5 Replies Latest reply on Feb 27, 2012 6:44 AM by hantsy

EntityManager from long running conversation injected in RequestScoped bean without propagation

miguelzp Feb 22, 2012 5:10 AM

What a strange thing using Seam managed persistence:

I. Producer.java

@ExtensionManaged

@Produces

@PersistenceUnit(unitName="db")

@ConversationScoped

EntityManagerFactory emf;

II. Managed Bean 1:

@ConversationScoped

public class Bean1 ...

...

@Inject

private EntityManager entityManager;

...

III. Simple href without params clicked during long running conversation with Bean1 implicated

<h:outputLink value="page2.xhtml" target="_blank">

<h:outputText value="Go" />

</h:outputLink>

IV. Managed Bean 2 with method called by s:viewAction in page2.xhtml:

@RequestScoped

public class Bean2 ...

@Inject

private EntityManager entityManager;

--> EntityManager injected in Bean2 is the same instance as in Bean1 without any cid param, cookie etc. that could propagate the conversation (I checked the http)

How could this behaviour be explained?

How can I force a new EntityManager (PC) instance for each request in Bean2?

Miguel

1. Re: EntityManager from long running conversation injected in RequestScoped bean without propagation

blabno Feb 23, 2012 1:51 AM (in response to miguelzp)

Display #{conversation.id} on the page to see if it's really different conversation. If it's different conversation then it can't be the same instance of EM. BTW. Remember that what you get injected is a proxy and not actual EM instance.
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2. Re: EntityManager from long running conversation injected in RequestScoped bean without propagation

miguelzp Feb 23, 2012 2:35 AM (in response to blabno)

Bernard,

thx for your answer. #{conversation.id} is null on page2.xhtml as Bean2 is RequestScoped and there is definitely no propagation. I get the same proxy with the same delegate (with the same entities and collections managed as after the last conversational request to Bean1).

My current workaround is to make Bean2 @ConversationScoped and to progagate the conversation with cid param.

Generally I prefer to use the less stateful scope...
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3. Re: EntityManager from long running conversation injected in RequestScoped bean without propagation

hantsy Feb 25, 2012 11:12 PM (in response to miguelzp)
From consversation scoped view to request scoped view, I use s:viewAction in the request scoped veiw to determine there is a Long conversation, if there is a long run conversation, end it directly.

<s:viewAction action=#{conversation.end} if=#{not conversation.transient}/>
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4. Re: EntityManager from long running conversation injected in RequestScoped bean without propagation

miguelzp Feb 26, 2012 10:31 AM (in response to hantsy)

Nice one, Hantsy! I'm sure I'll need to use it at some other point. However in the described case above I would still need the long running conversation for page1.xhtml as page2.xhtml opens in a new tab/window:

<h:outputLink value="page2.xhtml" target="_blank">
^^^^^^^
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5. Re: EntityManager from long running conversation injected in RequestScoped bean without propagation

hantsy Feb 27, 2012 6:44 AM (in response to miguelzp)
it is impossbile.

Add the viewAction in the page2.xhtml, and put the following code fragment in the template to check the current conversation. it worked as expected.here.

#{conversation.transient ? 'transient' : 'long-running, id: '.concat(conversation.id)}
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