* Moved experimental MVC project as a current mainstream.

gtkmvc/support/metaclasses.py

@@ -0,0 +1,81 @@
+#  Author: Roberto Cavada <cavada@irst.itc.it>
+#
+#  Copyright (c) 2005 by Roberto Cavada
+#
+#  pygtkmvc is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU Lesser General Public
+#  License as published by the Free Software Foundation; either
+#  version 2 of the License, or (at your option) any later version.
+#
+#  pygtkmvc is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+#  Lesser General Public License for more details.
+#
+#  You should have received a copy of the GNU Lesser General Public
+#  License along with this library; if not, write to the Free Software
+#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA.
+#
+#  For more information on pygtkmvc see <http://pygtkmvc.sourceforge.net>
+#  or email to the author Roberto Cavada <cavada@irst.itc.it>.
+#  Please report bugs to <cavada@irst.itc.it>.
+
+from metaclass_base import PropertyMeta
+import types
+
+
+class ObservablePropertyMeta (PropertyMeta):
+    """Classes instantiated by this meta-class must provide a method named
+    notify_property_change(self, prop_name, old, new)"""
+    def __init__(cls, name, bases, dict):
+        PropertyMeta.__init__(cls, name, bases, dict)
+        return    
+    
+    def get_setter_source(cls, setter_name, prop_name):
+        return """def %(setter)s(self, val): 
+ old = self._prop_%(prop)s
+ new = type(self).create_value('%(prop)s', val, self)
+ self._prop_%(prop)s = new
+ if type(self).check_value_change(old, new): self._reset_property_notification('%(prop)s')
+ self.notify_property_value_change('%(prop)s', old, val)
+ return
+""" % {'setter':setter_name, 'prop':prop_name}
+
+    pass #end of class
+
+
+class ObservablePropertyMetaMT (ObservablePropertyMeta):
+    """This class provides multithreading support for accesing
+    properties, through a locking mechanism. It is assumed a lock is
+    owned by the class that uses it. A Lock object called _prop_lock
+    is assumed to be a member of the using class. see for example class
+    ModelMT"""
+    def __init__(cls, name, bases, dict):
+        ObservablePropertyMeta.__init__(cls, name, bases, dict)
+        return 
+    
+    def get_setter_source(cls, setter_name, prop_name):
+        return """def %(setter)s(self, val): 
+ old = self._prop_%(prop)s
+ new = type(self).create_value('%(prop)s', val, self)
+ self._prop_lock.acquire()
+ self._prop_%(prop)s = new
+ self._prop_lock.release()
+ if type(self).check_value_change(old, new): self._reset_property_notification('%(prop)s')
+ self.notify_property_value_change('%(prop)s', old, val)
+ return
+""" % {'setter':setter_name, 'prop':prop_name}
+
+    pass #end of class
+
+
+try:
+    from gobject import GObjectMeta
+    class ObservablePropertyGObjectMeta (ObservablePropertyMeta, GObjectMeta): pass
+    class ObservablePropertyGObjectMetaMT (ObservablePropertyMetaMT, GObjectMeta): pass    
+except:
+    class ObservablePropertyGObjectMeta (ObservablePropertyMeta): pass
+    class ObservablePropertyGObjectMetaMT (ObservablePropertyMetaMT): pass
+    pass
+
+