Re: [Modeling-users] Partial dispose

[Sebastien B. <sbi...@us...>]

soif> Is there a way to do a partial dispose. In fact
soif> I have a problem with my EditingContext, as :
soif> - The EC is never disposed to avoid fetching objects
soif>   at each web application request. (better performance)
soif> - The only way to stop this is to call a ec.dispose()
soif>   but this drop all objects.
soif>
soif> After severals searches, I think the best for me, is
soif> to do a partial dispose . Let's say object that are
soif> in EC older than 10 minutes should be forget.
soif>
soif> Is there any plans to support things like this ?

mario> I think Sebastien is waiting for real requests for this todo
mario> item, to bump up its priority ;) Look at section 6.3.1 in the
mario> users guide...

Mario answered for me ;)

soif> I tried to call ec.forgetObject(object) if object
soif> is older than X min, but i get some really strange
soif> AttributeError when i try to access objects that
soif> i have forget.

Woo-oo, you didn't read forgetObject()'s docstring, did you ?) It
shouldn't be called.

  What you need is refaultObject() for which you'll find a patch at the
  end of the message. This is a somewhat dirty implementation,
  especially in DBContext.refaultObject(), but it works in a simple test
  also included at the end of the mail.

Instruction of use:

  - do NOT call DabaseContext.refaultObject(), just ec.refaultObject

  - do NOT try to call it on inserted, updated or deleted objects,

API: either ec.refaultObject(obj) or
            ec.refaultObject(anObject=obj) or
            ec.refaultObject(aGlobalID=gid)

Last, when refaulting an object, all its properties are cleared
(__init__ is called), hence you should not expect to find any attribute
after it's been refaulted. This will probably not stay as-is, this is
rude and dirty ; please experiment and tell what you think.


  BTW this is the first step towards what is exposed at the end of
  section 6.3.1

-- Sebastien.


Index: EditingContext.py
===================================================================
RCS file: /cvsroot/modeling/ProjectModeling/Modeling/EditingContext.py,v
retrieving revision 1.21
diff -c -r1.21 EditingContext.py
*** EditingContext.py   12 Mar 2003 15:45:54 -0000      1.21
--- EditingContext.py   26 Mar 2003 21:01:31 -0000
***************
*** 1013,1019 ****
      except AttributeError:
        return 0
  
!   def faultForGlobalID(self, aGlobalID, anEditingContext):
      """
      Searches for an object registered within the EditingContext with the
      supplied GlobalID, and returns it if it is found. If not, forwards the
--- 1013,1019 ----
      except AttributeError:
        return 0
  
!   def faultForGlobalID(self, aGlobalID, anEditingContext=None):
      """
      Searches for an object registered within the EditingContext with the
      supplied GlobalID, and returns it if it is found. If not, forwards the
***************
*** 1021,1026 ****
--- 1021,1029 ----
  
      If anEditingContext is a child of self, 
      """
+     if anEditingContext is None:
+       anEditingContext=self
+       
      if anEditingContext.isaChildOf(self):
        # One of our child ECs forwarded the message
        if aGlobalID.isTemporary():
***************
*** 1215,1220 ****
--- 1218,1252 ----
      """
      return self.parentObjectStore().ownsObject(anObject)
    
+   def refaultObject(self, anObject=None, aGlobalID=None, ec=None):
+     "TBD docstring refaultObject"
+     if ec is None: ec=self
+ 
+     if ec is not self:
+       return self.parentObjectStore().refaultObject(anObject, aGlobalID, ec)
+       
+     obj=anObject ; gid=aGlobalID
+     if ( obj is None and gid is None ) or \
+        ( obj is not None and gid is not None ):
+       raise ValueError, "Either parameter 'anObject' or 'aGlobalID' should be provided --not both"
+     if obj is None:
+       obj=self.objectForGlobalID(gid)
+     else:
+       gid=self.globalIDForObject(obj)
+ 
+     if gid is None:
+       raise ObjectNotRegisteredError
+     if gid.isTemporary():
+       raise ValueError, 'Cannot refault an newly created/inserted object'
+ 
+     if gid in self._pendingUpdatedObjects+self._updatedObjects:
+       raise ValueError, 'Cannot refault a modified object'
+     if gid in self._pendingDeletedObjects+self._deletedObjects:
+       raise ValueError, 'Cannot refault a deleted object'
+     
+     #self.forgetObject(obj)
+     return self.parentObjectStore().refaultObject(obj, gid, self)
+     
    def saveChangesInEditingContext(self, anEditingContext):
      """
      Called on the parent EditingContext when a child EditingContext saves
***************
*** 1360,1365 ****
--- 1392,1404 ----
            self.recordObject(obj, key_gid)
            db=self.rootObjectStore().objectStoreForObject(obj).database()
            db.incrementSnapshotCountForGlobalID(key_gid)
+           # time to update object's PK if a PK is set as class properties
+           from ModelSet import defaultModelSet
+           entity=defaultModelSet().entityNamed(obj.entityName())
+           pk_values=key_gid.keyValues()
+           for pk in entity.primaryKeyAttributes():
+             if pk.isClassProperty():
+               obj.takeStoredValueForKey(pk_values[pk.name()], pk.name())
        else:
          obj=self.objectForGlobalID(gid)
          new_gid=notification.userInfo().get(gid)
Index: ObjectStoreCoordinator.py
===================================================================
RCS file: /cvsroot/modeling/ProjectModeling/Modeling/ObjectStoreCoordinator.py,v
retrieving revision 1.9
diff -c -r1.9 ObjectStoreCoordinator.py
*** ObjectStoreCoordinator.py   14 Mar 2003 11:40:09 -0000      1.9
--- ObjectStoreCoordinator.py   26 Mar 2003 21:01:34 -0000
***************
*** 486,492 ****
      self.lock()
      try:
        store=self.objectStoreForObject(anObject)
!       store.refaultObject(anObject, aGlobalID, anEditingContext)
      finally:
        self.unlock()
        
--- 486,492 ----
      self.lock()
      try:
        store=self.objectStoreForObject(anObject)
!       return store.refaultObject(anObject, aGlobalID, anEditingContext)
      finally:
        self.unlock()
        
Index: DatabaseContext.py
===================================================================
RCS file: /cvsroot/modeling/ProjectModeling/Modeling/DatabaseContext.py,v
retrieving revision 1.14
diff -c -r1.14 DatabaseContext.py
*** DatabaseContext.py  14 Mar 2003 11:40:07 -0000      1.14
--- DatabaseContext.py  26 Mar 2003 21:01:52 -0000
***************
*** 1489,1496 ****
  
    def refaultObject(self, aDatabaseObject, aGlobalID, anEditingContext):
      """
      """
!     self.__unimplemented__()
      
    def rootObjectStore(self):
      """
--- 1489,1524 ----
  
    def refaultObject(self, aDatabaseObject, aGlobalID, anEditingContext):
      """
+     Do not call by hand -- please call EditingContext.refaultObject()
+     instead
      """
!     ## TBD roughly copy/pasted from faultForGlobalID()
!     ## TBD It should be fixed -- we do not check anything wrt the ec and 
!     ## TBD Should we also really clear properties? We'll see
!     try:
!       entityName=aGlobalID.entityName()
!     except AttributeError:
!       raise ValueError, \
!             "Parameter aGlobalID does not responds to message 'entityName()'"
!     cd=ClassDescription.classDescriptionForName(entityName)
!     
!     cd_root=cd.rootClassDescription()
!     root_keyGlobalID=KeyGlobalID(cd_root.entityName(), aGlobalID.keyValues())
! 
!     anEditingContext.forgetObject(aDatabaseObject)
!     faultHandler=AccessFaultHandler(root_keyGlobalID, self,
!                                     anEditingContext)
!     #aDatabaseObject.clearProperties()
!     aDatabaseObject.__init__()
!     aDatabaseObject.turnIntoFault(faultHandler)
!     trace('Registering fault w/ GlobalID: %s'%str(root_keyGlobalID))
!     anEditingContext.recordObject(aDatabaseObject, root_keyGlobalID)
!     # inheritance support
!     trace('Adding ec as an observer for GlobalIDChangedNotification & GlobalID: %s'%root_keyGlobalID)
!     NC.addObserver(anEditingContext, EditingContext.handleNotification,
!                    GlobalIDChangedNotification, root_keyGlobalID)
!     return aDatabaseObject
!     
      
    def rootObjectStore(self):
      """
------------------------------------------------------------------------

Optionally, add this to tests/test_EditingContext_Global.py

  def test_19_refaultObject(self):
    "[EditingContext] refaultObject()"
    ec=EditingContext()
    qualifier=qualifierWithQualifierFormat('lastName=="Rabelais"')
    fetchSpec=FetchSpecification(entityName='Writer', qualifier=qualifier)
    rabelais=ec.objectsWithFetchSpecification(fetchSpec)[0]
    db=ec.rootObjectStore().objectStoreForObject(rabelais).database()
    gid=ec.globalIDForObject(rabelais)
    
    lastName=rabelais.getLastName() # trigger fault
    self.failIf(rabelais.isFault())

    self.failUnless(db.snapshotForGlobalID(gid))
    ec.refaultObject(rabelais)
    self.failUnless(rabelais.isFault())
    self.failIf(db.snapshotForGlobalID(gid))

    lastName=rabelais.getLastName() # trigger fault again
    self.failIf(rabelais.isFault())
------------------------------------------------------------------------