Sequence Diagram Objects

Actor

An external person, process or something interacting with a system, sub-system or class. See Actors (OOM).

Object

Instance of a class. See Objects (OOM).

Activation

Execution of a procedure, including the time it waits for nested procedures to execute. See Activations (OOM).

Interaction Reference

Reference to another sequence diagram. See Interaction References and Interaction Activities (OOM).

Interaction Fragment

Collection of associated messages. See Interaction Fragments (OOM).

Message

Communication that conveys information with the expectation that action will ensue. See Messages (OOM).

Self Message

Recursive message: the sender and the receiver are the same object. See Messages (OOM).

Procedure Call Message

Procedure call message with a default activation. See Messages (OOM).

Self Call Message

Procedure call recursive message with a default activation. See Messages (OOM).

Return Message

Specifies the end of a procedure. Generally associated with a Procedure Call, the Return message may be omitted as it is implicit at the end of an activation. See Messages (OOM).

Self Return Message

Recursive message with a Return control flow type. See Messages (OOM).