programmatically setting filter query not working for me

[Steve Pruitt <bp...@opentext.com>]

My use case is programmatically setting a query filter before executing the query.  I have a search component in the /select first-components list.
This component determines the filter query value and sets it in the process method.  I pass in a custom param to trigger the filter creation

I grab the parms from the request
SolrParams solrParams = rb.req.getParams();

I next create a collection called rawParams with
Map<String, String[]> rawParams = SolrParams.toMultiMap(solrParams.toNamedList());

I create the structure to hold my filters and 
String[] filters = getFilter...

and then assign the new params like this
rawParams.put(CommonParams.FQ, filters);
solrParams = new MultiMapSolrParams(rawParams);
rb.req.setParams(solrParams);

The filter returns only a subset of the documents matching the terms.  In my test case its 2 out of 21 documents.
The problem is the response is all 21 documents.

I have a simple search component in the last-components list simply to set a breakpoint to see the query results.

I have tried two alternate tests using the Solr Admin console.

I first verified the filter query by directly pasting it in the fq field and it works ok.  I got back the expected 2 documents.

I next did the above and also included my custom params.  And this worked.  As expected, the SolarParms value of the req has a double entry for the filter.  The values are identical.

So without using the fq field in the Console, I can't determine why setting via the Solr parms with Commons.FQ key doesn't work.

As a separate experiment, created a custom handler and with a custom component sub classing QueryComponent.  I do the filter query setup as above and calling super.process(rb) works.
But, I don't want to use a custom handler.

Thanks in advance if anyone points out where my assumptions are wrong.

Thanks,
Steve