/**
  * Delete request mode means that the user requests the application to delete an existing bean. In
  * delete request mode, existing data is deleted from persistent storage. The request should
  * provide data for the {@link PersistentBean#getId()}. If the delete operation succeeds, the data
  * is displayed in a non-editable way, with a notice that signifies successful deletion. If the
  * delete operation fails, the data is displayed in a non-editable way, with an error notice. This
  * method first sets the id of the persistent bean from the request. Next, the persistent bean is
  * retrieved from the database. Only after that, the persistent bean will be deleted. This is done
  * to have an early warning of errors in the key, or access violations.
  *
  * @idea (jand) This would also make it possible to check here whether all information in the
  *     request matches the information in persistent storage during this transaction.
  * @pre form != null;
  * @pre form.getPersistentBean() != null;
  * @pre request != null;
  */
 private void templateDelete(final CrudDynaActionForm form, final HttpServletRequest request)
     throws CompoundPropertyException, IdException, TechnicalException {
   assert form != null;
   // assert form.getPersistentBean() != null;
   assert request != null;
   if (LOG.isDebugEnabled()) {
     LOG.debug("delete action ..."); // $NON-NLS-1$
   }
   form.setViewModeEdit(false);
   AsynchronousCRUD asyncCRUD = createAsynchronousCRUD(request);
   DeletedEvent pbdEvent = null;
   try {
     asyncCRUD.startTransaction();
     retrieveWithId(form, asyncCRUD); // IdException
     assert form.getPersistentBean() != null;
     pbdEvent = new DeletedEvent(form.getPersistentBean());
     asyncCRUD.deletePersistentBean(form.getPersistentBean());
     asyncCRUD.commitTransaction(form.getPersistentBean());
     assert form.getPersistentBean().getId() == null;
     form.beanToId(); // must be null
     form.setViewModeDeleted(true); // rae.isEmpty());
     if (LOG.isDebugEnabled()) {
       LOG.debug("delete action succeeded"); // $NON-NLS-1$
     }
   } catch (CompoundPropertyException cpExc) {
     asyncCRUD.cancelTransaction();
     form.setViewModeDeleted(false);
     throw cpExc;
   } catch (IdException pkvExc) {
     asyncCRUD.cancelTransaction();
     form.setViewModeDeleted(false);
     throw pkvExc;
   } finally {
     form.beanToForm(asyncCRUD);
     releaseAsynchronousCRUD(asyncCRUD);
   }
   fireCommittedEvent(pbdEvent);
   assert !form.isViewModeNew();
   assert !form.isViewModeEdit();
 }
 /**
  * Create request mode means that the user requests the application to create a new persistent
  * bean with supplied information.. In create request mode, new data is stored in persistent
  * storage. The request should provide data for all properties of the {@link PersistentBean},
  * except the {@link PersistentBean#getId()}. If the create operation succeeds, the data is simply
  * displayed in a non-editable way. If the create operation fails, the data is displayed in an
  * HTML form, so that it can be corrected.
  *
  * @pre form != null;
  * @pre form.getPersistentBean() != null;
  * @pre request != null;
  */
 private void templateCreate(final CrudDynaActionForm form, final HttpServletRequest request)
     throws CompoundPropertyException, TechnicalException {
   assert form != null;
   assert request != null;
   if (LOG.isDebugEnabled()) {
     LOG.debug("create action ..."); // $NON-NLS-1$
   }
   form.initBean();
   /*
    * BeanInstantiationException; this means that the app is wrongly
    * configured; this will generate a general error page.
    */
   assert form.getPersistentBean() != null;
   assert form.getPersistentBean().getId() == null;
   form.setViewModeDeleted(false);
   AsynchronousCRUD asyncCRUD = createAsynchronousCRUD(request);
   try {
     asyncCRUD.startTransaction();
     form.formToBean(asyncCRUD); // PropertyException, inside transaction
     form.getPersistentBean().setId(null);
     asyncCRUD.createPersistentBean(form.getPersistentBean());
     // PropertyException
     form.beanToId();
     form.beanToForm(asyncCRUD); // inside transaction
     asyncCRUD.commitTransaction(form.getPersistentBean());
     form.setViewModeEdit(false);
     CreatedEvent pbnEvent = new CreatedEvent(form.getPersistentBean());
     fireCommittedEvent(pbnEvent);
     assert !form.isViewModeNew();
     assert !form.isViewModeDeleted();
     if (LOG.isDebugEnabled()) {
       LOG.debug("create action succeeded"); // $NON-NLS-1$
     }
   } catch (CompoundPropertyException cpExc) {
     form.beanToForm(asyncCRUD);
     asyncCRUD.cancelTransaction();
     form.setViewModeNew(true);
     assert form.isViewModeEdit();
     assert !form.isViewModeDeleted();
     throw cpExc;
   } finally {
     releaseAsynchronousCRUD(asyncCRUD);
   }
 }
 /**
  * Update request mode means that the user requests the application to update existing information
  * with supplied information. In update request mode, data is stored in persistent storage. The
  * request should provide data for all properties of the {@link PersistentBean}. If the update
  * operation succeeds, the data is imply displayed in a non-editable way. If the update operation
  * fails, the data is displayed in an HTML form, so that it can be corrected. This method first
  * sets the id of the persistent bean from the request. Next, the persistent bean is retrieved
  * from the database. Only after that, the information from the request is filled out into the
  * bean. This is done to have an early warning of errors in the key, or access violations, but
  * mainly to make it possible to operate easily with a request that contains only partial
  * information, i.e., a request that only carries values for a subset of the properties of the
  * persistent bean. With this protocol, the given information will overwrite information that is
  * currently in persistent storage, but if there is no data in the request for a given property,
  * it's old value is retained. Once the data that is offered in the request is copied successfully
  * in the persistent bean, it is stored.
  *
  * @pre form != null;
  * @pre form.getPersistentBean() != null;
  * @pre request != null;
  */
 private void templateUpdate(final CrudDynaActionForm form, final HttpServletRequest request)
     throws IdException, CompoundPropertyException, TechnicalException {
   assert form != null;
   assert request != null;
   if (LOG.isDebugEnabled()) {
     LOG.debug("update action ..."); // $NON-NLS-1$
   }
   AsynchronousCRUD asyncCRUD = createAsynchronousCRUD(request);
   try {
     asyncCRUD.startTransaction();
     retrieveWithId(form, asyncCRUD); // IdException, TechnicalException
     assert form.getPersistentBean() != null;
     // @mudo (dvankeer): toString() needs to be replaced by something more
     //                   usefull.
     String oldBeanString = form.getPersistentBean().toString();
     form.formToBean(asyncCRUD); // PropertyException, inside transaction
     asyncCRUD.updatePersistentBean(form.getPersistentBean()); // PropertyException
     form.beanToForm(asyncCRUD); // inside transaction
     asyncCRUD.commitTransaction(form.getPersistentBean());
     releaseAsynchronousCRUD(asyncCRUD);
     // do not do this in a finally block; this can throw exceptions too
     form.setViewModeEdit(false);
     // @todo (jand): try to move this delta stuff to AsynchronousCRUD instead
     //               of here
     fireCommittedEvent(new UpdatedEvent(form.getPersistentBean(), oldBeanString));
   } catch (CompoundPropertyException cpExc) {
     form.beanToForm(asyncCRUD);
     if (LOG.isDebugEnabled()) {
       LOG.debug("update action failed; cancelling ...", cpExc); // $NON-NLS-1$
     }
     asyncCRUD.cancelTransaction();
     releaseAsynchronousCRUD(asyncCRUD);
     // do not do this in a finally block; this can throw exceptions too
     form.setViewModeEdit(true);
     LOG.debug("update action cancelled; rethrowing exeption"); // $NON-NLS-1$
     throw cpExc;
   }
   /*
    * on IdException, we go to a different page that shows a not found message.
    * For this page we do not need to set any information
    */
   form.setViewModeDeleted(false);
   form.setViewModeNew(false);
 }