Class, Sequence and UML Model

 Has actors and use cases

 Actors - entities whose behavior appears in the "Actor's Actions" column, *the entities whose behavior appears in the "System's Response" column are also actors  Use case - sequence of actions that provide something of measurable value to an actor

 circle

 A UML diagram that depicts: ◦ interactions between objects. ◦ how the business currently works by showing how various business objects interact.  Purpose: 1. Model flow of control 2. Identify synchronization 3. Illustrate typical scenarios

 The focus is less on messages themselves and more on the order in which messages occur.  The diagram conveys this information along 2 dimensions: ◦ the vertical dimension shows, top down, the time sequence of messages/calls as they occur, ◦ the horizontal dimension shows, left to right, the object instances that the messages are sent to.

 Example I

 read them from top to bottom.  As time increases, it depicts events happening in the system,  Also shows how various parts of the system react to each other.

 Purchase order

 Creating a new event in calendar

 These illustrate the dynamic nature of a system by modeling the flow of control from activity to activity.  An activity represents an operation on some class in the system that results in a change in the state of the system.

 depict the various states that an object may be in and the transitions between those states.

 Define states – condition or situation  Describe state – add more information on each state  Describe Transitions – join with arrows  Define transition triggers – define events  Define guard/Constraints – set constraints on the transition triggers

 State diagram for bank amount

 The Deployment Diagram helps to model the physical aspect of an Object-Oriented software system.  It models the run-time configuration in a static view and visualizes the distribution of components in an application.  Generally, it involves modeling the hardware configurations together with the software components that lived on.

 For a simple reservation system

 A Communication diagram models the interactions between objects or parts in terms of sequenced messages.  Communication diagrams represent a combination of information taken from Class, Sequence, and Use Case Diagrams describing both the static structure and dynamic behavior of a system.  Communication diagrams show which elements each one interacts with better, whereas, sequence diagrams show the order in which the interactions take place more clearly.