B2B Integration : A Practical Guide to Collaborative E-commerce

Middleware Technologies 237
applications and components. Some of the more popular CORBA
Services include:
• Naming Service — A directory service which allows clients to find
objects based on names, similar to the white pages of a telephone
book;
• Trading Service — A directory service which allows clients to find
objects based on their properties, similar to the yellow pages of a
telephone book;
• Event Service — Defines generic interfaces where supplier object
can input events and consumer objects can receive them;
• Notification Service — Adds event typing and filtering to the basic
event service; and
• Security Service — An interface for providing end-to-end security
over open channels.
There are also Object Service specifications for transactions,
messaging and licensing, as well as many others.
Horizontal CORBA facilities
CORBA facilities sit between the CORBA services and application
objects. CORBA facilities are application-level services that allow
developers to build component-based objects. An example of such a
facility is the Distributed Document Component Facility (DDCF), a
compound document common facility based on OpenDoc. Examples of
CORBA facilities include:
• Internationalization service;
• Secure time facility;
• Print facility; and
• Mobile agents facility.
CORBA domains
These interfaces fill roles similar to object services and common facilities
but are oriented towards specific industries. For example, one of the
first OMG RFPs issued for domain interfaces is for Product Data