Re: Using Hivemind to wrap a transaction around a request

[Alebu]

Hi Kaspar,
There is a tutorial on TSS about Hivemind by James Carman.
http://www.theserverside.com/tt/articles/article.tss?l=HivemindBuzz
And as example of interceptor there is a TransactionInterceptor.
Perhaps it can help you to start your own solution.
And dont be shy to ask help in mailing list. Hivemind is a great product 
but lack of
documentation is most is thing about it, so others people help is very 
important.

Kaspar Fischer wrote:
Dear Jean-François,

Thank you for your email. I think I get the basic idea of what you are 
saying:
Tell Hivemind to put the "begin()" and "commit()" around the relevant 
methods
of Tapestry (and make it call "rollback()" on uncaught exceptions). Is 
this
correct, so far?

One first uncertainty in this is what Tapestry method I should intercept?
It can't be around a single page-request as redirecting, rewinding, 
etc. won't
work then. Do you happen to know what might be the right method?

I've taken a look at HiveTranse and understand parts of it. However, I do
not know where to start -- obviously, I need to inject my own "begin()"
and "commit()" as I am neither running Hibernate, not JDBC, etc. 
directly.

Could you maybe provide a few directions on how to write my HiveMind 
interceptor?
Maybe it's easier without HiveTranse first?

I am sorry if my questions are very basic, and I imagine it's probably 
boring
for you. I can promise that I will post a solution to the tapestry 
list and
also extend the article I've written at the Alfresco Wiki:

  
http://wiki.alfresco.com/wiki/Alfresco_and_Tapestry_on_the_Same_Tomcat_Installation 


With this, you're help will hopefully not just help me but others as 
well.

Best,
Kaspar

On 05.12.2007, at 14:09, Jean-Francois Poilpret wrote:

Hi Kaspar,

I think you'd rather take a look at HiveMind interceptors rather than
factories.
You can create an Interceptor that will be called before and after any
method of another service.
There are several ways to create interceptors in HiveMind, take a 
look at
HiveMind website to see simple examples.

If you want to see a real-life implementation of such a system you 
may take
a look at hivetranse (http://hivetranse.sourceforge.net) which 
implements
the same kind of behavior as you are looking for. I think you could 
quite
easily adapt one of the numerous hivetranse interceptors (choose one 
-the
simples- as an example).

Cheers

Jean-Francois

-----Original Message-----
From: Kaspar Fischer [mailto:[EMAIL PROTECTED]
Sent: Wednesday, December 05, 2007 7:32 PM
To: user@hivemind.apache.org
Subject: Using Hivemind to wrap a transaction around a request

[Note: This is a cross-post; I have initially posted to the list
[EMAIL PROTECTED] but I guess the issue is more related to
hivemind,
so I post here.]

Hi list,

I need to wrap "begin transaction" and "end transaction" actions around
a task (a Tapestry web request, actually). I've read about Hivemind,

   http://www.nabble.com/hivemind-factory-service-tf251931.html#a704856

and configured a service point (see below). This works very well: my
transaction is created, but I cannot see when it is ended (committed/
rolled back).

More precisely, I am struggling with:

* What method is called on the object created by the factory when it
   is discarded? It is threadDidDiscardService(), right?

* How can I catch exceptions from my actual task so that I can do a
rollback
  instead of a commit?

I am new to Hivemind, so please excuse these rather simple questions.

Many thanks for you patience!
Kaspar

--
Here's my configuration:

  <service-point
interface="org.my.tapestry.alfresco.AlfrescoTransactionContext"
id="alfrescoContext">
   <invoke-factory service-id="AlfrescoTransactionFactory"
model="threaded" />
  </service-point>
  <service-point
interface="org.apache.hivemind.ServiceImplementationFactory"
id="AlfrescoTransactionFactory" parameters-occurs="none">
   <create-instance
class="org.my.tapestry.alfresco.AlfrescoTransactionFactory" />
  </service-point>

Here is my factory:

public class AlfrescoTransactionFactory implements
ServiceImplementationFactory, Discardable {

   public Object createCoreServiceImplementation
(ServiceImplementationFactoryParameters factoryParameters)
   {
     System.err.println("createCoreServiceImplementation"); // gets
called!
     UserTransaction transaction;
     ServiceRegistry serviceRegistry;
     try {
       transaction =
AlfrescoApplicationInitializer.createAndBeginAuthenticatedTransaction
(true);
       serviceRegistry =
AlfrescoApplicationInitializer.getServiceRegistry();
     }
     catch (Exception e) {
       throw new ApplicationRuntimeException("Could not create an
Alfresco transactoin.", e);
     }
     return new AlfrescoTransactionContextImpl(transaction,
serviceRegistry);
   }

   public void threadDidDiscardService()
   {
     System.err.println("threadDidDiscardService"); // never called!
     // ... end the transaction here (todo)
   }
}