Unify on Set.of

6 files changed, 11 insertions, 15 deletions

diff --git a/container-search/src/main/java/com/yahoo/prelude/fastsearch/FastHit.java b/container-search/src/main/java/com/yahoo/prelude/fastsearch/FastHit.java
index b5e5ed9ed8f..25aebfb5a00 100644
--- a/container-search/src/main/java/com/yahoo/prelude/fastsearch/FastHit.java
+++ b/container-search/src/main/java/com/yahoo/prelude/fastsearch/FastHit.java
@@ -13,7 +13,6 @@ import com.yahoo.data.access.Inspector;
 
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -62,7 +61,7 @@ public class FastHit extends Hit {
      * that most fields passes through the container with no processing most
      * of the time.
      */
-    private List<SummaryData> summaries = Collections.emptyList();
+    private List<SummaryData> summaries = List.of();
 
     /** Removed field values, which should therefore not be returned if present in summary data */
     private Set<String> removedFields = null;
@@ -481,7 +480,7 @@ public class FastHit extends Hit {
 
         private Set<String> createSet() {
             if (this.fieldSet != null) return this.fieldSet;
-            if ( ! hit.hasFields() && hit.summaries.isEmpty()) return Collections.emptySet(); // shortcut
+            if ( ! hit.hasFields() && hit.summaries.isEmpty()) return Set.of(); // shortcut
 
             Set<String> fields = new HashSet<>();
             if (hit.hasFields())
diff --git a/container-search/src/main/java/com/yahoo/prelude/query/parser/CustomParser.java b/container-search/src/main/java/com/yahoo/prelude/query/parser/CustomParser.java
index 44c0cb45732..520879be928 100644
--- a/container-search/src/main/java/com/yahoo/prelude/query/parser/CustomParser.java
+++ b/container-search/src/main/java/com/yahoo/prelude/query/parser/CustomParser.java
@@ -6,7 +6,6 @@ import com.yahoo.prelude.IndexFacts;
 import com.yahoo.prelude.query.Item;
 import com.yahoo.search.query.parser.Parser;
 
-import java.util.Collections;
 import java.util.Set;
 
 /**
@@ -23,7 +22,7 @@ public interface CustomParser extends Parser {
                        Set<String> toSearch, IndexFacts indexFacts, String defaultIndexName) {
         if (indexFacts == null)
             indexFacts = new IndexFacts();
-        return parse(queryToParse, filterToParse, parsingLanguage, indexFacts.newSession(toSearch, Collections.emptySet()), defaultIndexName);
+        return parse(queryToParse, filterToParse, parsingLanguage, indexFacts.newSession(toSearch, Set.of()), defaultIndexName);
     }
 
     Item parse(String queryToParse, String filterToParse, Language parsingLanguage,
diff --git a/container-search/src/main/java/com/yahoo/prelude/query/parser/Tokenizer.java b/container-search/src/main/java/com/yahoo/prelude/query/parser/Tokenizer.java
index 1c0d3ea2ee9..5a42efaaea0 100644
--- a/container-search/src/main/java/com/yahoo/prelude/query/parser/Tokenizer.java
+++ b/container-search/src/main/java/com/yahoo/prelude/query/parser/Tokenizer.java
@@ -8,8 +8,8 @@ import com.yahoo.prelude.Index;
 import com.yahoo.prelude.IndexFacts;
 import com.yahoo.prelude.query.Substring;
 
-import java.util.Collections;
 import java.util.List;
+import java.util.Set;
 
 import static com.yahoo.prelude.query.parser.Token.Kind.*;
 
@@ -63,7 +63,7 @@ public final class Tokenizer {
      * @return a read-only list of tokens. This list can only be used by this thread
      */
     public List<Token> tokenize(String string) {
-        return tokenize(string, new IndexFacts().newSession(Collections.emptySet(), Collections.emptySet()));
+        return tokenize(string, new IndexFacts().newSession(Set.of(), Set.of()));
     }
 
     /**
diff --git a/container-search/src/main/java/com/yahoo/search/handler/SearchHandler.java b/container-search/src/main/java/com/yahoo/search/handler/SearchHandler.java
index c1eff1eec67..c2a5ad0222d 100644
--- a/container-search/src/main/java/com/yahoo/search/handler/SearchHandler.java
+++ b/container-search/src/main/java/com/yahoo/search/handler/SearchHandler.java
@@ -3,7 +3,6 @@ package com.yahoo.search.handler;
 
 import ai.vespa.metrics.ContainerMetrics;
 import ai.vespa.cloud.ZoneInfo;
-import ai.vespa.metrics.ContainerMetrics;
 import com.yahoo.collections.Tuple2;
 import com.yahoo.component.ComponentSpecification;
 import com.yahoo.component.Vtag;
@@ -117,7 +116,7 @@ public class SearchHandler extends LoggingRequestHandler {
                          ZoneInfo zoneInfo) {
         this(metric, threadpool.executor(), queryProfileRegistry, embedders, executionFactory,
              config.numQueriesToTraceOnDebugAfterConstruction(),
-             config.hostResponseHeaderKey().equals("") ? Optional.empty() : Optional.of(config.hostResponseHeaderKey()),
+                config.hostResponseHeaderKey().isEmpty() ? Optional.empty() : Optional.of(config.hostResponseHeaderKey()),
              zoneInfo);
     }
 
diff --git a/container-search/src/main/java/com/yahoo/search/result/FeatureData.java b/container-search/src/main/java/com/yahoo/search/result/FeatureData.java
index 0f26ecdcce7..55a4c6c11f2 100644
--- a/container-search/src/main/java/com/yahoo/search/result/FeatureData.java
+++ b/container-search/src/main/java/com/yahoo/search/result/FeatureData.java
@@ -14,7 +14,6 @@ import com.yahoo.tensor.serialization.TypedBinaryFormat;
 import static com.yahoo.searchlib.rankingexpression.Reference.wrapInRankingExpression;
 
 import java.nio.charset.StandardCharsets;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
@@ -150,7 +149,7 @@ public class FeatureData implements Inspectable, JsonProducer {
 
     /** Returns the names of the features available in this */
     public Set<String> featureNames() {
-        if (this == empty) return Collections.emptySet();
+        if (this == empty) return Set.of();
         if (featureNames != null) return featureNames;
 
         featureNames = new HashSet<>();
diff --git a/container-search/src/main/java/com/yahoo/search/result/HitGroup.java b/container-search/src/main/java/com/yahoo/search/result/HitGroup.java
index 51c0caf38a9..ce403861014 100644
--- a/container-search/src/main/java/com/yahoo/search/result/HitGroup.java
+++ b/container-search/src/main/java/com/yahoo/search/result/HitGroup.java
@@ -718,7 +718,7 @@ public class HitGroup extends Hit implements DataList<Hit>, Cloneable, Iterable<
                 if (hitFilled.isEmpty()) {
                     filled = null;
                 } else if (hitFilled.size() == 1) {
-                    filled = Collections.singleton(hitFilled.iterator().next());
+                    filled = Set.of(hitFilled.iterator().next());
                 } else {
                     filled = new HashSet<>(hitFilled);
                 }
@@ -800,7 +800,7 @@ public class HitGroup extends Hit implements DataList<Hit>, Cloneable, Iterable<
             Set<String> hitFilled = hit.getFilled();
             if (hitFilled != null) {
                 filled = (hitFilled.size() == 1)
-                        ? Collections.singleton(hitFilled.iterator().next())
+                        ? Set.of(hitFilled.iterator().next())
                         : hitFilled.isEmpty() ? null : new HashSet<>(hitFilled);
                 setFilledInternal(filled);
             }
@@ -931,9 +931,9 @@ public class HitGroup extends Hit implements DataList<Hit>, Cloneable, Iterable<
     private Set<String> getFilledSingle(String summaryName, Set<String> summaryNames, Iterator<Hit> iterator) {
         while (true) {
             if (summaryNames == null) {
-                return Collections.singleton(summaryName);
+                return Set.of(summaryName);
             } else if (!summaryNames.contains(summaryName)) {
-                return Collections.emptySet();
+                return Set.of();
             }
             summaryNames = getSummaryNamesNextFilledHit(iterator);
         }