Re: [Jython-users] instantiating jython orbjects in Java

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

Hi.

> 
> How do I run a piece of frozen python script within an embedded jython 
> interpreter?

First jythonc and the interpeter are not incompatible but do not 
collabarate much. See:

http://aspn.activestate.com/ASPN/Mail/Message/555125

In your case is not a problem because you want construct
your Python/Java object on Java side.


> i.e. How do I get the following contrived example to work?
> 
> Foo.py:
> class Foo:
>         def __init__(self, blah):
>                 self.blah = blah
>         def doSomething():
>                 blah.doSomethingElse()
> 
> Foo.py is precompiled to Foo.class using jythonc,

This produces a java class that correspond to a Python module
not to a class, the java class has just basically a main method.

If you want a Java (proxy) class corresponding to a python class,
your python class should inherit from Java:

import java

class Foo(java.lang.Object):
         def __init__(self, blah):
                 "@sig public Foo(String blah)"
                 self.blah = blah
         def doSomething():
                 blah.doSomethingElse()

The @sig doc strings are a feature only of jythonc, they make a
method java visible (the class will have a concrete java method
with that signature) otherwise unless overriding a method is just a
 pure Python method not directly accessible from Java side.
So in in this case doSomething will remain a pure Python method.
 
> 
> PyObject f = new Foo(); // how do I call __init__ with arguments?

Now something like this

Foo f = new Foo("blah");

should work.

Notice that java side Foo class does not inherit form PyObject
in this case.

> 
> PythonInterpreter interp = new PythonInterpreter();
> interp.set("foo", f);
> interp.exec("foo.doSomething()");

This works because the java/python conversion behind the scene
accesssz the full-fledged python instance, for which the java class
Foo is just a proxy :) .
 
> 
> Alternatively, how would I bytecompile a script, and pass the code object 
> to the interpreter?  I tried to use jythonc to create a class file, and 
> then used that as a source for an InputStream to 
> PythonInterpreter.exexfile(), 
This doesn't work.

> but that just gave me syntax errors on the 
> binary data at runtime.  I guess it needs to be a python byte compiled 
> file instead...?
No jython does not never deal with python bytecode.

 
> bar.py:
> print "hello world"
> print "bye world"
> 
> How do I bytecompile bar.py?
> how do I then load and run the bytecompiled bar.py using a 
> PythonInterpreter instance?
> 

*warning* hack:

org.python.core.PyRunnable bar = new bar._PyInner();
PyObject code = bar.getMain();
interp.exec(code)

or some flavor of what was in the posting cited 
above.

regards.