1. Sequence Diagram
A Sequence diagram is an interaction diagram that shows how processes operate with one another and in what order. It is a construct of a Message Sequence Chart. A sequence diagram shows object interactions arranged in time sequence. It depicts the objects and classes involved in the scenario and the sequence of messages exchanged between the objects needed to carry out the functionality of the scenario. Sequence diagrams are typically associated with use case realizations in the Logical View of the system under development. Sequence diagrams are sometimes called event diagrams or event scenarios.
A sequence diagram shows, as parallel vertical lines (lifelines), different processes or objects that live simultaneously, and, as horizontal arrows, the messages exchanged between them, in the order in which they occur. This allows the specification of simple run time scenarios in a graphical manner.
Sequence diagram of e-mail message sequence
2. Decision Diagram
A Decision diagrams or decision tree is a decision support tool that uses a tree-like graph or model of decisions and their possible consequences, including chance event outcomes, resource costs, and utility.
Decision Diagram
3. Loop or Iteration Diagram
Not indicated in this diagram for clarity is the fact that when a Stop Iteration is raised in the
iteration method, the callback function and the state update are still performed before exiting the loop.
Loop or Iteration Diagram
