[aspectj-users] How to advise setters in JPA entities using AOP?

[Eric B <ebenzacar@xxxxxxxxx>]

I've posted this question on StackOverflow (http://stackoverflow.com/q/24786391/827480), but am sending it here as well as not everyone monitors StackOverflow.

 have the need to log any changes to fields in an entity - whether it is a String change, or addition/deletion to a collection/map.

Given a JPA entity with a bunch of primitive fields, it is fairly trivial to write an pointcut that will intercept any set(..) methods on the fields.

However, where I am stuck is how to write the pointcut to handle Collections/Sets/Embedded/etc.

Given the following entity:

@Entity
public class Provider implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private Long id;


    private String name;

    @Column(name="type", nullable=false)
    @Enumerated(EnumType.STRING)
    private ProviderType providerType;


    @ManyToMany
    private List<Contact> contacts;

    @Embedded
    private Validity validity;

   // setters and getters omitted for brevity

}

where Contact is a simple entity with a bunch of primitive fields and Validity is a non-entity object with some primitive fields.

The following pointcut will intercept all set() methods in the class:

pointcut fieldSetter() : set(!static !final !transient * *.Provider) && args(val) && target(o);

to which I can write a before/after/around advice.

before( Object val, Object o) : fieldSetter{
  String fieldName = thisJoinPointStaticPart.getSignature().getName();
  System.out.println( "Object being changed: " + o.toString() );
  System.out.println( "New Value for: " + fieldname + " is: " + v.toString() );
}

But how do I handle that case for an Embedded object or a Collection? For an Embedded object, if I just put my advice around the setter method in the object, how do I know which is the parent object that is actually being modified/persisted?

And in the case of collections/sets/maps/etc, how do I advise against the add/remove methods? What I need to end up doing is advising the getCollection().add() methods as well as the getCollection.remove() methods. But I can't seem to figure out a good way.

Thanks,

Eric