Actor: User Application

Goal: Cancel a sent message.

Description: Cancel a sent message.

Preconditions:

1. The engine must be started.
2. The message transmission is not complete.
3. The message to cancel must be valid.

None.

Priority: High

Related Use Cases:

UC18.0 - Send Peer Message
UC25.0 - Build Peer Message

Notes and Issues:

None

Event Flow:

1. The application asks the engine to cancel a message sent to a peer.
2. The engine cancels the message transmission
3. The engine removes the message from its in-progress list.

UC19.1 Engine is not started

1. The application asks the engine to cancel a sent message.
2. The engine returns an error that the it has not been started.

UC19.2 Message doesn't exist

1. The application asks the engine to cancel a sent message.
2. The engine returns an error that the message doesn't exist.

UC19.3 Message Already Set

1. The application asks the engine to cancel a sent message.
2. The engine returns an error that the engine has already sent the message.

Sequence Diagrams:

Revision History

Name	Date	Reason for Change	Version