164 lines
5.2 KiB
Python
164 lines
5.2 KiB
Python
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# *****************************************************************************
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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# See NOTICE file for details.
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#
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# *****************************************************************************
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"""
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JPype Pickle Module
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--------------------
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This module contains overloaded Pickler and Unpickler classes that operate
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on Java classes. Pickling of Java objects is restricted to classes
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that implement Serializable. Mixed pickle files containing both
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Java and Python objects are allowed. Only one copy of each Java object
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will appear in the pickle file even it is appears multiple times in the
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data structure.
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JPicklers and JUnpickler use Java ObjectOutputStream and ObjectInputStream
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to serialize objects. All of the usual Java serialization errors may be
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thrown.
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This is backed by the native cPickler implementation.
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Example:
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.. code-block:: python
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myobj = jpype.JClass('java.util.ArrayList')()
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myobj.add("test")
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from jpype.pickle import JPickler, JUnpickler
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with open("test.pic", "wb") as fd:
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JPickler(fd).dump(myobj)
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with open("test.pic", "rb") as fd:
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newobj = JUnpickler(fd).load()
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Proxies and other JPype specific module resources cannot be pickled currently.
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"""
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from __future__ import absolute_import
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import _jpype
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import pickle
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from copyreg import dispatch_table
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# TODO: Support use of a custom classloader with the unpickler.
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# TODO: Use copyreg to pickle a JProxy
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__ALL__ = ['JPickler', 'JUnpickler']
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# This must exist as a global, the real unserializer is created by the JUnpickler
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class JUnserializer(object):
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def __call__(self, *args):
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raise pickle.UnpicklingError("Unpickling Java requires JUnpickler")
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class _JDispatch(object):
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"""Dispatch for Java classes and objects.
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Python does not have a good way to register a reducer that applies to
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many classes, thus we will substitute the usual dictionary with a
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class that can produce reducers as needed.
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"""
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def __init__(self, dispatch):
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self._encoder = _jpype.JClass('org.jpype.pickle.Encoder')()
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self._builder = JUnserializer()
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self._dispatch = dispatch
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# Extension dispatch table holds reduce method
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self._call = self.reduce
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# Pure Python _Pickler uses get()
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def get(self, cls):
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if not issubclass(cls, (_jpype.JClass, _jpype.JObject)):
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return self._dispatch.get(cls)
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return self._call
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# Python3 cPickler uses __getitem__()
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def __getitem__(self, cls):
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if not issubclass(cls, (_jpype.JClass, _jpype.JObject)):
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return self._dispatch[cls]
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return self._call
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def reduce(self, obj):
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byte = bytes(self._encoder.pack(obj))
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return (self._builder, (byte, ))
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class JPickler(pickle.Pickler):
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"""Pickler overloaded to support Java objects
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Parameters:
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file: a file or other writeable object.
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*args: any arguments support by the native pickler.
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Raises:
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java.io.NotSerializableException: if a class is not serializable or
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one of its members
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java.io.InvalidClassException: an error occures in constructing a
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serialization.
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"""
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def __init__(self, file, *args, **kwargs):
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pickle.Pickler.__init__(self, file, *args, **kwargs)
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# In Python3 we need to hook into the dispatch table for extensions
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self.dispatch_table = _JDispatch(dispatch_table)
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class JUnpickler(pickle.Unpickler):
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"""Unpickler overloaded to support Java objects
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Parameters:
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file: a file or other readable object.
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*args: any arguments support by the native unpickler.
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Raises:
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java.lang.ClassNotFoundException: if a serialized class is not
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found by the current classloader.
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java.io.InvalidClassException: if the serialVersionUID for the
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class does not match, usually as a result of a new jar
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version.
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java.io.StreamCorruptedException: if the pickle file has been
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altered or corrupted.
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"""
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def __init__(self, file, *args, **kwargs):
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self._decoder = _jpype.JClass('org.jpype.pickle.Decoder')()
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pickle.Unpickler.__init__(self, file, *args, **kwargs)
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def find_class(self, module, cls):
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"""Specialization for Java classes.
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We just need to substitute the stub class for a real
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one which points to our decoder instance.
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"""
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if cls == "JUnserializer":
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decoder = self._decoder
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class JUnserializer(object):
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def __call__(self, *args):
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return decoder.unpack(args[0])
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return JUnserializer
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return pickle.Unpickler.find_class(self, module, cls)
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