serialization.py

   1 # This file is part of jack_mixer
   2 #
   3 # Copyright (C) 2006 Nedko Arnaudov <nedko@arnaudov.name>
   4 #
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation; version 2 of the License
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU General Public License
  15 # along with this program; if not, write to the Free Software
  16 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  17
  18 class SerializationBackend:
  19     '''Base class for serialization backends'''
  20     def get_root_serialization_object(self, name):
  21         '''Returns serialization object where properties of root object
  22            will be serialized to'''
  23         # this method should never be called for the base class
  24         raise NotImplementedError
  25
  26     def get_child_serialization_object(self, name, backend_object):
  27         # this method should never be called for the base class
  28         raise NotImplementedError
  29
  30 class SerializationObjectBackend:
  31     '''Base class for serialization backend objects where real object
  32        properties will be serialized to or unserialized from.'''
  33     def add_property(self, name, value):
  34         '''Serialize particular property'''
  35         pass
  36
  37     def get_childs(self):
  38         pass
  39
  40     def get_properties(self):
  41         pass
  42
  43     def serialization_name(self):
  44         return None
  45
  46 class SerializedObject:
  47     '''Base class for object supporting serialization'''
  48     def serialization_name(self):
  49         return None
  50
  51     def serialize(self, object_backend):
  52         '''Serialize properties of called object into supplied serialization_object_backend'''
  53         pass
  54
  55     def serialization_get_childs(self):
  56         '''Get child objects tha required and support serialization'''
  57         return []
  58
  59     def unserialize_property(self, name, value):
  60         pass
  61
  62     def unserialize_child(self, name):
  63         return None
  64
  65 class Serializator:
  66     def __init__(self):
  67         pass
  68
  69     def serialize(self, root, backend):
  70         self.serialize_one(backend, root, backend.get_root_serialization_object(root.serialization_name()))
  71
  72     def unserialize(self, root, backend):
  73         backend_object = backend.get_root_unserialization_object(root.serialization_name())
  74         if backend_object == None:
  75             return False
  76
  77         return self.unserialize_one(backend, root, backend_object)
  78
  79     def unserialize_one(self, backend, object, backend_object):
  80         #print "Unserializing " + repr(object)
  81         properties = backend_object.get_properties()
  82         for name, value in properties.iteritems():
  83             #print "%s = %s" % (name, value)
  84             if not object.unserialize_property(name, value):
  85                 return False
  86
  87         backend_childs = backend_object.get_childs()
  88         for backend_child in backend_childs:
  89             name = backend_child.serialization_name()
  90             child = object.unserialize_child(name)
  91             if not child:
  92                 return False
  93             if not self.unserialize_one(backend, child, backend_child):
  94                 return False
  95
  96         return True
  97
  98     def serialize_one(self, backend, object, backend_object):
  99         object.serialize(backend_object)
 100         childs = object.serialization_get_childs()
 101         for child in childs:
 102             #print "serializing child " + repr(child)
 103             self.serialize_one(backend, child,
 104                                backend.get_child_serialization_object(
 105                                        child.serialization_name(), backend_object))