/jython-2.1a1/jython.jar:$CLASSPATH" 
org.python.util.jython "$@"

If I add the "setSize" method into the intermediate class it runs properly.

Rich

On Friday 04 May 2001 08:56, brian zimmer wrote:
> Rich,
>
> I don't get the StackOverflow, but instead a KeyError.  I'm not much of a
> Swing guy, but I'm willing to bet that processInputMethodEvent is a
> protected method on some object (probably JFrame).  Check out my bug at
> sourceforge #416871 for Jython and see what the downloadable code does for
> you.  I'm quite curious.  I used to get the StackOverflow, but some changes
> to the core fixed that, but in doing so have caused me problems with Jython
> not building all the appropriate methods if I subclass (in Python-sp ak) a
> Java interface.  To workaround it I implement all the methods that fail
> (always protected methods such as .clone() and .finalize()).  I don't know
> if this makes any sense to you, but love to have someone else experience
> this problem.  I've spoken with Finn and he is unable to reproduce it.
>
> thanks,
>
> brian
>
> So I went and checked the Javadoc and .processInputMethodEvent() is indeed
> protected.  My theory holds.
>


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Re: [Jython-dev] Problem with method overrides in latest CVS jython?

[brian z. <bz...@zi...>]

Rich,

I don't get the StackOverflow, but instead a KeyError.  I'm not much of a Swing guy, but I'm willing to bet that processInputMethodEvent is a protected method on some object (probably JFrame).  Check out my bug at sourceforge #416871 for Jython and see what the downloadable code does for you.  I'm quite curious.  I used to get the StackOverflow, but some changes to the core fixed that, but in doing so have caused me problems with Jython not building all the appropriate methods if I subclass (in Python-speak) a Java interface.  To workaround it I implement all the methods that fail (always protected methods such as .clone() and .finalize()).  I don't know if this makes any sense to you, but love to have someone else experience this problem.  I've spoken with Finn and he is unable to reproduce it.

thanks,

brian

So I went and checked the Javadoc and .processInputMethodEvent() is indeed protected.  My theory holds.

At 08:31 AM 5/4/2001 -0700, Rich Seddon wrote:

>Hi,
>
>I've been playing with the latest jython from CVS, and I'm having some 
>trouble getting my code to work with it. When I attempt to call a Java method 
>that is overridden in a python class, but not overridden in all intermediate 
>python classes, I get a stack overflow. 
>
>The following test program fails using the latest CVS, but works fine if I 
>pull jython using the "Release_2_1alpha1" tag:
>
>from javax.swing import *
>
>class fooFrame(JFrame):
>    def __init__(self):
>        JFrame.__init__(self)
> 
>class barFrame(fooFrame):
>    def __init__(self):
>        fooFrame.__init__(self)
> 
>    def setSize(self, width, height):
>        fooFrame.setSize(self, width, height)
> 
> 
>if __name__ == "__main__":
>    frm = barFrame()
>    frm.setSize(100,100)
> 
>    frm.show()
>
>Regards,
>
>Rich Seddon
>
>_________________________________________________________
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>Get your free @yahoo.com address at http://mail.yahoo.com
>
>
>_______________________________________________
>Jython-dev mailing list
>Jyt...@li...
>http://lists.sourceforge.net/lists/listinfo/jython-dev 

[Jython-dev] Problem with method overrides in latest CVS jython?

[Rich S. <rse...@ya...>]

Hi,

I've been playing with the latest jython from CVS, and I'm having some 
trouble getting my code to work with it. When I attempt to call a Java method 
that is overridden in a python class, but not overridden in all intermediate 
python classes, I get a stack overflow. 

The following test program fails using the latest CVS, but works fine if I 
pull jython using the "Release_2_1alpha1" tag:

from javax.swing import *

class fooFrame(JFrame):
    def __init__(self):
        JFrame.__init__(self)
 
class barFrame(fooFrame):
    def __init__(self):
        fooFrame.__init__(self)
 
    def setSize(self, width, height):
        fooFrame.setSize(self, width, height)
 
 
if __name__ == "__main__":
    frm = barFrame()
    frm.setSize(100,100)
 
    frm.show()

Regards,

Rich Seddon

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[Jython-dev] Error while getting FAQ-entries

[Waclawczyk J. <Jan...@ic...>]

Hi,

I've got rather strange behaviour, when trying following links:

http://jython.sourceforge.org/cgi-bin/faqw.py?req=index
 strange content-type needed
http://jython.sourceforge.net/cgi-bin/faqw.py?req=index
folowing message:
<H3>Traceback (innermost last):</H3>
<PRE>  File "/home/groups/j/jy/jython/cgi-bin/faqw.py", line 24, in ?
    os.chdir(FAQDIR)
<B>OSError: [Errno 2] No such file or directory: '/home/groups/jython/FAQ/data'
</B></PRE>
<BR>(times: user 0.05, sys 0.01, ch-user 0, ch-sys 0, real 0.12)

Regards

Janusz Waclawczyk

[Jython-dev] distrib/licensing

[Randy H. <he...@nc...>]

I'd like to know if it is possible (legally) to distribute Jython on a CD.

Some background:
We (NCSA at Univ of Illinois, Urbana-Champaign) are preparing to produce a CD
that will be given to academic partners (part of the NSF PACI program) who are
building Linux clusters.  Our NCSA visualization group has developed a
visualization tool that requires the use of Jython.  It would simply make life
simpler if we could put Jython on the Cd along with the other required
software.

thanks,
--Randy

---------------------------------------------------------------------
Randy Heiland                          |   he...@nc...
NCSA, University of Illinois           |
405 N. Mathews Ave., Urbana, IL 61801  |
217-244-7318      (fax)217-244-2909    |

[Jython-dev] Why do python classes show up in Java under weird names?

[<ken...@po...>]

Hi All.

I want to use jython as a an interpreted replacement for Java classes in 
my development cycle. However, the framework I'm using expects to find 
classes using Class.forName(), and python classes show up in Java with 
funny package names.

Is there a guide for how jython interfaces python classes into Java? Is 
there a good reason that python classes need to show up with the funny 
package names? If not, can someone give me a pointer as to where to fix 
up the code so that python classes show up in Java as with the same name?

Thanks!

-Kenny

[Jython-dev] long(hexstring, 16) troubles

[Robert W. B. <rb...@di...>]

Hello all,

The current atol in PyString doesn't handle hexstring's. 
Use of hex string in long() currently looks like:

>>> long("0x12", 16)
Traceback (innermost last):
  File "<console>", line 1, in ?
ValueError: invalid literal for __int__: 0x12

It also seems the ValueError argument should be '__long__'
instead of '__int__', is that right?

Proposed change would allows hex strings when base=16 is
specified, and changes '__int__' to '__long__'. This means:

>>> long("0x12")
Traceback (innermost last):
  File "<console>", line 1, in ?
ValueError: invalid literal for __long__: 0x12
>>>
>>> long("0x12", 16)
18L
>>>

=========begin diff -u===========
--- local/org/python/core/PyString.java	Sun Apr 29 21:15:08 2001
+++ org/python/core/PyString.java	Sun Apr 29 21:45:46 2001
@@ -1326,6 +1326,10 @@
             } else
                 base = 8;
         }
+        if (base == 16) {
+            if (str.charAt(b+1) == 'x' || str.charAt(b+1) == 'X')
+                b += 2;
+        }
         if (base < 2 || base > 36)
             throw Py.ValueError("invalid base for long literal:" + base);
 
@@ -1340,9 +1344,9 @@
                 bi = new java.math.BigInteger(str, base);
             return new PyLong(bi);
         } catch (NumberFormatException exc) {
-            throw Py.ValueError("invalid literal for __int__: "+str);
+            throw Py.ValueError("invalid literal for __long__: "+str);
         } catch (StringIndexOutOfBoundsException exc) {
-            throw Py.ValueError("invalid literal for __int__: "+str);
+            throw Py.ValueError("invalid literal for __long__: "+str);
         }
     }
=========end diff=========

Cheers,
Robert 

Re: [Jython-dev] Event handling by Registered Listener in interactive mode

[Stuart S. <st...@me...>]

Whoops, wrong list.
My apologies.

Stuart

[Jython-dev] PyServlet questions

[Arun S. <ar...@sh...>]

Can someone here help me with PyServlet question mailed to
jython-users ?

http://www.geocrawler.com/lists/3/SourceForge/7017/0/5646196/

	-Arun

Hi, 

I'm trying to use PyServlet along with tomcat and ran into a couple of
problems:

(a) Is there a way to load a python servlet (init.py) on startup ? For java  
    servlets, I use load-on-startup=1
(b) Python servlets get reloaded when I make changes, but other python
    modules they "import" don't get reloaded when they're changed. I understand
    that this is the default java behavior, but is there a way to change this
    in python ? Will save me a restart, if I can do that.

Thanks!

	-Arun

[Jython-dev] Event handling by Registered Listener in interactive mode

[Stuart S. <st...@me...>]

Hi Folks,

    I'm a jython newbie, and I'm trying to utilize Jython so I can
fiddle with/glue Java code I've
written (and debugged).  I have a CORBA server running, and I'm using
CORBA client code
written in Java that I'm calling from the jython command line:

 from com.adaclabs.camelot.CORBAImageServices import *
 from java.net import *
orbURL = URL("http://localhost");
adapter =
CORBADataAccessAdapter(orbURL.toString(),"EventServiceForSTUARTS","");
mylistener = CORBAClientListenerAdapter();
 adapter.InitializeConnection(orbURL,mylistener);
strUID=adapter.ListPatientData("<DICOMQueryPatientRoot/>","ftp://anywhere.com");

---
The Class CORBAClientListenerAdapter prints some stuff to System.err
as well as dumping the incoming event (translated from a CORBA Any) to a
file on the local file system.

The Server side sees the request and responds (which I can observe in
the console for the server),
and the CORBA Event channel receives the message from the server.
I just don't see anything coming in on the client, nor is a file created
(containing an incoming event).

There are multiple threads running when I do this without jython (the
client spins in a loop
and sleeps for a few seconds per iteration of the loop after having made
a request via CORBA),
and the code has been working reasonably well for months (including
others making use of it).


Is there something I need to be doing with threads within the jython
client ?

Are there any particular references in the documentation that might help
?
I really did try to find something in the jython docs, python docs, and
the swing example code in jython,
but I just don't see it...

Thank You,

Stuart
P.S.
I'm aware that there are Python bindings for CORBA, but I'm really more
interested in hooking in
to my Java code,  the CORBA stuff is just my latest grind...

[Jython-dev] java beans in Jython

[Zain ul a. <zai...@ya...>]

Hi,
  can we make java beans in Jython? and if we can can
you refer me to any documentation for it.
  thanks, 


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Re: [Jython-dev] dead link

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

[Bobby Impollonia]

>hey, folks. on the front page, you have a link to psa (under "exits"), but
>that link goes to a page saying that psa no longer exists and "is replaced
>by the Python Software Foundation". update time.

Done, thanks.

regards,
finn

Re: [Jython-dev] Regd try-except-finally block

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

Hello,

from the python manual online at
http://www.python.org/doc/current/ref/try.html

There are two forms of try statement: try...except and
try...finally. These forms cannot be mixed (but they
can be nested in each other). 

regards,

Charles Simons


--- "Saravanan Balasubramani (EWU)"
<Sar...@am...> wrote:
> Hi,
> Iam trying to use try, except and finally block in
> my jython program and it
> givs a syntax error for my finally line:
> 
> class test1(test):
> 	def __init__(self)
> 		test.__init__(self)
> 
> 	def setInt(self, num)
> 		try:
> 			test.setInt(num)
> 		except Exception, e:
> 			print e.toString()
> 		finally:
> 			print 'program ends here ..'
> 
> When I compile this program, I always get syntax
> error for finally.
> Can u help me on this.
> 
> thanks,
> saravanan
> 
> 
> 


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[Jython-dev] Regd try-except-finally block

[Saravanan B. (EWU) <Sar...@am...>]

Hi,
Iam trying to use try, except and finally block in my jython program and it
givs a syntax error for my finally line:

class test1(test):
	def __init__(self)
		test.__init__(self)

	def setInt(self, num)
		try:
			test.setInt(num)
		except Exception, e:
			print e.toString()
		finally:
			print 'program ends here ..'

When I compile this program, I always get syntax error for finally.
Can u help me on this.

thanks,
saravanan

RE: [Jython-dev] Null pointer exception in Demo/embed/SimpleEmbedded...

[Mika R. <mry...@ma...>]

[Jayson S Baird]

>Hiho,
>
>   I'm a developer who is trying to embed Python code into Java, so of
>course I came to Jython. When trying to run your example after compiling,
>I get the following stack dump:
>  Exception in thread "main" java.lang.NullPointerException
>   at org.python.core.PyJavaClass.lookup(PyJavaClass.java:39)
>   at org.python.core.PyObject.<init>(PyObject.java:46)
>   at org.python.core.PySingleton.<init>(PySingleton.java:8)
>   at org.python.core.PyNone.<init>(PyNone.java:7)
>   at
org.python.core.PySystemState.initStaticFields(PySystemState.java:341)
>   at org.python.core.PySystemState.initialize(PySystemState.java:320)
>   at org.python.core.PySystemState.initialize(PySystemState.java:294)
>   at org.python.core.PySystemState.initialize(PySystemState.java:287)
>   at org.python.util.PythonInterpreter.<init>(PythonInterpreter.java:61)
>   at org.python.util.PythonInterpreter.<init>(PythonInterpreter.java:45)
>   at SimpleEmbedded.main(SimpleEmbedded.java:6)
>
>Any idea what's causing this? no one has mentioned it in the FAQ's or the
>list archives...

Hello!
The original post was rather old, but as there was no solutions I thought
I'd suggest something. I've been using Jython for three days now, so if
this is something obvious, please don't flame me :-)  I encountered this
problem today (exactly the same exception as above). I had installed
full Jython (with sources). 

I was using "classpath=c:\windows\jython-2.1a1;.". I think this means that
most Jython classes are loaded from dir 
"c:\windows\jython-2.1a1\org\python\core". For some reason
there was no corresponding compiled .class files for
"InternalTables1.java", "InternalTables2.java" and
"exceptions.java" included in that directory.

The problem was fixed either by compiling these three files, or changing
classpath to use the ready-made
jar: "classpath=c:\windows\jython-2.1a1\jython.jar;.". I hope this is
helpful to someone!

--
Mika

[Jython-dev] get_syntax()

[Pasha A. <par...@en...>]

I need to know exactly how the get_syntax() method works in the regex API
because it is no longer supported by the re.py API and I need it becuase
some of my python scripts make calls to it.  Thanks!
____________________________
Pasha Arshadi
Software Engineer
Endeavors Technology
19700 Fairchild, Suite 200
Irvine, CA 92612
(949) 833-2800 x110
www.endeavors.com
par...@en...

Re: [Jython-dev] how to integrate readline ??

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

[taxpro]

>Hi
>Hoping this message does'n bother anyone, please reply:
>1:how to integrate readline with jython

Jython already have some support for integration of a readline library.

  http://www.bablokb.de/java/readline.html

In the CVS version the ReadlineConsole class is already included with
the distribution (this include the entire "Support for JPython" section
which is no longer needed with the current CVS version of Jython). So in
the next release the readline support can be installed by setting the
registry option

  python.console=org.python.util.ReadlineConsole

and installing Bablok's java binding to readline. I don't yet know how
this java binding is compiled or installed (I don't use *nix myself) but
I hope someone else will contribute a description.

I expect the readline support to be streamlined and improved during the
2.1 release cycle.

regards,
finn

Re: [Jython-dev] Running Jython from Java

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

[Andreas Jakobik]

>Hi
> 
>to ease the use of a Java library from Jython I have written conversion 
>routines between PyDictionary and mylib.XClass. It works fine when I run
>this from the Jython interpreter, but when I want to test my conversion
>routines from Java (using JUnit) I get a NullPointerException at
>org.python.core.InternalTables.createInternalTables.

Could you post the exception traceback?

>This happens when I want to (e.g.) create a PyDictionary object.
> 
>I guess I missed initializing the library somehow.

You can initialize the runtime by calling one of the
PySystemState.initialize() methods. This is normally done automaticly
when using the PythonInterpreter class. If you are not using this
utility class, you may have to call one of the initialize() methods
yourself.

If you can post a complete failing example, maybe we can improve jython
in this respect.

>Is there a system property I must set??

The exception traceback will tell us more.

>Using Jython-2.0.

regards,
finn

[Jython-dev] Jython script help

[Pasha A. <par...@en...>]

I have Python scripts that import the python regex modules and i am trying
to run the python scripts on jython.  When i change the file containing the
regex import to re, the new replacement for regex, i get an
error stating that the regex module is not found, this is displayed after I
have changed all of the instances of regex with re, there is also a
regex.compile(line[A]) that I replace with re.compile(line[A]) and for some
reason
it still says no module names regex.  I was wondering if anyone can help me
out? Thanks.

Pasha

____________________________
Pasha Arshadi
Software Engineer
Endeavors Technology
19700 Fairchild, Suite 200
Irvine, CA 92612
(949) 833-2800 x110
www.endeavors.com
par...@en...

[Jython-dev] How can I use jython fro cgi/web tasks?

[Janusch W. <Jan...@ic...>]

Hi,

how can I improve the jython performace in the cgi work ? (something
like FastCGI, mod_python or PyApache).
Can I use jython while working with Zope ?

Regards
Janusch Waclawczyk

[Jython-dev] how to integrate readline ??

[v <ta...@xn...>]

Hi
Hoping this message does'n bother anyone, please reply:
1:how to integrate readline with jython