def propagate(self, event):
"""Re-emit state change for the derived union (as Derived*Event's).
TODO: We should fetch the old and new state of the namespace item in
stead of the old and new values of the item that changed.
If multiplicity is [0..1]:
send DerivedSet if len(union) < 2
if multiplicity is [*]:
send DerivedAdded and DerivedDeleted
if value not in derived union and
"""
if event.property not in self.subsets:
return
# Make sure unions are created again
self.version += 1
if not isinstance(event, AssociationUpdated):
return
values = self._union(event.element, exclude=event.property)
if self.upper == 1:
assert isinstance(event, AssociationSet)
old_value, new_value = event.old_value, event.new_value
# This is a [0..1] event
if not self.single:
new_values = set(values)
if new_value:
new_values.add(new_value)
if len(new_values) > 1:
# In an in-between state. Do not emit notifications
return
if values:
new_value = next(iter(values))
# Only one subset element, so pass the values on
self.handle(DerivedSet(event.element, self, old_value, new_value))
else:
if isinstance(event, AssociationSet):
old_value, new_value = event.old_value, event.new_value
if old_value and old_value not in values:
self.handle(DerivedDeleted(event.element, self, old_value))
if new_value and new_value not in values:
self.handle(DerivedAdded(event.element, self, new_value))
elif isinstance(event, AssociationAdded):
new_value = event.new_value
if new_value not in values:
self.handle(DerivedAdded(event.element, self, new_value))
elif isinstance(event, AssociationDeleted):
old_value = event.old_value
if old_value not in values:
self.handle(DerivedDeleted(event.element, self, old_value))
elif isinstance(event, AssociationUpdated):
self.handle(DerivedUpdated(event.element, self))
else:
log.error("Don't know how to handle event " + str(event) +
" for derived union")
def propagate(self, event):
"""
Re-emit state change for the derived properties as Derived*Event's.
TODO: We should fetch the old and new state of the namespace item in
stead of the old and new values of the item that changed.
If multiplicity is [0..1]:
send DerivedSet if len(union) < 2
if multiplicity is [*]:
send DerivedAdded and DerivedDeleted
if value not in derived union and
"""
if event.property in self.subsets:
if not isinstance(event, AssociationUpdated):
return
# mimic the events for Set/Add/Delete
if self.upper == 1:
# This is a [0..1] event
# TODO: This is an error: [0..*] associations may be used for updating [0..1] associations
# assert isinstance(
# event, AssociationSet
# ), f"Can only handle [0..1] set-events, not {event} for {event.element}"
old_value = self._get(event.element)
# Make sure unions are created again
self.version += 1
new_value = self._get(event.element)
if old_value != new_value:
self.handle(
DerivedSet(event.element, self, old_value, new_value))
else:
# Make sure unions are created again
self.version += 1
if isinstance(event, AssociationSet):
self.handle(
DerivedDeleted(event.element, self, event.old_value))
self.handle(
DerivedAdded(event.element, self, event.new_value))
elif isinstance(event, AssociationAdded):
self.handle(
DerivedAdded(event.element, self, event.new_value))
elif isinstance(event, AssociationDeleted):
self.handle(
DerivedDeleted(event.element, self, event.old_value))
elif isinstance(event, AssociationUpdated):
self.handle(DerivedUpdated(event.element, self))
else:
log.error("Don't know how to handle event " + str(event) +
" for derived union")