Question

I would like my other classes to interact with my domain’s interfaces rather than implementation, and i would like to avoid hardcoding the implementation in the code, such as this example :

public void addToMyList(String s, int i) {
  DomainModel model = new DefaultDomainModelImpl(); // it's hardcoding the implementation here
  model.setName(s).setAge(i);
  myList.add(model);
}

If i use spring container, with the prototype scope, i can use something like :

// <bean id="myDomainBean" scope="prototype" class="my.package.domain.MyDomainImpl" />
DomainModel myDomainModel = springContext.getBean("myDomainBean"); 

But i would like to avoid accessing springContext explicitly in my code.

I wonder what’s the clean way to do this ?

Im currently thinking of creating a factory implementation for each domain implementation, and autowire the factory to create the beans, but that means different implementations of my domain will have different implementations of the factory also.

Please share your opinions, thank you !

Answer 1

Im currently thinking of creating a factory implementation for each domain implementation, and autowire the factory to create the beans, but that means different implementations of my domain will have different implementations of the factory also.

That is not 100% correct. You can have a factory that take the Interface (class) of the Domain objects that needs to be create. You can inject that factory in you class.
So you will get all the requriements you asked for:

• no hard coded new
• the domain object code has no dependence to spring
• you only have one factory class and one factory method.

example

@Inject
MyStrangeSpringHiddingFactory myStrangeSpringHiddingFactory;

DomainModel myDomainModel = this.myStrangeSpringHiddingFactory.
                            createInstanceOf(DomainModel.class); 


class MyStrangeSpringHiddingFactory implements MyStrangeSpringHiddingFactory {
   @Inject
   ApplicationContext springContext:

   public <T> createInstanceOf(Class<T> clazz) {
      return springContext.getBean(clazz); 
   }
}

This are only my thoughts, because I do not know your use case: Do you really need such in abstraction? Do you really have a domain model where a domain class have several subclasses that need a factory.