When to use SDO (Service Data Object) in SOA

Question

I joined a new team that intensively use SDOs. The concept is new to me but I understand that it is used for unified view of data. I'm used to accessing the Java persistence entities on the service via DAO's and I find the additional SDO layer a bit heavy. Can you give real life scenario where you successfully used SDOs? Thank you in advance.

Answer 1

Note: I'm the EclipseLink SDO lead and a member of the SDO (JSR-235) expert group.

An SDO DataObject is definitely heavier than a corresponding POJO. Some advantages of SDOs are the following:

1. Model can be entirely dynamic, no need for a static model. The generation of static interfaces are optional.
2. There is a very rich metamodel wrt Type and Property vs regular reflection in Java.
3. When ChangeSummary is used you have a built in mechanism for tracking changes.
4. Data can be queried by path not just property name.