CavalliumDBEngine/src/main/java/it/cavallium/dbengine/lucene/searcher/TopDocsSearcher.java

package it.cavallium.dbengine.lucene.searcher;

import java.io.IOException;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.index.NumericDocValues;
import org.apache.lucene.misc.search.DiversifiedTopDocsCollector;
import org.apache.lucene.search.BulkScorer;
import org.apache.lucene.search.Collector;
import org.apache.lucene.search.FieldDoc;
import org.apache.lucene.search.HitQueue;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.LeafCollector;
import org.apache.lucene.search.MultiCollectorManager.Collectors;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Scorable;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.ScoreMode;
import org.apache.lucene.search.Sort;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.search.TopDocsCollector;
import org.apache.lucene.search.TopFieldCollector;
import org.apache.lucene.search.TopScoreDocCollector;
import org.apache.lucene.search.TotalHits.Relation;

class TopDocsSearcher {

	@SuppressWarnings({"unchecked", "rawtypes"})
	public static TopDocsCollector<ScoreDoc> getTopDocsCollector(Sort luceneSort,
			int limit,
			ScoreDoc after,
			int totalHitsThreshold) {
		TopDocsCollector<ScoreDoc> collector;
		if (luceneSort == null) {
			if (after == null) {
				collector = TopScoreDocCollector.create(limit, totalHitsThreshold);
			} else {
				collector = TopScoreDocCollector.create(limit, after, totalHitsThreshold);
			}
		} else {
			if (after == null) {
				collector = (TopDocsCollector<ScoreDoc>) (TopDocsCollector) TopFieldCollector.create(luceneSort, limit, totalHitsThreshold);
			} else if (after instanceof FieldDoc afterFieldDoc) {
				collector = (TopDocsCollector<ScoreDoc>) (TopDocsCollector) TopFieldCollector.create(luceneSort, limit, afterFieldDoc, totalHitsThreshold);
			} else {
				throw new UnsupportedOperationException("GetTopDocs with \"luceneSort\" != null requires \"after\" to be a FieldDoc");
			}
		}
		return collector;
	}
}