IS0514Slide 1 IS0514 Lecture - Week 1 (Semester 2) Business Systems Development Tools and Techniques

IS0514Slide 2 Learning Outcomes 6. Discuss an object-oriented development lifecycle and the role of UML techniques within it. 7. Explain fundamental principles of object-orientation as applied during analysis and design. 8. Specify system requirements in analysis by means of use cases and use case diagrams. 9. Identify classes in a domain and allocate responsibilities to them. 10. Interpret a realistic domain model in UML class diagram notation. 11. Use UML class diagram notation for simple modelling tasks such as producing a simple class diagram of domain concepts or extending/changing existing models.

IS0514Slide 3 Business Systems Development Tools and Techniques Semester 2 –Unified Modelling Language (UML) –Unified Process –Object Orientation –Use case Diagrams –Class Diagrams –CRC Cards

IS0514Slide 4 Assignments One assignment –Set Week 7 –Due 12/05/2008 Object Oriented Modelling Exercise

IS0514Slide 5 Module Team Module Tutor –Paula Brumby Team –Dr Akhtar AliRoom PB101Ext 3521 Please contact us at the seminar / lecture in the first instance Please see module tutor for admin issues

IS0514Slide 6 Today's Lecture What is modelling? Why model? Introduction to UML.

IS0514Slide 7 What is modelling? Information System Development is too complex to carry out in your head Analysis and design produce models In Information System Development, models are: –Abstract / None physical Software in non-tangible –Visible You wish to visualise non-tangible items

IS0514Slide 8 What is a model? Some definitions: A hypothetical description of a complex entity or process A simplified representation or description of a system under investigation The act of representing something A representation of some aspect of external reality in a program

IS0514Slide 9 Exercise 1 In groups of 3-4 spend 5 minutes discussing and identifying –Diagrams you have come across –What purpose they serve –Are they sufficient in themselves? At the end of that time you will be asked to share your thoughts with the rest of the group.

IS0514Slide 10 Exercise 1 – Possible Suggestions

IS0514Slide 11 Exercise 1 Also need –Data –Documentation Street signs Material information / craft skill –OK so how do I build this wall here? Organisation knowledge –What does a managing director do? Technical information –Is this in Java? –Is the database oracle or access?

IS0514Slide 12 Aims of modelling Aims in modelling : 1.helps visualise the system as it is, or as we want it to be 2.permits the specification of the structure and behaviour of the system 3.provides a template which guides construction of the system 4.documents the decisions that have been made 5.provides a common language for all stakeholders 6.facilitates clarity and understanding

IS0514Slide 13 Principles of modelling What is modelled affects: –How problems are attacked? –How the solution is shaped? Every model may be expressed at different levels of –Detail – amount modelled –Precision – how much information supplied The best models are connected to reality No single model is sufficient. –non-trivial system is best approached through a small set of nearly independent models –we need several model types representing different views Each model has different diagram(s) – we need several diagrams to model different views

IS0514Slide 14 Object Oriented Modelling In systems, there are two main ways to approach modelling: –Structured – focuses on processing, data and time aspects – separate but related decompositions of these –Object Oriented – based on objects and classes object – a “thing” of interest, which has uniqueness, state and behaviour (i.e. processing & data) class – description of a group of objects We are looking at Object-oriented modelling in this module

IS0514Slide 15 Why Model? A model is a simplification of reality –Choose details to represent –Choose details to ignore A model can evolve as our understanding does A model can represent real and abstract things Creating models allow a system to be better understood A model can be used to communicate ideas The larger the system the more important the models A model can be used to simulate a real system A model is quicker and easier to build than a real system!

IS0514Slide 16 Exercise 2 In groups of 3-4 spend 5 minutes discussing models you have come across –What is the difference between a diagram and a model At the end of that time you will be asked to share your thoughts with the rest of the group.

IS0514Slide 17 Exercise 2 - Answer

IS0514Slide 18 Brief History of Modelling tools Up to late 1980s –Structured System Analysis and Design (SSADM) / Yourdon / etc –Focus upon processes and data Late 1980s-1997 –Rise of Object Oriented Technologies –Useful / disparate – need for standardisation 1995 – now –Unified Modelling Language (UML)

IS0514Slide 19 Why UML? Best practice model –Consolidation of other languages (e.g., OMT, OOSE) Internationally accepted – ISO standard - ISO/IEC UK government mandate –e-Government Interoperability Framework (e-GIF) Intuitive Tool support Widely Used

IS0514Slide 20 Use of UML Surveys of development managers show –20% of organisations use UML on all development projects –59% of organisations use UML on some development projects –18% of organisations never use UML –3% of organisations have used UML in the past and have no plans to use it again –(Skidmore S (2004))

IS0514Slide 21 Introducing the Unified Modelling Language (UML) UML is a language for –visualising communication complexity –specifying models which are precise, unambiguous and complete –constructing maps to a programming language like C++, JAVA –documentation

IS0514Slide 22 Where UML is used? banking and financial systems telecommunications transportation and distribution defence and aerospace retail medical electronics scientific systems distributed web-based services business modelling government computer industry

IS0514Slide 23 Diagrams / Models In UML a model is a collection of diagrams which describe a system from different views Need to check –Consistency –Completeness – show all that is required –Simplicity of representation –Hierarchical representation Different diagrams showing different amounts of detail

IS0514Slide 24 UML in this module use case modelling – for requirements identification/analysis of candidate objects class diagrams – for specifying classes & relationships Class, Responsibility, Collaboration (CRC) cards – for responsibilities & interactions

IS0514Slide 25 This weeks reading SUPPORTING READING Dennis A, Wixom B, and Tegarden D (2005) System Analysis and Design with UML version 2 second edition, Wiley – Pages Bennett S., McRobb, S. and Farmer, R. (2002) Object- Oriented Systems Analysis and Design using UML, 2 nd Edition, McGraw-Hill – Chapter 5 CRaG Systems (2004) A UML Introduction Tutorial –Available at: –Accessed 27/01/2008 Priestley M. (2003) Practical object-oriented design with UML, 2 nd Edition, McGraw-Hill – Chapter 1

IS0514Slide 26 Summary What is modelling Why modelling Introduction to UML Next Week –Best Practice Development Methodology