Custom messages while publishing and using storage extension

Question

Scenario: (In SDL Tridion 2011 SP1 HR1)

We have a storage extension which indexes the Component Presentation in SOLR, now If due to some reason this indexing is failed, we want to rollback the publishing and emit a Failure status to CME GUI with a Custom message.

What we have achieved so far and what is the issue:

We are able to rollback and emit the failure to GUI successfully. We sent the custom message as well but it get displayed twice on the CME GUI along with some default message from Tridion.

What we need:

We want to show only non-redundant custom message that we sent through storage extension. Is it possible to control this behaviour and is it possible to show a specific custom message on rollback and failure through storage extension. Did any one in the group come across any out of the box or tailor made solution.

Per Bart's suggestion Below is the code I am using for sending back the custom messages in the Storage Extension written for Dynamic Component Presentation:

public void create(ComponentPresentation itemToCreate, ComponentPresentationTypeEnum componentPresentationType)
    throws StorageException
    {

      try
      {
           .. Code for Indexing the Data in SOLR and capturing any error..

           if(<Indexing is successful>) {do nothing}
           else
           {
              throw new StorageException(<Custom Error Message>);
           }

      } 

      catch(Exception ex)
      {
        throw new StorageException(<Custom Error Message>); 
      }  

    }

Answer 1

Your first thrown exception will be caught in your catch(), as you are catching all Exceptions. You could be more specific in the kinds of exceptions you are catching - or at least make an exception for StorageExceptions, like this:

public void create(ComponentPresentation itemToCreate, ComponentPresentationTypeEnum componentPresentationType)
    throws StorageException
    {

      try
      {
           .. Code for Indexing the Data in SOLR and capturing any error..

           if(<Indexing is successful>) {do nothing}
           else
           {
              throw new StorageException(<Custom Error Message>);
           }

      } 
      catch(StorageException ex)
      {
        throw ex;
      }  
      catch(Exception ex)
      {
        throw new StorageException(<Custom Error Message>); 
      }  

    }

Answer 2

Assuming that you're showing messages via the Event System. If you subscribed to an event that encompasses two or more child events, for example PublishEventArgs is a parent for PublishOrUnPublishEventArgs and SetPublishStateEventArgs, then your logic would be triggered in instances of both of the child events. This would explain why you see the error message twice. You need to narrow down and subscribe to the most specific event so that it is the only one you show a message on.

If you share your code/which event(s) you've subscribed to, to fire the message, we can help further.