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