162 Chapter 12. Presentation (Bebop) Tutorial
12.7.1. Implementing and Registering a Process Listener
Your process listener must be anamed Java class in orderfor it to be used bya persistent form. If your
form listener needs certain parameters with specific names and data types, ensure that the listener
implements the com.arsdigita.formbuilder.AttributeMetaDataProviderinterface.
You register the listener by going to the formbuilder admin interface mounted under /formbuilder.
On the index page, choose to add a new persistent form and supply the name of the listener that was
implemented.
You may now notify any application administrator that the form is ready for editing. If the lis-
tener implements the com.arsdigita.formbuilder.AttributeMetaDataProvider interface,
the formbuilder admin UI will make sure that the persistent form complies with this contract and
submits the parameters that the listener needs.
12.7.2. Mounting a Persistent Form in an Application
The formbuilder admin UI represents persistent forms via the
com.arsdigita.formbuilder.SimpleQuestionnaire class. You may retrieve an instance of
this class via its integer id or via the admin name that you specified in the admin UI (the admin name
is unique).
Once you have created the instance of SimpleQuestionnairethat you need, you have two options:
• The dynamic option involves adding a com.arsdigita.bebop.MetaForm to the page and will
ensure that admin changes to the form will take immediate effect.
• The static approach involves adding a normal Bebop com.arsdigita.bebop.Form to your ap-
plication page so that admin changes to the form will take effect only after server startup.
The dynamic approach is more convenient for the administrator, in that he can immediately see how
the form will look in the application. However, if the page has a heavy load of users, the static ap-
proach is preferable, since it is much more efficient. This is because it does not dynamically build the
component hierarchy of the form on every request.
Your decision to use static or dynamic will be based upon your usage patterns. One good method to
follow is to use the dynamic approach when in heavy development of an application and it’s forms,
then switch to static when the pages go to the live server and are subject to public loads. It is usually
preferred to keep the approach static on a non-production, site-development server. When you switch
to the static approach, it is recommended to restart the server regularly (e.g. with a daily cron job) so
as to capture changes made by application administrators.
Example 12-1 is an example of static mounting of apersistent form. In this case, the formis built only
once upon server startup. The web server must be restarted for any changes to take effect.
Page applicationPage = new Page();
SimpleQuestionnaire questionnaire =
new SimpleQuestionnaire(new BigDecimal("773"));
applicationPage.add(questionnaire.createComponent());
applicationPage.lock();
Example 12-1. Static Mounting of a Persistent Form
Example 12-2 is an example of dynamic mounting of a persistent form. Changes to the form by the
administrator will take immediate effect on the application page.
