Does Grails / GORM permit relationships in separate java packages? - grails

Question

Grails 3 application -- I've been having trouble with a hasMany property in Grails not populating. I just realized that the owning class is in a different package from the owned class. Am I doing something silly by relating across package boundaries?
Basic example of what I'm doing and observing, in case that doesn't make sense:
Owning Domain Class:
package com.example.project
import com.example.project.configuration.ConfigFile
class MotherClass {
String name
static hasMany = [ configFiles: ConfigFile ]
}
Owned Domain Class:
package com.example.project.configuration
import com.example.project.*
class ConfigFile {
String name
MotherClass motherClass
}
In Bootstrap.groovy:
MotherClass motherClass = new MotherClass(name:"mother").save(failOnError: true)
new ConfigFile(name: "file1", motherClass: mother).save(failOnError: true)
new ConfigFile(name: "file1", motherClass: mother).save(failOnError: true)
assert motherClass.configFiles.size() > 0 #this assertion would fail
In a random service:
assert MotherClass.findByName("mother").configFiles.size() > 0 #this would fail too.
My assertion fails may be caused by some other issue I'm experiencing, but I wanted to verify that crossing package boundaries wasn't to blame.

Answer 1

If you didn't make a mistake in typing above, you are defining a 'motherClass' object but in ConfigFiles setting the motherClass to a 'mother' object.
I assume that's not the case - then, I think you are not providing Grails with enough information about the owner-child relationship.
Typically you would add the children to the owner class and save the owner class and let the saves cascade to children.
MotherClass mother = new MotherClass(name:"mother")
mother.addToConfigFiles(new ConfigFile(name: "file1", motherClass: mother))
mother.addToConfigFiles(new ConfigFile(name: "file1", motherClass: mother))
mother.save(failOnError: true)
And ideally you should have belongsTo clause on the ConfigFile side - otherwise the deletes won't be cascaded. see: http://docs.grails.org/3.1.1/ref/Domain%20Classes/belongsTo.html

Answer 2

The failure of the assertion in BootStrap.groovy makes sense because GORM populates associated, hasMany, sets when an entity is loaded into the Hibernate session. But in this example, GORM won't automatically search the session and add a newly persisted entity into the hasMany sets of its owning entity.
Try the assertion from the other side.
assert ConfigFile.findAllByMotherClass(motherClass)
I know that doesn't solve your problem, but hopefully it points you int the right direction.