Hello
I don't know if it's the right place to post but hope to hear some
answer to my question.
I'm building the simple application using NetBeans 6.
I've created Enterprise Project.
I've created one entity called product with two fields product_id,
product_name.
I indicated that product_name should be unique.
I've created one stateless session bean with a business method called
createProduct that accepts productName as a parameter, creates Product
entity instance and simply calls EntityManager.persist();
I'm calling this method from a web application that uses Visual Java
Server Faces Framework.
When I'm creating a product with some name everything works fine and
updated table is displayed to the user. The problem is that if user
tries to create a product that already exists, I should notify him about
this.
So I created DuplicateEntityException business Exception class and I'm
throwing it from my business method located in Stateless session bean.
But in order to throw that exception I should catch another one that's
thrown after calling em.persist();
I found out that em.persist() throws exception when I'm creating already
existing product but that exception is thrown in the Web layer. If I
call em.flush(); after em.persist() that exception is thrown in my
stateless session bean method.
The question is: Is it "correct" to call em.flush() to achieve such
functionality. If it's not "correct" is there any other "correct" way of
doing this?
Thank you.
--
Vano Beridze
Software Developer
Silk Road Group