• model the interactions between objects in some behaviour
  • visualize the interaction behaviour of the system in the context of objects
  • describe the message flow in the system
  • used to look at behaviour of the system within a single use case
  • modelled with 2 diagrams
    • collaboration/communication
    • sequence

Communication Diagram

Sequence Diagram

Sequence DiagramCommunication Diagram
Show the sequence or ordering of the messageFocus on links and organization of objects
Large set of detailed notationsFewer notation options
Consumes horizontal spaceRequire less space
Difficult during brainstormingEasy & flexible to draw during brainstorming
Message order is depicted clearlyDifficult to see the sequence of messages