In the built-in simple faceting, I get a Ruby response like this:
'facet_counts'=>{
'facet_queries'=>{},
'facet_fields'=>{
'subject_genre_facet'=>{
'Biography.'=>2605,
'Congresses.'=>1837,
'Bibliography.'=>672,
'Exhibitions.'=>642,
'Periodicals.'=>615},
...
This is using &facet.limit=5 and no sort specified, so the items are
being written in the proper order, however they are written as a Ruby
Hash syntax, which does not iterate in a predictable order (like
Java's Map). This really should be an Array in order for the client
to assume the response is in a specified order. I think the response
is best formatted as:
'facet_counts'=>{
'facet_queries'=>{},
'facet_fields'=>{
'subject_genre_facet'=>[
{'Biography.'=>2605},
{'Congresses.'=>1837},
{'Bibliography.'=>672},
{'Exhibitions.'=>642},
{'Periodicals.'=>615}],
...
This makes the navigation of the results a bit clunkier because each
item in a fields array is a single element Hash(Map), but the facets
of a field really need to be in an array to maintain order.
I presume this same dilemma is in the Python/JSON format too? In
XML, the <lst> has the right semantics, and a parser would easily be
able to deal with it in order:
<lst name="facet_counts">
<lst name="facet_queries"/>
<lst name="facet_fields">
<lst name="subject_genre_facet">
<int name="Biography.">2605</int>
<int name="Congresses.">1837</int>
<int name="Bibliography.">672</int>
<int name="Exhibitions.">642</int>
<int name="Periodicals.">615</int>
</lst>
...
Thoughts?
Erik
