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A bridge interface between Python and Java (ctypes/cffi-based rubicon-java)

Project description

**Currently only as placeholder (because a base package jtypes.jvm is still in development)**


A bridge between the Java Runtime Environment and Python.


| **jtypes.rubicon** is a bridge between Python and Java, allowing these to intercommunicate.
| It is an effort to allow Python programs full access to Java class libraries.

`PyPI record`_.

| **jtypes.rubicon** is a lightweight Python package, based on the *ctypes* or *cffi* library.
| It is an almost fully compliant implementation of Steve Menard's **JPype** package
by reimplementing whole its functionality in a clean Python instead of C/C++.

About Rubicon-Java:

Borrowed from the `original website`_:


**Rubicon-Java** is a bridge between the Java Runtime Environment and Python.
It enables you to:

* Instantiate objects defined in Java,
* Invoke static and instance methods on objects defined in Java,
* Access and modify static and instance fields on objects defined in Java, and
* Write and use Python implementations of interfaces defined in Java.


Rubicon-Java consists of three components:

1. A Python library,
2. A JNI library, and
3. A Java JAR file.

A ``Makefile`` has been provided to compile the JNI and JAR components. Type::

$ make

to compile them. The compiled output will be placed in the ``dist`` directory.

.. admonition:: Cross platform support

This Makefile currently only works under OS/X; however, the build commands
aren't complicated; it should be fairly easy to reproduce the build on other
platforms. Pull requests to make the ``Makefile`` cross-platform are welcome.

To use Rubicon-Java, you'll need to ensure:

1. ``rubicon.jar`` is in the classpath when you start your Java VM.

2. The Rubicon library file is somewhere that it will be found by dynamic
library discovery. This means:

a. Under OS X, put the directory containing ``librubicon.dylib`` is in your ``DYLD_LIBRARY_PATH``

b. Under Linux, put the directory containing ```` is in your ``LD_LIBRARY_PATH``

c. Under Windows.... something :-)

3. The ``rubicon`` Python module is somewhere that can be added to a
``PYTHONPATH``. You can install rubicon using::

$ pip install rubicon-java

If you do this, you'll need to reference your system Python install when
setting your ``PYTHONPATH``.

The Rubicon bridge starts on the Java side. Import the Python object::

import org.pybee.rubicon.Python;

Then start the Python interpreter, and run a Python file::

# Initialize the Python VM
String pythonHome = "/path/to/python";
String pythonPath = "/path/to/dir1:/path/to/dir2";
if (Python.start(pythonHome, pythonPath, null) != 0) {
System.out.println("Error initializing Python VM.");

# Start a Python script
if ("/path/to/") != 0) {
System.out.println("Error running Python script.");

# Shut down the Python VM.

The ``PYTHONPATH`` you specify must enable access to the ``rubicon`` Python

In your Python script, you can then reference Java objects::

>>> from import JavaClass

# Wrap a Java class
>>> URL = JavaClass("java/net/URL")

# Then instantiate the Java class, using the API
# that is exposed in Java.
>>> url = URL("")

# You can then call methods on the Java object as if it
# were a Python object.
>>> print url.getHost()

It's also possible to provide implementations of Java Interfaces in Python.
For example, lets say you want to create a Swing Button, and you want to
respond to button clicks::

>>> from import JavaClass, JavaInterface

# Wrap the Java interface
>>> ActionListener = JavaInterface('java/awt/event/ActionListener')

# Define your own implementation
>>> class MyActionListener(ActionListener):
... def actionPerformed(self, event):
... print "Button Pressed"

# Instantiate an instance of the listener
>>> listener = MyActionListener()

# Create a button, and set the listener
>>> Button = JavaClass('javax/swing/JButton')
>>> button = Button('Push it')
>>> button.setActionListener(listener)

Of course, this sample code won't work unless it's in the context of a larger
application starting a Swing GUI and so on.


To run the Rubicon test suite:

1. Configure your shell environment so that the Python, Java, and Rubicon
dynamic libraries can be discovered by the dynamic linker.

* On OSX, using Python 2.7.7 built under Homebrew::

export DYLD_LIBRARY_PATH=/usr/local/Cellar/python/2.7.7_2/Frameworks/Python.framework/Versions/2.7/lib/:`/usr/libexec/java_home`/jre/lib/server:./dist

2. Build the libraries::

$ make clean
$ make all

3. Run the test suite::

$ java org.pybee.rubicon.test.Test

This is a Python test suite, invoked via Java.

.. Documentation
.. -------------

.. Full documentation for Rubicon can be found on `Read The Docs`_.


Rubicon is part of the `BeeWare suite`_. You can talk to the community through:

* `@pybeeware on Twitter`_

* The `pybee/general`_ channel on Gitter.

We foster a welcoming and respectful community as described in our
`BeeWare Community Code of Conduct`_.


If you experience problems with this backend, `log them on GitHub`_. If you
want to contribute code, please `fork the code`_ and `submit a pull request`_.



+ Python 2.7 or higher or 3.4 or higher

* 2.7 and 3.6 are primary test environments.

+ pip and setuptools


To install run::

python -m pip install --upgrade jtypes.rubicon

To ensure everything is running correctly you can run the tests using::

python -m jt.rubicon.tests


Visit `development page`_

Installation from sources:

Clone the `sources`_ and run::

python -m pip install ./jtypes.rubicon

or on development mode::

python -m pip install --editable ./jtypes.rubicon


+ Development is strictly based on *tox*. To install it run::

python -m pip install tox


| Copyright (c) 2016-2018, Adam Karpierz
| Licensed under the BSD license
| Please refer to the accompanying LICENSE file.


* Adam Karpierz <>

.. _PyPI record:
.. _original website:
.. _development page:
.. _sources:

.. _BeeWare suite:
.. _Rubicon suite:
.. _Read The Docs:
.. _@pybeeware on Twitter:
.. _pybee/general:
.. _BeeWare Community Code of Conduct:
.. _log them on Github:
.. _fork the code:
.. _submit a pull request:


0.1.0a2 (2018-11-08)
- Update of the required setuptools version.
- Minor setup and tests improvements.

0.1.0a0 (2016-11-30)
- Initial version.

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