Overview of the "OOAD" OOAD

• What is object-oriented?

OOP: Object-oriented Programming (object Oriented Programming,oop, OO programming) is a computer programming architecture. One of the basic tenets of OOP is that a computer program is composed of a single unit or object that can act as a subroutine.
OOA: Object-oriented analytics (object-oriented analysis, OOA) is an approach to identifying requirements or business, and analyzing the business in terms of object-oriented thinking.
OOD: Object-oriented design (object-oriented Design,ood) method is an intermediate transition in Oo method. Its main role is to further standardize the results of OOA analysis so that it can be directly accepted by OOP.

If the traditional process programming language is process -centric and algorithm -driven, the object-oriented programming language is object -centric and message -driven. In the formula, the process programming language is: program = algorithm + data; object-oriented programming language: Program = object + Message .
Object-oriented is not a replacement for process-oriented.

• Why object-oriented?

Consistent with the way of thinking of human habits;
Good stability;
Reusability is good;
Easier to develop large-scale software products;
Maintainability is good.

• What is an object-oriented thinking method?

1, first determine who to do, and then determine how to do;
2, the first consideration of the whole, followed by partial;
3, first of all to consider the abstract, followed by specific;

• How should you learn to object-oriented?

1. Mastering an object-oriented language grammar;
2, grasp the object-oriented thinking mode;
3, familiar with object-oriented design principles;
4. Master object-oriented design mode

• Object

Object three elements: Object flags, properties, and services.
Object identifier, which is the name of the object, that uniquely identifies the object within the system.
Attribute (attribute), also known as State or data, is used to describe the static characteristics of an object.
Services (service), also called operations (operation), behaviors (behavior), or methods, are used to describe the dynamic characteristics of an object.
What is the object?
From a conceptual level, an object is an abstraction of a certain responsibility.
From a specification level, an object is a series of public interfaces that can be used by other objects.
From a language implementation level, objects encapsulate code and data.

An object contains three basic features, namely, object identity, object state, and object behavior.
Each object must have a name to distinguish it from other objects, which is the object identity; State is used to describe some of the characteristics of an object; object behavior is used to encapsulate the business operations owned by an object.
For example, for the teacher Bobby, including the gender, age, position and other personal status information, but also has the behavior characteristics of teaching, then Bobby is a typical object after encapsulation.

• Classes and instances

A class is an abstract collection of objects that have the same properties and functionality.
Instantiation: An instance is a real object
Instantiation is the process of creating an object, created using the New keyword.

A class is an abstraction of an object that is a concrete instance of a class.
The relationships of classes and objects can be summarized as:
1) Each object is an instance of a class.
2) Each class has 0 or more instances at a time.
3) classes are static, their existence, semantics, and relationships are defined before the program executes, objects are dynamic, and they can be created and deleted when the program executes.
4) class is the template that generates the object.

The class does not occupy memory, and the object occupies memory.
Format: Class Name Object name = new class name ();
Class: Stack memory
Object: Heap Memory (reference data type)
A class is an abstract concept, just a template, such as: "People".
object is a concrete entity that you can see and touch, such as "George W. Bush", "Obama"

• Ooad

Ooad is the process of analyzing and designing software systems according to OO methodology.
OOA Analysis Phase
OOD design Phase

Defining the Ood Phase
The design phase mainly addresses the following issues
How to solve a specific business problem
The supporting elements needed to bring the system to work
? Define the implementation strategy of the system
The core issue to be addressed at this stage is "how does?" ”

In the process of learning ooad and development of the project has some sentiment and ideas, sorting out and writing some learning materials, the end of the article gives the "Ooad and UML Things" directory index links and sample code download, limited capacity, some casual mistakes are unavoidable, here's friends, If you find any errors and improper, please timely feedback to me, which is the greatest support and encouragement.
"Ooad and UML" directory index
Http://www.cnblogs.com/Bobby0322/p/4178333.html

OOAD OOAD Overview