Java 类org.apache.lucene.search.FilterCollector 实例源码

private Collector getInsanityWrapper(final String field, Collector collector) {
  SchemaField sf = searcher.getSchema().getFieldOrNull(field);
  if (sf != null && !sf.hasDocValues() && !sf.multiValued() && sf.getType().getNumberType() != null) {
    // it's a single-valued numeric field: we must currently create insanity :(
    // there isn't a GroupedFacetCollector that works on numerics right now...
    return new FilterCollector(collector) {
      @Override
      public LeafCollector getLeafCollector(LeafReaderContext context) throws IOException {
        LeafReader insane = Insanity.wrapInsanity(context.reader(), field);
        return in.getLeafCollector(insane.getContext());
      }
    };
  } else {
    return collector;
  }
}