Question

Sometimes you have a huge entity with numerous fields and it would be nice to split up the entity into separate classes to handle the complexity.

Say I have a table Foo with columns

someStuff, aThingBlah, aThingEtc, bThingWhatever, bThingBacon

and this class (annotations left out)

class Foo {
  String someStuff;
  String aThingBlah;
  String aThingEtc;
  String bThingWhatever;
  String bThingBacon;
}

I’d like to refactor this (without changing the db table) to

class Foo {
  String someStuff;
  AThing aThing;
  BThing bThing;
}
class AThing {
  String blah;
  String etc;
}
class BThing {
  String whatever;
  String bacon;
}

Is it possible to do this and how?

Answer 1

Here’s the basics…

class Foo {

  String someStuff;

  @Embedded
  @AttributeOverrides({
     @AttributeOverride( name = "blah", column = @Column(name="aThingBlah") ),
     ...
  })
  AThing aThing;

};

@Embeddable
class AThing {

  @Column(...)
  String blah;

}