Java factory method example 2016-12-15 03:28
Factory method pattern is used to create different "product" when you overridden the create method in subclass. Your business logic code is handle the "product" which created by overridden method. The diagram of it is like following.
1. Factory
public abstract class Factory {
public String showProductName() {
// start your business logic code
Product product = createProduct();
return product.getProductName();
}
abstract Product createProduct();// override this method to create different product in subclass
}
public class ConcreteFactoryA extends Factory {
@Override
public Product createProduct() {
return new ProductA();
}
}
public class ConcreteFactoryB extends Factory {
@Override
public Product createProduct() {
return new ProductB();
}
}
2. Product
public interface Product {
String getProductName();
}
public class ProductA implements Product {
@Override
public String getProductName() {
return "this is productA";
}
}
public class ProductB implements Product {
@Override
public String getProductName() {
return "this is productB";
}
}
3. Client
public class Client {
public static void main(String[] args) {
Factory factory = new ConcreteFactoryA();
//Factory factory = new ConcreteFactoryB();
System.out.println(factory.showProductName());
}
}
The key of factory method pattern is overriding the method which create "product". Subclass don't care about the business logic, it's only responsible for creating different products. If you need another products just extend the Factory class and override the createProduct() method.