Design Patterns

hi,

Factory

Define an interface for creating an object but let subclasses decide which class to instantiate.

This means that an abstract Creator class defines an abstract create method (or provides a default create method) which returns an abstract Product.
A ConcreteCreator class implements the abstract create method to return a ConcreteProduct. This enables the Creator to defer Product creation to a subclass.
Factory Method is often used in the Abstract Factory pattern to implement the create methods

Pros

* shields clients from concrete classes

*the Creator create method can be coded to return a default Product

  

cons
* coding a new Product means writing two classes
* one for the concrete Product and one for the concrete Creator
* static 

* inheritance based

Abstract Factory:

Provide an interface for creating families of related or dependent objects without specifying their concrete classes

This means that a family of abstract create methods are grouped in an AbstractFactory interface.
ConcreteFactory implementations implement the abstract create methods to
produce ConcreteProducts.

Pros.
* shields clients from concrete classes
* easy to switch product family at runtime
* just change concrete factory
* keep it in the family
* enforces product family grouping

Cons.
* adding a new product means changing factory interface + all concrete actories

hope this help.

Hi Muthu,

Difference between factory and abstract factory:

http://c2.com/cgi/wiki?AbstractFactoryVsFactoryMethod
http://objectmix.com/object/10922-difference-between-factory-abstract-factory.html

If you want to know all the patterns then

http://www.dofactory.com/Patterns/Patterns.aspx

There's a post in this thread which explains it well:

http://stackoverflow.com/questions/6409926/factory-vs-abstract-factory-design-pattern