def modelWasSet(self): """Perform additional set up of the store after the model is set.""" ModelUser.modelWasSet(self) self._threaded = self.setting('Threaded') if self._threaded: self._hasChanges = set() # keep track on a per-thread basis self._newObjects = PerThreadList() self._deletedObjects = PerThreadList() self._changedObjects = PerThreadDict() else: self._hasChanges = False self._newObjects = NonThreadedList() self._deletedObjects = NonThreadedList() self._changedObjects = NonThreadedDict() self._objects = self.emptyObjectCache() # dict; keyed by ObjectKeys
def modelWasSet(self): """ Performs additional set up of the store after the model is set. """ ModelUser.modelWasSet(self) self._threaded = self.setting('Threaded') if self._threaded: self._hasChanges = {} # keep track on a per-thread basis self._newObjects = PerThreadList() self._deletedObjects = PerThreadList() self._changedObjects = PerThreadDict() else: self._hasChanges = 0 self._newObjects = NonThreadedList() self._deletedObjects = NonThreadedList() self._changedObjects = NonThreadedDict()
class ObjectStore(ModelUser): """The object store. NOT IMPLEMENTED: * revertChanges() FUTURE * expanded fetch """ ## Init ## def __init__(self): self._model = None self._newSerialNum = -1 self._verboseDelete = False def modelWasSet(self): """Perform additional set up of the store after the model is set.""" ModelUser.modelWasSet(self) self._threaded = self.setting('Threaded') if self._threaded: self._hasChanges = set() # keep track on a per-thread basis self._newObjects = PerThreadList() self._deletedObjects = PerThreadList() self._changedObjects = PerThreadDict() else: self._hasChanges = False self._newObjects = NonThreadedList() self._deletedObjects = NonThreadedList() self._changedObjects = NonThreadedDict() self._objects = self.emptyObjectCache() # dict; keyed by ObjectKeys def emptyObjectCache(self): if self.setting('CacheObjectsForever', False): return {} else: return WeakValueDictionary() ## Manipulating the objects in the store ## def hasObject(self, obj): """Check if the object is in the store. Note: this does not check the persistent store. """ key = obj.key() if key is None: return False else: return key in self._objects def object(self, a, b=NoDefault, c=NoDefault): """Return object described by the given arguments, or default value. store.object(anObjectKey) - return the object with the given key, or raise a KeyError if it does not reside in memory. store.object(anObjectKey, defaultValue) - return the object or defaultValue (no exception will be raised) store.object(someClass, serialNum) - return the object of the given class and serial num, or raise a KeyError store.object(someClass, serialNum, defaultValue) - return the object or defaultValue (no exception will be raised) `someClass` can be a Python class, a string (the name of a class) or a MiddleKit.Core.Klass """ if isinstance(a, ObjectKey): return self.objectForKey(a, b) else: return self.objectForClassAndSerial(a, b, c) def objectForClassAndSerial(self, klass, serialNum, default=NoDefault): if isinstance(klass, BaseKlass): klass = klass.name() elif isinstance(klass, (type, ClassType)): klass = klass.__name__ else: assert isinstance(klass, str) key = ObjectKey().initFromClassNameAndSerialNum(klass, serialNum) return self.objectForKey(key, default) def objectForKey(self, key, default=NoDefault): """Return an object from the store by its given key. If no default is given and the object is not in the store, then an exception is raised. Note: This method doesn't currently fetch objects from the persistent store. """ if default is NoDefault: return self._objects[key] else: return self._objects.get(key, default) def add(self, obj, noRecurse=False): return self.addObject(obj, noRecurse) def addObject(self, obj, noRecurse=False): """Add the object and all referenced objects to the store. You can insert the same object multiple times, and you can insert an object that was loaded from the store. In those cases, this is a no-op. The noRecurse flag is used internally, and should be avoided in regular MiddleKit usage; it causes only this object to be added to the store, not any dependent objects. """ if not obj.isInStore(): assert obj.key() is None # Make the store aware of this new object self.willChange() self._newObjects.append(obj) obj.setStore(self) if not noRecurse: # Recursively add referenced objects to the store obj.addReferencedObjectsToStore(self) # 2000-10-07 ce: Decided not to allow keys for non-persisted objects # Because the serial num, and therefore the key, will change # upon saving. # key = obj.key() # if key is None: # key = ObjectKey(obj, self) # obj.setKey(key) # self._objects[key] = obj def deleteObject(self, obj): """Delete object. Restrictions: The object must be contained in the store and obviously you cannot remove it more than once. """ # First check if the delete is possible. Then do the actual delete. # This avoids partially deleting objects only to have an exception # halt the process in the middle. objectsToDel = {} detaches = [] self._deleteObject(obj, objectsToDel, detaches) # compute objectsToDel and detaches self.willChange() # detaches for obj, attr in detaches: if id(obj) not in objectsToDel: obj.setValueForAttr(attr, None) # process final list of objects objectsToDel = objectsToDel.values() for obj in objectsToDel: obj._mk_isDeleted = True self._deletedObjects.append(obj) obj.updateReferencingListAttrs() del self._objects[obj.key()] def _deleteObject(self, obj, objectsToDel, detaches, superobject=None): """Compile the list of objects to be deleted. This is a recursive method since deleting one object might be deleting others. obj - the object to delete objectsToDel - a running dictionary of all objects to delete detaches - a running list of all detaches (eg, obj.attr=None) superobject - the object that was the cause of this invocation """ # Some basic assertions assert self.hasObject(obj), safeDescription(obj) assert obj.key() is not None v = self._verboseDelete if v: if superobject: cascadeString = 'cascade-' dueTo = ' due to deletion of %s.%i' % ( superobject.klass().name(), superobject.serialNum()) else: cascadeString = dueTo = '' print 'checking %sdelete of %s.%d%s' % ( cascadeString, obj.klass().name(), obj.serialNum(), dueTo) objectsToDel[id(obj)] = obj # Get the objects/attrs that reference this object referencingObjectsAndAttrs = obj.referencingObjectsAndAttrs() # cascade-delete objects with onDeleteOther=cascade for referencingObject, referencingAttr in referencingObjectsAndAttrs: onDeleteOther = referencingAttr.get('onDeleteOther', 'deny') if onDeleteOther == 'cascade': self._deleteObject(referencingObject, objectsToDel, detaches, obj) # Determine all referenced objects, constructing a list of (attr, referencedObject) tuples. referencedAttrsAndObjects = obj.referencedAttrsAndObjects() # Check if it's possible to cascade-delete objects with onDeleteSelf=cascade for referencedAttr, referencedObject in referencedAttrsAndObjects: onDeleteSelf = referencedAttr.get('onDeleteSelf', 'detach') if onDeleteSelf == 'cascade': self._deleteObject(referencedObject, objectsToDel, detaches, obj) # Deal with all other objects that reference or are referenced by this object. # By default, you are not allowed to delete an object that has an ObjRef pointing to it. # But if the ObjRef has onDeleteOther=detach, then that ObjRef attr will be set to None # and the delete will be allowed; and if onDeleteOther=cascade, then that object will # itself be deleted and the delete will be allowed. # # You _are_ by default allowed to delete an object that points to other objects # (by List or ObjRef) but if onDeleteSelf=deny it will be disallowed, or if # onDeleteSelf=cascade the pointed-to objects will themselves be deleted. # Remove from that list anything in the cascaded list referencingObjectsAndAttrs = [(o, a) for o, a in referencingObjectsAndAttrs if id(o) not in objectsToDel] # Remove from that list anything in the cascaded list referencedAttrsAndObjects = [(a, o) for a, o in referencedAttrsAndObjects if id(o) not in objectsToDel] # Check for onDeleteOther=deny badObjectsAndAttrs = [] for referencingObject, referencingAttr in referencingObjectsAndAttrs: onDeleteOther = referencingAttr.get('onDeleteOther', 'deny') assert onDeleteOther in ('deny', 'detach', 'cascade') if onDeleteOther == 'deny': badObjectsAndAttrs.append((referencingObject, referencingAttr)) if badObjectsAndAttrs: raise DeleteReferencedError( 'You tried to delete an object (%s.%d) that is referenced' ' by other objects with onDeleteOther unspecified or set to deny' % (obj.klass().name(), obj.serialNum()), obj, badObjectsAndAttrs) # Check for onDeleteSelf=deny badAttrs = [] for referencedAttr, referencedObject in referencedAttrsAndObjects: onDeleteSelf = referencedAttr.get('onDeleteSelf', 'detach') assert onDeleteSelf in ['deny', 'detach', 'cascade'] if onDeleteSelf == 'deny': badAttrs.append(referencedAttr) if badAttrs: raise DeleteObjectWithReferencesError( 'You tried to delete an object (%s.%d) that references' ' other objects with onDeleteSelf set to deny' % (obj.klass().name(), obj.serialNum()), obj, badAttrs) # Detach objects with onDeleteOther=detach for referencingObject, referencingAttr in referencingObjectsAndAttrs: onDeleteOther = referencingAttr.get('onDeleteOther', 'deny') if onDeleteOther == 'detach': if v: print 'will set %s.%d.%s to None' % ( referencingObject.klass().name(), referencingObject.serialNum(), referencingAttr.name()) detaches.append((referencingObject, referencingAttr)) # Detach objects with onDeleteSelf=detach # This is actually a no-op. There is nothing that needs to be set to zero. ## Changes ## def hasChangesForCurrentThread(self): """Return whether the current thread has changes to be committed.""" if self._threaded: threadid = thread.get_ident() return threadid in self._hasChanges else: return self._hasChanges def hasChanges(self): """Return whether any thread has changes to be committed.""" if self._threaded: return bool(self._hasChanges) return self._hasChanges def willChange(self): if self._threaded: threadid = thread.get_ident() self._hasChanges.add(threadid) else: self._hasChanges = True def saveAllChanges(self): """Commit object changes to the object store. Done by invoking commitInserts(), commitUpdates() and commitDeletions() all of which must by implemented by a concrete subclass. """ self.commitDeletions(allThreads=True) self.commitInserts(allThreads=True) self.commitUpdates(allThreads=True) if self._threaded: self._hasChanges = set() else: self._hasChanges = False def saveChanges(self): """Commit object changes to the object store. Done by invoking commitInserts(), commitUpdates() and commitDeletions() all of which must by implemented by a concrete subclass. """ self.commitDeletions() self.commitInserts() self.commitUpdates() if self._threaded: self._hasChanges.discard(thread.get_ident()) else: self._hasChanges = False def commitInserts(self): """Commit inserts. Invoked by saveChanges() to insert any news objects add since the last save. Subclass responsibility. """ raise AbstractError(self.__class__) def commitUpdates(self): """Commit updates. Invoked by saveChanges() to update the persistent store with any changes since the last save. """ raise AbstractError(self.__class__) def commitDeletions(self): """Commit deletions. Invoked by saveChanges() to delete from the persistent store any objects deleted since the last save. Subclass responsibility. """ raise AbstractError(self.__class__) def revertChanges(self): """Revert changes. Discards all insertions and deletions, and restores changed objects to their original values. """ raise AbstractError(self.__class__) ## Fetching ## def fetchObject(self, className, serialNum, default=NoDefault): """Fetch onkect of a given class. Subclasses should raise UnknownObjectError if an object with the given className and serialNum does not exist, unless a default value was passed in, in which case that value should be returned. """ raise AbstractError(self.__class__) def fetchObjectsOfClass(self, className, isDeep=True): """Fetch all objects of a given class. If isDeep is True, then all subclasses are also returned. """ raise AbstractError(self.__class__) def fetch(self, *args, **namedArgs): """An alias for fetchObjectsOfClass().""" return self.fetchObjectsOfClass(*args, **namedArgs) ## Other ## def clear(self): """Clear all objects from the memory of the store. This does not delete the objects in the persistent backing. This method can only be invoked if there are no outstanding changes to be saved. You can check for that with hasChanges(). """ assert not self.hasChanges() assert self._newObjects.isEmpty() assert self._deletedObjects.isEmpty() assert self._changedObjects.isEmpty() self._objects = self.emptyObjectCache() self._newSerialNum = -1 def discardEverything(self): """Discard all cached objects. This includes any modification tracking. However, objects in memory will not change state as a result of this call. This method is a severe form of clear() and is typically used only for debugging or production emergencies. """ if self._threaded: self._hasChanges = set() else: self._hasChanges = False self._objects = self.emptyObjectCache() self._newObjects.clear() self._deletedObjects.clear() self._changedObjects.clear() self._newSerialNum = -1 ## Notifications ## def objectChanged(self, obj): """Mark attributes as changed. MiddleObjects must send this message when one of their interesting attributes change, where an attribute is interesting if it's listed in the class model. This method records the object in a set for later processing when the store's changes are saved. If you subclass MiddleObject, then you're taken care of. """ self.willChange() self._changedObjects[obj] = obj # @@ 2000-10-06 ce: Should this be keyed by the obj.key()? Does it matter? ## Serial numbers ## def newSerialNum(self): """Return a new serial number for a newly created object. This is a utility methods for objects that have been created, but not yet committed to the persistent store. These serial numbers are actually temporary and replaced upon committal. Also, they are always negative to indicate that they are temporary, whereas serial numbers taken from the persistent store are positive. """ self._newSerialNum -= 1 return self._newSerialNum ## Self utility ## def _klassForClass(self, aClass): """Return a Klass object for the given class. This may be: - the Klass object already - a Python class - a class name (e.g., string) Users of this method include the various fetchObjectEtc() methods which take a "class" parameter. """ assert aClass is not None if not isinstance(aClass, BaseKlass): if isinstance(aClass, type): # new Python classes aClass = self._model.klass(aClass.__name__) elif isinstance(aClass, ClassType): # old Python classes aClass = self._model.klass(aClass.__name__) elif isinstance(aClass, basestring): aClass = self._model.klass(aClass) else: raise ValueError('Invalid class parameter. Pass a Klass,' 'a name or a Python class. Type of aClass is %s.' ' aClass is %s.' % (type(aClass), aClass)) return aClass
class ObjectStore(ModelUser): """ NOT IMPLEMENTED: * revertChanges() FUTURE * expanded fetch """ ## Init ## def __init__(self): self._model = None self._objects = {} # keyed by ObjectKeys self._newSerialNum = -1 self._verboseDelete = 0 def modelWasSet(self): """ Performs additional set up of the store after the model is set. """ ModelUser.modelWasSet(self) self._threaded = self.setting('Threaded') if self._threaded: self._hasChanges = {} # keep track on a per-thread basis self._newObjects = PerThreadList() self._deletedObjects = PerThreadList() self._changedObjects = PerThreadDict() else: self._hasChanges = 0 self._newObjects = NonThreadedList() self._deletedObjects = NonThreadedList() self._changedObjects = NonThreadedDict() ## Settings ## def setting(self, name, default=NoDefault): """ Returns the given setting for the store, which is actually just taken from the model. """ return self._model.setting(name, default) ## Manipulating the objects in the store ## def hasObject(self, object): """ Checks if the object is in the store. Note: this does not check the persistent store. """ key = object.key() if key is None: return 0 else: return self._objects.has_key(key) def object(self, key, default=NoDefault): """ Returns an object from the store by it's given key. If no default is given and the object is not in the store, then an exception is raised. Note: This method doesn't currently fetch objects from the persistent store. """ if default is NoDefault: return self._objects[key] else: return self._objects.get(key, default) def addObject(self, object, noRecurse=0): """ Add the object and all referenced objects to the store. You can insert the same object multiple times, and you can insert an object that was loaded from the store. In those cases, this is a no-op. The noRecurse flag is used internally, and should be avoided in regular MiddleKit usage; it causes only this object to be added to the store, not any dependent objects. """ if not object.isInStore(): assert object.key() == None # Make the store aware of this new object self.willChange() self._newObjects.append(object) object.setStore(self) if not noRecurse: # Recursively add referenced objects to the store object.addReferencedObjectsToStore(self) # 2000-10-07 ce: Decided not to allow keys for non-persisted objects # Because the serial num, and therefore the key, will change # upon saving. #key = object.key() #if key is None: # key = ObjectKey(object, self) # object.setKey(key) #self._objects[key] = object def deleteObject(self, object): """ Restrictions: The object must be contained in the store and obviously you cannot remove it more than once. """ # First check if the delete is possible. Then do the actual delete. This avoids partially deleting # objects only to have an exception halt the process in the middle. objectsToDel = {} detaches = [] self._deleteObject(object, objectsToDel, detaches) # compute objectsToDel and detaches self.willChange() # detaches for obj, attr in detaches: if not objectsToDel.has_key(id(obj)): obj.setValueForAttr(attr, None) # deleted objects objectsToDel = objectsToDel.values() self._deletedObjects.extend(objectsToDel) # remove deleted objects from main list of objects for obj in objectsToDel: del self._objects[obj.key()] def _deleteObject(self, object, objectsToDel, detaches, superobject=None): """ Compile the list of objects to be deleted. This is a recursive method since deleting one object might be deleting others. object - the object to delete objectsToDel - a running dictionary of all objects to delete detaches - a running list of all detaches (eg, obj.attr=None) superobject - the object that was the cause of this invocation """ # Some basic assertions assert self.hasObject(object) assert object.key() is not None v = self._verboseDelete if v: if superobject: cascadeString = 'cascade-' dueTo = ' due to deletion of %s.%i' % ( superobject.klass().name(), superobject.serialNum()) else: cascadeString = dueTo = '' print 'checking %sdelete of %s.%d%s' % (cascadeString, object.klass().name(), object.serialNum(), dueTo) objectsToDel[id(object)] = object # Deal with all other objects that reference or are referenced by this object. By default, you are not allowed # to delete an object that has an ObjRef pointing to it. But if the ObjRef has # onDeleteOther=detach, then that ObjRef attr will be set to None and the delete will be allowed; # and if onDeleteOther=cascade, then that object will itself be deleted and the delete # will be allowed. # # You _are_ by default allowed to delete an object that points to other objects (by List or ObjRef) # but if onDeleteSelf=deny it will be disallowed, or if onDeleteSelf=cascade the pointed-to # objects will themselves be deleted. # Get the objects/attrs that reference this object referencingObjectsAndAttrs = object.referencingObjectsAndAttrs() # Remove from that list anything in the cascaded list referencingObjectsAndAttrs = [(o, a) for o, a in referencingObjectsAndAttrs if not objectsToDel.has_key(id(o))] # Determine all referenced objects, constructing a list of (attr, referencedObject) tuples. referencedAttrsAndObjects = [] for attr in object.klass().allDataAttrs(): if isinstance(attr, ObjRefAttr): obj = object.valueForAttr(attr) if obj: referencedAttrsAndObjects.append((attr, obj)) elif isinstance(attr, ListAttr): for obj in object.valueForAttr(attr): referencedAttrsAndObjects.append((attr, obj)) # Remove from that list anything in the cascaded list referencedAttrsAndObjects = [(a, o) for a, o in referencedAttrsAndObjects if not objectsToDel.has_key(id(o))] # Check for onDeleteOther=deny badObjectsAndAttrs = [] for referencingObject, referencingAttr in referencingObjectsAndAttrs: onDeleteOther = referencingAttr.get('onDeleteOther', 'deny') assert onDeleteOther in ('deny', 'detach', 'cascade') if onDeleteOther == 'deny': badObjectsAndAttrs.append((referencingObject, referencingAttr)) if badObjectsAndAttrs: raise DeleteReferencedError( 'You tried to delete an object (%s.%d) that is referenced by other objects with onDeleteOther unspecified or set to deny' % (object.klass().name(), object.serialNum()), object, badObjectsAndAttrs) # Check for onDeleteSelf=deny badAttrs = [] for referencedAttr, referencedObject in referencedAttrsAndObjects: onDeleteSelf = referencedAttr.get('onDeleteSelf', 'detach') assert onDeleteSelf in ['deny', 'detach', 'cascade'] if onDeleteSelf == 'deny': badAttrs.append(referencedAttr) if badAttrs: raise DeleteObjectWithReferencesError( 'You tried to delete an object (%s.%d) that references other objects with onDeleteSelf set to deny' % (object.klass().name(), object.serialNum()), object, badAttrs) # cascade-delete objects with onDeleteOther=cascade for referencingObject, referencingAttr in referencingObjectsAndAttrs: onDeleteOther = referencingAttr.get('onDeleteOther', 'deny') if onDeleteOther == 'cascade': self._deleteObject(referencingObject, objectsToDel, detaches, object) # Check if it's possible to cascade-delete objects with onDeleteSelf=cascade for referencedAttr, referencedObject in referencedAttrsAndObjects: onDeleteSelf = referencedAttr.get('onDeleteSelf', 'detach') if onDeleteSelf == 'cascade': self._deleteObject(referencedObject, objectsToDel, detaches, object) # Detach objects with onDeleteOther=detach for referencingObject, referencingAttr in referencingObjectsAndAttrs: onDeleteOther = referencingAttr.get('onDeleteOther', 'deny') if onDeleteOther == 'detach': if v: print 'will set %s.%d.%s to None' % ( referencingObject.klass().name(), referencingObject.serialNum(), referencingAttr.name()) detaches.append((referencingObject, referencingAttr)) # Detach objects with onDeleteSelf=detach # This is actually a no-op. There is nothing that needs to be set to zero. ## Changes ## def hasChangesForCurrentThread(self): ''' return whether the current thread has changes to be committed ''' if self._threaded: threadid = thread.get_ident() return self._hasChanges.get(threadid, 0) else: return self._hasChanges def hasChanges(self): ''' return whether any thread has changes to be committed ''' if self._threaded: return 1 in self._hasChanges.values() return self._hasChanges def willChange(self): if self._threaded: threadid = thread.get_ident() self._hasChanges[threadid] = 1 else: self._hasChanges = 1 def saveAllChanges(self): """ Commits object changes to the object store by invoking commitInserts(), commitUpdates() and commitDeletions() all of which must by implemented by a concrete subclass. """ self.commitDeletions(allThreads=1) self.commitInserts(allThreads=1) self.commitUpdates(allThreads=1) self._hasChanges = {} def saveChanges(self): """ Commits object changes to the object store by invoking commitInserts(), commitUpdates() and commitDeletions() all of which must by implemented by a concrete subclass. """ self.commitDeletions() self.commitInserts() self.commitUpdates() if self._threaded: self._hasChanges[thread.get_ident()] = 0 else: self._hasChanges = 0 def commitInserts(self): """ Invoked by saveChanges() to insert any news objects add since the last save. Subclass responsibility. """ raise AbstractError, self.__class__ def commitUpdates(self): """ Invoked by saveChanges() to update the persistent store with any changes since the last save. """ raise AbstractError, self.__class__ def commitDeletions(self): """ Invoked by saveChanges() to delete from the persistent store any objects deleted since the last save. Subclass responsibility. """ raise AbstractError, self.__class__ def revertChanges(self): """ Discards all insertions and deletions, and restores changed objects to their original values. """ raise NotImplementedError ## Fetching ## def fetchObject(self, className, serialNum, default=NoDefault): """ Subclasses should raise UnknownObjectError if an object with the given className and serialNum does not exist, unless a default value was passed in, in which case that value should be returned. """ raise AbstractError, self.__class__ def fetchObjectsOfClass(self, className, isDeep=1): """ Fetches all objects of a given class. If isDeep is 1, then all subclasses are also returned. """ raise AbstractError, self.__class__ ## Other ## def clear(self): """ Clears all objects from the memory of the store. This does not delete the objects in the persistent backing. This method can only be invoked if there are no outstanding changes to be saved. You can check for that with hasChanges(). """ assert not self.hasChanges() assert self._newObjects.isEmpty() assert self._deletedObjects.isEmpty() assert self._changedObjects.isEmpty() self._objects = {} self._newSerialNum = -1 def discardEverything(self): """ Discards all cached objects, including any modification tracking. However, objects in memory will not change state as a result of this call. This method is a severe form of clear() and is typically used only for debugging or production emergencies. """ if self._threaded: self._hasChanges = {} else: self._hasChanges = 0 self._objects = {} self._newObjects.clear() self._deletedObjects.clear() self._changedObjects.clear() self._newSerialNum = -1 ## Notifications ## def objectChanged(self, object): """ MiddleObjects must send this message when one of their interesting attributes change, where an attribute is interesting if it's listed in the class model. This method records the object in a set for later processing when the store's changes are saved. If you subclass MiddleObject, then you're taken care of. """ self.willChange() self._changedObjects[ object] = object ## @@ 2000-10-06 ce: Should this be keyed by the object.key()? Does it matter? ## Serial numbers ## def newSerialNum(self): """ Returns a new serial number for a newly created object. This is a utility methods for objects that have been created, but not yet committed to the persistent store. These serial numbers are actually temporary and replaced upon committal. Also, they are always negative to indicate that they are temporary, whereas serial numbers taken from the persistent store are positive. """ self._newSerialNum -= 1 return self._newSerialNum ## Self utility ## def _klassForClass(self, aClass): """ Returns a Klass object for the given class, which may be: - the Klass object already - a Python class - a class name (e.g., string) Users of this method include the various fetchObjectEtc() methods which take a "class" parameter. """ assert aClass is not None if not isinstance(aClass, BaseKlass): if type(aClass) is ClassType: aClass = self._model.klass(aClass.__name__) elif type(aClass) is StringType: aClass = self._model.klass(aClass) else: raise ValueError, 'Invalid class parameter. Pass a Klass, a name or a Python class. Type of aClass is %s. aClass is %s.' % ( type(aClass), aClass) return aClass