Accessing Base Project Entities (User Table) from an Add-on Project

Support
#1

Hi Team,
I’m working with a Jmix add-on architecture:

  • Base project containing User entity
  • Add-on projects need to access base entities (e.g., fetch first_name , last_name from User )

Specific questions :

  1. Standard way to access base entities from add-ons?
  2. Correct approach for cross-module entity access?
  3. Special considerations needed?

Environment : Jmix version 1.7.1

Looking for best practices or code examples. Thanks!

#2

Hi Team,

Just following up on this thread to check if there are any updates or guidance on the recommended approach for accessing base entities from Jmix add-ons.

Would appreciate any insights, best practices, or references when you get a chance.

#3

Any Answer???

#4

Hi,
You can utilize “inversion of control” programming pattern for your purpose.
That is, add-on shouldn’t depend on User entity. Instead, both add-on and target project should depend on other abstraction - on the interface that contains necessary methods.

  1. Create an interface in the add-on project, that should be implemented by User entity in any project working with this add-on. It should contain all necessary methods: getFirstName(), getLastName() and others. E.g. “AddonUser”.
  2. Implement this interface by the User entity in your base project.
  3. Use interface in the add-on where you need to access certain attributes of users. Cast types to this interface where necessary.
#5

Standard Approach: Use interface-based inversion of control:

// Add-on defines interface
public interface AddonUser {
String getFirstName();
String getLastName();
}

// Base project implements it
@Entity
public class User implements AddonUser {
// Existing getters satisfy interface
}

What if you want optional add-ons? :x: This interface approach won’t work because your base project won’t compile without the add-on dependency.

#6

Then you need to define some small mandatory core add-on, which is going to be included to every project.
It may define this interface and optionally some other common definitions.

Like jmix-core dependency which is present in every Jmix project.