The activation bar represents the duration of execution of the message. In our diagram, the Hotel issues a self call to determine if a room is available. If so, then the Hotel creates a Reservation and a Confirmation . The diagram has a clarifying note , which is text inside a dog-eared rectangle. Notes can be put into any kind of UML diagram.
Collaboration diagrams Collaboration diagrams are also interaction diagrams.
They convey the same information as sequence diagrams, but they focus on object roles instead of the times that messages are sent. In a sequence diagram, object roles are the vertices and messages are the connecting links. Each message in a collaboration diagram has a sequence number . The top-level message is numbered 1. Statechart diagrams Objects have behaviors and state.