1. Informática II Prof. Dr. Gustavo Patiño MJ 16- 18 05-09-2013

2. Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

3.  A model is a simplification of reality.  Main reason for developing models:  Understanding the system being developed.  We build models of complex systems because we can not comprehend such a system in its entirety. Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

4.  The choice of the model has a significant impact on how the problem is approached and how a solution is devised.  A model can be expressed at different levels of precision.  A good model is connected to reality.  A single model is not sufficient to represent most systems. ▪ A set of nearly independent models are required. Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

5.  Modeling is an essential part of all the disciplines in engineering, including software engineering.  The importance of having a “good” model increases with the complexity of the project. Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

6.  Software engineering is an engineering discipline.  A modeling technique suitable for the programming approach should be used.  Since object-oriented approach has proven to be superior to other approaches, models designed for this approach are widely used in software engineering. Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

7.  Objects are abstractions of real-world or system entities and manage themselves.  Objects are independent and encapsulate state and representation information. Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

8.  System functionality is expressed in terms of object services.  Shared data areas are eliminated. Objects communicate by message passing.  Objects may be distributed and may execute sequentially or in parallel. Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

9.  Easier maintenance.  Objects may be understood as stand-alone entities.  Objects are appropriate reusable components.  For some systems, there may be an obvious mapping from real world entities to system objects. Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

11.  OOA is concerned with developing an object model of the application domain.  OOD is concerned with developing an object- oriented system model to implement requirements.  OOP is concerned with realising an OOD using an OO programming language such as Java or C++. Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

12.  Object Orientation  Abstraction  Encapsulation  Modularity  Hierarchy Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

13.  A model that includes most important aspects of a given problem while ignoring less important details.  An example of an item purchasing abstraction. Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2 Counter Queue Item

14.  Hide implementation from clients  Clients depend on interface Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

15.  The breaking up of something complex into manageable pieces or modules Canteen System Queue Order Placement Delivery Billing Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

16.  Level of abstraction Increasing abstraction Decreasing Abstraction Art Music FilmsSculptures R&B RapSci-Fi Action Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

17.  Object  Class  Attributes  Operation  Interface (Polymorphism)  Components  Package  Subsystem  Relationships Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

18.  Informally, an object represents an entity, either physical, conceptual, or software  Physical entity  Conceptual entity  Software entity truck Chemical Process Linked List Data Structure Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

20.  An object is a concept, abstraction, or thing with sharp boundaries and meaning for an application  An object is something that has  State  Behavior  Identity Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

21.  The state of an object is one of the possible conditions in which an object may exist  The state of an object normally changes over time  Represented by: Attribute values + Links (relationship instances) Y.Welikala Name: Employee ID: Date hired: Status: Y.Welikala 567138 Oct 18, 2004 Teaching Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

22.  Behavior determines how an object acts and reacts to requests from other objects  Behavior is represented by the set of messages it can respond to (the operations the object can perform) Registration System Assign Y.Welikala (Returns: confirmation) CS 201 Course Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

23.  Each object has a unique identity, even if its state is identical to that of another object Y. Welikala Teaches OOP “Y.Welikala” Teaches OOP Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

24.  An object is represented as rectangles with underlined names : Lecturer Y.Welikala : Lecturer Class Name Only Class and Object Name Y.Welikala Object Name Only Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

25. Intro to OO 201 Algebra 110 Electricity 100 Algorithms 202 ThermalDynamics 110 Electronics 110 English 101 Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

26.  A class is a description of a group of objects with common properties (attributes), behavior (operations), relationships, and semantics.  An object is an instance of a class Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

27.  A class is an abstraction in that it:  Emphasizes relevant characteristics  Suppresses other characteristics Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

28. Class Course Properties Name Location Days offered Credit hours Start time End time Behavior Add a student Delete a student Get course roster Determine if it is full Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

29.  How many class can you see? Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

30.  A class is an abstract definition of an object  It defines the structure and behavior of each object in the class  It serves as a template for creating objects  Objects may be grouped into classes Lecturer Lecturer YohanLecturer ChinthanaLecturer Smith Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

31. Class Attribute CourseOffering number startTime endTime :CourseOffering Number=CS201 endTime=1230 startTime=1030 Object Attribute Value :CourseOffering Number=CS202 endTime=1500 startTime=1300 Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

32. CourseOffering addStudent deleteStudent getStartTime getEndTime Class Operation Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

33.  What are the game’s objects?  What do those objects know how to do?  What properties do they have? Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

34.  What are the game’s objects?  piece, board  Capabilities: What do those objects know how to do?  piece: ▪ be created ▪ fall ▪ rotate ▪ stop at collision Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2

35.  board: ▪ be created ▪ remove rows ▪ check for end of game  Properties: What attributes and components do they have?  piece: ▪ orientation ▪ Position ▪ shape ▪ color  board: ▪ size ▪ rows Informática II. Facultad de Ingeniería. Universidad de Antioquia. 2013-2