Changeset 119b7d in indico

Timestamp:

10/18/09 23:31:20 (4 years ago)

Author:

David Martín Clavo <david.martin.clavo@…>

Branches:

master, burotel, hello-world-walkthrough, ipv6, new-webex, prov-dual-interface, v0.97-series, v0.98-series, v0.98.2, v0.98.3, v0.98b1, v0.98b2, v0.99, 051b2622c51afb171a1dedb46a0df4fbb0cbd02e, d9941f8582b36b24821a11ea5ba16fda6a457fb1

Children:

f4ad5a

Parents:

498147

git-author:

David Martín Clavo <david.martin.clavo@…> (10/07/09 09:49:13)

git-committer:

David Martín Clavo <david.martin.clavo@…> (10/18/09 23:31:20)

Message:

[REFACTOR] New observer mechanism, simpler and more escalable

Location:

indico/MaKaC

Files:

• conference.py (modified) (14 diffs)
• plugins/Collaboration/base.py (modified) (3 diffs)

indico/MaKaC/conference.py

@@ -2008 +2008 @@
         self._sortUrlTag = ""
 
-        self._titleChangeObservers = []
-        self._dateChangeObservers = []
-        self._deleteObservers = []
+        self._observers = []
 
         if PluginsHolder().hasPluginType("Collaboration"):
@@ -2676 +2674 @@
         """deletes the conference from the system.
         """
-        #we notify the observers that the conference
-        for observer in self.getDeleteObservers():
+        #we notify the observers that the conference has been deleted
+        for observer in self.getObservers():
             try:
                 observer.notifyDeletion()
@@ -2707 +2705 @@
         indexes.IndexesHolder().getById("OAIPrivateConferenceModificationDate").unindexConference(self)
 
-    def getDeleteObservers(self):
-        if not hasattr(self, "_deleteObservers"):
-            self._deleteObservers = []
-        return self._deleteObservers
-
-    def addDeleteObserver(self, observer):
-        self.getDeleteObservers().append(observer)
-        self._p_changed=1
-
-    def removeDeleteObserver(self, observer):
-        self.getDeleteObservers().remove(observer)
-        self._p_changed=1
-    
-    
-
     def getConference( self ):
         return self
+    
+    def getObservers(self):
+        if not hasattr(self, "_observers"):
+            self._observers = []
+        return self._observers
+
+    def addObserver(self, observer):
+        self.getObservers().append(observer)
+        self._p_changed=1
+
+    def removeObserver(self, observer):
+        self.getObservers().remove(observer)
+        self._p_changed=1
 
     def setDates( self, sDate, eDate=None, check=1, moveEntries=1 ):
@@ -2741 +2737 @@
         self.cleanCategoryCache()
         
-        for observer in self.getDateChangeObservers():
+        for observer in self.getObservers():
             try:
                 observer.notifyEventDateChanges(oldStartDate, self.getStartDate(), oldEndDate, self.getEndDate())
@@ -2797 +2793 @@
         #if everything went well, we notify the observers that the start date has changed
         if notifyObservers:
-            for observer in self.getDateChangeObservers():
+            for observer in self.getObservers():
                 try:
                     observer.notifyEventDateChanges(oldSdate, sDate, None, None)
@@ -2824 +2820 @@
         #if everything went well, we notify the observers that the start date has changed
         if notifyObservers:
-            for observer in self.getDateChangeObservers():
+            for observer in self.getObservers():
                 try:
                     observer.notifyEventDateChanges(sdate, self.startDate, None, None)
@@ -2912 +2908 @@
         #if everything went well, we notify the observers that the start date has changed
         if notifyObservers:
-            for observer in self.getDateChangeObservers():
+            for observer in self.getObservers():
                 try:
                     observer.notifyEventDateChanges(None, None, oldEdate, eDate)
@@ -2932 +2928 @@
         #if everything went well, we notify the observers that the start date has changed
         if notifyObservers:
-            for observer in self.getDateChangeObservers():
+            for observer in self.getObservers():
                 try:
                     observer.notifyEventDateChanges(None, None, edate, self.endDate)
@@ -2962 +2958 @@
     ##################################
 
-    def getDateChangeObservers(self):
-        if not hasattr(self, "_dateChangeObservers"):
-            self._dateChangeObservers = []
-        return self._dateChangeObservers
-
-    def addDateChangeObserver(self, observer):
-        self.getDateChangeObservers().append(observer)
-        self._p_changed=1
-
-    def removeDateChangeObserver(self, observer):
-        self.getDateChangeObservers().remove(observer)
-        self._p_changed=1
-
     def setScreenEndDate(self, date):
         if date == self.getEndDate():
@@ -3008 +2991 @@
         oldTimezone = self.timezone
         self.timezone = tz
-        for observer in self.getDateChangeObservers():
-            observer.notifyTimezoneChange(oldTimezone, tz)
+        
+        for observer in self.getObservers():
+            try:
+                observer.notifyTimezoneChange(oldTimezone, tz)
+            except Exception, e:
+                try:
+                    Logger.get('Conference').error("Exception while notifying the observer %s of a timezone change from %s to %s for conference %s: "%
+                                                   (observer.getObserverName(), str(oldTimezone), str(tz), self.getId(), str(e)))
+                except Exception, e2:
+                    Logger.get('Conference').error("Exception while notifying a timezone change: %s (origin: %s)"%(str(e2), str(e)))
 
     def getTimezone(self):
@@ -3052 +3043 @@
     def setTitle(self, title):
         """changes the current title of the conference to the one specified"""
+        oldTitle = self.title
         
+        self.title = title
+        self.cleanCategoryCache()
+        self.notifyModification()
         
         #we notify the observers that the conference's title has changed
-        for observer in self.getTitleChangeObservers():
+        for observer in self.getObservers():
             try:
-                observer.notifyTitleChange(self.title, title)
+                observer.notifyTitleChange(oldTitle, title)
             except Exception, e:
                 try:
@@ -3064 +3059 @@
                 except Exception, e2:
                     Logger.get('Conference').error("Exception while notifying a conference title change: %s (origin: %s)"%(str(e2), str(e)))
-        
-        self.title = title
-        self.cleanCategoryCache()
-        self.notifyModification()
-
-    def getTitleChangeObservers(self):
-        if not hasattr(self, "_titleChangeObservers"):
-            self._titleChangeObservers = []
-        return self._titleChangeObservers
-
-    def addTitleChangeObserver(self, observer):
-        self.getTitleChangeObservers().append(observer)
-        self._p_changed=1
-
-    def removeTitleChangeObserver(self, observer):
-        self.getTitleChangeObservers().remove(observer)
-        self._p_changed=1
 
     def getDescription(self):
@@ -4931 +4909 @@
 class Observer(object):
     """ Base class for Observer objects.
-        Provides the getObserverName method (used when writing info to the Indico log)
+        Inheriting classes should overload the following boolean class attributes:
+            _shouldBeTitleNotified
+            _shouldBeDateChangeNotified
+            _shouldBeDeletionNotified
+        And set them to True if they want to be notified of the corresponding event.
+        In that case, they also have to implement the corresponding methods:
+            _notifyTitleChange (for title notification)
+            _notifyEventDateChanges and _notifyTimezoneChange (for date / timezone notification)
+            _notifyDeletion (for deletion notification).
+        The interface for those methods is also specified in this class. If the corresponding
+        class attribute is set to False but the method is not implemented, an exception will be thrown.
     """
+    _shouldBeTitleNotified = False
+    _shouldBeDateChangeNotified = False
+    _shouldBeDeletionNotified = False
+    
     def getObserverName(self):
         name = "'Observer of class" + self.__class__.__name__
@@ -4941 +4933 @@
             pass
         return name
+    
+    def notifyTitleChange(self, oldTitle, newTitle):
+        if self._shouldBeTitleNotified:
+            self._notifyTitleChange(oldTitle, newTitle)
+            
+    def notifyEventDateChanges(self, oldStartDate = None, newStartDate = None, oldEndDate = None, newEndDate = None):
+        if self._shouldBeDateChangeNotified:
+            self._notifyEventDateChanges(oldStartDate, newStartDate, oldEndDate, newEndDate)
+            
+    def notifyTimezoneChange(self, oldTimezone, newTimezone):
+        if self._shouldBeDateChangeNotified:
+            self._notifyTimezoneChange(oldTimezone, newTimezone)
+            
+    def notifyDeletion(self):
+        if self._shouldBeDeletionNotified:
+            self._notifyDeletion()
+            
+    def _notifyTitleChange(self, oldTitle, newTitle): 
+        """ To be implemented by inheriting classes
+            Notifies the observer that the Conference object's title has changed
+        """
+        raise MaKaCError("Class " + str(self.__class__.__name__) + " did not implement method _notifyTitleChange")
+    
+    def _notifyEventDateChanges(self, oldStartDate, newStartDate, oldEndDate, newEndDate):
+        """ To be implemented by inheriting classes
+            Notifies the observer that the start and / or end dates of the object it is attached to has changed.
+            If the observer finds any problems during whatever he needs to do as a consequence of
+            the event dates changing, he should write strings describing the problems
+            in the 'dateChangeNotificationProblems' context variable (which is a list of strings).
+        """
+        raise MaKaCError("Class " + str(self.__class__.__name__) + " did not implement method notifyStartDateChange")
+    
+    def _notifyTimezoneChange(self, oldTimezone, newTimezone):
+        """ To be implemented by inheriting classes.
+            Notifies the observer that the end date of the object it is attached to has changed.
+            This method has to return a list of strings describing problems encountered during
+            whatever the DateChangeObserver object does as a consequence of the notification.
+            If there are no problems, the DateChangeObserver should return an empty list.
+        """
+        raise MaKaCError("Class " + str(self.__class__.__name__) + " did not implement method notifyTimezoneChange")
+    
+    def _notifyDeletion(self):
+        """ To be implemented by inheriting classes
+            Notifies the observer that the Conference object it is attached to has been deleted
+        """
+        raise MaKaCError("Class " + str(self.__class__.__name__) + " did not implement method notifyDeletion")
 
 class TitleChangeObserver(Observer):

indico/MaKaC/plugins/Collaboration/base.py

@@ -47 +47 @@
     """
     
+    _shouldBeTitleNotified = True
+    _shouldBeDateChangeNotified = True
+    _shouldBeDeletionNotified = True
+    
     def __init__(self, conf):
         """ Constructor for the CSBookingManager class.
@@ -65 +69 @@
         self._managers = {}
         
-        #we register as a date change observer of the conference
-        self._conf.addTitleChangeObserver(self)
-        
-        #we register as a date change observer of the conference
-        self._conf.addDateChangeObserver(self)
-        
-        #we register as a delete observer of the conference
-        self._conf.addDeleteObserver(self)
+        #we register as an observer of the conference
+        self._conf.addObserver(self)
 
     def getOwner(self):
@@ -80 +78 @@
     
     def restoreAsObserver(self):
-        if not self in self._conf.getTitleChangeObservers():
-            self._conf.addTitleChangeObserver(self)
-        if not self in self._conf.getDateChangeObservers():
-            self._conf.addDateChangeObserver(self)
-        if not self in self._conf.getDeleteObservers():
-            self._conf.addDeleteObserver(self)
+        if not self in self._conf.getObservers():
+            self._conf.addObserver(self)
     
     def isCSAllowed(self):