Inheritance/class Abstraction/interfaces - xml vs old and known Pojo's OOP.

[ray.frid]

Hi All,

I am doing my current project on Spring and I have debate.

Right now I am in the stage of writing the interfaces and the abstraction level.

I am used to write those classes in the old fasion as we all know( declase java class as abstract/interface):

public abstract class Superclass implements SuperInterface
{ ...}

I saw in Spring that you can also declare an abstraction via xml.

<bean id="Superclass " abstract="true">
		... />
	</bean>

and then initiate it this way:

<bean id="MyClass " parent="Superclass " 
	    class="com.spring">
		..
	</bean>

Same goes for overriding methods.

I find it little confusing.

what would be the cons and pros of doing it the xml way or the old an fasion way or mybe I should mix them? but when it will be good/effective to do so?


Thanks,
ray.

[Marten Deinum]

An abstract bean declaration has NOTHING to do with an abstract base class. The abstract bean declaration can even be without a class attribute (I suggest you read the reference guide chapter 3), an abstract bean definition is just a placeholder for common properties which can be attached to other beans (like a sessionfactory on daos but they don't have to share the same parent class).

Also if you should or shouldn't use interfaces ask 10 developers and get 12 answers. I like interfaces for services, for repositories/daos I generally leave them (sometimes I just use the sessionofactory/entitymanager in my service layer why create an additional layer which only does a pass through to save/delete, for complex queries I tend to use the repositories).


In short abstract bean declaration and abstract classes have no relation and one should not seek a relation between them.

[ray.frid]

Gotcha, thanks. hope you could reply to my other post as well
thanks again.