Software design and architecture Lecture#4

Sequence diagrams Sequence diagrams are used to show a design team how objects in a program interact with each other to complete tasks Boxes lifelines Solid line arrows Dotted line arrows Small rectangles Actors

Example

Example(cont’d)

State diagrams technique used to describe how systems behave and respond. They follow the states of a system or a single object and show changes between the states as a series of events occur in the system. State Start Terminate Active State name Variables Activity

Transitions Arrows indicate transitions from one state to another. Transitions are typically triggered by an event. This event is generally described above the arrow. Event[condition]/action The transition and action happens from a given state if the event occurs and the condition is true.