jython-users — Discussion of and questions about using Jython

[Jython-users] Re: String[][] (was: [Jython-dev] A new FAQ-entry)

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

Hi. (This may be of general interest)

[me on jython-dev answering to Janusch.Waclawczyk ]
> Maybe we should provide better support for this (?).
> 
> [ Janusch Waclawczyk]
> > I wanted to create a new entry to a FAQ, but I failed:
> > 
> > 3.8. How can I create 2-dimen. Java arrays from jython?
> 
> The following works (not that intuitive):
> >>> from java.lang import String,Object
> >>> from jarray import array
> >>> a=array(["a","b"],String)
> >>> a
> array(['a', 'b'], java.lang.String)
> >>> # this is wrong:                             
> >>> b=array([a,a],type(a)) # or a.__class__
> >>> b
> array([array(['a', 'b'], java.lang.String), array(['a', 'b'], 
> java.lang.String)], org.python.core.PyArray)
> >>> # this works !
> >>> b=array([a,a],Object.getClass(a))
> >>> b
> array([array(['a', 'b'], java.lang.String), array(['a', 'b'], 
> java.lang.String)], [Ljava.lang.String;) 
> >>> 
> # [Ljava.lang.String; is the java internal name for (class) type 
> #  java.lang.String[]
> # b is a (jython side) java.lang.String[][]
> 
I forgot to point out, that typically one does not need to work with
java arrays on jython side, lists do the job:

given:

public class Wrap {}

-----

public class Dummmy {

 public static void dummy(Wrap[][] a) {}

}

all this works:
>>> import Dummy
>>> Dummy.dummy([])
>>> Dummy.dummy([[]])
>>> a,b,c,d = [ Wrap() for i in range(0,4) ]
>>> Dummy.dummy([[a,b]])
>>> Dummy.dummy([[a,b],[c,d]])

regards, Samuele Pedroni

Re: [Jython-users] Safe Deployment

[Darrell G. <da...@do...>]

What your looking for isn't far from what Gordon provides here-->
http://www.mcmillan-inc.com/builder.html

Check out ihooks.py in the standard python dist.
Also see archive_rt.py in the above installer.

--Darrell

----- Original Message ----- 
From: "David Huttleston Jr"
> 
> I am resisting delivering class files created by jythonc
> because it's another layer of complexity (and another source
> of bugs).  Ideally a signed jar could be used as a virtual
> file system by jython.  That would be sweet!
> 

Re: [Jython-users] Safe Deployment

[David H. Jr <dh...@hd...>]

Thanks for your response, Charles.  For the systems on
our LAN your 'rsh' suggestion could work quite well.  But
most of our users are not under our direct control-- many
users are working at home.  We can, however, dictate the
runtime enviroment.

Currently we are distributing the alpha version of this app
using a cdrom/web solution.  We send a cdrom with the JRE and
Jython install files, also included is a small jython script
to download the latest jars from our server. For the java
classes, this works quite well.  But I am less satisfied
with the jython situation.

The only solution I have thought of so far is to have the
client download a signed jar and unpack it to the file system.
Then when a script is run the java framework checks the 
integrity of the script by comparing to known MD5 hashs stored
on the server. Yuck. This would be a nightmare for imports and
such.

I am resisting delivering class files created by jythonc
because it's another layer of complexity (and another source
of bugs).  Ideally a signed jar could be used as a virtual
file system by jython.  That would be sweet!

Thanks again,
  Dave

On Mon, 05 Mar 2001 15:44:02 -0700, you wrote:
> If you have progs on other machines that you want to 
> start running, without knowing the details of what
> you are doing, one way is just to "rsh" them into
> existence and have them call back (via sockets)
> to the master node/dispatching machine, which can
> be running a daemon-communications server to handle
> subsequent communications. You can mess around with
> permissions to beef up security (like setuid to 
> certain user when run).  
> 
> Charles
> 
> 
> David Huttleston Jr wrote:
> > 
> > Hey Jythoneers,
> >   I am looking for ideas to deploy a distributed
> > app in a secure fashion.  We are using jython for the
> > client gui and logic, and java for the server and
> > communication framework.
> > 
> > A few notes:
> > 1) We are free to install JDK1.3 and Jython on all
> >    clients.
> > 2) We must make sure a script can not be run if it has
> >    been modified.
> > 3) We must be able to conveniently deliver new versions
> >    over the web, but we are flexible as to how.
> > 
> > Obviously, a signed Jar is designed to solve these issues.
> > Is there a way to deploy jython programs without
> > compiling them and using a signed Jar?
> > 
> > Thanks,
> >   Dave
> > 
> > _______________________________________________
> > 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
> 
> 

Re: [Jython-users] Safe Deployment

[David H. Jr <dh...@hd...>]

Thanks for your response, Charles.  For the systems on
our LAN your 'rsh' suggestion could work quite well.  But
most of our users are not under our direct control-- many
users are working at home.  We can, however, dictate the
runtime enviroment.

Currently we are distributing the alpha version of this app
using a cdrom/web solution.  We send a cdrom with the JRE and
Jython install files, also included is a small jython script
to download the latest jars from our server. For the java
classes, this works quite well.  But I am less satisfied
with the jython situation.

The only solution I have thought of so far is to have the
client download a signed jar and unpack it to the file system.
Then when a script is run the java framework checks the 
integrity of the script by comparing to known MD5 hashs stored
on the server. Yuck. This would be a nightmare for imports and
such.

I am resisting delivering class files created by jythonc
because it's another layer of complexity (and another source
of bugs).  Ideally a signed jar could be used as a virtual
file system by jython.  That would be sweet!

Thanks again,
  Dave

On Mon, 05 Mar 2001 15:44:02 -0700, you wrote:
> If you have progs on other machines that you want to 
> start running, without knowing the details of what
> you are doing, one way is just to "rsh" them into
> existence and have them call back (via sockets)
> to the master node/dispatching machine, which can
> be running a daemon-communications server to handle
> subsequent communications. You can mess around with
> permissions to beef up security (like setuid to 
> certain user when run).  
> 
> Charles
> 
> 
> David Huttleston Jr wrote:
> > 
> > Hey Jythoneers,
> >   I am looking for ideas to deploy a distributed
> > app in a secure fashion.  We are using jython for the
> > client gui and logic, and java for the server and
> > communication framework.
> > 
> > A few notes:
> > 1) We are free to install JDK1.3 and Jython on all
> >    clients.
> > 2) We must make sure a script can not be run if it has
> >    been modified.
> > 3) We must be able to conveniently deliver new versions
> >    over the web, but we are flexible as to how.
> > 
> > Obviously, a signed Jar is designed to solve these issues.
> > Is there a way to deploy jython programs without
> > compiling them and using a signed Jar?
> > 
> > Thanks,
> >   Dave
> > 
> > _______________________________________________
> > 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
> 
> 

Re: [Jython-users] Safe Deployment

[David H. Jr <dh...@hd...>]

Thanks for your response, Charles.  For the systems on
our LAN your 'rsh' suggestion could work quite well.  But
most of our users are not under our direct control-- many
users are working at home.  We can, however, dictate the
runtime enviroment.

Currently we are distributing the alpha version of this app
using a cdrom/web solution.  We send a cdrom with the JRE and
Jython install files, also included is a small jython script
to download the latest jars from our server. For the java
classes, this works quite well.  But I am less satisfied
with the jython situation.

The only solution I have thought of so far is to have the
client download a signed jar and unpack it to the file system.
Then when a script is run the java framework checks the 
integrity of the script by comparing to known MD5 hashs stored
on the server. Yuck. This would be a nightmare for imports and
such.

I am resisting delivering class files created by jythonc
because it's another layer of complexity (and another source
of bugs).  Ideally a signed jar could be used as a virtual
file system by jython.  That would be sweet!

Thanks again,
  Dave

On Mon, 05 Mar 2001 15:44:02 -0700, you wrote:
> If you have progs on other machines that you want to 
> start running, without knowing the details of what
> you are doing, one way is just to "rsh" them into
> existence and have them call back (via sockets)
> to the master node/dispatching machine, which can
> be running a daemon-communications server to handle
> subsequent communications. You can mess around with
> permissions to beef up security (like setuid to 
> certain user when run).  
> 
> Charles
> 
> 
> David Huttleston Jr wrote:
> > 
> > Hey Jythoneers,
> >   I am looking for ideas to deploy a distributed
> > app in a secure fashion.  We are using jython for the
> > client gui and logic, and java for the server and
> > communication framework.
> > 
> > A few notes:
> > 1) We are free to install JDK1.3 and Jython on all
> >    clients.
> > 2) We must make sure a script can not be run if it has
> >    been modified.
> > 3) We must be able to conveniently deliver new versions
> >    over the web, but we are flexible as to how.
> > 
> > Obviously, a signed Jar is designed to solve these issues.
> > Is there a way to deploy jython programs without
> > compiling them and using a signed Jar?
> > 
> > Thanks,
> >   Dave
> > 
> > _______________________________________________
> > 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
> 
> 

Re: [Jython-users] Safe Deployment

[charles c. <cc...@ps...>]

If you have progs on other machines that you want to 
start running, without knowing the details of what
you are doing, one way is just to "rsh" them into
existence and have them call back (via sockets)
to the master node/dispatching machine, which can
be running a daemon-communications server to handle
subsequent communications. You can mess around with
permissions to beef up security (like setuid to 
certain user when run).  

Charles


David Huttleston Jr wrote:
> 
> Hey Jythoneers,
>   I am looking for ideas to deploy a distributed
> app in a secure fashion.  We are using jython for the
> client gui and logic, and java for the server and
> communication framework.
> 
> A few notes:
> 1) We are free to install JDK1.3 and Jython on all
>    clients.
> 2) We must make sure a script can not be run if it has
>    been modified.
> 3) We must be able to conveniently deliver new versions
>    over the web, but we are flexible as to how.
> 
> Obviously, a signed Jar is designed to solve these issues.
> Is there a way to deploy jython programs without
> compiling them and using a signed Jar?
> 
> Thanks,
>   Dave
> 
> _______________________________________________
> Jython-users mailing list
> Jyt...@li...
> http://lists.sourceforge.net/lists/listinfo/jython-users

[Jython-users] Safe Deployment

[David H. Jr <dh...@hd...>]

Hey Jythoneers,
  I am looking for ideas to deploy a distributed
app in a secure fashion.  We are using jython for the
client gui and logic, and java for the server and 
communication framework.

A few notes:
1) We are free to install JDK1.3 and Jython on all 
   clients.
2) We must make sure a script can not be run if it has
   been modified.
3) We must be able to conveniently deliver new versions
   over the web, but we are flexible as to how.

Obviously, a signed Jar is designed to solve these issues.
Is there a way to deploy jython programs without
compiling them and using a signed Jar?

Thanks,
  Dave

RE: [Jython-users] Cocoa from Jython on MacOSX

[Michael R. <ro...@ct...>]

Hi Steve,

just for reference, I recently spent an evening playing with the Cocoa Java 
classes from the Jython interpreter. It all worked, except that it soon 
became apparent how much work Interface Builder actually does behind the 
scenes. I'm no Cocoa expert, but it looked as if there are a nontrivial 
amount of bookkeeping type of classes required in a Cocoa app that IB takes 
care of automatically and it isn't at all obvious to me what calls to make 
in the interpreter.

On the other hand, the experience was positive enough to start thinking 
about how to use Jython with IB.

best

Michael


************************************************
Assoc. Prof. Michael Rose
Center for Tele-Information,    Technical University of Denmark
(45) 45 25 51 72                mailto:ro...@ct...
Off the Desktop - http://converge.cti.dtu.dk/news
'and what is the use of a computer' thought Alice 'without pictures or
conversation'       with apologies to Lewis Carroll
*************************************************

Re: [Jython-users] traceback in jython

[Barry H. <b.h...@sc...>]

Thanks for that. It seems I was using a CVS version of jython, which didn't
include traceback. I've switched to the 2.0 release version and all seems well.

cheers
Barry

On Wed, 28 Feb 2001, Ype Kingma wrote:
> Barry,
> you wrote:
> >
> >I'd like to do something like the following in jython
> >
> >import traceback
> >try:
> >#...
> >except:
> >	traceback.print_exc()
> >
> >But the module traceback doesn't seem to be included in jython. Instead I use
> >something like
> 
> Module traceback works fine for me under jython 2.0.
> The other day I was bitten by this:
> 
> import sys. traceback
> 
> which gives a somewhat confusing error message about
> traceback module not found, or something like that.
> The fix was to use a comma instead of a dot.
> I hope your case is about as simple. When not do a
> 
> import sys
> print sys.path
> 
> and check that the traceback.py module is on the path (in
> "jythondir"/Lib IIRC)
> 
> Good luck,
> Ype
> 
> _______________________________________________
> Jython-users mailing list
> Jyt...@li...
> http://lists.sourceforge.net/lists/listinfo/jython-users

Re: [Jython-users] Re: [Pythonmac-SIG] Cocoa from Jython on MacOSX

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

[Steven D. Majewski]

>...

>I changed the jython shell script to add the path:
>
>/System/Library/Frameworks/JavaVM.framework/Versions/1.2/Home/bin/java
>-Dpython.home=/Users/sdm7g/jython-2.0 -classpath
>"/Users/sdm7g/jython-2.0/jython.jar:/System/Library/Java:$CLASSPATH" org.python.util.jython
>"$@"
>
>
>I don't know anything about how the installer works -- if there is a place
>for platform dependent mods, it might be nice to add that.

At the moment the MacOSX is considered a unix from the installer POV.

>(Also: strictly 
>speaking, the initial path OUGHT to be:
>	 /System/Library/Frameworks/JavaVM.framework/Home/bin/java
>which is symbolically linked to the current version. This script works,
>but it won't antomatically track any Java upgrades. If it's not simple
>to change, 

The installer uses the java.home property directly AFAICT. If the value
there isn't the right one, there is nothing the installer can about it.
Please try this 

>>> import java
>>> java.lang.System.getProperty("java.home")
'I:\\JAVA\\JDK1.3\\jre'
>>>

>you might just want to keep it in mind as another possible
>FAQ -- you may need to reinstall jython if you upgrade Java VM. )   
>
>
>I was able to get a slightly modified version of one of my PyObjC 
>AppKit  test programs to work in Jython. The main difference is 
>that the CPython <-> Objective-C bridge does a different name
>mangling than the Java bridge does. PyObjC tries to pythonify
>the objective-C method names -- for example 
>
>the objective-c statement:
>
> [ win initWithContentRect:rect styleMask:mask  backing:YES defer:NO ];
>
>actually uses the message selector:
>
>  initWithContentRect:style:Mask:backing:defer: 
>
>which gets name mangled by PyObjC to:
>
>  win.initWithContentRect_styleMask_backing_defer_ (frame, mask, YES, NO )
>
>
>but Jython gets to use the Java bridge's use of Java overloading of
>different polymorphic versions of the same method name (so there are
>a couple of different initWithContentRect 's with different numbers
>of args. ).
>
>In Jython:
>
>  win.initWithContentRect( frame, mask, YES, NO )
>
>
>( I don't know yet what happens when there are are two objective-c
>  methods with the same number but different args. ) 

Jython will succesfully call the correct method. It works flawlessly in
99.9% of all cases. For some of the remaining cases a helper object can
be used to specify which overloaded function to call. See:

   http://www.jython.org/docs/usejava.html

section

   "Overloaded Java Method Signatures"

For the remaining cases, like this:

  void foo(int x);
  void foo(Integer x);

jython picks one, and there is no way to select.

>I think there was some discussion on the old pyobjc-sig mailing list
>on whether or not to attempt this sort of overloading or to keep the
>more explicit name transformation. We may wish to revisit this 
>decision -- it would be nice to have the same Cocoa bindings for Jython 
>and CPython+PyObjC. 

The pure pleasure of having overloading just work suggest that it is
worth the additional implementation. The ability of calling overloaded
java methods from jython without any manual mangling, was a fundamental
necessity for jython's success.

OTOH, there is a performance issue, at least with the way Jython
implements overloaded methods.

Overloaded methods are sorted according to the precedents of the
arguments and when a method is called, the runtime will attempt to
coerce the actual arguments into the argument that each of the
overloaded java method expect. If there is a lot of overloaded method 
with the same number of args, all the coercion attempts will take time.

As an example look at String.valueOf method:

>>> import java
>>> java.lang.String.valueOf
<java function valueOf at 5314727>
>>> java.lang.String.valueOf.argslist
<list of java methods that the argument will be attempted coerced into>

regards,
finn

Re: [Jython-users] traceback in jython

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

Barry,
you wrote:
>
>I'd like to do something like the following in jython
>
>import traceback
>try:
>#...
>except:
>	traceback.print_exc()
>
>But the module traceback doesn't seem to be included in jython. Instead I use
>something like

Module traceback works fine for me under jython 2.0.
The other day I was bitten by this:

import sys. traceback

which gives a somewhat confusing error message about
traceback module not found, or something like that.
The fix was to use a comma instead of a dot.
I hope your case is about as simple. When not do a

import sys
print sys.path

and check that the traceback.py module is on the path (in
"jythondir"/Lib IIRC)

Good luck,
Ype

Re: [Jython-users] Re: [Pythonmac-SIG] Cocoa from Jython on MacOSX

[Steven D. M. <sd...@vi...>]

On Wed, 28 Feb 2001, Finn Bock wrote:

> >% cd jython-2.0/
> >% setenv CLASSPATH /System/Library/Java/
> 
> I wonder, would other java programs which access Cocoa, also need this
> setenv? 
> 
> It is possible that ordinary java programs don't need it, in which case
> your solution is a good answer to a faq.

Since I didn't see any mention of this setting in Apple's Java/Cocoa
examples, I'm guessing that if you use ProjectBuilder/InterfaceBuilder
(Apple's GUI developer frontend tools -- which the example code does
use) it probably gets magically taken care of for you, but if you use
command-line javac/java tools, it needs to be told where to look. 

( I'll test the assumption when I have a chance )


I changed the jython shell script to add the path:

/System/Library/Frameworks/JavaVM.framework/Versions/1.2/Home/bin/java
-Dpython.home=/Users/sdm7g/jython-2.0 -classpath
"/Users/sdm7g/jython-2.0/jython.jar:/System/Library/Java:$CLASSPATH" org.python.util.jython
"$@"


I don't know anything about how the installer works -- if there is a place
for platform dependent mods, it might be nice to add that. (Also: strictly 
speaking, the initial path OUGHT to be:
	 /System/Library/Frameworks/JavaVM.framework/Home/bin/java
which is symbolically linked to the current version. This script works,
but it won't antomatically track any Java upgrades. If it's not simple
to change, you might just want to keep it in mind as another possible
FAQ -- you may need to reinstall jython if you upgrade Java VM. )   


I was able to get a slightly modified version of one of my PyObjC 
AppKit  test programs to work in Jython. The main difference is 
that the CPython <-> Objective-C bridge does a different name
mangling than the Java bridge does. PyObjC tries to pythonify
the objective-C method names -- for example 

the objective-c statement:

 [ win initWithContentRect:rect styleMask:mask  backing:YES defer:NO ];

actually uses the message selector:

  initWithContentRect:style:Mask:backing:defer: 

which gets name mangled by PyObjC to:

  win.initWithContentRect_styleMask_backing_defer_ (frame, mask, YES, NO )


but Jython gets to use the Java bridge's use of Java overloading of
different polymorphic versions of the same method name (so there are
a couple of different initWithContentRect 's with different numbers
of args. ).

In Jython:

  win.initWithContentRect( frame, mask, YES, NO )


( I don't know yet what happens when there are are two objective-c
  methods with the same number but different args. ) 

I think there was some discussion on the old pyobjc-sig mailing list
on whether or not to attempt this sort of overloading or to keep the
more explicit name transformation. We may wish to revisit this 
decision -- it would be nice to have the same Cocoa bindings for Jython 
and CPython+PyObjC. 


-- Steve Majewski

[Jython-users] traceback in jython

[Barry H. <b.h...@sc...>]

Hi 

I'd like to do something like the following in jython

import traceback
try:
#...
except:
	traceback.print_exc()

But the module traceback doesn't seem to be included in jython. Instead I use
something like

import sys
try:
#...
except Exception, detail:
                print  sys.exc_info()[0] , detail
                print(sys.exc_info()[2]).dumpStack()

But is there a better way? ie, is there an equivalent to traceback in jython ?

cheers
Barry	

[Jython-users] Help required urgently

[Parvathini S G. <par...@mi...>]

Hi All,

   I am trying to download jython-2.0.class on Windows-2000. After
downloading
i am getting 62.4k sized jython-2.0.class. Let me know if you have one =
more
source to download.

  One more, Is there any library module to interact with the EJB which =
is
running in weblogic server.

Thanks in advance,

Gangadhar

Re: [Jython-users] Re: [Pythonmac-SIG] Cocoa from Jython on MacOSX

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

[Steven D. Majewski]

>Nevermind -- found them.

Cool.

>They're not in a jar and they're not in:
>	/System/Library/Frameworks/JavaVM.framework/Classes 
>with the other java, com.sun & com.apple classes, but in 
>separate class files in /System/Library/Java.
>
>ls /System/Library/Java/com/apple/
>cocoa     misc      net       security  util
>
>
>% cd jython-2.0/
>% setenv CLASSPATH /System/Library/Java/

I wonder, would other java programs which access Cocoa, also need this
setenv? 

It is possible that ordinary java programs don't need it, in which case
your solution is a good answer to a faq.

regards,
finn

[Jython-users] Re: [Pythonmac-SIG] Cocoa from Jython on MacOSX

[Steven D. M. <sd...@vi...>]

Nevermind -- found them.

They're not in a jar and they're not in:
	/System/Library/Frameworks/JavaVM.framework/Classes 
with the other java, com.sun & com.apple classes, but in 
separate class files in /System/Library/Java.

ls /System/Library/Java/com/apple/
cocoa     misc      net       security  util


% cd jython-2.0/
% setenv CLASSPATH /System/Library/Java/
% ./jython
Jython 2.0 on java1.2.2 (JIT: null)
Type "copyright", "credits" or "license" for more information.
>>> import com.apple 
>>> dir()
['__doc__', '__name__', 'com']
>>> dir(com.apple)
['__name__', 'buckyball', 'cocoa', 'jdirect', 'misc', 'mrj', 'net',
'scripting', 'security', 'util']
>>> from com.apple.cocoa import foundation 
>>> foundation.NSBundle.allFrameworks()  

[ ... bunch os error messages from having no autoreleasePool 
class NSCFString autoreleased with no pool in place - just leaking
Feb 26 16:17:49 java[420] *** _NSAutoreleaseNoPool(): Object 0x8928350
... ]

(
    NSBundle </System/Library/Frameworks/Foundation.framework> (loaded), 
    NSBundle </usr/lib/java> (loaded), 
    NSBundle </usr/lib> (loaded), 
    NSBundle </System/Library/Frameworks/JavaVM.framework> (loaded)
)
>>> 

-- Steve

[Jython-users] Cocoa from Jython on MacOSX

[Steven D. M. <sd...@vi...>]

OK -- I know I was one of several people who suggested that
one ought to be able to access macosx Cocoa classes from Jython,
however, now that I've actually tried to do it, I can't seem to
find those classes anywhere. 

Importing com.apple.cocoa (or com.apple.cocoa.foundation) doesn't work:

Jython 2.0 on java1.2.2 (JIT: null)
Type "copyright", "credits" or "license" for more information.
>>> import com.apple.cocoa
Traceback (innermost last):
  File "<console>", line 1, in ?
ImportError: No module named cocoa
>>> import com.apple
>>> dir(com.apple)
['__name__', 'buckyball', 'jdirect', 'mrj', 'scripting']
>>> 


And looking in the jar-files, I can't find it either. 

I'm guessing this has something to do with cocoa being 
implemented by the special java<->objective-c bridge.

Anybody else got it working?
Any clues? 

-- Steve Majewski 

Re: [Jython-users] Fwd: Java printf

[John M. <joh...@ya...>]

Thanks.  That got me searching again.  Here's a recent one (Oct, 2000)
from Sun that's free "for NON-COMMERCIAL or COMMERCIAL purposes".

http://developer.java.sun.com/developer/technicalArticles/Programming/sprintf/



--- Scott Schenkein <sch...@vi...> wrote:
> Here is a widley used implementation of printf in java:
> 
> http://www.braju.com/
> 
> Scott
> 


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[Jython-users] newbie -- input buffer

[vitaly k. <try...@ya...>]

I just installed jython on my second Linux machine,
and although the installation seems identical to the
first, the "up arrow" on the keyboard doesn't scroll
through the input buffer of the interactive session
anymore but gives ^]]A (with other arrows producing
B,C, and D).

What's the trick, please?

Vitaly

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Re: [Jython-users] Fwd: Java printf

[Jan D. <jd...@ma...>]

John Mudd wrote:
> 
> Any comments on the following.  I'm translating Jython code to Java and
> I need help formatting numbers.  Is the printf-style formatting code in
> Jython available on a stand-alone basis?  Any suggestions?

Implementing printf-style formatting schouldn't take more than a few
pages of code. I wrote something like it in C++ once, because the
standard printf could deal only with basic types. It took surprisingly
little code, even though it supported all printf-features. It was built
on top of the C++ stream I/O facilities, making the job easier, but I
assume similar basic I/O formatting facilities exist in Java. 

So if you can't really find code implementing printf in Java, just
implement it yourself. 

Besides that, as far as I understand I would think there's no problem in
reusing the Jython implementation (provided you give proper credit to
it's source here and there) ... but then again, I'm not a lawyer!

Regards,
Jan

[Jython-users] Fwd: Java printf

[John M. <joh...@ya...>]

Any comments on the following.  I'm translating Jython code to Java and
I need help formatting numbers.  Is the printf-style formatting code in
Jython available on a stand-alone basis?  Any suggestions?



--- John Mudd <joh...@ya...> wrote:
> Date: Sat, 24 Feb 2001 19:09:38 -0800 (PST)
> From: John Mudd <joh...@ya...>
> Subject: Java printf
> To: xxxxxxxxxxxxxxxxxxxxxxx
> 
> This is the best printf answer I've seen so far.  See FAQ answer down
> below.
> 
> Hmmm... I wonder what others on my project use??  Hmmm... Jython has
> the print format capability built-in.  It looks like it's in
> org/python/core/PyString.java.  But I can't just steal that code...
> even though I'm free to use Jython as a whole?  Hmmm...  or can I?
> 
> 
> The Lava jprintf license is only $100 for source.  The web page says
> it's "the best".
> 
> I downloaded the horstmann code.  Here's a sample from Jython
> interpreter sesion.  Good enough but...  [[[ Permission to use, copy,
> modify, and distribute this software and its documentation for
> NON-COMMERCIAL purposes ]]].  Ugh... I technically can't use it.
> 
> 
>  Linux: /home/mudd/misc[1]  jython
> Jython 2.0 on java1.2.2-RC2 (JIT: javacomp)
> Type "copyright", "credits" or "license" for more information.
> >>> import Format
> >>> Format('%05d').form(123)
> '00123'
> >>> Format('------>%05d<-------').form(123)
> '------>00123<-------'
> >>> 
> 
> 
> Oh!  Try to format stuff using native Java crap.  This might be the
> best example of weakness in Java.  Geez!
> 
> 
> 
> 
> ---
> 
> FAQ:
> http://www.landfield.com/faqs/computer-lang/java/programmers/faq/
> 
> ---
> 
>  13. (Sect. 7) How do I do formatted I/O of floating point numbers?
> 
>      [*] Use the class java.text.NumberFormat.
> 
>      Or use http://www.newbie.net/sharky/lava/. Or use Cay
> Horstmann's
>      http://www.horstmann.com/corejava/Format.java
>      Although many utilities claim to handle all varieties of C's
> printf, as
>      far as has been found, this is the only one to correctly handle
> the
>      equivalent of %e in printf.
> 
>      See also the standard packages java.text.DecimalFormat and
>      java.text.NumberFormat
> 
> __________________________________________________
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Re: [Jython-users] (no subject)

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

On Sat, Feb 17, 2001 at 10:59:26AM -0800, Eli Ateljevich wrote:
| Hi. I have inherited a jpython application that makes use of user-defined 
| java time series classes. These classes have overloaded operators that do 
| pretty much what you would expect. For instance, given a time series x and 
| a time series y, x+y returns a new time series with the elements of x and y 
| added at corresponding times.
| 
| It would be very useful to be able to define x>y the same way. However, 
| when I write my own __cmp__ method jpython ignores it. The results from

You should use jython instead of jpython.

| x>y
| are an arbitrary scalar value, as if I had left comparisons undefined. If I 
| call my method directly by name:
| x.__cmp__(y)
| it works fine. Any advice?
| 

I just realized what is wrong here.  

x>y doesn't call __cmp__, but __gt__ instead

I think it would be good to RTFM some more.  Find out where __cmp__ is
used (list.sort uses it) and where __gt__, __lt__, etc. are used.

(I don't know, so I can't help any more than this, but the Fine Manual
can ;-))

HTH,
-D

Re: [Jython-users] problem using my java exception in jython?

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

On Fri, Feb 23, 2001 at 01:44:16PM -0800, John Mudd wrote:
| Just add the following at the top of yout Jython script to fix the
| problem!
| 
| 	from java.lang      import Exception
| 

I wouldn't recommend this since its name clashes with Python's builtin
Exception.

Instead I would use :

try :
    pass
except java.lang.Exception , error :
    pass


or 

from java.lang import Exception as JavaException

try :
    pass
except JavaException , error :
    pass


-D

Re: [Jython-users] problem using my java exception in jython?

[John M. <joh...@ya...>]

Just add the following at the top of yout Jython script to fix the
problem!


	from java.lang      import Exception









--- John Mudd <joh...@ya...> wrote:
> I'm trying to use an exception (written in java) in my jython code. 
> But I seem to get an error.  Any suggestions?
> 
> 
> 
> $ cat MyException.java 
> class MyException extends Exception {
>     int Code;
>     String Description;
> 
>     public MyException(int Code, String Description) {
>         //super();
> 
>         this.Code = Code;
>         this.Description = Description;
>     }
> 
>     public String toString() {
>         return "MyException: Code=" + Code + ", Description=" +
> Description;
>     }
> }
> 
> 
> $ javac MyException.java    
> 
> 
> $ cat testException.py
> #! /usr/bin/env jython
> 
> import MyException
> 
> try:
>     #raise MyException(-1, 'xxxxxxxxx')
>     de = MyException(-1, 'xxxxxxxxx')
>     print 'de=%s' % `de`
>     raise de
> except Exception, e:
>     print 'e=%s' % `e`
> 
> 
> $ testException.py          
> de=MyException: Code=-1, Description=xxxxxxxxx
> Traceback (innermost last):
>   File "testException.py", line 9, in ?
> MyException: Code=-1, Description=xxxxxxxxx
>         at java.lang.reflect.Constructor.newInstance(Native Method)
>         at
>
org.python.core.PyReflectedConstructor.__call__(PyReflectedConstructor.java:125)
>         at
> org.python.core.PyJavaInstance.__init__(PyJavaInstance.java:61)
>         at org.python.core.PyJavaClass.__call__(PyJavaClass.java:786)
>         at org.python.core.PyObject.__call__(PyObject.java:285)
>         at org.python.pycode._pyx0.f$0(testException.py)
>         at org.python.pycode._pyx0.call_function(testException.py)
>         at org.python.core.PyTableCode.call(PyTableCode.java:155)
>         at org.python.core.Py.runCode(Py.java:1055)
>         at org.python.core.__builtin__.execfile(__builtin__.java:288)
>         at org.python.core.__builtin__.execfile(__builtin__.java:292)
>         at
>
org.python.util.PythonInterpreter.execfile(PythonInterpreter.java:155)
>         at org.python.util.jython.main(jython.java:159)
> 
> MyException: MyException: Code=-1, Description=xxxxxxxxx
> $ 
> 
> 
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[Jython-users] problem using my java exception in jython?

[John M. <joh...@ya...>]

I'm trying to use an exception (written in java) in my jython code. 
But I seem to get an error.  Any suggestions?



$ cat MyException.java 
class MyException extends Exception {
    int Code;
    String Description;

    public MyException(int Code, String Description) {
        //super();

        this.Code = Code;
        this.Description = Description;
    }

    public String toString() {
        return "MyException: Code=" + Code + ", Description=" +
Description;
    }
}


$ javac MyException.java    


$ cat testException.py
#! /usr/bin/env jython

import MyException

try:
    #raise MyException(-1, 'xxxxxxxxx')
    de = MyException(-1, 'xxxxxxxxx')
    print 'de=%s' % `de`
    raise de
except Exception, e:
    print 'e=%s' % `e`


$ testException.py          
de=MyException: Code=-1, Description=xxxxxxxxx
Traceback (innermost last):
  File "testException.py", line 9, in ?
MyException: Code=-1, Description=xxxxxxxxx
        at java.lang.reflect.Constructor.newInstance(Native Method)
        at
org.python.core.PyReflectedConstructor.__call__(PyReflectedConstructor.java:125)
        at
org.python.core.PyJavaInstance.__init__(PyJavaInstance.java:61)
        at org.python.core.PyJavaClass.__call__(PyJavaClass.java:786)
        at org.python.core.PyObject.__call__(PyObject.java:285)
        at org.python.pycode._pyx0.f$0(testException.py)
        at org.python.pycode._pyx0.call_function(testException.py)
        at org.python.core.PyTableCode.call(PyTableCode.java:155)
        at org.python.core.Py.runCode(Py.java:1055)
        at org.python.core.__builtin__.execfile(__builtin__.java:288)
        at org.python.core.__builtin__.execfile(__builtin__.java:292)
        at
org.python.util.PythonInterpreter.execfile(PythonInterpreter.java:155)
        at org.python.util.jython.main(jython.java:159)

MyException: MyException: Code=-1, Description=xxxxxxxxx
$ 


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