State diagrams. Master system behaviour.
What is a state diagram?
A state diagram is the graphical representation of a state machine and one of the 14 UML diagram types for software and systems. State diagrams show a behavioural model consisting of states, state transitions and actions. UML state diagrams are based on the concept of state diagrams by David Harel. State diagrams depict the permitted states and transitions as well as the events that effect these transitions.