[SFSB] Passivation question
Mikalai Zaikin
Ranch Hand
Posts: 3403
16
posted 13 years ago
Hello,
Specification says :
Instance variable of stateful session bean CAN hold reference to resource manager connection factory.
Does that means that DataSource instance variable will be handled by EJB container automatically during passivation/activation ?
Specification says :
Instance variable of stateful session bean CAN hold reference to resource manager connection factory.
Does that means that DataSource instance variable will be handled by EJB container automatically during passivation/activation ?
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Kathy Sierra
Cowgirl and Author
Rancher
Rancher
Posts: 1589
5
posted 13 years ago
Yes! That's exactly what it means!
On page 71 in the EJB 2.0 spec, you have a whole list of things that will be passivated automatically by the Container, without you worrying about it...
Here's a little summary, for example -- at the end of ejbPassivate(), your non-transient instance variables MUST be one of the following:
* null
* Serializable object
* a bean's Remote component interface
* a bean's Remote home interface
* a bean's local component interface
* a bean's local home interface
* a reference to a SessionContext
* a reference to the environment naming context (java:comp/env)
* a reference to a UserTransaction
* a reference to a DataSource (or other resource manager connection factory)
But... you must close other non-serializable resources like a JDBC connection.
And don't forget the warning about transient -- of course you should mark transient variables 'transient', but you should ALSO set them to null (or primitives to default values) before passivation, since there is no guarantee about how those variables will come back in activation (as opposed to pure Serialization, which guarantees that transient variables will come back with default values for that type).
cheers,
Kathy
On page 71 in the EJB 2.0 spec, you have a whole list of things that will be passivated automatically by the Container, without you worrying about it...
Here's a little summary, for example -- at the end of ejbPassivate(), your non-transient instance variables MUST be one of the following:
* null
* Serializable object
* a bean's Remote component interface
* a bean's Remote home interface
* a bean's local component interface
* a bean's local home interface
* a reference to a SessionContext
* a reference to the environment naming context (java:comp/env)
* a reference to a UserTransaction
* a reference to a DataSource (or other resource manager connection factory)
But... you must close other non-serializable resources like a JDBC connection.
And don't forget the warning about transient -- of course you should mark transient variables 'transient', but you should ALSO set them to null (or primitives to default values) before passivation, since there is no guarantee about how those variables will come back in activation (as opposed to pure Serialization, which guarantees that transient variables will come back with default values for that type).
cheers,
Kathy
