Communication diagram

The Collaboration Diagram is a diagram kind of the Unified Modeling Language (UML).

A Collaboration diagram models the interactions between objects in terms of sequenced messages. Collaboration diagrams represent a combination of information taken from Class, Sequence, and Use Case Diagrams describing both the static structure and dynamic behavior of a system.

Collaboration and sequence diagrams describe similar information, and as typically implemented, can be transformed into one another without difficulty.

However, collaboration diagrams use the free-form arrangement of objects and links as used in Object diagrams. In order to maintain the ordering of messages in such a free-form diagram, messages are labeled with a chronological number and placed near the link the message is sent over. Reading a Collaboration diagram involves starting at message 1.0, and following the messages from object to object.

In UML 2.0, the Collaboration diagram has been simplified and renamed the Communication diagram.