Question

I used to put everything in packages like this:

com.company.app.module1
com.company.app.module2

But it has made package-based AOP pointcuts difficult, and resulted in huge packages that need an IDE to make sense of.

So now I realize I need a deeper package structure, but I am constantly torn. Give modules preference, like this?

com.company.app.module1.domain
com.company.app.module1.logic
com.company.app.module1.persistence
com.company.app.module2.domain
com.company.app.module2.logic
com.company.app.module2.persistence

or give layers preference, like this?

com.company.app.domain.module1
com.company.app.domain.module2
com.company.app.logic.module1
com.company.app.logic.module2
com.company.app.persistence.module1
com.company.app.persistence.module2

Pros and cons of each?

Answer 1

Modules-first.

I had a project that was initially layer-first, but it became too bulky to read and maintain, so we refactored it. It used AOP as well – without any problems. We just used .. in the middle of the package definition (we used spring aop with aspectj syntax). Here’s how it looks like:

execution(* com.foo.app.modules..service..*.*(..))

This matches both modules.module1.service and modules.module2.service