Communication Paradigms - Connect

Subscription Models (continued)
Content-based
Generalization of topic-based allowing the expression of
subscriptions over a range of fields in an event notification.
The filter is a query defined in terms of compositions of
constraints over the values of event attributes
Significantly more expressive but with significant new
challenges introduced in terms of implementation
Type-based
Intrinsically linked with (typed) object-based approaches
Subscriptions defined in terms of this type (signature/ methods/
attributes), with matching defined in terms of types or subtypes
of the given filter
Can be integrated elegantly into programming languages and
can also check type correctness of subscriptions.
Adv. Dist. Systems G. Blair/ F. Taiani 40