Using Design Patterns to Build a Framework for Multimedia Networking

By: J.A. van den Broecke, J.O. Coplien
Published in: BLTJ, Winter 1997
Pages: 166-187
Category: Multimedia

Experience with MediaBuilder, a framework for networked multimedia applications, to build a conferencing application that adapts to different multimedia and network standards.

Related patterns: Builder [Gamma+95], Command [Gamma+95], Facade [Gamma+95], Layers, Observer [Gamma+95],

Pattern: Parties & Media as First Class Citizens

Have each session maintain the parties and media in the session. Use a third object to maintain the state for each party associated with the medium. Parties and media thus become first class citizens in a session.

Pattern: Pluggable Factory

Create objects from a repository. When a client requests an object from the repository, a reseller object can instantiate a class in the repository by name. Clients can also query the repository for a list of class names.

• This pattern is an extension of Factory Method [Gamma+95] and Abstract Factory [Gamma+95]

Pattern: Session Control & Observation

Control and maintain the state of a networked multimedia session, and notify those interested in that state.

• Session state uses Parties & Media as First Class Citizens. Command [Gamma+95] controls the session state; Builder [Gamma+95] realizes a session context local to the application.
• This pattern is a specialization of Model-View-Controller