Introduction to UML Hazleen Aris Software Eng. Dept., College of IT, UNITEN. …Unified Modeling Language

What is UML? UML is a language for: Visualising Specifying Constructing Documenting UML is NOT a visual programming language.

What is it for? Describing a system at a high level of abstraction A model of the system Used for requirements and specifications

Why UML? Use graphical notation to communicate more clearly than natural language (imprecise) and code (too detailed). Help acquire an overall view of a system. UML is not dependent on any one language or technology. UML moves us from fragmentation to standardization.

Its Use? In software-intensive areas like: Enterprise information system Banking and financial Telecommunications Transportation Defense and aerospace Retail Medical electronics Scientific Distributed web-based services

Its Use? … However, it is expressive enough to model non-software systems.

The History

The History …

Standard: Its Importance

Software Development Life Cycle

Vocabulary of UML The vocabulary of the UML comprises three kinds of building blocks: Things Relationships Diagrams

The Things Structural things The nouns of UML models. Behavioural things The verbs of the models. Grouping things The organisational parts of the models. Annotational things The explanatory parts of the models.

Structural Things (1 of 7) Use case A description of a set of sequence of actions that a system performs that yields an observable result of value to a particular actor.

Structural Things (2 of 7) Collaboration A collaboration defines an interaction and is a society of roles and other elements that work together to provide some cooperative behaviour that is bigger than the sum of all the elements.

Structural Things (3 of 7) Class A description of a set of objects that share the same attributes, operations, relationships and semantics.

Structural Things (4 of 7) Interface A collection of operations that specify a service of a class or component.

Structural Things (5 of 7) Active class A class whose objects own one or more processes or threads and therefore can initiate control activity.

Structural Things (6 of 7) Component A physical and replaceable part of a system than conforms to and provides the realisation of a set of interfaces.

Structural Things (7 of 7) Node A physical element that exists at run time and represents a computational resource, generally having at least some memory and, often, processing capability.

Behavioural Things (1 of 2) Interaction A behaviour that comprises a set of messages exchanged among a set of objects within a particular contact to accomplish a specific purpose. display

Behavioural Things (2 of 2) State machine A behaviour that specifies the sequences of states an object or interaction goes through during its lifetime in response to events, together with its responses to those events.

Grouping Things (1 of 1) Package A general purpose mechanism for organising elements into groups.

Annotational Things (1 of 1) Note A symbol for rendering constraints and comments attached to an element or a collection of elements.

The Relationships There are four kinds of relationships in UML: Dependency Association Generalisation Realisation

Dependency A semantic relationship between two things in which a change to one thing may affect the semantics of the other thing.

Association A structural relationship that describes a set of links, a link being a connection among objects.

Generalisation A specialisation/generalisation relationship in which objects of the specialised element (the child) are substitutable for objects of the generalised element (the parent).

Realisation A semantic relationship between classifiers, wherein one classifier specifies a contract that another classifier guarantees to carry out.

The Diagrams Use case diagram Class diagram Object diagram Sequence diagram Collaboration diagram State diagram Activity diagram Component diagram Deployment diagram

The Diagrams … Class diagram Object diagram Component diagram Deployment diagram Use case diagram Sequence diagram Collaboration diagram State diagram Activity diagram static dynamic

The Diagrams … Class diagram* Object diagram Component diagram Deployment diagram Use case diagram* Sequence diagram* Collaboration diagram* State diagram* Activity diagram

Summary Introduction to UML What? Why? History Basics of UML Notations Relationships Diagrams