JBoss.org Community Documentation
As we've mentioned before, JBoss DNA is able to work with existing JCR repositories. Your client applications make changes to the information in those repositories, and JBoss DNA automatically uses its sequencers to extract additional information from the uploaded files.
Configuring JBoss DNA sequencers is a bit more manual than is ideal. As you'll see, JBoss DNA uses dependency injection to allow a great deal of flexibility in how it can be configured and customized. However, the next release will provide a much easier mechanism for configuring not only the sequencer service but also the upcoming federation engine and JCR implementation.