Modeling with UML

Use Case, Class, Sequence, Collaboration, State chart, Activity, Component and Deployment diagrams are used in UML. Describe each of the eight (8) main diagrams used in UML.

I refer to Wikipedia (2009) for the following descriptions.

Use Case diagram shows the functionality provided by a system in terms of actors, their goals represented as use cases, and any dependencies among those use cases.

Class diagram describes the structure of a system by showing the system's classes, their attributes, and the relationships among the classes.

Sequence diagram shows how objects communicate with each other in terms of a sequence of messages. Also indicates the lifespans of objects relative to those messages.

Collabration diagram displays an interaction organized around the objects and their links to one another. Numbers are used to show the sequence of messages.

State Chart diagram describes many systems, from computer programs to business processes with standardized notation.

Activity diagram represents the business and operational step-by-step workflows of components in a system. An activity diagram shows the overall flow of control.

Component diagram depicts how a software system is split up into components and shows the dependencies among these components.

Deployment diagram serves to model the hardware used in system implementations, and the execution environments and artifacts deployed on the hardware.

Use Case and Activity Diagrams help you to describe system functional requirements - it is important to note that the user may be a human or another software or hardware process. In either case it is referred to as an actor. Use Cases help with the problem of definition of requirements and analysis.

The following Use Case diagram shows a credit card processing system. The actors are the parties who interact with the system and the use cases are the functionalities of the system.

Actor: Customer, Shipping & Customer Service

Use Case: Update Order Staus, Update Inventory, View Outsatanding Orders, Get Product Information, Check Order Status, Add Product to Order Form, View Order Form, Place Order, Credit Card Rejected & Calculate Total.

Fig1. (Source: SmartDraw 2007 template)

The following Activity diagram shows the workflow of the Order Processing system. It starts with 'Place Order' and ends with 'Receive Order'.

Fig.2 ( Source: SmartDraw 2007 template)

Use a table (see below) to start your thinking, where business processes are taken from the SME and an object modelling table is used to help show development of your ideas, using very simple object modelling techniques. Here is a simple way to model your objects. Use the level 1 and 3 tables for designing any object in the e-business application:
Level 1 - User and system tasks table

Fig.3

Level 2 – Abstraction

The next step is called finding the level of abstraction, where the business objects build on each other to form classes from the most general and abstract – root class, to the more refined and concrete. What could be more concrete than an automatic telling machine (ATM)? Here the actor is human and the use case are withdraw cash; make a deposit; or request a balance.

Level 3 - Object description table

Use the level 3 table below to detail your design with the example used in object-oriented design.

Fig.4

Reference

Wikipedia 2009, Unified Modeling Language, Wikipedia, The free encyclopedia, last modified 15 June 2009, Wikimedia Foundation, Inc., US, viewed 17 June 2009, <http://en.wikipedia.org/wiki/Unified_Modeling_Language>.