Message type modules

Messaging provides base classes, which defines the component interfaces for MTM implementations. The base classes also provide implementations of some methods. The interfaces allows MTM components to be used polymorphically. As part of these interfaces, User Interface, Client-side, and User Interface Data MTMs must all support a function that allows message client applications to query the supported functionality: for example, the maximum message size, or whether attachments are supported.

MTM components must also be able to offer protocol-specific functionality not provided by base class interface functions. A MTM component defines UIDs that correspond to each protocol-specific capability offered, and implements a function that allow clients to access these capabilities by passing in the appropriate UID. Two versions of this function are available, supporting synchronous and asynchronous behaviour respectively.