possible to pass python objects into java without jython?

Steve Menard foo at bar.com
Wed Nov 10 08:07:35 EST 2004


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



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