Java API

The Java API provides facilities to use Python classes and objects from Java code.

Summary

1. If necessary, call Python.start().

2. Call Python.getInstance() to get the interface to Python.

3. Call getModule() or getBuiltins() to get a PyObject representing a Python module.

4. Use the PyObject methods to access the module’s functions, classes and other objects.

Examples

The following all assume py is a Python instance.

Modules, classes, attributes and methods:

# Python code                             // Java equivalent
import zipfile                            PyObject zipfile = py.getModule("zipfile")
zf = zipfile.ZipFile(                     PyObject zf = zipfile.callAttr("ZipFile",
  "example.zip")                                                         "example.zip");
zf.debug = 2                              zf.put("debug", 2);
zf.comment                                zf.get("comment");
zf.write(                                 zf.callAttr("write",
  "filename.txt",                                     "filename.txt",
  compress_type=zipfile.ZIP_STORED)                   new Kwarg("compress_type",
                                                                zipfile.get("ZIP_STORED")));

Primitive types:

# Python code                             // Java equivalent
import sys                                PyObject sys = py.getModule("sys");
sys.maxsize                               sys.get("maxsize").toLong();
sys.version                               sys.get("version").toString();
sys.is_finalizing()                       sys.callAttr("is_finalizing").toBoolean();

Container types:

# Python code                             // Java equivalent
import sys                                PyObject sys = py.getModule("sys");
sys.version_info[0]                       sys.get("version_info").asList().get(0).toInt();

import os                                 PyObject os = py.getModule("os");
os.environ["HELLO"]                       os.get("environ").asMap().get("HELLO").toString();
os.environ["HELLO"] = "world"             os.get("environ").asMap().put(
                                              PyObject.fromJava("HELLO"),
                                              PyObject.fromJava("world"));

Reference

For full documentation, see the Javadoc.