jython-users — Discussion of and questions about using Jython

[Jython-users] String Object id question

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

Hi all,

I've ran into a bit of confusion with the id() of characters in
Jython compared with Python.  Here's something similar to the code
that started the confusion:

----------------------------------------------------------
S = "abc"
L = ["a", "b", "c"]
LoL = [L, L, L]
stringtest = S[1]
listtest = L[1]
loltest = LoL[1]

def test(obj1, obj2):
    if ( id(obj1) != id(obj2) ):
        return 0

assert(test(loltest, LoL[1])), "List-of-lists test failed"
assert(test(listtest, L[1])), "List test failed"
assert(test(stringtest, S[1])), "String test failed"
----------------------------------------------------------

In CPython, all passes, but in Jython, there's always an AE:
String test failed.  Is this expected? unavoidable?

Tnx

-Robert

RE: [Jython-users] A big problem for me!

[O'Brien-Strain, E. <eo...@ex...>]

Personally I keep a bookmark on my desktop to the Java API reference at ...

  http://java.sun.com/j2se/1.3/docs/api/overview-summary.html

... to which I frequently go to answer questions like this.

In this case if you go to that page, click on "Index" at the top, click on
"E", and scroll down -- you will see that there are "enableEvents" methods
in two different classes.  Following the links to those two methods should
help you figure out which one to use and what to pass as its arguments.

__
Eamonn


-----Original Message-----
From: cindy [mailto:inf...@pi...]
[...]For instance,
one of the statements in  an example reads like this,
"enableEvents(AWTEvent.WINDOW_EVENT_MASK)".
How would I go about determining which class/package to
import and  how would I know what qualifiers to us for
"enableEvents"?
[...]

[Jython-users] A big problem for me!

[cindy <inf...@pi...>]

Hi,
The book I'm learning java from doesn't give a detail
structure of the trees for java (inheritance). For instance,
one of the statements in  an example reads like this,
"enableEvents(AWTEvent.WINDOW_EVENT_MASK)".
How would I go about determining which class/package to
import and  how would I know what qualifiers to us for
"enableEvents"?
Thanks.
Wayne

Re: [Jython-users] Even -o option fails on NetWare

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

[Brad Clements]

>One other comment about NetWare. If I try to install using -o option I get
>
>can not get flavour null for os 'NetWare_5.00'
>
>exits with status 1
>
>--
>
>Seems to me that the -o option should still unzip itself, even if it doesn't know how to 
>handle the target platform.

Perhaps, but the very first thing that liftoff does is initialize itself
with the right platform action class. If that fails it simply gives up.

You can try to force a platform: windows, unix, mac. I'm guessing
"windows" will work the best, but the created .bat will be useless.

>I don't think many folks would consider opening a .class file 
>with Winzip to work around this issue.

Perhaps there should be a "simple" flavor that didn't try to create any
scripts?

regards,
finn

Re: [Jython-users] Object Persistence?

[Jim A. <ji...@tr...>]

Dameron Midgette wrote:
> 
> Hello all!
>     I have an application that will be storing graphics(200k-20M) and
> derived data in an object tree. I'd like to find the easiest way to store
> the data, and have persistance. (simply, if possible). I'd rather not use
> an RDBMS, if I can help it.
>     I looked at shelve, but the docs mention that keeping data size small
> is advised. It's API is about ideal, though. What else is out there,
> python, or Java? Many thanks for any thoughts you all might have.

Well, there is always Java Serialization to start with: if you can
change all your classes to implement 'Serializable' and just
Outputstream them.

If you need multi-user or network access things get more complex. There
are lots of small to large commercial JAVA ODBMS's that will store your
objects.

And then there is Ozone, a persistent object project for Java. I have
not used it but it looks powerful and flexible..although I don't know
about 'easy'. It requires changes to your classes also. Definitely worth
checking out:

  http://www.ozone-db.org/ozone_main.html
                                                                                                         

-- 
                                 __o
Jim Adrig                      _ \<,_
ji...@tr...          ' `/ ' `
                  ___________ `-'  `-'

[Jython-users] Object Persistence?

[Dameron M. <dam...@ro...>]

Hello all!
    I have an application that will be storing graphics(200k-20M) and
derived data in an object tree. I'd like to find the easiest way to store
the data, and have persistance. (simply, if possible). I'd rather not use
an RDBMS, if I can help it. 
    I looked at shelve, but the docs mention that keeping data size small
is advised. It's API is about ideal, though. What else is out there,
python, or Java? Many thanks for any thoughts you all might have.

																																																				Cheers,

																																																				Dameron

FW: Re: [Jython-users] How to qualify "super"?

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

Bringing this answer to a private question back to the list.  (I got
the wrong list the first time, oops).

-D

----- Forwarded message from D-Man <ds...@ri...> -----

From: D-Man <ds...@ri...>
Date: Mon, 26 Mar 2001 15:19:29 -0500
To: cindy <inf...@pi...>
Cc: tu...@py...
User-Agent: Mutt/1.2.5i
Mail-Followup-To: cindy <inf...@pi...>, tu...@py...


The following works for me.

>>> import javax
>>> class Foo( javax.swing.JFrame ) :
...     def __init__( self , title ) :
...             javax.swing.JFrame.__init__( self , title )
...             self.setVisible( 1 )
...
>>> frame = Foo( "Hello World" )
>>>


It doesn't matter what module you instantiate the class from.  One thing to point out -- if you change the widget (is call setTitle or something) after it is visible, it won't be updated unless you call repaint().

Send your code (to the list) and we'll see what isn't right with it.

-D

On Tue, Mar 27, 2001 at 02:47:10AM -0500, cindy wrote:
| Hi,
|
| Thanks for the reply. I like to change the scenario a bit beacuse I
| can't get the title
| to show in the title bar.
| I have a module name Foo.py and it inherit JFrame thus, class
| foo(swing.JFrame).
| The init in Foo looks like this def__init__(self, title).
| In another module Bar.py I do a composit on  Foo thus, self.aFoo =
| Foo('title').
| The title doesn't show. When I try to put a constructor in Foo,  -
| swing.JFrame__init__(self, title),
| I get an error tell me that there is a constructor already.
| These are small example I could send you if you like.
| Thanks.
| Wayne

----- End forwarded message -----

[Jython-users] Even -o option fails on NetWare

[Brad C. <bk...@mu...>]

One other comment about NetWare. If I try to install using -o option I get

can not get flavour null for os 'NetWare_5.00'

exits with status 1

--

Seems to me that the -o option should still unzip itself, even if it doesn't know how to 
handle the target platform. I don't think many folks would consider opening a .class file 
with Winzip to work around this issue.



Brad Clements,                bk...@mu...   (315)268-1000
http://www.murkworks.com                          (315)268-9812 Fax
netmeeting: ils://ils.murkworks.com               AOL-IM: BKClements

[Jython-users] How to add support for other OS's in Jython installer?

[Brad C. <bk...@mu...>]

I'd like to add support for NetWare in the installer.. How do I go about doing that?

The OS type reported (on my platform) is "NetWare 5.00", though "NetWare*" should 
be used to match any version of NetWare.

To install, the .class needs to be unzipped somewhere (I suggest sys:Jython)

(yes, that's right, "sys:Jython"  NetWare uses volume:path/path/file) 

After unzipping to the target directory (wherever the user specified, might be 
vol1:jython) these steps are needed:

1. Add jython.jar to classpath by appending a line like this to the file sys:etc/java.cfg


CLASSPATH=$CLASSPATH;sys:Jython/jython.jar

(substitute the correct path)

(anyone know if SERVLETCLASSPATH should be updated as well?)

2. Create two files in the target installation directory, like this:

filename:  jython.ncf

Contents:

java -ns -Dpython.home=sys:jython org.python.util.jython %1 %2 %3 %4 %5 %6 %7 %8 %9


Note that the correct path needs to be inserted in place of "sys:jython", there's just one 
line in the .ncf file.

filename: jythonc.ncf

Contents:

java -ns -Dpython.home=sys:jython org.python.util.jython 
"sys:jython/Tools/jythonc/jythonc.py" %1 %2 %3 %4 %5 %6 %7 %8 %9

(should be all one line, also put the correct path to sys:jython in both locations)


3. Admonish the user after installation with the following message:

------
You must unload java to complete the installation. Unload java by typing the command 
"unload java" at the system console. Note that this will unload any DirXML drivers you 
may have loaded.

You may wish to add <installationdir> to the system search path by adding the following 
line to sys:system/autoexec.ncf:

search add <installationdir>
-----
(replace <installationdir> with the appropriate path to where the .ncf files ended up)


----

If someone could tell me how to make these changes to the installer (and submit a 
patch) or if someone could just make the changes and I'll test (hint hint) I'd would be 
very happy, and so would many NetWare users..

Thanks!


Brad Clements,                bk...@mu...   (315)268-1000
http://www.murkworks.com                          (315)268-9812 Fax
netmeeting: ils://ils.murkworks.com               AOL-IM: BKClements

Re: [Jython-users] How to qualify "super"?

[Sarwar R. <raz...@ya...>]

The super method is invoked implicitly on the current
object.

Hence super(title) is equivalent to this.super(title).
All you're doing is calling the superclass (in this
case Frame) constructor. You do not need to import any
classes for this functionality; all subclasses have
access to their superclasses using this construct.

-Sarwar
--- cindy <inf...@pi...> wrote:
> Hi,
> The book I'm using  to learn Java has a statement
> in one of its examples that is "super(title)".
> This statement is in a module that extends Frame.
> What
> qualifiers do I need for "super" and what do I have
> to import?
> Thanks.
> Wayne
> 
> 
> _______________________________________________
> Jython-users mailing list
> Jyt...@li...
>
http://lists.sourceforge.net/lists/listinfo/jython-users


=====
*************************
Sarwar S Raza
NMS Software Engineer
CommWorks Corporation
http://www.wpi.edu/~sraza
*************************

__________________________________________________
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Get email at your own domain with Yahoo! Mail. 
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Re: [Jython-users] How to qualify "super"?

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

On Mon, Mar 26, 2001 at 09:21:19PM -0500, cindy wrote:
| Hi,
| The book I'm using  to learn Java has a statement
| in one of its examples that is "super(title)".
| This statement is in a module that extends Frame. What
| qualifiers do I need for "super" and what do I have to import?

Java only supports single inheritance.  "super" is a keyword in Java
that refers to a super class of the current class (the first super
class with the specified method).  Here is an example, first in Java
then Python (Jython -- same grammar):

public class MyFrame extends java.awt.Frame
{
    /**
     * A ctor for this class.  Must call Frame's ctor to init it as
     * well.
     */
    public MyFrame( )
    {
        // call java.awt.Frame's ctor
        super( ) ;
    }
}



# bring the "java" module into the current namespace
import java

class MyFrame( java.awt.Frame ) :
    # A initializer (ctor) for this class.  Must call Frame's ctor to
    # init it as well.
    def __init__( self ) :
        # call the java.awt.Frame's ctor
        java.awt.Frame.__init__( self )


The main difference is that Python supports multiple inheritance.
Thus the meaning of "super" in python isn't quite clear and if a
particular meaning is settled on it may not work as expected/intended
in some cases.  As a result python's designers didn't include "super"
as a keyword, but instead you have to specify the super class
explicitly by name.  The end result is the same, just a liitle
different look to the code.

BTW, I just tested the python part, and Jython very nicely translated
the python idiom of calling __init__ into the java ctor of Frame (as
obviously java.awt.Frame doesn't have a method named __init__).

HTH,
-D

Re: [Jython-users] unrelated Mac related question

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

On Mon, Mar 26, 2001 at 01:35:09PM +0200, Samuele Pedroni wrote:
| Hi.
| 
| I do not have access to a mac but I would like some
| comfirmation about the following (from anybody actually playing with Macs 
| <wink>):
| 
| It is true that under plain old Mac OS jvms
| set os.name property to "macos" or "mac os"
| and under MacOS X to "darwin" ?

I haven't really touched a mac in a long time, but I have heard OSX
referred to as "darwin" so it wouldn't surprise me.  In case you
didn't know, OSX is a new Mac gui (looks similar to Aqua theme for
sawfish) around a *BSD (FreeBSD I think) kernel.  It has libraries so
older apps will still work.  It also has tcsh, etc, to give access to
the BSD functionality.

probably-not-very-helpful-but-FYI-anyways, -D

[Jython-users] How to qualify "super"?

[cindy <inf...@pi...>]

Hi,
The book I'm using  to learn Java has a statement
in one of its examples that is "super(title)".
This statement is in a module that extends Frame. What
qualifiers do I need for "super" and what do I have to import?
Thanks.
Wayne

[Jython-users] unrelated Mac related question

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

Hi.

I do not have access to a mac but I would like some
comfirmation about the following (from anybody actually playing with Macs 
<wink>):

It is true that under plain old Mac OS jvms
set os.name property to "macos" or "mac os"
and under MacOS X to "darwin" ?

Note: I'm not interested in actual upper/lowercase 

Thanks, Samuele Pedroni

Re: [Jython-users] A Few Q.

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

On Sat, Mar 24, 2001 at 01:27:15AM -0500, cindy wrote:
| Hi,
| I was using Blackdown distro but decided to change to IBM rel. 1.3.0.
| I'm writting few simple programs to learn jython and came across some
| problems.
| I have a statement  in one of my test module that looks like this;
| "self.aFrame.setBackground(java.awt.Color.green)".  When I
| run the module  it displays green, but within the batt-of-the-eye the
| background
| color turn to gray. I should point out that when I start this module I
| get
| an error message that looks like this;
| Warning: Cannot allocate colormap entry for default background
| Can someone give me a solution for this.

Get a new video card <wink>.  I have seen this happen on various
systems with various programs.  I have never had any colormap problems
on my x86 Linux system because I run X at 32bpp.  The SPARC Solaris
systems in the school's labs however run at 8bpp (it sucks, btw).  If
I XDMCP to my Linux box I get an interesting rainbow effect with GDM
and other stuff, simply because the solaris display not having all the
colors (or resolution) I have.  I used AfterStep for a while in the
lab and had lots of colormap problems.  AfterStep used a lot of colors
for it's dock and stuff so Xfig and Netscape would lose out.  Netscape
is a color hog too.  If you don't want a new video card then try
adjusting your X settings or quit applications that hog the colors.

| Second problem is terninating the window. I use the window manager to
| close
| the window. That works ok. However I don't get the command line return
| to
| me until I use cntrl-d to kill the process. Is this action going to
| persist until I close my window with a java statement?

When you start your app there is a main thread.  Then you create some
AWT widgets and an AWT thread and an AWT_EventQueue thread is started.
your "main" method will terminate after initializing the window and
the main thread will die.  The AWT thread is still running, however,
and it is not a daemon thread.  Thus your app won't quit and return to
the commandline until that thread is killed or you call
java.lang.System.exit() (or sys.exit()).  Even if you get uncaught
exceptions, there are still non-daemon threads running so the app
won't quit.

HTH,
-D

[Jython-users] Question (IDE for Jython?)

[inahurry i. <ina...@al...>]

There is an Integrated Development Environment for Jython ? like PythonWin? 
 
Thanks!! 
 
 


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[Jython-users] Question(IDE for Jython?)

[inahurry i. <ina...@al...>]

There is an Integrated Development Environment for Jython ? like PythonWin?

Thanks!!


Find the best deals on the web at AltaVista Shopping!
http://www.shopping.altavista.com

Re: [Jython-users] I forgot this problem with installing jython

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

On Sat, 24 Mar 2001, cindy wrote:
> "Robert W. Bill" wrote:
> 
> > My guess is no.  Seeing code would help in the case of those errors.
> 
> Here is the code.
> 
> from pawt import swing
> import java
> import java.awt
> 
> class Mytest:
>       self.aFrame   = swing.JFrame('MY TEST')
>       self.theKit     = self.aFrame.getToolkit()
>       self.wndSize = self.theKit.getScreenSize()
> 
>       self.aFrame.setBounds(self.wndSize.width/4, self.wndSize.height/4,
>                                                self.wndSize.width/2,
> self.wndSize.height/2)
>       self.aFrame.setBackground(java.awt.Color.green)
>       self.aFrame.show().
> 
> if __name__ == '__main__':
>       aMyTest = MyTest()
> 
> Thanks for looking at the code.
> Wayne

Thanks for forwarding the code Wayne.  This is an interesting
snippet to look at because of the JFrame.

One glitch is "self" being used when there's no instance
methods defined.  Your previous description of how the code
works means this is just an omission while transferring code into
the mail, so let's assume all the "self.something" lines are in
def __init__(self):

The real catch is JFrame.  Here's what I
mean:

-A JFrame should close when you click the window
close box, but it does _not_ exit the interpreter when you close
the last JFrame. You must explicitly add a WindowListener for the
window exit event which calls System.exit.  The code example
below adds a simple exit class that takes care of this.
Without the windowListnener, you must use Ctrl-D to exit your
example as noted in your previous post.

-When using a JFrame you actually work with the content
pane.  Note the use of "contentPane" in the code below.  The
getContentPane and setContentPane methods may also be useful for
you. With your example this means that the background (green)
stays visible when it is set in the contentPane as opposed to
blinking green as it previously did.

Here's the revised code that should be closer to what you want:
---------------------------------------------------------------
from pawt import swing
import java

class MyTest:
    def __init__(self):
        self.aFrame   = swing.JFrame('MY TEST', visible=1)
        self.theKit     = self.aFrame.getToolkit()
        self.wndSize = self.theKit.getScreenSize()
        self.aFrame.setBounds(self.wndSize.width/4, 
                              self.wndSize.height/4,
                              self.wndSize.width/2,
                              self.wndSize.height/2)

        #WindowListener needed- jvm will not exit without this
        self.aFrame.addWindowListener(exit())

        #Use contentPane to change background color correctly
        self.aFrame.contentPane.setBackground(
            java.awt.Color.green)

        self.aFrame.show()

class exit(java.awt.event.WindowAdapter):
    def windowClosing(self, event):
        java.lang.System.exit(0)

if __name__ == '__main__':
      aMyTest = MyTest()
---------------------------------------------------------------


Cheers,
Robert

Re: [Jython-users] concatination +

[Jim A. <ji...@tr...>]

cindy wrote:
> 
> Hi again,
> In another one of my test modules I use a statement like this;
> 
> System.out.println(" a Point is now at: " + self.aPoint)
> 
> I get an error " TypeError: __add__ nor __radd__  defind fo these
> operands

You may need the `` (BACK-quotes) around 'self.aPoint' if it is a
Int/Float.

-- 
                                 __o
Jim Adrig                      _ \<,_
ji...@tr...          ' `/ ' `
                  ___________ `-'  `-'

Re: [Jython-users] concatination +

[Chris M. <ch...@hd...>]

What is self.aPoint? if it isn't a string you can't concatenate it to a string. You could try:

System.out.println("a Point is now at: " + str(self.aPoint))

This should work if self.aPoint is something that can be converted to a string.

Chris

On Sat, 24 Mar 2001 03:36:09 -0500, you wrote:
> Hi again,
> In another one of my test modules I use a statement like this;
> 
> System.out.println(" a Point is now at: " + self.aPoint)
> 
> I get an error " TypeError: __add__ nor __radd__  defind fo these
> operands
> 
> Is the concatenation not excepted in jython?
> When I use python's print statement everthing is ok.
> Wayne
> 
> 
> _______________________________________________
> Jython-users mailing list
> Jyt...@li...
> http://lists.sourceforge.net/lists/listinfo/jython-users
> 
> 

[Jython-users] concatination +

[cindy <inf...@pi...>]

Hi again,
In another one of my test modules I use a statement like this;

System.out.println(" a Point is now at: " + self.aPoint)

I get an error " TypeError: __add__ nor __radd__  defind fo these
operands

Is the concatenation not excepted in jython?
When I use python's print statement everthing is ok.
Wayne

Re: [Jython-users] I forgot this problem with installing jython

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

On Sat, 24 Mar 2001, cindy wrote:
> Hi,
> The first module I ran after installing the new Java I got this error.
> *sys-package-mgr*: Can't write index file.

I think this means you don't have write permissions in jython's cachedir.
a chmod a+w cachedir should fix it.

> Could this be the source of my other errors metion in a prior message?\

My guess is no.  Seeing code would help in the case of those errors.

[Jython-users] I forgot this problem with installing jython

[cindy <inf...@pi...>]

Hi,
The first module I ran after installing the new Java I got this error.
*sys-package-mgr*: Can't write index file.

Could this be the source of my other errors metion in a prior message?\
Wayne

[Jython-users] A Few Q.

[cindy <inf...@pi...>]

Hi,
I was using Blackdown distro but decided to change to IBM rel. 1.3.0.
I'm writting few simple programs to learn jython and came across some
problems.
I have a statement  in one of my test module that looks like this;
"self.aFrame.setBackground(java.awt.Color.green)".  When I
run the module  it displays green, but within the batt-of-the-eye the
background
color turn to gray. I should point out that when I start this module I
get
an error message that looks like this;
Warning: Cannot allocate colormap entry for default background
Can someone give me a solution for this.

Second problem is terninating the window. I use the window manager to
close
the window. That works ok. However I don't get the command line return
to
me until I use cntrl-d to kill the process. Is this action going to
persist until I close my window with a java statement?

Thanks.
Wayne

p.s.  I know my messages show cindy in them. I'm using her machine.

Re: [Jython-users] Upgrade from 1.1 to 2.0 problems

[John E. C. <jc...@ve...>]

Hi Finn,

>Not very helpfull I know, but your example works for me. ...you somehow
have both jpython.jar and jython.jar on your
>classpath.

Actually you were most helpful!  While I did make sure I was not using both
jars during my tests, after reading your email, I noticed that I had a
branch of my development tree with jpython classes in it.  

After removing this old code, both problems no longer occurred.

thanks very much,
John

At 09:56 AM 3/23/01 +0000, you wrote:
>[John E. Conlon]
>
>>Hi jython-users,
>>
>>While upgrading to Jython 2.0 from JPython 1.1, I have encountered a couple
>>of comparability problems with my old working code and 2.0.  Enclosed is a
>>java file that demonstrates both problems.
>>
>>Problem #1. This code also throws a java.lang.NullPointerException
>>	at
>>org.python.core.InternalTables.createInternalTables(InternalTables.java:44)
>>
>>If I uncomment the PySystemState.initialize();  line it will run.  I don't
>>need this in 1.1.   Why now?  
>>
>>Problem #2. This code will also (When first problem is not encountered)
>>throw a 
>>Traceback (innermost last):
>>  File "<string>", line 7, in ?
>>java.lang.NoSuchMethodError
>>	at org.python.core.MakeProxies.makeAdapter(MakeProxies.java:40)...
>>
>>If I remove the , 'actionPerformed=exit' from the JButton it will run. This
>>error is not thrown in 1.1.
>
>Not very helpfull I know, but your example works for me. Both with and
>without the initialize() call. The NoSuchMethodError exception could
>indicate that you somehow have both jpython.jar and jython.jar on your
>classpath.
>
>If you can't find the cause of the problems, please post the entire
>stacktraces for both siruations. Maybe that will give me a clue.
>
>regards,
>finn
> 
************************************************************************
John E. Conlon
jc...@ve...
tel: (770) 886-5470
fax: (770) 888-6894
<http://www.verticon.com/>www.verticon.com
************************************************************************