ToOne<target> field is package-private ? Need to use getter / setter to work.

[GerritDeMeulder]

Basics

• ObjectBox version : 0.9.15
• Reproducibility: always

Reproducing the bug

Description

If you have data-models in one package and access them from another package,
and use a ToOne relation in an entity without explicit (and normally redundant) "public"
(since the entity itself is public + as in online documentation)
setTarget etc. don't work, since the ToOne field is package-private you need to explicitly declare "public" ToOne relation in an entity, to get "setTarget" to work.

Code

package com.objectboxtest.model;`
@Entity
public class User {
@Id
long id;

PUBLIC ToOne<Organization> organization;
...

then accessing :

package com.objectboxtest.activities;
...
organization1 = new Organization();
organization1.setName("Organization 1");
organizationsBox.put(organization1);
User user1 = new User();
user1.organization.setTarget(organization1);
....

-> works
Following :

package com.objectboxtest.model;
@Entity
public class User {

@Id
long id;
 
ToOne<Organization> organization;
...

then accessing

package com.objectboxtest.activities;
  ...
 organization1 = new Organization(); 
 organization1.setName("Organization 1");
 organizationsBox.put(organization1);
 User user1 = new User();
 user1.organization.setTarget(organization1);
 ....

-> does not work, organization for user 1 is not found, since it's not public

[greenrobot]

@GerritDeMeulder Just to be on the safe side here: in which file do you get a compile error? Is it generated by ObjectBox?

[DJafari]

@GerritDeMeulder it's normal, when you define a field as private, in outer package can not access to it, you can do it by :

@Entity
public class User {
	@Id Long id;
	ToOne<Organization> organization;

	public void setOrganization(Organization organization) {
		this.organization.setTarget(organization);
	}
}

User user1 = new User();
user1.setOrganization(organization1);

[GerritDeMeulder]

@greenrobot : it's not a compiler error, maybe more of a documentation issue
/ how to use in multiple package understanding issue ?
Android Studio already complains in the editor : it will not let you pick the user1.organisation. field, (that's at the ToOne side of the relation), in the activity package ( while all entities are declared in the model package) unless it's explicitly declared public.
If it should be package private, then I'm afraid that I don't understand how to access the "setTarget" method from another package, like in my example above?

@DJafari : I agree in theory, but disagree if I follow the documentation : normally fields are private and you access them with getters/setters, but to my understanding that's not how it should be used here, it's not a field but a relation, and the Objectbox relations documentation clearly states that this is the way to access this relation target entity :

Updating ToOne

The ToOne class offers the following methods to update the relation:

• setTarget(entity) makes the given entity (new or existing) the new relation target; pass null to clear the relation
• setTargetId(entityId) sets the relation to the given ID of an existing target entity; pass 0 (zero) to clear the relation

example:

order.customer.setTarget(customer); // or order.customer.setCustomerId(customer.getId());
orderBox.put(order);

So customer is the "ToOne field" directly accessed for the setTarget method in the example here.

[greenrobot]

@GerritDeMeulder If it's your code, can't you just provide a setter for the relation target? Something like this (for Customer class in the example):

public void setCustomer(Customer customer) {
    customer.setTarget(customer); // customer is a ToOne field
}

Let me know if we are not on track regarding your question.

[GerritDeMeulder]

Ok, @greenrobot I think I understand it now, seen your discussion with @DJafari about #145 : if it's not in the same package, you should just add the boilerplate code (getter / setter) for the relation.
I can live with that. Could this be updated in the documentation?

[lucassales2]

How to solve this in Kotlin? Example

@Entity
data class EntityA (
@Id
var id: Long = 0.toLong(),
var entityB: ToOne<EntityB>? = null)

The generated class cant access entityB

[greenrobot]

@lucassales2 Will try to reproduce and do a fix in 1.0.1 if required. Thanks!

[greenrobot]

@lucassales2 This is the same as #175 - right? Does the @JvmField workaround work for you?

[greenrobot]

I think we fixed everything in upcoming 1.0.1.

[greenrobot]

1.0.1 is published - please retest, thank you!

[lucassales2]

Error is gone! Its working now, thanks