OOP And OOAD

 SOLID Object Oriented Principles

The Single Responsibility Principle

DEMO:  The Problem

In this class diagram, Rectangle class depends on GUI library package.  Same way Graphical Application and Geometry Service are using Rectangle Class.  If anything changes on GUI  will affect the Rectangle class, hence it should be compiled likewise Geometry services and Graphical Application should be compiled.

The problem in Business Implementation

Problem Analysis

Refactoring Better Design

The Open / Closed Principle

DEMO:  The Problem

The problem Analysis

Refactoring to a Better Design

Adding New rule easily

The Liskov Substitution Principle

Demo: The Problem

Refactoring to a Better Design

The Interface Segregation Principle

DEMO:  The problem

Problem 1:

Note:  In order to use Validate method inside of membership provider, we need to implement all other abstract base members which we do not use.

Problem 2:

Problem Analysis

Refactoring to a Better Design

Design Smells and Tips

The Dependency Inversion Principle

DEMO:The Problem

Refactoring to a Better Design

Design Smells

The Dependency Inversion Principle, Part 2

Traditional Programming

Refactoring Class Dependencies

First step is need to change the Static method to Instance method.

The Don't Repeat Yourself Principle, Part 1

Demo App and Analysis

Refactor Magic Strings

Refactoring Connection String

Refactoring Print Statements

Refactoring Magic Numbers

Refactoring Format Strings

Refactoring Duplicate Logic

Refactoring Repeated If-then Logic

Refactoring Conditional Polymorphism

The Don't Repeat Yourself Principle, Part 2

Test and Static Cling

Demo of Adding Integration Tests

Demo of Adding Unit Tests

Demo of MOCK Objects

Principles of Object Oriented Design - The Don't Repeat Yourself Principle, Part 3

Repeated Execution Pattern

Demo of Refactoring using Action of T

Demo of Refactor Data Access

Demo:  Find Duplicate Code – Atomiq

Code Generation

Repetition in process

Demo of Automation with MS Build

Dependency Inversion

Dependency Inversion

Introduction

Bob’s Copy Program Example

Copy program without DIP

If we add more Writing functionality then this program will become more difficult and complicated because it lots more depending on lower modules.

Copy program with DIP

Layering

Button/Lamp Example

In this button Lamp example, button is dependent on Lamp.  If you want to control the Lamp in some other way or Use that button in some other purpose then it is very difficult.  As this implementation is tightly coupled.

This below implementation is Loosely coupled, we could add more devices in that button if we implement below design.

Inversion of Control

Interface Inversion

Interfaces without Inversion of Control

If we use more Interfaces then it will create problem when we use that interfaces in Client or user level.  For example, if you want to make match between IKangaroo and MikeTyson, you have to know about Method inside of those interfaces.  Here low level Kangaroo class define its own interface.

Here the Client boxing Match is creating IBoxer interface, all the low lever classes should implement this.

Flow Inversion

Creation Inversion

Dependency Injection

Below picture represent the Class with have all of its dependencies together.  Basically it does not implement dependency inversion.

Below picture represent the Class will get all of its dependencies from someone else like caterers.

Constructor Injection

Setting Injection

Interface Injection

Building an IoC Container

Visualizing Container

Demo of Manual Dependency Injection

Resolving Dependencies

Building the Real IOC Container

Using Unity

What is Unity?

Setting up Unity

Registering

Using the Container

Overriding Parameter

Controlling Life Cycle of Container Objects

Singleton Style

Using Castle Windsor

Setting up the Castle Windsor

Registering

Using the Castle Windsor

Controlling the Life Cycle of object

Singleton

Non Singleton

Using Structure Map

Setting up the Structure Map

Registering

Using the Container

Controlling Life Cycle

Not Singleton

Singleton

Using Ninject

What is Ninject

Setting up Ninject

Registering

Using the Container

Controlling Life Cycle

Non Singleton

Singleton

Object Oriented Programming with C#

 Procedural code Approach

• It works top to bottom 

• Here all the business logic are inside the main procedure 

 Encapsulation approach

• Here procedural code needs to be broken up into multiple pieces with abstraction 

• In this approach gives experience driving car without knowing about how engine works.

Inheritance and Polymorphism

Inheritance is always problem in Software engineer when derived class inherits some base abstract classes.  In inheritance, we do not know who is calling whom, who will call the implemented method in derived class and so on.....

Interface Implementation



Interface plays important role when we face the situation where to derive multiple base classes.
This is perfect solution for all the inheritance problem which we faced before.

Directional Dependencies

Dependencies Point Out

Dependencies Point In