How to Extend a Parameterized Factory Method in Java?

How can I extend a parameterized factory method in Java?

// Example of a parameterized factory method in Java
public class ProductFactory {
    public static Product createProduct(String type) {
        switch (type) {
            case "A": return new ProductA();
            case "B": return new ProductB();
            default: throw new IllegalArgumentException("Unknown product type");
        }
    }
}

Extending a parameterized factory method in Java involves creating new product types or modifying the factory logic to accommodate more complex construction processes. This adds flexibility and adheres to design principles such as the Open/Closed Principle from SOLID design principles.

// Extended factory method example
public class ExtendedProductFactory extends ProductFactory {
    public static Product createProduct(String type, String customization) {
        Product product = createProduct(type);
        product.customize(customization);
        return product;
    }
}

Causes

• Need to introduce new product types without modifying existing factory code.
• Desire to integrate additional parameters into the factory methods for further customization.

Solutions

• Create sub-factories for new product types that extend from the original factory. This preserves the original method while allowing for new functionalities.
• Use design patterns like Factory Method or Abstract Factory to manage the creation of products more dynamically.
• Override or add methods in subclasses to handle the creation of more complex products with additional parameters.

Mistake: Not maintaining separation of concerns by adding too much logic to the factory method.

Solution: Keep factory methods focused solely on object creation. Use separate classes for customization and additional logic.

Mistake: Failing to handle exceptions appropriately when extending factory methods.

Solution: Ensure that all types are validated, and appropriate exceptions are thrown for invalid parameters.