Chapter 7: The Object-Oriented Approach to Requirements

Systems Analysis and Design in a Changing 7

7 The Unified Modeling Language and the Object Management Group  Object-oriented modeling notation is Unified Modeling Language (UML)  UML was presented to Object Management Group (OMG) as standard modeling technique  Purpose of Object Management Group  Promote theory and practice of object technology for development of distributed systems  Provide common architectural framework for OO Systems Analysis and Design in a Changing World, 3rd Edition 4

Object-Oriented Requirements  Systems development process starts with identification of events and things  Events are business processes that new system must address  Things are problem domain objects involved in business process 7 Systems Analysis and Design in a Changing World, 3rd Edition 5

Object-Oriented Approach Models  Class diagram – definition of system components  Use case diagrams and use case descriptions show user roles and how they use the system –  Systems sequence diagrams (SSDs) – define inputs and outputs and sequence of interactions between user and system for a use case  Statechart diagrams object – describe states of each  Activity diagrams – describe user activities 7 Systems Analysis and Design in a Changing World, 3rd Edition 6

Requirements Diagrams: Traditional and OO Models 7 Systems Analysis and Design in a Changing World, 3rd Edition 7

7 The System Activities – A Use Case / Scenario View  Use case analysis used to identify and define all business processes that system must support  Use Case - single function performed by system for those who use that function  Actors  Role played by user  Outside automation boundary and organization Systems Analysis and Design in a Changing World, 3rd Edition 8

Simple Use Case with an Actor 7 Systems Analysis and Design in a Changing World, 3rd Edition 10

Use Case Diagram with System Boundary 7 Systems Analysis and Design in a Changing World, 3rd Edition 11

Use Case of Customer Support System 7 Systems Analysis and Design in a Changing World, 3rd Edition 12

All Use Cases Including Customer 7 Systems Analysis and Design in a Changing World, 3rd Edition 13

Example of Order-Entry Subsystem with <> Use Cases (Figure 7-6) 7 <> Common Subroutines Systems Analysis and Design in a Changing World, 3rd Edition 15

7 Developing a Use Case Diagram  Starting points for use case development  Use event table  Identify all actors of the system  Identify functions actors perform with system  Develop flow of activities to identify various scenarios  Common internal use cases can be identified and separated into different use cases Systems Analysis and Design in a Changing World, 3rd Edition 16

Brief Description of

Create New Order

Use Case 7 Systems Analysis and Design in a Changing World, 3rd Edition 19

Intermediate Description of the Telephone Order Scenario for

Create New Order

7 Systems Analysis and Design in a Changing World, 3rd Edition 20

Intermediate Description of the Web Order Scenario for

Create New Order

7 Systems Analysis and Design in a Changing World, 3rd Edition 21

Fully Developed Description of Telephone Order Scenario for

Create New Order

7 Systems Analysis and Design in a Changing World, 3rd Edition 22

Fully Developed Description of Web Order Scenario for

Create New Order

7 Systems Analysis and Design in a Changing World, 3rd Edition 23

Activity Diagram: Telephone Order Scenario 7 Systems Analysis and Design in a Changing World, 3rd Edition 25

Activity Diagram: Web Order Scenario 7 Systems Analysis and Design in a Changing World, 3rd Edition 26

7 Problem Domain Modeling – The Domain Model Class Diagram  Class diagram is focal point of object-oriented development  Provides definition of system components  Contains important class structural information for implementation with object-oriented programming  Provides conceptual data model to describe classes for database definition  Consists of problem domain classes and implementation classes Systems Analysis and Design in a Changing World, 3rd Edition 37

RMO Domain Model Class Diagram 7 Systems Analysis and Design in a Changing World, 3rd Edition 39

Relationships Between OO Requirements Models 7 Systems Analysis and Design in a Changing World, 3rd Edition 41

Use Case Diagram for Inventory System 7 Systems Analysis and Design in a Changing World, 3rd Edition 42

Relationships Between OO Requirements Models (Figure 7-28) 7 Systems Analysis and Design in a Changing World, 3rd Edition 43