Apache Solr: bitwise operations to filter search r

I need to filter solr search results corresponding the access rights in our cms (drupal 7 + custom access control mechanism based on bitmasks).

There exists a Solr QParserPlugin plugin for search results filtering based on bitwise operations on integer fields: https://issues.apache.org/jira/browse/SOLR-1913.

I am using Solr 3.6.1 (+ the plugin in /var/lib/tomcat6/solr/lib/bitwise_filter_plugin.jar) on tomcat6 (on debian system) with the schema.xml provided by the drupal module search_api_solr and the solrconfig.xml found in the modules issue queue (extended as indicated in the SOLR-1913 issue).

The Solr query ...

http://solr:8080/solr/select?qf=t_title&fl=*,score&fq={!bitwise field=is_bitmask op=AND source=1234}*

... fails with the following message in the error log:

Sep 27, 2012 8:57:41 AM org.apache.solr.core.SolrCore execute
INFO: [] webapp=/solr path=/select params={qf=t_title&fl=*,score&fq={!bitwise+field%3Dis_bitmask+op%3DAND+source%3D1234}} status=500 QTime=15 
Sep 27, 2012 8:57:41 AM org.apache.solr.common.SolrException log
SEVERE: java.lang.NullPointerException
  at org.apache.lucene.search.FilteredQuery.hashCode(FilteredQuery.java:268)
  at java.util.AbstractList.hashCode(AbstractList.java:542)
  at org.apache.solr.search.QueryResultKey.<init>(QueryResultKey.java:49)
  at org.apache.solr.search.SolrIndexSearcher.getDocListC(SolrIndexSearcher.java:1084)
  at org.apache.solr.search.SolrIndexSearcher.search(SolrIndexSearcher.java:375)
  at org.apache.solr.handler.component.QueryComponent.process(QueryComponent.java:394)
  at org.apache.solr.handler.component.SearchHandler.handleRequestBody(SearchHandler.java:186)
  at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:129)
  at org.apache.solr.core.SolrCore.execute(SolrCore.java:1376)
  at org.apache.solr.servlet.SolrDispatchFilter.execute(SolrDispatchFilter.java:365)
  at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:260)
  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
  at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
  at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
  at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
  at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
  at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
  at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
  at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
  at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
  at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
  at java.lang.Thread.run(Thread.java:636)

The only thing I can see in the error message is that the plugin is invoked by solr.

Any help would be appreciated, Thanks.

Instead of making Solr do it your way, you might want to try it Solr's way. Solr already implements boolean logic.

Split your bitfield into a set of named boolean fields. They can even be bit_0, bit_1, etc. if you are short on inspiration. You can use a dynamic field to save typing and allow later expansion.

Index them as bit_0:true and so on for each doc.

Use those fields in the filter query to do selection: bit_0:true AND bit_24:true.

This is likely to run much, much faster than a bitwise comparison on each field. The bitwise comparise probably needs a full table scan on each query. Well, full field value scan, since Solr does not have tables.