What is the best way to safely update hibernate entity?

Question

First to explain the context. I have backend Java (Spring/Hibernate) application that I access via JMS. I have client app (RESTfull) that I access via Url. I have a complex entity with more than one list (most of it are lazy) and this entity is composition of xy other entities.

Problem: Since I access it via URL, I create Java object in client app from URL parameters. I'm sending it to backend via JMS, but on the backEnd, I do not have Hibernate object, so I cant simple merge it.

I can go trough all that came from client like:

• get hibernate object by id
• check what is different
• set new values
• update

and repeat it for every composition entity, but I'm wondering if there is more elegant and "easy to maintain" way to update this entity with all changes.

I hope I explained it well. Thanks in advance!

Answer 1

From your description it seem the steps you follow are right. The first(get object) and last(update object) steps are inevitable. The only place where you can optimize is the checking/setting part. For that you can write a generalized method which accepts two objects and compares them for changes using Reflection. This way it can be reused again.

Here is a sample code using reflection. Change it to suit your need