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From Kaspar Fischer <fisch...@inf.ethz.ch>
Subject Re: Using Hivemind to wrap a transaction around a request
Date Tue, 11 Dec 2007 15:22:58 GMT
Dear Jean-Fran├žois,

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:fischerk@inf.ethz.ch]
> 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
> users@tapestry.apache.org 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)
>    }
> }
>


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