Understanding Unified Modeling Language (UML): An Overview of Its Concepts and Applications

1. Unified Modeling Language(UML)BY Touseef Tahir Touseeftahir@ciitlahore.edu.pk Lecturer CS COMSATS Institute of Information Technology, Lahore

2. Overview • Introduction • History • Goals • Diagrams and Examples • Latest Changes • Disadvantages • Conclusion

3. What is UML? • Unified Modeling Language (UML) is a standard language for specifying, visualizing, constructing software artifacts. • Not necessarily restricted to software systems – used in business modeling. • Has proven successful in modeling of large and complex systems. • Uses graphical notations to describe the architecture of software.

4. Goals • Provide users a expressive, visual language to enable sharing of meaningful models. • Enables developers to compare models before implementation phase. • Independent of programming language and development process. • Encourage growth of Object Oriented Tools market.

5. History • First modeling languages – 1970’s. • More than 50 modeling languages present during 1994. Lead to “method wars”. • Methods began to incorporate each other’s techniques. • In 1994, Grady Booch and Jim Rumbaugh (Rational Software Corporation) unified Booch and Object Modeling Technique methods to create UML. • Ivar Jacobson incorporated the OOSE method in 1995, leading to UML version 0.9 in late 1996.

6. UML Versions • UML 1.0 was created through a collaboration of various organizations: Microsoft, IBM, HP, etc. • Today, UML is on Version 2.0. • It is managed by the Object Management Group – not for profit consortium. UML specification is available for download at http://www.uml.org/ • Tools that conform the latest 2.0 specification – Rational Software Architect, Sparx System Architect, Star UML, etc.

7. Types of UML diagrams

8. Class Diagram

9. Class diagram • Abstraction • Inheritance • Polymorphism • Encapsulation • Message Sending • Associations • Multiplicity • Aggregation

10. Class diagram

11. Inheritance • Generalization in UML

12. Inheritance (Cont..)

13. Aggregation • Two types of Association • Part-whole association • Composition

14. Aggregation • Part-whole association • Multiplicity

15. Aggregation • Multiplicity

16. Aggregation • Composition • A strong type of aggregation. Each component in composite can belong to just one whole. • The Diamond shape used for composition is same but its just filled.

17. Package • UML Packages are a grouping of objects into sets of objects that provide related services. The package has responsibilities that are strongly related. • Coupling & cohesion

18. Stereotype and comments

19. Generalization

20. State Diagrams

21. State Diagrams • State diagram • Behavior of systems • Finite number of states • Components of state diagram

22. State diagram • An object’s state and behaviour can be affected by: • Changes to attribute values • Results of operations • Changes of links with other objects • Internal events • External events

23. Three models • Object model: • Static structure of objects in a system and their relationships. • Contains class diagrams. • dynamic model; • describes aspects that change over time: state transition diagrams • functional model; • Use Case diagrams

24. State and Events • A state is an abstraction of the attribute. Sets of values are grouped together into a state according to properties that affect the gross behaviour of the object. • A change of state is called a transition

25. Event classes • Event occurrences are grouped into event classes • Flight 123 departs from Chicago / Flight 456 departs from Rome • Event class is Flight Departs • Attributes of event classes • Departure origin of flight • Flight number • destination • Data values are Attributes

26. Event Classes and Attributes • Aeroplane flight departs (airline, flight no, city) • Mouse button pushed (button, location) • Input string entered (text) • phone receiver lifted( True, False) • digit dialled (digit) • engine speed enters danger zone

27. Events • Something that happens at a point in time • Mouse button clicked / Signal changes • Logically ordered events - causally related • Concurrent events - causally unrelated • do not effect each other • there is no order between them • 1-way transmission of information from one object to another

28. Characterisations of a state • State: Alarm ringing • Description: alarm on watch is ringing to indicate target time • Event sequence that produces the state: • set alarm (target time) • any sequence not including clear alarm • current time = target time

29. How to make state diagram • Identify states and identify which variables identify states • Identify events • Create state chart • Create state table with all finite stated and event

30. Example

31. ExampLe

32. State Transition Diagram