Changed generic observer pattern and project dependency in plots to be a two-way selection-listener model.

The project listens to selections done in plot and broadcasts it back to all plots (including source) which allows them to redraw properly.

system/project.py

@@ -12,35 +12,20 @@ class Project:
 
         self.name = name
         self.dim_names = []
-        self._observers = {}
+        self._selection_observers = []
         self.current_data = None
         self.datasets = []
         self.sel_obj = dataset.Selection()
         
-    def attach(self,observer,key):
-        """Attach observer for selection updates"""
-        if not self._observers.has_key(key):
-            self._observers[key]=[]        
-        if not observer in self._observers[key]:
-            self._observers[key].append(observer)
-
-    def detach(self,observer,key):
-        """Detach observer for selection updates"""
-        try:
-            self._observers[key].remove(observer)
-        except ValueError:
-            pass
-
-    def notify(self,key,modifier=None):
+    def notify_selection_listeners(self):
         """Notifies observers"""
-        for observer in self._observers[key]:
-            if modifier != observer:
-                observer.update(key)
+        for observer in self._selection_observers:
+            observer.selection_changed(self.get_selection())
 
     def set_selection(self,dim_name,selection):
         """Sets a current selection and notify observers"""
         self.sel_obj.current_selection[dim_name] = set(selection)
-        self.notify('selection_update')
+        self.notify_selection_listeners()
 
     def get_selection(self):
         """Returns the current selection object"""
@@ -71,10 +56,9 @@ class Project:
                 self.add_dataset(d)
                 self.data_tree_insert(it, d.get_name(), d)
             elif isinstance(d, plots.Plot):
-#                self.add_view(d)
                 self.data_tree_insert(it, d.get_title(), d)
-                d.set_project(self)
-                self.attach(d, 'selection_update')
+                d.set_selection_listener(self.set_selection)
+                self._selection_observers.append(d)
 
     def data_tree_insert(self, parent, text, data):
         tree = self.data_tree