Difference between Dependency Injection and Factory Pattern.

SpringObject Oriented ProgrammingProgramming

Factory and Dependency injection both are the design pattern which can be used to enhance loose coupling abilities between the software components. 

Factory design pattern is used to create objects. But, injection and life cycle management of the object should be handled by programmer within the application. There is no way to configure everything in a single place. Therefore, programmers need to call object creation logic wherever it needed which eventually hinder the loose coupling abilities.

In DI design pattern, creation of object, injecting of the instance and life cycle management of the instance can be handled outside the code. In spring, Instantiation ,Injection and Lifecycle management are handled by IOC container.

Sr. No.KeyFactory design patternDI design pattern
1
Object Creation
It is used to create objects. We have separate Factory class which contains creation logic. 
It is responsible for creation and injection of the object.  
2
State Of the Object 
It is responsible for creation of stateful objects. 
It is responsible to create stateless objects 
3
Runtime /Compile time
Create object at compile time
Configure objects at runtime
4
Code Change
In case of change in business requirements, object creation logic may be changed.
No code change required
5
M echanism   
Class is dependent on factory method which in turn have dependency on concrete classes 
Parent object and all dependent object can be created at single location

Example of Factory pattern

static class PizzaFactory{
   public Pizza buildPizza(String pizzaType){
      ........

      Pizza pizza= //create pizza based on type
      return pizza;
   }
}
static void Main(){
   Pizza pizza = PizzaFactory.buildPizza("Greek style");
}

Example of Dependency Injection

public class CustomerExample {
   public Address address
   public CustomerExample(Address address) {
      this.address = address;
   }
}
public class Address {
   ..............
}
raja
Published on 09-Sep-2020 12:22:05
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