In other words, subclasses are responsible to create the instance of the class. A Factory Pattern or Factory Method Pattern says that just define an interface or abstract class for creating an object but let the subclasses decide which class to instantiate. Factory Method Pattern. Identification: Factory methods can be recognized by creation methods, which create objects from concrete classes, but return them as objects of abstract type or interface. Let us understand with an example: Overview of Example It defines a method that we can use to create an object instead of using its constructor. Download sample - 1.1 KB; Overview. All the shapes are derived from an abstract shape class (or interface). The static factory method described in Usage examples: The Factory Method pattern is widely used in C++ code. Usage examples: The Factory Method pattern is widely used in C# code. Factory Method Design Pattern Intent. Factory Pattern: An Example. This type of design pattern comes under creational pattern as this pattern provides one of the best ways to create an object. The Factory method is a creational design pattern that provides an interface for creating objects without specifying their concrete classes. Recently, I found a use for it in a project I was working on and since I found it useful for my purposes, I thought I might share a tutorial on how the Factory pattern can be used in C++. The idea is to use a static member-function (static factory method) which creates & returns instances, hiding the details of … Factory Method lets a class defer instantiation to subclasses. This driver class demonstrates how to get different types of dogs from the factory: If I quote Joshua Bloch: “a static factory method is not the same as the Factory Method pattern from Design Patterns [Gamma95, p. 107]. The new operator considered harmful. Define an interface for creating an object, but let subclasses decide which class to instantiate. It’s very useful when you need to provide a high level of flexibility for your code. The problem with the given examples of factory method patterns is that they are static factory methods. This factory is also called as factory of factories. The Java Factory pattern example driver program. Up until now, I never really used the Factory pattern that often in C++. Simple Factory Pattern is a Factory class in its simplest form (In comparison to Factory Method Pattern or Abstract Factory Pattern). Please read our previous article where we discussed the Factory Design Pattern in C# with one real-time example. Now that I’ve created my dog factory, the Dog interface, and all of the dog sub-types, I’ll create a “driver” program named JavaFactoryPatternExample to test the Dog factory. Applicability & Examples. Abstract Factory patterns work around a super-factory which creates other factories. In another way, we can say: In simple factory pattern, we have a factory class which has a method that returns different types of object based on given input. A factory class ShapeFactory is defined as the next step. Identification: Factory methods can be recognized by creation methods, which create objects from concrete classes, but return them as objects of abstract type or interface. It’s very useful when you need to provide a high level of flexibility for your code. I am going to create a Shape interface as well as concrete classes implementing the Shape interface. Problem Defining a "virtual" constructor. Probably the factory pattern is one of the most used patterns. In our implementation the drawing framework is the client and the shapes are the products. In Factory pattern, we create object without exposing the creation logic to client and the client use the same common interface to create new type of object. In this article, I am going to discuss the Factory Method Design Pattern in C# with an example. Factory Method Design Pattern in C# with Real-time Example. For example a graphical application works with shapes.