Breadcrumbs in JHeadstart 10.1.2.1

Question

Dear JHeadstart Team,
Following the instructions found in chapter 5 of the JHeadstart Developer's Guide I have tried to influence the generation of breadcrumbs in UIX pages generated with JHeadstart 10.1.2.1. The situation I have generated and then post-generation modified is like this. I have a table overview (say, Departments) with an Edit button (Edit Department). I then made a change to have a button that allows to search (Search Department) an existing record before clicking the create button (Create Department). Basically I replaced the create button in the second UIX page to go to the Search page and added a create button in the Search page that leads back to the second page but now in create mode.
This introduces some unwanted behaviour with the breadcrumbs stack. From the user's point of view, a breadcrumbs list <overview> <edit> <search> <create> is expected. But when clicking the Create button, the breadcrumbs stack is rolled back and the Edit label is modified into Create.
In order to circumvent this behaviour, I have added
<set-property property="rollbackBreadcrumbStack" value="false"/>
to the appropriate actions in struts-config.xml which means that clicking the create button will not rollback the breadcrumbs stack and leave Edit there and add Create after Search. So far so hoopy.
But this means that ANY action that is related to the Edit/Create action will add another breadcrumb to the stack. When the Edit breadcrumb is clicked after clicking the Create button, another Edit breadcrumb is added to the stack. Moreover, when sorting a table (e.g. a detail table that is shown on the same page as Edit) several times, several additional breadcrumbs are added to the stack.
I noticed there are separate entries for the Edit and Create labels in the resource bundle of our application and the JHeadstart Developer's Guide mentions this as well (page 5-60). Is there any way of treating Edit and Create separately without creating mile long breadcrumb stacks? If not, are there any plans to make this possible? It will probably very difficult to explain this behaviour to future users of our application you see.
Thanks in advance,
Wouter van Reeven
AMIS

Answer 1

Wouter,
Basically, your problem with the breadcrumb mechanism is that there always is only one breadcrumb per DataAction, OR one breadcrumb per "set of" DataActions that have the same "breadcrumbKey" property (so 1:1 or 1:n), but not multiple breadcrumbs for one action (n:1). The first possible solution I gave was to overcome your problem by creating two DataPage, one for New and one for Edit, so that two separate breadcrumbs, one for each DataPage, could be put on the stack. If I understand correctly you did create the second DataPage but used the breadcrumbKey property to have them share a single breadcrumb, while the whole reason for creating a second DataPage was so it could have its own, separate breadcrumb.
I will put the EL expressions idea on our Enhancements list, but I don't think we will put it in any time soon. We prioritize on a "how many developers will benefit, and how often" basis. Furthermore, my gut feeling is that there will be a lot of "small stuff" to deal with, especially with rolling back, when multiple breadcrumbs in the stack could have originated from a single DataPage.
It is very possible to create your own BreadcrumbManager, by extending the JhsActionServlet and overriding this method:
protected boolean processBreadcrumbs(HttpServletRequest request, ActionMapping mapping, ActionForward forward)
BreadcrumbManager manager = BreadcrumbManager.getBreadcrumbManager(....);
return manager.processBreadcrumbs(request,mapping,forward);
You can copy or subclass the three classes in the JhsRuntime that deal with breadcrumbs (they can all be found in the package oracle.jheadstart.util.breadcrumbs, and use your own version instead.
Kind regards,
Peter Ebell
JHeadstart Team