Design Object Oriented Solutions Object Oriented Analysis Design

Design Object Oriented Solutions Object Oriented Analysis & Design Lecturer: Mr. Mohammed Elhajj (Mhajj@aou. edu. lb) 1

Basic Object-Oriented Concepts n n n Object/Class/Message Encapsulation Interfaces Inheritance Polymorphism 2

Structured Programming Approach n n Basic, Pascal and C are examples of structured programming languages The structured Programming Approach is based on the Functional Decomposition procedure n n To solve a problem, identify the different steps of the solution and then design/code each step separately Programs in these languages consists of a set of “operational elements” n E. g. Procedures, Functions, Operations, Methods, etc 3

Database approach n n A Database model consists of “data elements”, known as “data objects” Each “Data Object” is characterised by a set of attributes or properties However, no operations are assigned to the “Data Objects” A similar concepts can be found in “structured programming”: Structures is a collection of data with no operations. 4

Object-Oriented Approach n n C++, JAVA, C# are object-oriented programming languages Objects are the elements in these languages. They have both data (properties, attributes) and behaviour (functions, operations, methods) So, the OO approach can be assumed as combination of the database and the structured programming ones OO approach is more realistic, closer to our interpretation of the world 5

Object Oriented Modelling n n n A system consists of objects Objects interact by exchanging messages Each object is the instance of a general category: class Objects have data & behaviour Data & behaviour of an object may or may not be accessible by other objects Classes are organised in hierarchical trees 6

Benefits of OOAD n n Modelling is closer to the human interpretation of the world Easy to extend Easy to test Easy to reuse 7

Developing Object Oriented Solutions Introduction to UML Lecturer: Mr. Mohammed Elhajj (Mhajj@aou. edu. lb) 8

Some UML sources 9

Learning outcomes of this session n Scope & History of UML n Software Development Processes n Review of UML diagrams 10

UML questions n What is UML? n What UML is not? n Why do we need UML? 11

What is UML? The Unified Modelling language (UML) n is a graphical language for n n n visualising specifying constructing documenting applies to n n n software systems businness modelling non-software systems 12

What UML is not? n It is not a software development process. n It is not a visual programming language. n It is not a software modelling tool. 13

Why do we need UML? 14

Why do we need UML? n To establish a common language among the people of the software development community. n UML is independent on the process, the programming language and the software tool. 15

UML History n n n Object Oriented Programming Languages (mid ’ 60 s till today) Method Wars (Early ’ 90 s) UML 0. 8 (1995), UML 1. 0 (1996) by Three Amigos UML (1. 1 -1. 5) managed by OMG (19972003) UML 2. 0 (2004 -today) 16

Software Development Processes n n n Waterfall Model Spiral Model Unified Process Rational Unified Process and many more… 17

Waterfall Model 18

Spiral Model 19

Unified Process: Iterative-Incremental 20

UML Summary n n n n n Use Case Diagram Class Diagram Sequence Diagram Collaboration Diagram State Diagram Activity Diagram Package Diagram Component Diagram Deployment Diagram }Interaction Diagrams }Physical Diagrams 21

System Views n Use Case View n n Static View n n n Use Case Diagram Class Diagram Package Diagram Component Diagram … Dynamic View n n n Sequence Diagram Collaboration Diagram Activity Diagram State Diagram … 22

Summary n n n UML is a graphical modelling language used mainly for Object Oriented Systems UML is not a software development process. Many software development processes use the UML diagrams, e. g. the Unified Process The current version is UML 2. 0 UML provides a wide range of diagrams Different diagrams are used to represent different system views 23