CODEWITHSUNDEEP
jpaejb-3.1glassfish-4
Alexander
Alexander

Reputation: 1

EJB Session beans/methods transaction attributes

I am became in charge EJB 3.1/JPA part of our project running on Glassfish 4.0. I am quite new to EJB and so not very confident in Session beans(and/or their methods) transaction attributes. I am dealing with stateless session beans. I read that NOT_SUPPORTED, NEVER, SUPPORTS transaction attributes should be used with caution because their behavior varies app server vendor. Actually, I could not find statements like that in other sources. Are they really vendor specific? Also, is that correct that not annotating method or bean defaults to REQUIRED transaction attribute for it?

And also here the situation. Let's I have transaction T and two stateless beans A and B with methods mA and mB. mA calls mB. What are the possible combinations for the transaction attributes of these methods so that the transaction T will go successfully? I know that if mA has REQUIRED and mB has NEVER the exception throw. Is SUPPORTS on mB good for any kind for incoming transaction - like a safe option to make sure any transaction will go through this method without error? Thank you

Upvotes: 0

Views: 267

Answers (1)

wypieprz
wypieprz

Reputation: 8219

GlassFish 4.0 is the reference implementation of Java EE 7 and according to the release notes it supports Enterprise JavaBeans 3.2 (JSR-345).

I read that NOT_SUPPORTED, NEVER, SUPPORTS transaction attributes should be used with caution because their behavior varies app server vendor. I could not find alerts in other sources rather than the one i mentioned. Please advice me If I should concerned about that.

Basically EJB specification says what to implement not how to implement thus there still may be some rare corner cases since we are not living in a perfect world. I suppose this is why you have been alerted. From the other hand I wouldn't concern about that as GlassFish is widely used across the world and it surely conforms the JSR specification.

Also, is that correct that not annotating method or bean defaults to REQUIRED transaction attribute?

Yes, this is correct. According to EJB 3.2 Specification, chapter 8.3.7 Specification of the Transaction Attributes for a Bean’s Methods:

By default, the value of the transaction attribute for a method of a
bean with container-managed transaction demarcation is the REQUIRED
transaction attribute, and the transaction attribute does not need to
be explicitly specified in this case.

Can you please advice a me source where I can find correct or in incorrect combinations of the transaction attributes on different methods of different EJBs in one call stack for one given transaction.

The ultimate source of knowledge is the mentioned EJB Specification (chapter 8.6 to be more specific) but you will find a lot of useful posts around. In general take a closer look at transaction propagation and transaction demarcation related topics.

Will SUPPORTS attribute adapt method/bean to a calling method/bean with whatever transaction attribute, so that no error will occur?

Not really. I would say SUPPORTS propagates a transaction context (if any) of a calling method/bean, so you may safely query data within but you should avoid operations that change the persistence context.

Upvotes: 0

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