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Understanding unified modelling language


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This slide give you a basic understanding of UML

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Understanding unified modelling language

  2. 2.  Introduction to Modelling What is UML? Building Blocks for UML ◦ Things, Relationships Types of UML Diagrams Identifying the Problem Domain ReferencesOUTLINES
  3. 3.  Because there is a limit to how much a person can understand at any one time, every complex system can be modelled Modelling is basically a way of expressing information or knowledge of a system by concentrating on the essentials Models help get an abstract idea of the object the software product consists of and their interactions Models are also: ◦ A means of understanding the problem involved in building something ◦ An aid in communication between those involved in the project(requirement analyst and the user) Modelling therefore provide these key benefits ◦ Visualization ◦ Complexity management ◦ And clear communicationWhat is Modelling?
  4. 4.  Because models are constructed to express your understanding of a particular system in expectation that the model will help you pass the understanding to others Choose a modelling language that is: ◦ Sufficiently expressive ◦ Easy enough to use In developing a software application according to the object oriented principles,UML has become an industry standard What is UML? ◦ UML stands for Unified Modelling Language and is a pictorial language use to make software blue prints ◦ UML can also be seen as a general purpose visual modelling language that helps you to :  Visualize  Specify  Construct  And document the artefacts of software systemWhat is UML?
  5. 5.  The basic building blocks of UML are ◦ Things and Relationships These are combined in different ways following different rules to create different types of diagrams Things are used to describe the different parts of a system. They can be: ◦ Structural ◦ Behavioural ◦ Annotational ◦ GroupingBasic Building Blocks
  6. 6.  Structural Things: These defines the static part of the model and represents the physical and conceptual elements Brief description of Structural Things ◦ Class: A set of objects that share the same attributes, operations, relationships and semantics. class  Symbol for a Class: Attributes ◦ Node: It describes a physical resource that exits in run time  Symbol : NodeStructural Things
  7. 7.  Interface: A set of operations which specify the responsibility of the class ◦ Symbol : Interface Collaboration: It defines the interaction between elements ◦ Symbol: Use Case: It describes a set of action a system performs that produces an observable result of value to a particular actor ◦ Symbol: usecase Component: It describes the physical and replaceable part that conforms to and provides realisation of a set if interface ◦ Symbol:
  8. 8.  Behavioural Things: These consist of the dynamic part of the UML model. They include: ◦ Interaction: It describes a set of messages exchanged among a set of objects within a particular context to accomplish a specific purpose  Symbol: ◦ State Machine: It specifies the sequence of state an object goes or interaction goes through during its lifetime in response to an event  Symbol: stateBehavioural Things
  9. 9.  Grouping Things can be defined as a mechanism to group elements of a UML model together ◦ Packages: Is a mechanism for organising elements into groups  Symbol: PackageGrouping Things
  10. 10.  Annotational Things can be defined as a mechanism to capture remarks, description and comments of a UML model elements ◦ Note: Is used to render comments,constraits etc of a UML element  Symbol :Annotational Things
  11. 11.  Relationship shows how the elements are associated with each other Relationship are used to connect things into well defined models (UML diagrams) ◦ TYPES OF RELATIONSHIPS Dependency: A semantic relationship between two things in which a change to one thing may affect the semantics of the dependent thing ◦ Symbol : ----- Association: A set of links that connects elements of an UML model ◦ Two Types : Aggregation and Composition ◦ Symbol:RELATIONSHIP
  12. 12.  Generalization: It is a relationship which connects a specialized element with a generalized element. It basically describes the inheritance relationship in the world of objects ◦ Symbol: Realization: It is a relationship in which two elements are connected. One element describes some responsibility which is not implemented and the other one implement them ◦ Symbol : --------Cont’d
  13. 13.  The output of all the above is a UML diagram All the Things and Relationships are used to make a complete UML diagram and the diagram represents the system. The various types of UML diagrams :  Class Diagram  Object Diagram  Use case Diagram  Sequence Diagram  Collaboration Diagram  Activity Diagram  Statechart Diagram  Deployment Diagram  Component DiagramUML DIAGRAMS
  14. 14.  Class Diagram : Static relationship between class; it shows how different entities ( people, things and data) relate to each other; in other words it shows the classes of the system, their interrelationship, and the attributes and operations of the classes Component Diagram: This provides a physical view of the system. Its purpose is to show the dependencies that the software has on other software components(e.g. software libraries) in the system Deployment Diagram: This shows the hardware for the system, the software that is installed on that hardware, and the middleware used to connect the disparate machines to one anotherUSES of UML DIAGRAMS
  15. 15.  Package Diagram: Simplify complex class diagrams by grouping them into packages( a collection of logically related UML elements) Use case Diagram: It helps you clarify what exactly the system is supposed to do. The main purpose of a use case diagram is to help development team visualize the functional requirements of the system, including the relationship of actors(human beings who will interact with the system) to essential processes, as well as relationship among different use cases State machine: It displays sequence of states that an object of an interaction goes through during its life in response to received stimuli, together with its responses and actionsDiagram cont’
  16. 16.  Activity Diagram: It shows the procedural flow of control between two or more class objects while processing an activity Object Diagram: It can be described as an instance of class diagram, and are useful for exploring real world examples of objects and the relationship between them Sequence Diagram: It shows how the object interacts with others in a particular scenario of a use case
  17. 17.  It should be pointed out that, in developing a system; there is a need to focus on the Problem Domain Problem Domain is simply looking at the topics you are interested in and excluding everything else. Hence each model will have their own problem domain For instance in coming up with a Class diagram, you need to write a problem domain class definition This will help you define all the possible Classes, attributes, methods and instances and their relationship Doing all this will enable you come out with a complete Class Diagram The same approached applies to other UML diagramsConclusion-Problem Domain
  18. 18.  Introduction UML,Mikael Akerholm,Ivica Crnkovic,Goran Mustapic verview.htm UML basic: An introduction to Unified Modelling language by Donald BellReferences