ADF FACES: how to preserve the sort criteria for an af:table

Question

How can I preserve the sort criteria on an af:table across page invocations? I've searched all through the forum and I don't see anything on this topic.
I simply want the sort criteria (from when the user clicks on a column header) to be remembered across multiple uses of the page. I know that the control handles this itself for multiple invocations of the same page (like when you page through the table). But I need to preserve the sort order so I can install it again when someone leaves the page and then returns to it.
I've tried various attempts using a SortListener to record the sort criteria, but I can't figure out how to reinstall the criteria without generating exceptions from the table control.
Any pointers on how to do this would be greatly appreciated.
Thanks.
Larry.

Answer 1

Ok, I've solved the problems with the odd behavior by always creating a new model when the table data changes and copying the sort criteria into the new model, like this:
        // Construct our own CollectionModel from this result set
        if(_model == null) {
            // Construct the initial data model and set the starting sort criteria
            ListDataModel m = new ListDataModel(results);
            _model = new SortableModel(m);
            // Set the sort criteria to last name
            ArrayList criteria = new ArrayList();
            criteria.add(new SortCriterion("lastName", true));
            _model.setSortCriteria(criteria);
        } else {
            // Construct a new model so the table "sees" the change
            ListDataModel m = new ListDataModel(results);
            SortableModel sm = new SortableModel(m);
            sm.setSortCriteria(_model.getSortCriteria());
            _model = sm;
        }But, I end up with one final thing that doesn't work. In the "then" clause above, I try to set the initial sort criteria for the table - it has no effect. When the table is rendered, it is not sorted in any way.
How can I specify an initial sort order for the table? Why is it ignoring the sort criteria on the model?
Thanks.