I've recently upgraded to Solr 1.3 using Lucene 2.4. One of the reasons I
upgraded was because of the nicer SearchComponent architecture that let me
add a needed feature to the default request handler. Simply put, I needed to
filter a query based on some additional parameters. So I subclassed
QueryComponent and replaced the line
rb.setQuery( parser.getQuery() );
with one that wrapped the parsed query in a FilteredQuery
Query query = parser.getQuery();
String arguments = params.get("param-name");
if( arguments != null) {
query = new FilteredQuery(query, new MyCustomFilter(arguments));
}
rb.setQuery(query);
The filter class I used can be seen here: http://privatepaste.com/021ZH27tKG.
And is nearly verbatim from the Lucene in Action book, when describing a way
to do security filtering.
This seems to work fine, although I'm getting some strange behavior when
exercising this code through some unit tests from my Rails app. Sometimes I
get an NPE when doing the filtering.
at top level in at
org.apache.lucene.index.MultiSegmentReader$MultiTermDocs.doc(MultiSegmentReader.java
at line 533
at <MyQueryComponent>$MyCustomFilter.bits(Unknown Source)
at top level in at org.apache.lucene.search.Filter.getDocIdSet(Filter.java
at line 49
at top level in at
org.apache.lucene.search.FilteredQuery$1.scorer(FilteredQuery.java at line
105
at top level in at
org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java at line 132
at top level in at org.apache.lucene.search.Searcher.search(Searcher.java
at line 126
After some detective work I decided the problem had to do with an empty
index, and the termDocs iterator has 0 elements to iterate over and was
throwing this error. Since there is no size() method or analogous method on
the TermDocs iterator, I decided to use docFreq(term) as you can see in the
source code. But this didn't solve my problem either. This error is being
throw even when docFreq(term) returns more then 0 documents. I can't for the
life of me figure out why this iterator's doc() method throwing an NPE.
(Well I can deduce that the current member is null, but I don't know why.)
Is the index corrupted? I can see record in the index that should match my
Term through the solr /admin/ interface, and docFreq(term) returns a number
> 0. Yet this NPE keeps showing up.
Any help or guidance would be appreciated. If you need to see more source
I'd be happy to provide it, but I'm sure thats all the relevant stuff.
(I cross posted this to both Solr and Lucene lists.)
Comron
