What is the purpose of the Factory Method design pattern and how is it implemented?

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What is the purpose of the Factory Method design pattern and how is it implemented?

The purpose of the Factory Method design pattern is to provide an interface for creating objects, but allowing subclasses to decide which class to instantiate. It is used when there is a need to create multiple objects that share a common interface or superclass, but the specific class to be instantiated is determined at runtime.

The implementation of the Factory Method design pattern involves defining an abstract class or interface that declares the factory method. This factory method is responsible for creating and returning objects of the desired class. Subclasses of the abstract class or interface then implement the factory method to instantiate the specific class they want to create.

Here is a step-by-step implementation of the Factory Method design pattern:

1. Define an abstract class or interface that declares the factory method. This class or interface should also define a common interface or superclass for the objects to be created.

2. Create concrete classes that implement the common interface or extend the superclass. These classes represent the different types of objects that can be created.

3. Implement the factory method in the abstract class or interface. This method should return an object of the common interface or superclass.

4. Create subclasses of the abstract class or interface, each representing a specific implementation of the factory method. These subclasses override the factory method to instantiate and return the desired object.

5. In the client code, use the factory method to create objects without specifying their specific classes. This allows for flexibility and decoupling between the client code and the concrete classes.

By using the Factory Method design pattern, the client code can create objects without being tightly coupled to their specific classes. It provides a way to encapsulate object creation logic and allows for easy extension and modification of the object creation process.