Collaboration diagrams are another means for representing the
interactions and relationships between objects. Unlike
sequence diagrams, however, they
do not focus on the timeline of interaction, but on the structural
connections between collaborating objects. Of central interest are the
messages and their intent, when creating a
collaboration diagram. The
chronological order of messages is represented by numbers preceding each
message.
Objects - In collaborations, objects
represent different roles - these are specified as Classifier
Roles in Poseidon for UML.
Associations - Associations illustrate the
connections between collaborating objects. Messages are then
placed along them.
Messages - Just like in sequence diagrams,
messages are used to describe the interaction between objects. The
numbers in front of the given names represent the chronological
order of messages. Using the corresponding buttons in the toolbar
of the Properties tab, you can specify an action
for the message, and you
can change the direction of the message
.