Nested embeddable - AttributeOverride for embeddable within embeddable

Question

I have class Money which is an @Embeddable

@Embeddable
public class Money implements Serializable, Comparable<Money> {
    @Column(name = "amount", precision = 15, scale = 2)
    private BigDecimal amount;
}

When I useit multiple time inside entity, everything works fine. For example

@Entity
public class SomeEntity implements Serializable {

    @Embedded
    @AttributeOverride(name = "amount", column = @Column(name = "entry"))
    private Money entryValue;

    @Embedded
    @AttributeOverride(name = "amount", column = @Column(name = "leave"))
    private Money leaveValue;
}

Code above works perfectly.

Now the problem occurs when I have another @Embeddable that I want to have Money instances in it and that @Embeddable is used by an entity multiple times. Example:

1. Embeddable

   @Embeddable
   public class ReportCostValues implements Serializable {
   
       @Embedded
       @AttributeOverride(name = "amount", column = @Column(name = "covered_by_grant"))
       private Money coveredByGrant;
   
       @Embedded
       @AttributeOverride(name = "amount", column = @Column(name = "own_resources"))
       private Money foundedFromOwnResources;
   
       @Embedded
       @AttributeOverride(name = "amount", column = @Column(name = "personal_contribution"))
       private Money personalContribution;
   

2. Entity

    @Entity
    public class ReportCostEntity implements Identifiable<Long>, Serializable {
   
       @Id
       private Long id;
   
       @Embedded       
       private ReportCostValues contracted;
   
       @Embedded       
       private ReportCostValues current;
   
       @Embedded        
       private ReportCostValues previousReport;
   

This code above will not work. Any ideas how to approach this problem?

Answer 1

Hi you have to use @AttributeOverrides judicially,you have to override attributes once again in entity that you have done in embeddable ReportCostValues class, hope code below is what you are looking for.

@Entity 
public class ReportCostEntity implements  Serializable {

    @Id
    private Long id;

    @Embedded   
    @AttributeOverrides( {
        @AttributeOverride(name="coveredByGrant.amount", column = @Column(name="contracted_coveredByGrant") ),
        @AttributeOverride(name="foundedFromOwnResources.amount", column = @Column(name="contracted_foundedFromOwnResources")),
        @AttributeOverride(name="personalContribution.amount", column = @Column(name="contracted_personalContribution"))
    } )
    private ReportCostValues contracted;

    @Embedded
    @AttributeOverrides( {
        @AttributeOverride(name="coveredByGrant.amount", column = @Column(name="current_coveredByGrant") ),
        @AttributeOverride(name="foundedFromOwnResources.amount", column = @Column(name="current_foundedFromOwnResources")),
        @AttributeOverride(name="personalContribution.amount", column = @Column(name="current_personalContribution"))
    } )
    private ReportCostValues current;

    @Embedded 
    @AttributeOverrides( {
        @AttributeOverride(name="coveredByGrant.amount", column = @Column(name="previousReport_coveredByGrant") ),
        @AttributeOverride(name="foundedFromOwnResources.amount", column = @Column(name="previousReport_foundedFromOwnResources")),
        @AttributeOverride(name="personalContribution.amount", column = @Column(name="previousReport_personalContribution"))
    } )
    private ReportCostValues previousReport;




} 

Hope this helps !!!!!