Introduction

To learn Design patterns we should have knowledge in core java, Advance java (servlets, jsp and jdbc)

• it is purely related to application coding used more confident on experience.
• it is a methodology.

Architecture:

 The life of the project is dependent on design of the project.

• If we have a good design we can use the project for multiple years.
• if we use a good design on top of existing project we can construct/develop multiple other projects.
• The project architecture clearly tells us which component of the project is communicating with which other component of the other project.
• Sun Micro system has suggested two architectures/Design Patterns who develops the projects based on Java Software.

Design Patterns: (defn):

  Design pattern is set of rules which come as best solution for reoccuring problems of application development.
(or)
A design pattern is the best solution for repeatedly occured problems across multiple projects.

• Design patterns are best practices to use s/w technologyies and program languages effectively
• pattern means solution for problem.
• The worst solution for any problem is called ANTI PATTERN.
• ISO maintains the document of both design patterns and Anti patterns.
• For object oriented programming GOF (gang of Four) scientists have given 100 + design patterns and later they are standardised to 20+ patterns .
• we can find the design pattern documents in the internet
• These documents are prepared by the experienced persons who has worked in that area.
• Design patterns are independent of programming language
• the design patterns are not belongs to any specific language. We can use the Design patterns in every projects based on the requirements

Where do we use DAO design pattern