Builder Design Pattern

Builder pattern builds a complex object by using a step by step approach. Builder interface defines the steps to build the final object

Builder 

• This is an interface which is used to define all the steps to create a product 
• E.g. IVehicleBuilder

ConcreteBuilder

•  This is a class which implements the Builder interface to create complex product. 
• E.g. HeroBuilder & HondaBuilder

Product

• This is a class which defines the parts of the complex object which are to be generated by the builder interface.
• E.g. Vehicle

Director

• This is a class which is used to construct an object using the Builder interface.
• E.g. Vehicle Creator

When to use it?

• Need to create an object in several steps (a step by step approach).
• The creation of objects should be independent from the way the object's parts are assembled.
• Runtime control over the creation process is required.

http://www.dotnet-tricks.com/Tutorial/designpatterns/6aMR040613-Builder-Design-Pattern---C