Lecture#1 Introducing Modeling and Unified Modeling Language

Objectives:

• To understand what is Modeling and why it is important
• To know what is UML?
• To understand the purpose of Use Case Model
  Model:
  Model is a simplification of reality
  Example: When you go to buy a bungalow, you are shown a model bungalow and/or a plan (layout) of rooms etc. These are examples of model through which you are given an idea of how the model bungalow will look like and whether it meets your requirement or not.
  Modeling:
  The process of developing models is known as modeling
  Why we Model ?
  Modeling is done so that we can comprehend complex system and we can focus on particular aspects of the system
  Modeling Language:
  A modeling language provides notation as well as guidance regarding how these notations can be used to exhibit various aspects of the system. Using these notations and recommendations people can model useful views of the system
  Points to Remember
  • A single model can never be sufficient for a system that is not simple. For example when we go to purchase a house in a housing scheme that is about to be constructed, we are shown the floor plans of house so that we are informed about various aspects of house that we can understand. The floor plan includes information about the number of rooms, their arrangement, size, position of windows.
  However that’s not the only diagram/plan created. There are other plan/diagrams which explain the position of beams and columns (pillar) whose audience is the contractor. There may be other diagrams that explain the layout of electric and plumbing lines
  • Models should be drawn with different levels of precision, i.e. An initial model may explain the high level details where as a detailed version may be available for identifying low level details.
  For example an international bank may have a diagram that highlights the countries in which its branches are present. As the next level of detail, the bank may have diagrams for individual countries that highlight the cities of a particular country in which the branches are present. Finally, another level of detail may include a diagram that identifies the areas of a particular city in which branches
  • If the modeling is done properly and carefully then there are high chances that the system will be developed
  Importance of Standardized Modeling Language
  The importance of modeling was strongly felt by the industry when software solutions started becoming complex. Complexity of software required them to be modeled properly and in addition to this the development of software began to involve a number of roles. Thus the need for effective communication between these roles arose.
  Initially these needs were fulfilled by modeling languages that were not standardized i.e. Every vendor used a different set of notations to model artifacts of software. The problem in this approach was that the artifacts were not understandable by everyone and people outside the vendor organization found it very difficult to understand those models properly
  Unified Modeling Language
  UML is a language for visualizing, specifying, constructing and documenting the artifacts of a software intensive system.
  It is called unified, because three writers Booch, Rumbaugh and Jacobsons and countless other in the OO industry have created Unified Modeling language by merging all previous work and standardized to be accepted by everyone.
  UML Diagrams
  Structural Diagrams
  • Class Diagram
  • Use Case Diagram
  • Component Diagram
  • Deployment Diagram
  • Package Diagram
  Dynamic Diagrams
  • State
  • Activity
  • Interaction
  o Sequence
  o Collaboration