Automatic Generation of Menus

Hi Lenya developers,

today Felix and I discussed how the cryptic menu XSPs could
be replaced by a cleaner solution. Once we have a workflow
engine, we can probably integrate the menu generation in the
workflow management (see below). Until then, we have to find
an easier solution.

-------------------------------------------------------------
WITHOUT WORKFLOW
-------------------------------------------------------------

Our first idea looked like follows:

- Menu items contain:
   - a label
   - a link that can contain parameters for tasks or for the
     scheduler

- There is a default menu that is used by every page type.

- For every page type it is possible to
   - add menu items
   - remove menu items
   - override menu items

- The menu generation pipeline
   - looks if there is a specific menu overriding the default one
   - if no, it takes the default menu
   - if yes, it combines the default and the specific menu using
     aggregation and merges them using a stylesheet

- When the default menu is loaded, a stylesheet creates default
   menu items based on page parameters (URI, ...).

The default menu could look like:

<menu>
   <item id="edit-bitflux">Edit with Bitflux</item>
   <item id="edit-xopus">Edit with Xopus</item>
   <item id="publish">Publish</item>
   <item id="schedule">Schedule</item>
</menu>


The overriding menu could look like:

<menu>

   <!-- keep editing items untouched -->

   <!-- override publish item -->
   <item id="publish">
     <href>publish.html?page=<xsp:expr>headlinesUri</xsp:expr></href>
     Publish Article
   </item>

   <!-- remove schedule item -->
   <item id="schedule" show="false"/>

   <!-- add newsletter item -->
   <item id="newsletter">
     <href>newsletter.html?page=<xsp:expr>...</xsp:expr></href>
     Send Newsletter
   </item>

</menu>

This is just a first idea.

-------------------------------------------------------------
WITH WORKFLOW
-------------------------------------------------------------

I attached a PDF showing an analysis diagram for the connection
between workflow and menus:

- A page can contain 0..* documents.
- The page asks the workflow engine for the transitions
   that can fire for each document.
- For each transition, a menu item is created:

Document documents[] = page.getDocuments();
foreach document in documents {

     Transition transitions[]
         = Workflow.getNextTransitions(document);

     foreach transition in transitions {

         String eventLabel = transition.getEvent().getLabel();
	String doctypeLabel = document.getType().getLabel();

         addMenuItem(eventLabel + " " + doctypeLabel, ...);
	// "Publish Article"
     }
}

The menu item link must contain
   - a reference to the document to manipulate
   - the event (i.e. the transition to invoke)

Of course, there can also be menu items that are not
connected to the workflow.

But I don't know if this mechanism is powerful enough.
What do you think?

Andreas