Introduce and use a few more empty response type constants to o.e.c.lucene.Lucene

Shortening a few more pieces of production code using constants,
potentially saving a little in code size and allocation in some cases.

Author: original-brownbear

server/src/main/java/org/elasticsearch/action/search/DfsQueryPhase.java

@@ -9,6 +9,7 @@
 
 import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.join.ScoreMode;
+import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.index.query.NestedQueryBuilder;
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.search.SearchPhaseResult;
@@ -152,7 +153,7 @@ ShardSearchRequest rewriteShardSearchRequest(ShardSearchRequest request) {
             scoreDocs.sort(Comparator.comparingInt(scoreDoc -> scoreDoc.doc));
             String nestedPath = dfsKnnResults.getNestedPath();
             QueryBuilder query = new KnnScoreDocQueryBuilder(
-                scoreDocs.toArray(new ScoreDoc[0]),
+                scoreDocs.toArray(Lucene.EMPTY_SCORE_DOCS),
                 source.knnSearch().get(i).getField(),
                 source.knnSearch().get(i).getQueryVector()
             ).boost(source.knnSearch().get(i).boost()).queryName(source.knnSearch().get(i).queryName());

server/src/main/java/org/elasticsearch/action/search/SearchPhaseController.java

@@ -24,6 +24,7 @@
 import org.apache.lucene.util.SetOnce;
 import org.elasticsearch.common.breaker.CircuitBreaker;
 import org.elasticsearch.common.io.stream.DelayableWriteable;
+import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.lucene.search.TopDocsAndMaxScore;
 import org.elasticsearch.common.util.Maps;
 import org.elasticsearch.common.util.concurrent.AtomicArray;
@@ -66,7 +67,6 @@
 import static org.elasticsearch.search.SearchService.DEFAULT_SIZE;
 
 public final class SearchPhaseController {
-    private static final ScoreDoc[] EMPTY_DOCS = new ScoreDoc[0];
 
     private final BiFunction<
         Supplier<Boolean>,
@@ -195,7 +195,7 @@ static SortedTopDocs sortDocs(
             return SortedTopDocs.EMPTY;
         }
         final TopDocs mergedTopDocs = mergeTopDocs(topDocs, size, ignoreFrom ? 0 : from);
-        final ScoreDoc[] mergedScoreDocs = mergedTopDocs == null ? EMPTY_DOCS : mergedTopDocs.scoreDocs;
+        final ScoreDoc[] mergedScoreDocs = mergedTopDocs == null ? Lucene.EMPTY_SCORE_DOCS : mergedTopDocs.scoreDocs;
         ScoreDoc[] scoreDocs = mergedScoreDocs;
         int numSuggestDocs = 0;
         if (reducedCompletionSuggestions.isEmpty() == false) {
@@ -907,6 +907,6 @@ public record SortedTopDocs(
         Object[] collapseValues,
         int numberOfCompletionsSuggestions
     ) {
-        public static final SortedTopDocs EMPTY = new SortedTopDocs(EMPTY_DOCS, false, null, null, null, 0);
+        public static final SortedTopDocs EMPTY = new SortedTopDocs(Lucene.EMPTY_SCORE_DOCS, false, null, null, null, 0);
     }
 }

server/src/main/java/org/elasticsearch/action/search/SearchResponse.java

@@ -8,7 +8,6 @@
 
 package org.elasticsearch.action.search;
 
-import org.apache.lucene.search.TotalHits;
 import org.elasticsearch.TransportVersions;
 import org.elasticsearch.action.ActionResponse;
 import org.elasticsearch.action.OriginalIndices;
@@ -18,6 +17,7 @@
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
 import org.elasticsearch.common.xcontent.ChunkedToXContentHelper;
 import org.elasticsearch.common.xcontent.ChunkedToXContentObject;
@@ -1154,7 +1154,7 @@ public String toString() {
     // public for tests
     public static SearchResponse empty(Supplier<Long> tookInMillisSupplier, Clusters clusters) {
         return new SearchResponse(
-            SearchHits.empty(new TotalHits(0L, TotalHits.Relation.EQUAL_TO), Float.NaN),
+            SearchHits.empty(Lucene.TOTAL_HITS_EQUAL_TO_ZERO, Float.NaN),
             InternalAggregations.EMPTY,
             null,
             false,

server/src/main/java/org/elasticsearch/action/search/SearchResponseMerger.java

@@ -18,6 +18,7 @@
 import org.elasticsearch.action.search.SearchPhaseController.TopDocsStats;
 import org.elasticsearch.action.search.SearchResponse.Clusters;
 import org.elasticsearch.action.search.TransportSearchAction.SearchTimeProvider;
+import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.lucene.search.TopDocsAndMaxScore;
 import org.elasticsearch.core.Releasable;
 import org.elasticsearch.index.shard.ShardId;
@@ -177,7 +178,7 @@ public SearchResponse getMergedResponse(Clusters clusters) {
             final TotalHits totalHits;
             if (searchHits.getTotalHits() == null) {
                 // in case we didn't track total hits, we get null from each cluster, but we need to set 0 eq to the TopDocs
-                totalHits = new TotalHits(0, TotalHits.Relation.EQUAL_TO);
+                totalHits = Lucene.TOTAL_HITS_EQUAL_TO_ZERO;
                 assert trackTotalHits == null || trackTotalHits == false;
                 trackTotalHits = false;
             } else {

server/src/main/java/org/elasticsearch/common/lucene/Lucene.java

@@ -101,7 +101,10 @@ public class Lucene {
 
     public static final ScoreDoc[] EMPTY_SCORE_DOCS = new ScoreDoc[0];
 
-    public static final TopDocs EMPTY_TOP_DOCS = new TopDocs(new TotalHits(0, TotalHits.Relation.EQUAL_TO), EMPTY_SCORE_DOCS);
+    public static final TotalHits TOTAL_HITS_EQUAL_TO_ZERO = new TotalHits(0, TotalHits.Relation.EQUAL_TO);
+    public static final TotalHits TOTAL_HITS_GREATER_OR_EQUAL_TO_ZERO = new TotalHits(0, TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO);
+
+    public static final TopDocs EMPTY_TOP_DOCS = new TopDocs(TOTAL_HITS_EQUAL_TO_ZERO, EMPTY_SCORE_DOCS);
 
     private Lucene() {}
 

server/src/main/java/org/elasticsearch/lucene/grouping/SinglePassGroupingCollector.java

@@ -36,6 +36,7 @@
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.search.grouping.GroupSelector;
+import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.util.Maps;
 import org.elasticsearch.core.Nullable;
 import org.elasticsearch.index.mapper.MappedFieldType;
@@ -202,7 +203,7 @@ public TopFieldGroups getTopGroups(int groupOffset) throws IOException {
 
         if (groupMap.size() <= groupOffset) {
             TotalHits totalHits = new TotalHits(totalHitCount, TotalHits.Relation.EQUAL_TO);
-            return new TopFieldGroups(groupField, totalHits, new ScoreDoc[0], groupSort.getSort(), new Object[0]);
+            return new TopFieldGroups(groupField, totalHits, Lucene.EMPTY_SCORE_DOCS, groupSort.getSort(), new Object[0]);
         }
 
         if (orderedGroups == null) {

server/src/main/java/org/elasticsearch/lucene/grouping/TopFieldGroups.java

@@ -16,6 +16,7 @@
 import org.apache.lucene.search.TopFieldDocs;
 import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.util.PriorityQueue;
+import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.util.CollectionUtils;
 
 import java.util.ArrayList;
@@ -225,7 +226,7 @@ public static TopFieldGroups merge(Sort sort, int start, int size, TopFieldGroup
                     queue.pop();
                 }
             }
-            hits = hitList.toArray(new ScoreDoc[0]);
+            hits = hitList.toArray(Lucene.EMPTY_SCORE_DOCS);
             values = groupList.toArray(new Object[0]);
         }
         TotalHits totalHits = new TotalHits(totalHitCount, totalHitsRelation);

server/src/main/java/org/elasticsearch/search/SearchHits.java

@@ -34,7 +34,7 @@
 public final class SearchHits implements Writeable, ChunkedToXContent, RefCounted, Iterable<SearchHit> {
 
     public static final SearchHit[] EMPTY = new SearchHit[0];
-    public static final SearchHits EMPTY_WITH_TOTAL_HITS = SearchHits.empty(new TotalHits(0, Relation.EQUAL_TO), 0);
+    public static final SearchHits EMPTY_WITH_TOTAL_HITS = SearchHits.empty(Lucene.TOTAL_HITS_EQUAL_TO_ZERO, 0);
     public static final SearchHits EMPTY_WITHOUT_TOTAL_HITS = SearchHits.empty(null, 0);
 
     private final SearchHit[] hits;

server/src/main/java/org/elasticsearch/search/aggregations/metrics/TopHitsAggregator.java

@@ -20,7 +20,6 @@
 import org.apache.lucene.search.TopFieldCollector;
 import org.apache.lucene.search.TopFieldDocs;
 import org.apache.lucene.search.TopScoreDocCollector;
-import org.apache.lucene.search.TotalHits;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.action.search.MaxScoreCollector;
 import org.elasticsearch.common.lucene.Lucene;
@@ -233,11 +232,7 @@ public SearchExecutionContext getSearchExecutionContext() {
     public InternalTopHits buildEmptyAggregation() {
         TopDocs topDocs;
         if (subSearchContext.sort() != null) {
-            topDocs = new TopFieldDocs(
-                new TotalHits(0, TotalHits.Relation.EQUAL_TO),
-                new FieldDoc[0],
-                subSearchContext.sort().sort.getSort()
-            );
+            topDocs = new TopFieldDocs(Lucene.TOTAL_HITS_EQUAL_TO_ZERO, new FieldDoc[0], subSearchContext.sort().sort.getSort());
         } else {
             topDocs = Lucene.EMPTY_TOP_DOCS;
         }

server/src/main/java/org/elasticsearch/search/query/QueryPhase.java

@@ -22,7 +22,6 @@
 import org.apache.lucene.search.ScoreMode;
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.TopDocs;
-import org.apache.lucene.search.TotalHits;
 import org.apache.lucene.search.Weight;
 import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.lucene.search.TopDocsAndMaxScore;
@@ -76,11 +75,7 @@ static void executeRank(SearchContext searchContext) throws QueryPhaseExecutionE
             searchContext.size(0);
             QueryPhase.executeQuery(searchContext);
         } else {
-            searchContext.queryResult()
-                .topDocs(
-                    new TopDocsAndMaxScore(new TopDocs(new TotalHits(0, TotalHits.Relation.EQUAL_TO), Lucene.EMPTY_SCORE_DOCS), Float.NaN),
-                    new DocValueFormat[0]
-                );
+            searchContext.queryResult().topDocs(new TopDocsAndMaxScore(Lucene.EMPTY_TOP_DOCS, Float.NaN), new DocValueFormat[0]);
         }
 
         List<TopDocs> rrfRankResults = new ArrayList<>();
@@ -124,11 +119,7 @@ static void executeRank(SearchContext searchContext) throws QueryPhaseExecutionE
     static void executeQuery(SearchContext searchContext) throws QueryPhaseExecutionException {
         if (searchContext.hasOnlySuggest()) {
             SuggestPhase.execute(searchContext);
-            searchContext.queryResult()
-                .topDocs(
-                    new TopDocsAndMaxScore(new TopDocs(new TotalHits(0, TotalHits.Relation.EQUAL_TO), Lucene.EMPTY_SCORE_DOCS), Float.NaN),
-                    new DocValueFormat[0]
-                );
+            searchContext.queryResult().topDocs(new TopDocsAndMaxScore(Lucene.EMPTY_TOP_DOCS, Float.NaN), new DocValueFormat[0]);
             return;
         }
 

server/src/main/java/org/elasticsearch/search/query/QueryPhaseCollectorManager.java

@@ -400,7 +400,7 @@ private static class WithHits extends QueryPhaseCollectorManager {
             } else if (trackTotalHitsUpTo == SearchContext.TRACK_TOTAL_HITS_DISABLED) {
                 // don't compute hit counts via the collector
                 hitCountThreshold = 1;
-                shortcutTotalHits = new TotalHits(0, TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO);
+                shortcutTotalHits = Lucene.TOTAL_HITS_GREATER_OR_EQUAL_TO_ZERO;
             } else {
                 // implicit total hit counts are valid only when there is no filter collector in the chain
                 final int hitCount = hasFilterCollector ? -1 : shortcutTotalHitCount(reader, query);

x-pack/plugin/async-search/src/main/java/org/elasticsearch/xpack/search/MutableSearchResponse.java

@@ -14,6 +14,7 @@
 import org.elasticsearch.action.search.SearchResponseMerger;
 import org.elasticsearch.action.search.ShardSearchFailure;
 import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.util.concurrent.AtomicArray;
 import org.elasticsearch.common.util.concurrent.ThreadContext;
 import org.elasticsearch.core.Releasable;
@@ -38,7 +39,6 @@
  * run concurrently to 1 and ensures that we pause the search progress when an {@link AsyncSearchResponse} is built.
  */
 class MutableSearchResponse implements Releasable {
-    private static final TotalHits EMPTY_TOTAL_HITS = new TotalHits(0L, TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO);
     private final int totalShards;
     private final int skippedShards;
     private final Clusters clusters;
@@ -95,7 +95,7 @@ class MutableSearchResponse implements Releasable {
         this.queryFailures = totalShards == -1 ? null : new AtomicArray<>(totalShards - skippedShards);
         this.isPartial = true;
         this.threadContext = threadContext;
-        this.totalHits = EMPTY_TOTAL_HITS;
+        this.totalHits = Lucene.TOTAL_HITS_GREATER_OR_EQUAL_TO_ZERO;
         this.localClusterComplete = false;
     }
 

x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/profile/ProfileService.java

@@ -9,7 +9,6 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.search.TotalHits;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.ElasticsearchStatusException;
 import org.elasticsearch.ExceptionsHelper;
@@ -40,6 +39,7 @@
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.Fuzziness;
 import org.elasticsearch.common.xcontent.XContentHelper;
@@ -265,11 +265,7 @@ public void updateProfileData(UpdateProfileDataRequest request, ActionListener<A
     public void suggestProfile(SuggestProfilesRequest request, TaskId parentTaskId, ActionListener<SuggestProfilesResponse> listener) {
         tryFreezeAndCheckIndex(listener.map(response -> {
             assert response == null : "only null response can reach here";
-            return new SuggestProfilesResponse(
-                new SuggestProfilesResponse.ProfileHit[] {},
-                0,
-                new TotalHits(0, TotalHits.Relation.EQUAL_TO)
-            );
+            return new SuggestProfilesResponse(new SuggestProfilesResponse.ProfileHit[] {}, 0, Lucene.TOTAL_HITS_EQUAL_TO_ZERO);
         }), SEARCH_SHARDS).ifPresent(frozenProfileIndex -> {
             final SearchRequest searchRequest = buildSearchRequestForSuggest(request, parentTaskId);