try {
progress.setStatus("Purging index");
log.debug("deleting indexed documents of entity: " + entityClass.getName());
userTx = (UserTransaction)org.jboss.seam.Component.getInstance("org.jboss.seam.transaction.transaction");
userTx.begin();
EntityManager em = (EntityManager) Component.getInstance("entityManager");
FullTextSession ftSession = (FullTextSession)em.getDelegate();
// Delete all documents with "_hibernate_class" term of the selected entity