Mike Perico

I was reading the example found at: https://dev.liferay.com/develop/tutorials/-/knowledge_base/7-1/customizing-liferay-services-service-wrappers. 
Right in the first paragraph it explains that you can use servicewrappers if you have added a new field to User. Unfortunately it does not go into detail on how to add a new field to User. I know we can add expando fields, but I rather not use them.

I would like to create my own table for persisting my new data. Is this possible?

I think it was possible in 6.0 to create a hook on model entities, but it doesn't seem possible to do that now. If I wanted to add about 8 fields to User how would I go about doing this? Is there an example?

The basic rule is: You can't change an implementation's interface.

The sentence that you're referring to is

Perhaps you’ve added a new field to Liferay’s User object and you want its value to be saved whenever the addUser or updateUser methods of Liferay’s API are called.

You can add fields to any of Liferay's entity by using "Expando" (their API name) or Custom Fields (their UI name). But changing the interface would not work, as it would invalidate all other plugins (e.g. servicewrappers) that are not aware of the new methods. This applies to services as well as to entities.

Olaf,

Is it possible (recommended) to create an osgi module that will hook UserImpl in someway? I don't want to change the User interface, but can I add methods to UserImpl that can link together a new model entity with the existing User entity?

Olaf,

 Would it be possible to create a serviceBuilder module for say, Employee, that would contain my custom fields. Inside the module create a ModelWrapper (let's name it UserModelWrapper) for User that would add employee.

@Component(
    immediate = true,
    property = {
    },
    service = ModelWrapper.class
)
public class UserModelWrapper extends UserWrapper {

    /**
     *
     */
    private static final long serialVersionUID = 1L;

    @Reference
    EmployeeLocalService employeeLocalService;

    @Activate
    void activate() throws Exception {
        System.out.println("Activating " + this.getClass().getSimpleName());
    }

    public UserModelWrapper() {
            super(null);
    }
    
    private Employee employee;

    public Employee getEmployee() {
            return employee;
    }

    public void setEmployee(Employee _employee) {
            this.employee = _employee;
    }

}

Then would need to create a wrapper for UserLocalService to update all the CRUD methods to add my new Employee object to the User? If so, would I have to override the current methods or can I create new method signaures, as example.

    public com.liferay.portal.kernel.model.User addUser(User user) {

        employeeLocalService.addEmployee(user.getEmployee());
        return userLocalService.addUser(user);
    }

or would I need to do this:

    public UserModelWrapper addUser(UserModelWrapper user) {
        employeeLocalService.addEmployee(user.getEmployee());
        try {
            getWrappedService().addUser(getWrappedService().getUser(user.getUserId()));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return user;
    }

Olaf,

 Thank You.