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Java

Posted by azimjon karimov
azimjon karimov
9,004 Points

Making our model video. Why you made two DAOs?

Couldn't quite get what is going on there. Would be better if this explained more in details. what is the role of courseIdeaDAO, simpleCourseIdeaDAO? Little confusing.

1 Answer

Alexander Nikiforov
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Alexander Nikiforov
Java Web Development Techdegree Graduate 22,175 Points
Alexander Nikiforov
.a{fill-rule:evenodd;}techdegree seal-36
Alexander Nikiforov
Java Web Development Techdegree Graduate 22,175 Points

I agree, in later courses like 'Spring Data Rest' he'll switch to Spring Convention:

CourseDao -> CourseDaoImpl

This was we know what is interface, and what is the implementation.

The roles... ? Well

One is the interface and other is the implementation. That is it. We always use interface, so that later on we can be flexible and change the implementations, without changing a lot of code of our Application.

Trying to be Object-Oriented Programmers...

Does that sound more helpful ?

azimjon karimov
azimjon karimov
9,004 Points

Thanks, Alexander. I got that one of them is interface and other implementation, but the whole concept is very loosely taking place in my mind. I wanted to have some concrete explanation. I wanted to get this once and forever. So, basically we could use just one class but that would disable us from changing data provider if we wanted in the future. Is that correct?

Alexander Nikiforov
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Alexander Nikiforov
Java Web Development Techdegree Graduate 22,175 Points

So, basically we could use just one class but that would disable us from changing data provider if we wanted in the future. Is that correct?

Yes.In fact it is a very bad practice. And I know that when big companies that software architects to check the architecture of the big Java and other Obj, Oriented languages, those people check for such things (i.e. using Implementation without interface) and report as errors.