NexusIndexer indexer = prepare();
Query q = indexer.constructQuery( MAVEN.GROUP_ID, "commons", SearchType.SCORED );
UniqueArtifactFilterPostprocessor filter = new UniqueArtifactFilterPostprocessor();
filter.addField( MAVEN.GROUP_ID );
filter.addField( MAVEN.ARTIFACT_ID );
IteratorSearchRequest request = new IteratorSearchRequest( q, filter );
IteratorSearchResponse response = indexer.searchIterator( request );