CODEWITHSUNDEEP
javajpatransactionsejb-3.0
Muhammad Hewedy
Muhammad Hewedy

Reputation: 30058

looking up entity manager in EJB Helper classes

I am trying to inject entity manager in some helper class, I can pass it to the helper from the session bean, but the problem is I need to use the entity manager in the static init block of the helper class (some thing like):

class MySessionBeanHelperClass
{
 // staff here...


    static
 {
  SomeClass s = new SomeClass(entityManager);
 }
}

So, I think the only way is to lookup the entity manager instead of injecting it. and also using the passed SessionContent will not work here. (is it????) (this is the first question)

The second question is: If I used the ordinary way to lookup a resource (in this case the entity manager) (something like the following:)

Context ic = new InitialContext(); 
em = (EntityManager) ic.lookup("java:comp/env/persistence/em");

Is this will convert all transactions used by this entity manager to Bean-managed transaction??

Thanks!

Upvotes: 0

Views: 1350

Answers (2)

Adeel Ansari
Adeel Ansari

Reputation: 39887

Answer to your second question, No.

First question, its not really a good idea. BTW, what are you up to? In case you need EntityManager in your helper class, its better to make it a private instance level variable, and pass that from your session bean using helper class constructor.

Upvotes: 1

Enno Shioji
Enno Shioji

Reputation: 26882

I don't think it's a good idea to do that from static initializer. You have to be sure that all necessary services (such as JNDI, JPA) are up before the lookup occurs, but you can't guarantee that when you do it from a static initializer.

It's a known problem in EJB that there is no "standard" way of performing one-time task upon app. start/stop, but you can use the trick in the following link:

How to perform a DB cleanup operation upon shutdown in an EJB container

The example is for performing action upon app. stop, but you can override Servlet#init instead.

Upvotes: 1

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