jython-users — Discussion of and questions about using Jython

[Jython-users] PortableRemoteObject.narrow ClassCastException with JDK1.3 but no t JDK1.2.2

[Coleman, D. <don...@em...>]

I get a ClassCastException trying to narrow a reference to an EJB home using
JDK1.3 (on Win32).  This code works fine with JDK1.2.2 (on Win32).  I get
the same problem with jpython-1.1.  Am I doing something wrong or is this a
bug?

CODE THAT CAUSES THE PROBLEM

    jndiContext = InitialContext()
    object = jndiContext.lookup("emax.ContainerManager")
    # next line blows up with JDK 1.3 but not JDK1.2.2
    managerHome = PortableRemoteObject.narrow(object,
ContainerManagerHome.class)
    manager = managerHome.create()

STACK TRACE
  
File "e:\home\ESM\src\com\emax\container\c.py", line 69, in
getContainerManage
r
java.lang.ClassCastException
        at
com.sun.corba.se.internal.javax.rmi.PortableRemoteObject.narrow(Porta
bleRemoteObject.java:296)
        at
javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:137)
        at java.lang.reflect.Method.invoke(Native Method)
        at
org.python.core.PyReflectedFunction.__call__(PyReflectedFunction.java
:158)
        at
org.python.core.PyReflectedFunction.__call__(PyReflectedFunction.java
:166)
        at org.python.core.PyObject.__call__(PyObject.java:285)
        at org.python.core.PyObject.invoke(PyObject.java:2119)
        at
c$py.getContainerManager$4(e:\home\ESM\src\com\emax\container\c.py)
        at c$py.call_function(e:\home\ESM\src\com\emax\container\c.py)
        at org.python.core.PyTableCode.call(PyTableCode.java:155)
        at org.python.core.PyTableCode.call(PyTableCode.java:200)
        at org.python.core.PyFunction.__call__(PyFunction.java:93)
        at org.python.pycode._pyx6.f$0(<console>)
        at org.python.pycode._pyx6.call_function(<console>)
        at org.python.core.PyTableCode.call(PyTableCode.java:155)
        at org.python.core.Py.runCode(Py.java:1055)
        at org.python.core.Py.exec(Py.java:1076)
        at
org.python.util.PythonInterpreter.exec(PythonInterpreter.java:145)
        at
org.python.util.InteractiveInterpreter.runcode(InteractiveInterpreter
.java:87)
        at
org.python.util.InteractiveInterpreter.runsource(InteractiveInterpret
er.java:68)
        at
org.python.util.InteractiveInterpreter.runsource(InteractiveInterpret
er.java:42)
        at
org.python.util.InteractiveConsole.push(InteractiveConsole.java:83)
        at
org.python.util.InteractiveConsole.interact(InteractiveConsole.java:6
2)
        at org.python.util.jython.main(jython.java:178)

java.lang.ClassCastException: java.lang.ClassCastException

Re: [Jython-users] Strange behavior of Integer and Double

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

[Will]

>I have run into some surprising behavior of Java Integer objects while using
>jython:
>
>public class Test {
>
>	public void foo(Integer I) {
>		System.out.println("Called with an Integer.");
>	}
>
>  	public void foo(int i) {
> 		System.out.println("Called with an int.");
>  	}
>
>	public static void main(String[] args) {
>
>		... initialize PythonInterpreter ...
>
>		myInterpreter.exec("test = Test()");
>		myInterpreter.exec("test.foo(Integer(1))");
>		myInterpreter.exec("test.foo(2)");
>	}
> }
>
>
>Expected output:
>	Called with an Integer.
>	Called with an int.
>
>Actual output:
>	Called with an int.
>	Called with an int.
>
>
>I have noticed similar behavior with Double objects.
>
>What am I doing wrong?  How can I keep Integer and Double objects from being
>converted to Java primitives?

You can't. The eagerness with which Jython converts the java.lang.*
wrapper classes to instances of native python classes have been
discussed previousely:

http://mail.python.org/pipermail/jpython-interest/1999-December/002590.html

It is basicly the same problem you have re-discovered. I'm still not
convinved that it is a net win to reduce this eagerness.

http://mail.python.org/pipermail/jpython-interest/1999-December/002596.html


>Also, why does the following call to equals() on an Integer object...
>
>	myInterpreter.set("myInteger", new Integer(1));
>	myInterpreter.exec("myInteger.equals(Integer(1))");
>
>...result in an exception?
>
>	Exception in thread "main" Traceback (innermost last):
>	  File "<string>", line 1, in ?
>	AttributeError: 'int' object has no attribute 'equals'

Use this instead:

	myInterpreter.set("myInteger", 
			new PyJavaInstance(new Integer(1)));
	myInterpreter.exec("myInteger.equals(Integer(1))");


regards,
finn

[Jython-users] Strange behavior of Integer and Double

[Byrd, W. <Wil...@co...>]

I have run into some surprising behavior of Java Integer objects while using
jython:

public class Test {

	public void foo(Integer I) {
		System.out.println("Called with an Integer.");
	}

  	public void foo(int i) {
 		System.out.println("Called with an int.");
  	}

	public static void main(String[] args) {

		... initialize PythonInterpreter ...

		myInterpreter.exec("test = Test()");
		myInterpreter.exec("test.foo(Integer(1))");
		myInterpreter.exec("test.foo(2)");
	}
 }


Expected output:
	Called with an Integer.
	Called with an int.

Actual output:
	Called with an int.
	Called with an int.


I have noticed similar behavior with Double objects.

What am I doing wrong?  How can I keep Integer and Double objects from being
converted to Java primitives?


Also, why does the following call to equals() on an Integer object...

	myInterpreter.set("myInteger", new Integer(1));
	myInterpreter.exec("myInteger.equals(Integer(1))");

...result in an exception?

	Exception in thread "main" Traceback (innermost last):
	  File "<string>", line 1, in ?
	AttributeError: 'int' object has no attribute 'equals'

Note that the following version works just fine:

	myInterpreter.exec("myInteger = Integer(1)");
	myInterpreter.exec("myInteger.equals(Integer(1))");


Thanks.

	Regards,

	Will

Re: [Jython-users] pickle and java objects

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

[Donatas Simkunas]

>Is there ability using jython  and pickle  save objects which classes is java 
>classes ?

No (as you have dicovered yourself).

>for example:
>
>>>> import cPickle
>>>> from java.awt import Rectangle
>>>> r=Rectangle(1,1,200,300)
>>>> f=open("fileout","w")
>>>> cPickle.dump(r,f)
>Traceback (innermost last):
>  File "<console>", line 1, in ?
>PicklingError: Unable to pickle java objects.
>
>>>> import pickle
>>>> pickle.dump(r,f)
>Traceback (innermost last):
>  File "<console>", line 1, in ?
>  File "/home/donce/jython-2.0/Lib/pickle.py", line 888, in dump
>  File "/home/donce/jython-2.0/Lib/pickle.py", line 100, in dump
>  File "/home/donce/jython-2.0/Lib/pickle.py", line 202, in save
>  File "/home/donce/jython-2.0/Lib/pickle.py", line 421, in save_inst
>AttributeError: class 'java.awt.Rectangle' has no attribute '__module__'
>>>
>
>Is there something what i missed ?
>
>Workaround for this is to use java objects serialization, but if i use python 
>there should be ability to use python serialization.

I suppose it is possible to extend the pickle protocol to contain tags
for serialized java objects and to use the pickle.memo table to detect
and resolve circular graphs amoung the javaobject, but it is not
something I will add. 

Patches will be accepted.

regards,
finn

Re: [Jython-users] How to use PythonInterpreter.getLocals() and setLocals()

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

[William Byrd]

>[...] 
>The getLocals() method returns a
>*reference* to the PythonInterpreter.locals object, rather than a deep copy.
>The result is that the object referenced by 'initialState' is modified when
>I make additional calls to PythonInterpreter.exec().
>
>Peeking at the source code for PythonInterpreter allowed me to create the
>following hack:
>
>		... Set up the initial state of myInterpreter, as before ...
>
>		// Save the initial state of myInterpreter.
>		PyStringMap localsMap = (PyStringMap)
>                                        myInterpreter.getLocals();
>		PyObject initialState = (PyObject) localsMap.copy();
>
>		... Change the state of myInterpreter, as before ...
>
>		// Restore the initial state of myInterpreter.  
>		myInterpreter.setLocals(((PyStringMap)
>                                          initialState).copy());
>
>Of course, this code will break if the return type of getLocals() ever
>changes.

Right. While the odds are low for that to happen the hack of casting to
a specific subtype is both wrong and fragile. The right (IMO) way is use
only the methods on PyObject to call the methods in the PyStringMap:

	... Set up the initial state of myInterpreter, as before ..
	// Save the initial state of myInterpreter.
	PyObject localsMap = myInterpreter.getLocals();
	PyObject initialState = localsMap.invoke("copy");

	... Change the state of myInterpreter, as before ...

	// Restore the initial state of myInterpreter.  
	myInterpreter.setLocals(initialState.invoke("copy"));

This will work as long as the "locals" is an object that conforms to the
mapping interface (whatever that actually mean). This is true for both
PyStringMap and PyDictionary as well as any python object that implement
the __[get|set]item__ and copy methods.

>How can I achieve the same result without resorting to a hack?  Should
>getLocals() return a deep copy of PythonInterpreter.locals?  

No.

>Am I using the getLocals() and setLocals() inappropriately?

No.

regards,
finn

[Jython-users] pickle and java objects

[Donatas S. <do...@no...>]

Is there ability using jython  and pickle  save objects which classes is java 
classes ?
for example:

>>> import cPickle
>>> from java.awt import Rectangle
>>> r=Rectangle(1,1,200,300)
>>> f=open("fileout","w")
>>> cPickle.dump(r,f)
Traceback (innermost last):
  File "<console>", line 1, in ?
PicklingError: Unable to pickle java objects.

>>> import pickle
>>> pickle.dump(r,f)
Traceback (innermost last):
  File "<console>", line 1, in ?
  File "/home/donce/jython-2.0/Lib/pickle.py", line 888, in dump
  File "/home/donce/jython-2.0/Lib/pickle.py", line 100, in dump
  File "/home/donce/jython-2.0/Lib/pickle.py", line 202, in save
  File "/home/donce/jython-2.0/Lib/pickle.py", line 421, in save_inst
AttributeError: class 'java.awt.Rectangle' has no attribute '__module__'
>>

Is there something what i missed ?

Workaround for this is to use java objects serialization, but if i use python 
there should be ability to use python serialization.

-- 
Donatas Simkunas

[Jython-users] How to use PythonInterpreter.getLocals() and setLocals()

[Byrd, W. <Wil...@co...>]

Hello all.

I am trying to embed jython in a Java app, but I have encountered a
stumbling block.

I want to instantiate and initialize a PythonInterpreter object, immediately
save the initialized state of the interpreter object, and periodically
restore that initialized state.  The PythonInterpreter getLocals() and
setLocals() methods seem to be just what I need:

		myInterpreter = new PythonInterpreter();
		
		// Set up the initial state of myInterpreter.
		myInterpreter.exec("from java.lang import Integer");
		... much more setup code here ...

		// Save the initial state of myInterpreter.
		PyObject initialState = myInterpreter.getLocals();

		// Change the state of myInterpreter.
		myInterpreter.exec("from java.util import Random");
		... much more code here ...

		// Try to restore the initial state of myInterpreter.
		// This doesn't work, since 'initialState' was modified 
		// by the previous invocation of exec().
		myInterpreter.setLocals(initialState);

Unfortunately, this code does not work.  The getLocals() method returns a
*reference* to the PythonInterpreter.locals object, rather than a deep copy.
The result is that the object referenced by 'initialState' is modified when
I make additional calls to PythonInterpreter.exec().

Peeking at the source code for PythonInterpreter allowed me to create the
following hack:

		... Set up the initial state of myInterpreter, as before ...

		// Save the initial state of myInterpreter.
		PyStringMap localsMap = (PyStringMap)
myInterpreter.getLocals();
		PyObject initialState = (PyObject) localsMap.copy();

		... Change the state of myInterpreter, as before ...

		// Restore the initial state of myInterpreter.  
		myInterpreter.setLocals(((PyStringMap)
initialState).copy());

Of course, this code will break if the return type of getLocals() ever
changes.

How can I achieve the same result without resorting to a hack?  Should
getLocals() return a deep copy of PythonInterpreter.locals?  Am I using the
getLocals() and setLocals() inappropriately?

Thanks.

Regards,

-- William Byrd

Re: [Jython-users] Suse 7.0 Linux

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

Hello Gottfried,

On Wed, 24 Jan 2001, Gottfried F. Zojer wrote:

> Hi,
>
> Is somebody using jython 2.0 on a SUSE 7.0 box.
> I tried it with the old versions JPython but it never
> worked even when my Java-settings was ever correct
> because I used VisualAge and also ArgoUML pretty fine.
> Whats wrong with it.I can start and execute jythonc
> and jython but I cant do anything with it.Alone to do
> a 4+3 is not working.
> I can see the following when I start jython via
> tkdesk filemanager.
> Jython 2.0rc1 on java1.2.2 (J.I.T: sunwjit)
> type "copyright","credits" or "license" for more
> information.
> >>>>

Seeing the above information is a good sign.

I'm a bit confused when you say it doesn't work, but you get the
appropriate startup message.  What's missing is what happens _after_ you
see the ">>>".  Are you saying you are unable to type anything at this
prompt?  If so, start a bash shell and start Jython from there- is it any
different?  Do you see a traceback?  If you can type at the prompt, it is
likely working, i.e.-

>>>4+3
7
>>>

If this does not work, try making a file (test.py) with one line saying
"print 4+3" (without the quotes).  Then type "jython test.py" at the bash
prompt.  Do you see 7 or a traceback?  If it just hangs again as you say,
try export CLASSPATH="" and run it again.

The Linux distro doesn't really matter, the jvm does the work.  The things
that can create problems have always created tracebacks for me in all
*nix I've used, so it would be news if this really just froze as your note
implies.  If none of this works and you still can't get a useful
traceback, please forward more info- classpath, what ps aux says,
machine details, stuff like that.

Good luck,
-Robert

[Jython-users] Re: [Jython-dev] jython gui building tools?

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

Hello Anne,

[On Wed, 24 Jan 2001, Anne Wilson wrote]
> Hello jython developers,
>
> I am a devoted fan of python.  Six to nine months ago I looked into
> JPython but was disappointed to find that it did not support the tkinter
> module.  Is this because tkinter relies on tcl and tk?

"C" really- first things first.

> What kind of GUI tools does jython provide?

What Java provides.

> Anything based on swing?

Not really "based on"...

It's likely you spend a lot of time with CPython where there is a clear
distinction between the Python code and the C code.  CXX,
extensionclasses, swig, etc make for a intimidating bump between
C and Python.  However, it's this sense of boundary that evaporates in
Jython with ">>>import java".  You just may not realize it at first :)

In other words, it is AWT, Swing and GUI components written for java
because you import things that are Java.  The demos that are installed
with Jython include AWT and Swing demos.

> Are there any plans along these lines for the future?

Based on the above I'm tempted to say, "The future is here."  But that
would be melodramatic, opportunistic and painful<wink>.

Do visit the docs at http://jython.sourceforge.net/docs/index.html
then just try and stop yourself from going to:
http://jython.sourceforge.net/download.html.

Cheers,
-Robert


PS- forwarded from jython-dev to jython-users.

[Jython-users] Suse 7.0 Linux

[<go...@ya...>]

Hi,

Is somebody using jython 2.0 on a SUSE 7.0 box.
I tried it with the old versions JPython but it never
worked even when my Java-settings was ever correct
because I used VisualAge and also ArgoUML pretty fine.
Whats wrong with it.I can start and execute jythonc
and jython but I cant do anything with it.Alone to do
a 4+3 is not working.
I can see the following when I start jython via
tkdesk filemanager.
Jython 2.0rc1 on java1.2.2 (J.I.T: sunwjit)
type "copyright","credits" or "license" for more 
information.
>>>>

__________________________________________________
Do You Yahoo!?
Yahoo! Auctions - Buy the things you want at great prices. 
http://auctions.yahoo.com/

Re: [Jython-users] Ignoring Java Access

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

[Chris Atkins]

>I am embedding jython in my code.  How would I pass the -D options to the
>InteractiveConsole?

[finn]

> Take a look at 6.2 in the faq:
>
>   http://jython.sourceforge.net/cgi-bin/faqw.py?req=all#6.2
>
> You can set python.security.respectJavaAccessibility in the same way. It
> most be done before creating any python objects, including  the creation
> of the interpreter.

[back to Chris]

>In my java code I do the following:
>      java.util.Properties props = System.getProperties();
>add properties for other tools with names which do not conflict with python
>      PySystemState.initialize(pyProps, null, s_scriptArgs);

Is pyProps a typo? I guess you mean props.

>I start up my app with
>PYFLAGS="-Dpython.home=$JPYTHONDIR -Dpython.path=$JPYTHONPATH -D
>python.cachedir=$JPYTHONCACHEDIR"
>
>java -classpath . $PYFLAGS MyClass args
>
>This should have place the python properties in both the system properties
>and set them on the interactive console.  According to the rules, it should
>have picked up the $PYFLAGS over the registry 

No. The rules on the registry.html says

  Jython properties > registry files > System.properties.

i.e. the registry files will typically be searched before the
System.properties.

>since set on the PySystemState. 

That makes no difference. The org.python.util.jython class also calls
initialize with:

   PySystemState.initialize(System.getProperties(),
                            opts.properties, opts.argv);

where opts.properties contains the -D options found as argument to
jython class (aka Jython properties).

>It instead used what is in the registry.

Right. In your examples, the value for jython properties is null
(meaning empty) so the registry files is searched first. Only if nothing
is found there is the System.properties searched.

>I changed my code to do the following:
>
>      java.util.Properties pyProps = new java.util.Properties();
>      pyProps.setProperty("python.security.respectJavaAccessibility", "0");
>      if (s_scriptArgs == null) s_scriptArgs = new String[0];
>      PySystemState.initialize(pyProps, null, s_scriptArgs);

I guess this will do most of what you're after:

   java.util.Properties pyProps = new java.util.Properties();

   # Insert selected (or maybe all?) System.properties into
   # jython properties.
   String s = System.getProperty("python.home");
   if (s != null) pyProps.setProperty("python.home", s);
   s = System.getProperty("python.path");
   if (s != null) pyProps.setProperty("python.path", s);
   s = System.getProperty("python.cachedir");
   if (s != null) pyProps.setProperty("python.cachedir", s);

   # Set some application properties.
   pyProps.setProperty("python.security.respectJavaAccessibility", "0");

   PySystemState.initialize(System.getProperties(),
                                pyProps, s_scriptArgs);

>Can you explain this?

I hope the above helps.

All in all, I think the property lookup mechanism as mostly Ok. Perhaps
we should have a way of changing the lookup priority since I guess you
would rather use:

  Jython properties > System.properties > registry files

OTOH we shouldn't make it more complicated for novices.

The only real drawback I know off, is the use of the -D command line
option for jython properties. This is commonly used by the java command
as well and that can be confusing.

regards,
finn

RE: [Jython-users] Ignoring Java Access

[Chris A. <at...@nm...>]

>
> >I am embedding jython in my code.  How would I pass the -D
> options to the
> >InteractiveConsole?
>
> Take a look at 6.2 in the faq:
>
>   http://jython.sourceforge.net/cgi-bin/faqw.py?req=all#6.2
>
> You can set python.security.respectJavaAccessibility in the
> same way. It
> most be done before creating any python objects, including
> the creation
> of the interpreter.
>


In my java code I do the following:
      java.util.Properties props = System.getProperties();
add properties for other tools with names which do not conflict with python
      PySystemState.initialize(pyProps, null, s_scriptArgs);

I start up my app with
PYFLAGS="-Dpython.home=$JPYTHONDIR -Dpython.path=$JPYTHONPATH -D
python.cachedir=$JPYTHONCACHEDIR"

java -classpath . $PYFLAGS MyClass args

This should have place the python properties in both the system properties
and set them on the interactive console.  According to the rules, it should
have picked up the $PYFLAGS over the registry since set on the
PySystemState. It instead used what is in the registry.

I changed my code to do the following:

      java.util.Properties pyProps = new java.util.Properties();
      pyProps.setProperty("python.security.respectJavaAccessibility", "0");
      if (s_scriptArgs == null) s_scriptArgs = new String[0];
      PySystemState.initialize(pyProps, null, s_scriptArgs);

Now, since I am not setting python.home, python.path, python.cachedir in my
java code, they are not being picked up from the system properties set on
the command line.

Can you explain this?

I really want to pick up the properties which have path names from the
command line, but the application specific settings such as
respectJavaAccessibility from the application.

Chris Atkins

Re: [Jython-users] Ignoring Java Access

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

[Chris Atkins]

>It appears that the problem was that the registry had
>python.security.respectJavaAccessibility = true
>
>When I commented this out of the registry file it worked.
>
>
>Can you please explain the difference between:
>The Java system properties: typically passed in on the command line as
>options to the java interpreter.
>
>Jython properties: Specified on the command
>line as options to the jython class. See the -D option to the interpreter.
>
>I believe the top one says if I place the -D parms before the class name on
>the java statement as in:
>java -Dpython.security.respectJavaAccessibility=0 org.python.util.jython
>
>The second would be
>java org.python.util.jython -Dpython.security.respectJavaAccessibility=0

Correct. And because the "registry" file is read in between, it will
overwrites the values assigned as system properties.

>I am embedding jython in my code.  How would I pass the -D options to the
>InteractiveConsole?

Take a look at 6.2 in the faq:

  http://jython.sourceforge.net/cgi-bin/faqw.py?req=all#6.2

You can set python.security.respectJavaAccessibility in the same way. It
most be done before creating any python objects, including the creation
of the interpreter.

regards,
finn

Re: [Jython-users] cyphon

[Elisabeth u. A. H. <e.h...@ed...>]

> [Ype on the pairing of Jython and CPython through JNI]
>
I like this idea, too.
However, I don't like the solution of loading python.dll and then having
CPython do the work for the imported module.
Instead, I propose a C-Java-brigde via JNI in both directions:
For Jython as suggested.
For the C-extension module providing wrappers for the functions declared in
python.h that delegate the work back to Jython via JNI (using proxies for
allocated objects).
This should also solve the callback and subclassing problems.

Regards,
Andreas

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

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

On Fri, Jan 19, 2001 at 12:33:50PM +0000, Finn Bock wrote:
[snip]
| The Jython RE syntax is exactly the same as CPython2.0. What you have
| encountered is a bug in the Microsoft JVM. 

Surprising?  ;-)

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

IMO, you shouldn't be expending effort to fix M$ bugs Finn.  But I'm
sure the people using the M$ JVM will appreciate it.  You certainly
work hard to make jython work the Right Way.  :-)

| 
| regards,
| finn
| 

-D

Re: [Jython-users] Jython-2.0 released

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

Oops,  I didn't have the mailfolder listed in my MUA.  Wow.  The list
isn't dead.  :-)

On Fri, Jan 19, 2001 at 03:08:13PM +0000, Finn Bock wrote:
| On Thu, 18 Jan 2001 17:27:39 -0500, you wrote:
| 
| >How can you access Python classes / modules directly from Java? 
| 
| A python class can implement a java interface or java class by listing
| the java interface as a base class. Instances of such a python class can
| be passed to java code as a parameter and used as any other java class.
| 
| In addition, the command "jythonc" can be be used to create a java class
| from a python module. Such a java class be used from a java program as a
| normal java class. Including in a "new" statement.

I just found it in the FAQ -- I need to include @sig in the doc
string.  I was using jythonc, but it didn't create a Java interface
that matched my Python interface (it simply called into the
interpreter to execute the python stuff).

| 
| regards.
| finn

I'll check it out some more.

Thanks,
-D

[Jython-users] RE: javaos and stat

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

Hello,

(tnx for the speedy reply Finn!)

Unfortunately, I'm still stuck.  Maybe this is
different enough that I should include some code examples and the
full story:

In using Tomcat-3.2.1, Jython-2.0, sun jdk-1.2.2, win98.  I've
placed jython.jar in %TOMCAT_HOME%\webapps\jython\WEB-INF\lib and
would also like to place the below servlet (and many frozen
modules) in the same lib directory as jyDispatch.jar.  Ahhh, the
dream of an entirely frozen webapp that could be delivered to
clients in a *.war file just like all the java servlet/JSP
webapps out there, but secretly using Jython :)

Here's the code:
--------------------------------------------------------------
#filename: jyDispatch.py
import sys
sys.prefix="."
from javax import servlet
from javax.servlet import http
import os

class jyDispatch(http.HttpServlet):
	def service(self,req, res):
		'Jython servlet dispatcher'
		mtimes = {}
		ctx = self.getServletContext()

		#test junk
		out = res.getWriter()		
		out.println("<br>sys.path=" + str(sys.path))
		out.println("<br>sys.prefix=" + str(sys.prefix))
		out.println("<br>cwd=" + str(sys.getcwd()))

		# Get the path of the *.py file to be dispatched
		path = ctx.getRealPath( req.getServletPath() )
		mtime = os.stat(path)[7]

		#Other stuff...
----------------------------------------------------------------

The "sys.prefix='.'" was added as suggested and it was compiled
with the implied:
	
	jythonc -j jyDispatch.jar -a jyDispatch.py

However, none of the javaos code is accessible.  getcwd, and stat
in the example above are hidden.

It seems very much like the example you (Finn) used, but I'm
having no luck muxing with the sys.prefix or sys.path in the
servlet to get around this.

All hints and comments are welcome as always :)

Thanks in advance.

-Robert


[Robert W. Bill]

>>Freezing servlet applications have resulted in difficulty with
>>the javaos module.  The simple scenario is I need to use
>>os.stat(file), but all frozen applications return the error:
>>       
>>    AttributeError: class 'org.python.modules.os' has no
>>    attribute 'stat'
>>
>>When using jythonc, i've tried:
>>
>>    jythonc -a -j app.jar jyDispatch.py
>>    jythonc -a -j app.jar jyDispatch.py javaos os re string 
>>    jythonc -c -j app.jar jyDispatch.py javaos etc....
>>
>>All result in the above AttributeError.
>>
>>I've assumed stat requires os + javaos- does it?  

>Yes.

>>How do I freeze an application so that I can use it? 

>When I just tried to freeze this little module I got an NPE:
>
>  import os
>  print os.stat
>
>This is an unintended sideeffect on a hack I added to satisfy
>site.py's use of the os module. It occur when sys.prefix is None
>which typically happens for frozen applications.
>
>Changing the module to:
>
>  import sys
>  sys.prefix = "."
>
>  import os
>  print os.stat
>
>and it runs as expected. I compiled the module with the
>simple:
>
>  jythonc.bat -j app.jar -a app.py

>I'm not 100% sure this is the situation you are seeing, but
>please give it a try.

>regards,
>finn

RE: [Jython-users] Ignoring Java Access

[Chris A. <at...@nm...>]

It appears that the problem was that the registry had
python.security.respectJavaAccessibility = true

When I commented this out of the registry file it worked.


Can you please explain the difference between:
The Java system properties: typically passed in on the command line as
options to the java interpreter.



                                 Jython properties: Specified on the command
line as options to the jython class. See the -D option to the interpreter.

I believe the top one says if I place the -D parms before the class name on
the java statement as in:
java -Dpython.security.respectJavaAccessibility=0 org.python.util.jython

The second would be
java org.python.util.jython -Dpython.security.respectJavaAccessibility=0

I am embedding jython in my code.  How would I pass the -D options to the
InteractiveConsole?

Chris Atkins


> -----Original Message-----
> From: Finn Bock [mailto:bc...@wo...]
> Sent: Monday, January 22, 2001 4:32 PM
> To: jyt...@li...
> Cc: at...@nm...
> Subject: Re: [Jython-users] Ignoring Java Access
>
>
> [Chris Atkins]
>
> >I am running jython 2.0 release on hpux 11 with jdk1.2.2.07.
> >
> >I  run my jython interpretter
> >with -Dpython.security.respectJavaAccessibility= 0 and  =false.
> >
> >In both cases, I am unable to access protected methods of a class.
> >
> >I just switched out my jar file from using jpython1.1 to
> jython2.0, and it
> >works under under jpython1.1
> >
> >My python code looks like the following:
> >
> >print foo.toPrintString(obja, string1, string2)
> >
> >I get the following error:
> >TypeError: toPrintString(): expected 0-2 args; got 3
>
> Well, it works for me. I made some small changes:
>
> abstract public class fooBase {
>     public String toPrintString() {
>         return "here1";
>     }
>     public String toPrintString(String initialIndent) {
>         return "here2";
>     }
>     public String toPrintString(String initialIndent, String name) {
>         return "here3";
>     }
>     abstract protected String toPrintString(java.lang.Object fooObj,
>                                String initialIndent, String name);
> }
>
>
> public class foo extends fooBase {
>     protected String toPrintString(Object obj,
>                        String initialIndent, String name) {
>         return "here4";
>     }
> }
>
> jython -Dpython.security.respectJavaAccessibility=false
> Jython 2.0 on java1.3.0 (JIT: null)
> Type "copyright", "credits" or "license" for more information.
> >>> import foo
> >>> print foo().toPrintString(1, "string1", "string2")
> here4
> >>>
>
> regards,
> finn
>

Re: [Jython-users] Ignoring Java Access

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

[Chris Atkins]

>I am running jython 2.0 release on hpux 11 with jdk1.2.2.07.
>
>I  run my jython interpretter
>with -Dpython.security.respectJavaAccessibility= 0 and  =false.
>
>In both cases, I am unable to access protected methods of a class.
>
>I just switched out my jar file from using jpython1.1 to jython2.0, and it
>works under under jpython1.1
>
>My python code looks like the following:
>
>print foo.toPrintString(obja, string1, string2)
>
>I get the following error:
>TypeError: toPrintString(): expected 0-2 args; got 3

Well, it works for me. I made some small changes:

abstract public class fooBase {
    public String toPrintString() {
        return "here1";
    }
    public String toPrintString(String initialIndent) {
        return "here2";
    }
    public String toPrintString(String initialIndent, String name) {
        return "here3";
    }
    abstract protected String toPrintString(java.lang.Object fooObj,
                               String initialIndent, String name);
}


public class foo extends fooBase {
    protected String toPrintString(Object obj,
                       String initialIndent, String name) {
        return "here4";
    }
}

jython -Dpython.security.respectJavaAccessibility=false
Jython 2.0 on java1.3.0 (JIT: null)
Type "copyright", "credits" or "license" for more information.
>>> import foo
>>> print foo().toPrintString(1, "string1", "string2")
here4
>>>

regards,
finn

[Jython-users] Ignoring Java Access

[Chris A. <at...@nm...>]

I am running jython 2.0 release on hpux 11 with jdk1.2.2.07.

I  run my jython interpretter
with -Dpython.security.respectJavaAccessibility= 0 and  =false.

In both cases, I am unable to access protected methods of a class.

I just switched out my jar file from using jpython1.1 to jython2.0, and it
works under under jpython1.1

My python code looks like the following:

print foo.toPrintString(obja, string1, string2)

I get the following error:
TypeError: toPrintString(): expected 0-2 args; got 3

My java code looks like the following:

public class foo extends fooBase
{

  protected String toPrintString(Object obj,
                       String initialIndent, String name)
  {
  }
}

abstract public class fooBase {

  public String toPrintString()
  {
  }

    public String toPrintString(String initialIndent)
  {
  }

  public String toPrintString(String initialIndent, String name)
  {
  }

abstract protected String toPrintString(java.lang.Object fooObj,
                                          String initialIndent, String
name);
}

Re: [Jython-users] javaos and stat trouble

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

[Robert W. Bill]

>Freezing servlet applications have resulted in difficulty with
>the javaos module.  The simple scenario is I need to use
>os.stat(file), but all frozen applications return the error:
>	
>    AttributeError: class 'org.python.modules.os' has no attribute 'stat'
>
>When using jythonc, i've tried:
>
>    jythonc -a -j app.jar jyDispatch.py
>    jythonc -a -j app.jar jyDispatch.py javaos os re string others...
>    jythonc -c -j app.jar jyDispatch.py javaos etc....
>    jythonc -a -A c:\jython-2.0\lib\javaos -j app.jar jyDispatch.py os
>
>All result in the above AttributeError.
>
>I've assumed stat requires os + javaos- does it?  

Yes.

>How do I freeze an application so that I can use it? 

When I just tried to freeze this little module I got an NPE:

  import os
  print os.stat

This is an unintended sideeffect on a hack I added to satisfy site.py's
use of the os module. It occur when sys.prefix is None which typically
happens for frozen applications.

Changing the module to:

  import sys
  sys.prefix = "."

  import os
  print os.stat

and it runs as expected. I compiled the module with the simple:

  jythonc.bat -j app.jar -a app.py

I'm not 100% sure this is the situation you are seeing, but please give
it a try.

regards,
finn

[Jython-users] javaos and stat trouble

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

Freezing servlet applications have resulted in difficulty with
the javaos module.  The simple scenario is I need to use
os.stat(file), but all frozen applications return the error:
	
    AttributeError: class 'org.python.modules.os' has no attribute 'stat'

When using jythonc, i've tried:

    jythonc -a -j app.jar jyDispatch.py
    jythonc -a -j app.jar jyDispatch.py javaos os re string others...
    jythonc -c -j app.jar jyDispatch.py javaos etc....
    jythonc -a -A c:\jython-2.0\lib\javaos -j app.jar jyDispatch.py os

All result in the above AttributeError.

I've assumed stat requires os + javaos- does it?  How
do I freeze an application so that I can use it?  Which jythonc line above
was closest?

More on the servlet:

  I'm using Tomcat 3.2, Sun jdk 1.2.2, Win98 and Linux

  Context is jython and jython.jar + app.jar are in
  $TOMCAT_HOME/webapps/jython/WEB-INF/lib so that they can be *.war-ified
  easily.

Thank you in advance for any suggestions.

-Robert

[Jython-users] [ANN] release 1.2.4 of zxJDBC

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

I would like to announce a new release of zxJDBC, the nearly 100% Python DB
API 2.0 compliant interface for database connectivity in Jython. This
release fixes any known bugs and adds a number of new features to the dbexts
Python db wrapper script. It has been tested with the Jython 2.0 release and
it is fully functional at this time.  See the homepage at
http://www.ziclix.com/zxjdbc for more information.

Changes:

- fixed a memory leak by ensuring statements and result sets are closed in
finally blocks (thanks to Will Wohlman for pointing this out)
- implemented callproc
- added maxrows to raw and isql in dbexts
- added preExecute and postExecute for DataHandler
- forced a cast to String for InformixDataHandler on prepared statements
when object is PyString
- implemented nextset - updated dbexts.py to take advantage of the change

thanks,

brian

Re: [Jython-users] cyphon

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

Ype Kingma wrote:
> >It's only half-a-dozen source files at this stage -- a small job.  I'll
> >send you the source.
> 
> Looking forward to it. Could you put it in a jar?

Done -- see 

  http://web.one.net.au/~effbiae/cyphon.html


Jack.

Re: [Jython-users] cyphon

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

Ype Kingma <yk...@xs...> wrote:

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

It's mostly Java with a bit of C glue code for JNI.  It's an easy port
to UNIX -- nothing but JNI and the Python API are called -- everything
else is a bit of C or Java.

> >Anyway, having proved to myself that I can get this far, I've lost
> >motivation to complete it.  If there's a demand for cyphon, I may polish
> >it up a bit or if anyone can tell me the most convenient way to publish
> >it, let me know.  (it's only a few source files)
> 
> I'm certainly interested in using it under Unix, but that will take
> work. Would anyone have an idea how much?

It's only half-a-dozen source files at this stage -- a small job.  I'll
send you the source.


jack.