Design Patterns an Overview

Design patterns are an expedient way of using objects between programs and applications. It is as simple as writing the code and listing common interactions that a programmer can use. Design patterns are known since early 1980s where C++ was still an infant and Smalltalk was the most common Object Oriented Language. Structured programming language was quite famous at that time, then the languages supporting OOPS started driving the technology from there on; where the frameworks concepts got in to the books. Frameworks concepts lead the way to design pattern. One of the widely used is MVC – Model View Controller; which has three parts Model or Data Model where computational part will be taken care, View where presentation related requirements will be served and Controller which delegates the request to the corresponding classes or methods. One of the main objectives of the Objective Oriented Methodologies is to keep objects separated without inter binding between Models.

Helm and Erich Gamma familiarize the Design patterns by incorporating in ET++, a GUI application framework. They joined with Johnson and Vlissides to publish the book on Design patterns “Elements of Reusable Software”, first book of its kind. This book commonly referred to as Gang of Four or GoF. Design patterns are classified into three in major, Creational patterns, Structural patterns and Behavioral patterns.

Creational Patterns are patterns that create objects for you, rather creating them directly. This gives your program the flexibility of deciding which object to be created. We can create different object for different cases without changing the code.

Structural patterns will help you to compose groups of objects to structures, which can be used in your system / program like complex interfaces and computation.

Behavioral patterns will help you to define the communication between objects in your system / program. This would be of greater help in controlling flow in a complex program.

Keep visiting, lots more to come in this heading and we are going to discuss each pattern in detail with examples in coming days. Kindly share your comments and views.