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possible to pass python objects into java without jython?

P: n/a
Hi,

I have read that this had been asked before but there's no satisfactory
replies then.

I have a module (pA) written in python, which originally is called by
another python module (pB), and passes a python object (pO) to pB. Now I
require pA to be called in a java class (jC) and pass pO into jC. As pA
uses non-python modules, I am not able to use Jython on this.

Are there any way out in this?

Thanks in advance.

Maurice

Jul 18 '05 #1
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5 Replies


P: n/a
Maurice Ling <ma*********@acm.org> writes:
Hi,

I have read that this had been asked before but there's no
satisfactory replies then.

I have a module (pA) written in python, which originally is called by
another python module (pB), and passes a python object (pO) to pB. Now
I require pA to be called in a java class (jC) and pass pO into jC. As
pA uses non-python modules, I am not able to use Jython on this.

Are there any way out in this?


CORBA.

<mike
--
Mike Meyer <mw*@mired.org> http://www.mired.org/home/mwm/
Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.
Jul 18 '05 #2

P: n/a
Maurice Ling wrote:
Are there any way out in this?


No.

Jul 18 '05 #3

P: n/a
Maurice Ling wrote:
Hi,

I have read that this had been asked before but there's no satisfactory
replies then.

I have a module (pA) written in python, which originally is called by
another python module (pB), and passes a python object (pO) to pB. Now I
require pA to be called in a java class (jC) and pass pO into jC. As pA
uses non-python modules, I am not able to use Jython on this.

Are there any way out in this?

Thanks in advance.

Maurice


The simple answer is no. The complex answer is maybe, but not without
some work on your part.

As part of JPype I made the opposite : allow Python to use Java classes.
That was easy as python is very dynamic.

Going the other way around .... I don;t see how. The java part must want
to receive a specific Java type. Even if that type is Object (the root
of all object types in Java), tehre is no way for Python object to be
one of those.

Case #1 : the "main" program is in Python, and the Java type to be
received is a Java interface. In that specific case, JPype
(http://jpype.sourceforge.net) can help you. You can "wrap" your pO into
the correct Java type and apss it in.

Otherwise, as has been mantioned before, you will need some kind of
remoting mechanism. Corba might provide a middle ground, or XML-RPC/SOAP.

Good luck.

Steve
Jul 18 '05 #4

P: n/a

The simple answer is no. The complex answer is maybe, but not without
some work on your part.

As part of JPype I made the opposite : allow Python to use Java classes.
That was easy as python is very dynamic.

Going the other way around .... I don;t see how. The java part must want
to receive a specific Java type. Even if that type is Object (the root
of all object types in Java), tehre is no way for Python object to be
one of those.

Case #1 : the "main" program is in Python, and the Java type to be
received is a Java interface. In that specific case, JPype
(http://jpype.sourceforge.net) can help you. You can "wrap" your pO into
the correct Java type and apss it in.

Otherwise, as has been mantioned before, you will need some kind of
remoting mechanism. Corba might provide a middle ground, or XML-RPC/SOAP.

Good luck.

Steve


Hi,

Referring to this scenario again.....

pA.py contains
imports (something non-pure python)
def A(n):
...(does something)...
returns pO

pB.py comtains
import pA
def B(n):
(does something)
x = pA.A(n)
(does more things)

Perhaps if we lax the problem a little and allow Jython to be in
consideration and pB.py is implemented in Jython (as jyB.py), then using
jythonc to convert it into a Java package (jyB.jar containing
jython.jar, jyB.class and jyB$Inner.class). Am I then able to import jyB
in my Java codes? Is it possible to use Jython as the middle ground,
instead of CORBA or SOAP etc etc?

Thanks
Maurice
Jul 18 '05 #5

P: n/a
Maurice LING wrote:

The simple answer is no. The complex answer is maybe, but not without
some work on your part.

As part of JPype I made the opposite : allow Python to use Java
classes. That was easy as python is very dynamic.

Going the other way around .... I don;t see how. The java part must
want to receive a specific Java type. Even if that type is Object (the
root of all object types in Java), tehre is no way for Python object
to be one of those.

Case #1 : the "main" program is in Python, and the Java type to be
received is a Java interface. In that specific case, JPype
(http://jpype.sourceforge.net) can help you. You can "wrap" your pO
into the correct Java type and apss it in.

Otherwise, as has been mantioned before, you will need some kind of
remoting mechanism. Corba might provide a middle ground, or XML-RPC/SOAP.

Good luck.

Steve

Hi,

Referring to this scenario again.....

pA.py contains
imports (something non-pure python)
def A(n):
...(does something)...
returns pO

pB.py comtains
import pA
def B(n):
(does something)
x = pA.A(n)
(does more things)

Perhaps if we lax the problem a little and allow Jython to be in
consideration and pB.py is implemented in Jython (as jyB.py), then using
jythonc to convert it into a Java package (jyB.jar containing
jython.jar, jyB.class and jyB$Inner.class). Am I then able to import jyB
in my Java codes? Is it possible to use Jython as the middle ground,
instead of CORBA or SOAP etc etc?

Thanks
Maurice


Jython has a Java API that allows calling Python code. The simplest way
however would be to turn your pB into a class implementing a given Java
interface. Then java code can easily instantiate your Python class and
use it through the interface.

However the problem remains ... just what kind of object is this pO ?
Using Jython will not magically allow regular Java code to understand
python objects. NAd you still have to bridge between CPython and Jython ...

Steve
Jul 18 '05 #6

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