The javax.ejb.TransactionAttribute annotation (@TransactionAttribute) can be applied to a bean class or it's methods.
Usage of the @TransactionAttribute requires you to specify on of six different transaction attribute types defined via the javax.ejb.TransactionAttributeType enum.
- TransactionAttributeType.MANDATORY
- TransactionAttributeType.REQUIRED
- TransactionAttributeType.REQUIRES_NEW
- TransactionAttributeType.SUPPORTS
- TransactionAttributeType.NOT_SUPPORTED
- TransactionAttributeType.NEVER
Per EJB 3.0 the default transaction attribute for all EJB 3.0 applications is REQUIRED. The default transaction attribute for EJB 2.1, 2.0 and 1.1 applications is vendor specific. In OpenEJB EJB 2.1, 2.0 and 1.1 applications also use REQUIRED as the default.
Attribute Types summary
A simplistic way to visualize the transaction attributes is as follows.
|
Failing |
Correcting |
No Change |
|---|---|---|---|
Transacted |
MANDATORY |
REQUIRED, REQUIRES_NEW |
SUPPORTS |
Not Transacted |
NEVER |
NOT_SUPPORTED |
SUPPORTS |
MANDATORY
A MANDATORY method is guaranteed to always be executed in a transaction. However, it's the caller's job to take care of suppling the transaction. If the caller attempts to invoke the method outside of a transaction, then the container will block the call and throw them an exception.
REQUIRED
A REQUIRED method is guaranteed to always be executed in a transaction. If the caller attempts to invoke the method outside of a transaction, the container will start a transaction, execute the method, then commit the transaction.
REQUIRES_NEW
A REQUIRES_NEW method is guaranteed to always be executed in a transaction. If the caller attempts to invoke the method inside or outside of a transaction, the container will still start a transaction, execute the method, then commit the transaction. Any transaction the caller may have in progress will be suspended before the method execution then resumed afterward.
NEVER
A NEVER method is guaranteed to never be executed in a transaction. However, it's the caller's job to ensure there is no transaction. If the caller attempts to invoke the method inside of a transaction, then the container will block the call and throw them an exception.
NOT_SUPPORTED
A NOT_SUPPORTED method is guaranteed to never be executed in a transaction. If the caller attempts to invoke the method inside of a transaction, the container will suspend the caller's transaction, execute the method, then resume the caller's transaction.
SUPPORTS
A SUPPORTS method is guaranteed to adopt the exact transactional state of the caller. These methods can be invoked by caller's inside or outside of a transaction. The container will do nothing to change that state.