Improvement of Steve Muench's sample #62. Cascading Lists in JSF

Question

If you go to
http://radio.weblogs.com/0118231/stories/2004/09/23/notYetDocumentedAdfSampleApplications.html#dynamiccascadingpoplist
you will find sample application demonstrating use of Cascading ListBoxes in JSF using selectOneChoice and ADF Master/detail relation.
But it has one problem - if you delete required field "City" you can not longer use cascading list because of validation error. I came to one solution of this problem and I like share it with others.
1. add immediate="true" to selectOneChoice tag. This will prevent client-side validation (in conjunction with autoSubmit="true")
2. add
FacesContext.getCurrentInstance().renderResponse();in the end of onRegionListChanged() in backing.java to prevent server-side validation
There is no validation errors anymore, but now link between lists is broken
3. add following code to onRegionListChanged in backing.java
int position = (Integer)valueChangeEvent.getNewValue();
DCIteratorBinding regionDCIter = bindings.findIteratorBinding("RegionsIterator");
regionDCIter.setCurrentRowIndexInRange(position);Tip: easy way to get bindings in backing bean is to double click on some button in JSF design mode
4. Almost there. Cascading works but we have one small bug. Set some location to Europe/United Kingdom and commit. Now, try to change region to anything else. Doesn't works. If yours logs there is IndexOutOfBounds exception.
To solve this add following code to onRegionListChanged in backing.java:
bindings.findIteratorBinding("LocationsViewIterator").getCurrentRow()
     .setAttribute("CountryId", null);
getCountryIdSOC().setSubmittedValue(null);Tip: to create getCountryIdSOC() method you should edit binding attribute of the Country selectOneChoice
In the end your method will look something like this:
public void onRegionListChanged (ValueChangeEvent valueChangeEvent) {
     FacesContext.getCurrentInstance().getExternalContext().getRequestMap().put("RegionChanged", "x");
     bindings.findIteratorBinding("LocationsViewIterator").getCurrentRow()
          .setAttribute("CountryId", null);
     getCountryIdSOC().setSubmittedValue(null);
     int position = (Integer)valueChangeEvent.getNewValue();
     DCIteratorBinding regionDCIter = bindings.findIteratorBinding("RegionsIterator");
     regionDCIter.setCurrentRowIndexInRange(position);
     FacesContext.getCurrentInstance().renderResponse();
}Note: I casted bindings to DCBindingContainer.
I hope you will find this helpful.

Answer 1

To solve this add following code to
onRegionListChanged in backing.java:
bindings.findIteratorBinding("LocationsViewIterator").
getCurrentRow()
     .setAttribute("CountryId", null);
getCountryIdSOC().setSubmittedValue(null);Tip: to create getCountryIdSOC() method you should
edit binding attribute of the Country
selectOneChoice
What does that do? and what do you mean by editing the binding attribute of the selectonechoice?
Other than that I get what you're doing.