This ticket introduces a new search component called the ExpandComponent. The expand component expands a single page of results collapsed by the CollapsingQParserPlugin.
In the above query the results are collapsed on "fieldA" with the CollapsingQParserPlugin. The expand component expands the current page of collapsed results.
The initial implementation of the ExpandComponent takes three parameters:
expand=true (Turns on the ExpandComponent)
expand.sort=fieldB+asc,fieldC+desc (Sorts the documents based on a sort spec. If none is specified the documents are sorted by relevance based on the main query.)
expand.rows=10 (Sets the numbers of rows that groups are expanded to).