Introduction to Object Oriented PDF

Introduction to Object Oriented B Y CHA ITAT TA R A S O MB AT Contents The Importance of Modeling Principle of Modeling Object Oriented Modeling The Importance of Modeling A model is a simplification of reality. A model provides the blueprints of system. Every system may be described f...

Introduction to Object Oriented B Y CHA ITAT TA R A S O MB AT Contents The Importance of Modeling Principle of Modeling Object Oriented Modeling The Importance of Modeling A model is a simplification of reality. A model provides the blueprints of system. Every system may be described from different aspects using different models. A model may be structural, emphasizing the organization of the system, or it may be behavioral, emphasizing the dynamics of the system. The Importance of Modeling (cont.) Through modeling, we achieve four aims. 1. Models help us to visualize a system as it is or as we want it to be. 2. Models permit us to specify the structure or behavior of a system. 3. Models give us a template that guides us in constructing a system. 4. Models document the decisions we have made. Principle of Modeling 1. The choice of what models to create has a profound influence on how a problem is attacked and how a solution is shaped. 2. Every model may be expressed at different levels of precision. 3. The best models are connected to reality. 4. No single model or view is sufficient. Every nontrivial system is best approached through a small set of nearly independent models with multiple viewpoints. Object Oriented Modeling In software, there are several ways to approach a model. an algorithmic perspective, the main building block of all software is the procedure or function. an object oriented perspective, the main building block of all software systems is the object or class. an object is a thing, generally drawn from the vocabulary of the problem space or the solution space a class is a description of a set of common objects. Object Oriented Modeling (cont.) For example, consider a simple three tier architecture for a billing system. In the user interface, you will find concrete objects, such as buttons, menus, and dialog boxes. In the database, you will find concrete objects, such as tables representing entities from the problem domain, including customers, products, and orders. In the middle layer, you will find objects such as transactions and business rules, as well as higher level views of problem entities, such as customers, products, and orders. Object Oriented Modeling (cont.) Visualizing , Specifying, Constructing, and Documenting object oriented systems is exactly the purpose of the Unified Modeling Language (UML). More questions about this Lecture Note?