src/lib/MVP.py

   1 """ MVP.py
   2
   3 Module that provides a Model-View-Presenter framework for use with Straw
   4 """
   5 __copyright__ = "Copyright (c) 2002-2005 Free Software Foundation, Inc."
   6 __license__ = """
   7 Straw is free software; you can redistribute it and/or modify it under the
   8 terms of the GNU General Public License as published by the Free Software
   9 Foundation; either version 2 of the License, or (at your option) any later
  10 version.
  11
  12 Straw is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  14 A PARTICULAR PURPOSE. See the GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License along with
  17 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  18 Place - Suite 330, Boston, MA 02111-1307, USA. """
  19
  20
  21 import pygtk
  22 pygtk.require('2.0')
  23 from gtk import glade
  24 import Event
  25
  26
  27 __doc__ = "A MVP framework. Contains base classes for views and presenters."
  28
  29 class View(object):
  30     """Base class for widget-based view objects."""
  31     def __init__(self, widget, model = None, presenter = None):
  32         self._widget = widget
  33         self._model = model
  34         self._presenter = presenter
  35
  36         if model is not None:
  37             self._model_set()
  38         if presenter is not None:
  39             self._presenter_set()
  40
  41         self._initialize()
  42         self._connect_signals(widget)
  43
  44     def _connect_signals(self, widget):
  45         raise NotImplemented
  46
  47     def _initialize(self):
  48         """Called from the constructor after the instance variables have
  49         been set and the corresponding initialization functions have been
  50         called, but before connecting gtk signals."""
  51         pass
  52
  53     def _model_set(self):
  54         """Called when the model is set."""
  55         pass
  56
  57     def _presenter_set(self):
  58         """Called when the presenter is set."""
  59         pass
  60
  61     def get_model(self):
  62         return self._model
  63
  64     def set_model(self, model):
  65         self._model = model
  66         if model:
  67             # don't call model_set if model is None. This prevents objects
  68             # relying on model_set to fail (or gtk throwing a warning when
  69             # model is not a gtk.TreeModel).
  70             self._model_set()
  71     model = property(get_model, set_model, None, doc="The model object.")
  72
  73     def get_presenter(self):
  74         return self._presenter
  75
  76     def set_presenter(self, presenter):
  77         self._presenter = presenter
  78         self._presenter_set()
  79     presenter = property(get_presenter, set_presenter, None,
  80                          "The presenter object.")
  81
  82 class WidgetView(View):
  83     def __init__(self, widget, model=None, presenter=None):
  84         View.__init__(self, widget, model, presenter)
  85
  86     def _connect_signals(self, widget):
  87         xml = glade.get_widget_tree(widget)
  88         nameFuncMap = {}
  89         for key in dir(self.__class__):
  90             if key[:4] == '_on_':
  91                 nameFuncMap[key[1:]] = getattr(self, key)
  92         xml.signal_autoconnect(nameFuncMap)
  93
  94 class GladeView(View):
  95     def __init__(self, widget, model=None, presenter=None):
  96         View.__init__(self, widget, model, presenter)
  97
  98     def _connect_signals(self, widget):
  99         nameFuncMap = {}
 100         for key in dir(self.__class__):
 101             if key[:4] == '_on_':
 102                 nameFuncMap[key[1:]] = getattr(self, key)
 103         widget.signal_autoconnect(nameFuncMap)
 104
 105 class BasicPresenter(object, Event.SignalEmitter):
 106     """Base class for basic (non-composite) presenters."""
 107     def __init__(self, model = None, view = None):
 108         Event.SignalEmitter.__init__(self)
 109
 110         self._model = model
 111         self._view = view
 112
 113         if model is not None:
 114             self._model_set()
 115         if view is not None:
 116             view.model = model
 117             view.presenter = self
 118             self._view_set()
 119
 120         self._initialize()
 121
 122     def _initialize(self):
 123         pass
 124
 125     def _model_set(self):
 126         pass
 127
 128     def _view_set(self):
 129         pass
 130
 131     def get_view(self):
 132         return self._view
 133
 134     def set_view(self, view):
 135         self._view = view
 136         view.presenter = self
 137         view.model = self._model
 138         self._view_set()
 139
 140     view = property(get_view, set_view, None,
 141                     """The view component. Setting this als sets the view
 142                     object's presenter and model attributes.""")
 143
 144     def get_model(self):
 145         return self._model
 146
 147     def set_model(self, model):
 148         self._model = model
 149         if self._view is not None:
 150             self._view.model = model
 151         self._model_set()
 152
 153     model = property(get_model, set_model, None,
 154                      """The model component. Setting this also sets the view
 155                      object's (if defined) model attribute.""")