Dry up writing string collections via StreamOutput (#99087)

We can dry up and shorten a bunch of spots by using the overloads we already have in the code. Also, added a new overload for writing a map with string keys.
elastic · Sep 2, 2023 · 97ebcea · 97ebcea
1 parent 621f52f
commit 97ebcea
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Showing 208 changed files with 278 additions and 297 deletions.
diff --git a/...ava/org/elasticsearch/aggregations/pipeline/BucketSelectorPipelineAggregationBuilder.java b/...ava/org/elasticsearch/aggregations/pipeline/BucketSelectorPipelineAggregationBuilder.java
@@ -55,7 +55,7 @@ public BucketSelectorPipelineAggregationBuilder(StreamInput in) throws IOExcepti
 
     @Override
     protected void doWriteTo(StreamOutput out) throws IOException {
-        out.writeMap(bucketsPathsMap, StreamOutput::writeString, StreamOutput::writeString);
+        out.writeMap(bucketsPathsMap, StreamOutput::writeString);
         script.writeTo(out);
         gapPolicy.writeTo(out);
     }

diff --git a/...s/ingest-common/src/main/java/org/elasticsearch/ingest/common/GrokProcessorGetAction.java b/...s/ingest-common/src/main/java/org/elasticsearch/ingest/common/GrokProcessorGetAction.java
@@ -116,7 +116,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
         @Override
         public void writeTo(StreamOutput out) throws IOException {
-            out.writeMap(grokPatterns, StreamOutput::writeString, StreamOutput::writeString);
+            out.writeMap(grokPatterns, StreamOutput::writeString);
         }
     }
 

diff --git a/modules/ingest-geoip/src/main/java/org/elasticsearch/ingest/geoip/GeoIpTaskState.java b/modules/ingest-geoip/src/main/java/org/elasticsearch/ingest/geoip/GeoIpTaskState.java
@@ -127,7 +127,7 @@ public TransportVersion getMinimalSupportedVersion() {
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeMap(databases, StreamOutput::writeString, (o, v) -> {
+        out.writeMap(databases, (o, v) -> {
             o.writeLong(v.lastUpdate);
             o.writeVInt(v.firstChunk);
             o.writeVInt(v.lastChunk);

diff --git a/...-geoip/src/main/java/org/elasticsearch/ingest/geoip/stats/GeoIpDownloaderStatsAction.java b/...-geoip/src/main/java/org/elasticsearch/ingest/geoip/stats/GeoIpDownloaderStatsAction.java
@@ -208,10 +208,10 @@ public void writeTo(StreamOutput out) throws IOException {
             if (stats != null) {
                 stats.writeTo(out);
             }
-            out.writeCollection(databases, StreamOutput::writeString);
-            out.writeCollection(filesInTemp, StreamOutput::writeString);
+            out.writeStringCollection(databases);
+            out.writeStringCollection(filesInTemp);
             if (out.getTransportVersion().onOrAfter(TransportVersion.V_8_0_0)) {
-                out.writeCollection(configDatabases, StreamOutput::writeString);
+                out.writeStringCollection(configDatabases);
             }
         }
 

diff --git a/...acy-geo/src/main/java/org/elasticsearch/legacygeo/builders/GeometryCollectionBuilder.java b/...acy-geo/src/main/java/org/elasticsearch/legacygeo/builders/GeometryCollectionBuilder.java
@@ -51,7 +51,7 @@ public GeometryCollectionBuilder(StreamInput in) throws IOException {
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeNamedWriteableList(shapes);
+        out.writeNamedWriteableCollection(shapes);
     }
 
     public GeometryCollectionBuilder shape(ShapeBuilder<?, ?, ?> shape) {

diff --git a/modules/rank-eval/src/main/java/org/elasticsearch/index/rankeval/RankEvalResponse.java b/modules/rank-eval/src/main/java/org/elasticsearch/index/rankeval/RankEvalResponse.java
@@ -88,8 +88,8 @@ public String toString() {
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         out.writeDouble(metricScore);
-        out.writeMap(details, StreamOutput::writeString, (o, v) -> v.writeTo(o));
-        out.writeMap(failures, StreamOutput::writeString, StreamOutput::writeException);
+        out.writeMap(details, (o, v) -> v.writeTo(o));
+        out.writeMap(failures, StreamOutput::writeException);
     }
 
     @Override

diff --git a/modules/rank-eval/src/main/java/org/elasticsearch/index/rankeval/RankEvalSpec.java b/modules/rank-eval/src/main/java/org/elasticsearch/index/rankeval/RankEvalSpec.java
@@ -98,7 +98,7 @@ public RankEvalSpec(StreamInput in) throws IOException {
     public void writeTo(StreamOutput out) throws IOException {
         out.writeCollection(ratedRequests);
         out.writeNamedWriteable(metric);
-        out.writeMap(templates, StreamOutput::writeString, (o, v) -> v.writeTo(o));
+        out.writeMap(templates, (o, v) -> v.writeTo(o));
         out.writeVInt(maxConcurrentSearches);
     }
 

diff --git a/...c/main/java/org/elasticsearch/action/admin/cluster/allocation/DesiredBalanceResponse.java b/...c/main/java/org/elasticsearch/action/admin/cluster/allocation/DesiredBalanceResponse.java
@@ -76,7 +76,6 @@ public void writeTo(StreamOutput out) throws IOException {
         }
         out.writeMap(
             routingTable,
-            StreamOutput::writeString,
             (shardsOut, shards) -> shardsOut.writeMap(
                 shards,
                 StreamOutput::writeVInt,
@@ -308,7 +307,7 @@ public static ShardAssignmentView from(StreamInput in) throws IOException {
 
         @Override
         public void writeTo(StreamOutput out) throws IOException {
-            out.writeCollection(nodeIds, StreamOutput::writeString);
+            out.writeStringCollection(nodeIds);
             out.writeVInt(total);
             out.writeVInt(unassigned);
             out.writeVInt(ignored);

diff --git a/...org/elasticsearch/action/admin/cluster/node/shutdown/NodePrevalidateShardPathRequest.java b/...org/elasticsearch/action/admin/cluster/node/shutdown/NodePrevalidateShardPathRequest.java
@@ -37,7 +37,7 @@ public NodePrevalidateShardPathRequest(StreamInput in) throws IOException {
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
-        out.writeCollection(shardIds, (o, value) -> value.writeTo(o));
+        out.writeCollection(shardIds);
     }
 
     public Set<ShardId> getShardIds() {

diff --git a/.../main/java/org/elasticsearch/action/admin/cluster/shards/ClusterSearchShardsResponse.java b/.../main/java/org/elasticsearch/action/admin/cluster/shards/ClusterSearchShardsResponse.java
@@ -37,7 +37,7 @@ public ClusterSearchShardsResponse(StreamInput in) throws IOException {
     public void writeTo(StreamOutput out) throws IOException {
         out.writeArray(groups);
         out.writeArray(nodes);
-        out.writeMap(indicesAndFilters, StreamOutput::writeString, (o, s) -> s.writeTo(o));
+        out.writeMap(indicesAndFilters, (o, s) -> s.writeTo(o));
     }
 
     public ClusterSearchShardsResponse(

diff --git a/.../main/java/org/elasticsearch/action/admin/cluster/snapshots/get/GetSnapshotsResponse.java b/.../main/java/org/elasticsearch/action/admin/cluster/snapshots/get/GetSnapshotsResponse.java
@@ -150,7 +150,7 @@ public int remaining() {
     public void writeTo(StreamOutput out) throws IOException {
         out.writeCollection(snapshots);
         if (out.getTransportVersion().onOrAfter(GetSnapshotsRequest.MULTIPLE_REPOSITORIES_SUPPORT_ADDED)) {
-            out.writeMap(failures, StreamOutput::writeString, StreamOutput::writeException);
+            out.writeMap(failures, StreamOutput::writeException);
             out.writeOptionalString(next);
         } else {
             if (failures.isEmpty() == false) {

diff --git a/.../org/elasticsearch/action/admin/cluster/snapshots/get/shard/GetShardSnapshotResponse.java b/.../org/elasticsearch/action/admin/cluster/snapshots/get/shard/GetShardSnapshotResponse.java
@@ -40,7 +40,7 @@ public class GetShardSnapshotResponse extends ActionResponse {
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         out.writeOptionalWriteable(latestShardSnapshot);
-        out.writeMap(repositoryFailures, StreamOutput::writeString, (o, err) -> err.writeTo(o));
+        out.writeMap(repositoryFailures, (o, err) -> err.writeTo(o));
     }
 
     public Optional<RepositoryException> getFailureForRepository(String repository) {

diff --git a/...rg/elasticsearch/action/admin/cluster/snapshots/status/TransportNodesSnapshotsStatus.java b/...rg/elasticsearch/action/admin/cluster/snapshots/status/TransportNodesSnapshotsStatus.java
@@ -210,11 +210,7 @@ public Map<Snapshot, Map<ShardId, SnapshotIndexShardStatus>> status() {
         public void writeTo(StreamOutput out) throws IOException {
             super.writeTo(out);
             if (status != null) {
-                out.writeMap(
-                    status,
-                    (o, s) -> s.writeTo(o),
-                    (output, v) -> output.writeMap(v, (o, shardId) -> shardId.writeTo(o), (o, sis) -> sis.writeTo(o))
-                );
+                out.writeMap(status, (o, s) -> s.writeTo(o), StreamOutput::writeMap);
             } else {
                 out.writeVInt(0);
             }

diff --git a/server/src/main/java/org/elasticsearch/action/admin/cluster/stats/AnalysisStats.java b/server/src/main/java/org/elasticsearch/action/admin/cluster/stats/AnalysisStats.java
@@ -301,7 +301,7 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeCollection(usedBuiltInTokenFilters);
         out.writeCollection(usedBuiltInAnalyzers);
         if (out.getTransportVersion().onOrAfter(SYNONYM_SETS_VERSION)) {
-            out.writeMap(usedSynonyms, StreamOutput::writeString, (o, v) -> v.writeTo(o));
+            out.writeMap(usedSynonyms, (o, v) -> v.writeTo(o));
         }
     }
 

diff --git a/server/src/main/java/org/elasticsearch/action/admin/cluster/stats/FieldStats.java b/server/src/main/java/org/elasticsearch/action/admin/cluster/stats/FieldStats.java
@@ -42,7 +42,7 @@ public class FieldStats extends IndexFeatureStats {
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         out.writeVInt(scriptCount);
-        out.writeCollection(scriptLangs, StreamOutput::writeString);
+        out.writeStringCollection(scriptLangs);
         fieldScriptStats.writeTo(out);
     }
 

diff --git a/server/src/main/java/org/elasticsearch/action/admin/cluster/stats/RuntimeFieldStats.java b/server/src/main/java/org/elasticsearch/action/admin/cluster/stats/RuntimeFieldStats.java
@@ -53,7 +53,7 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeString(type);
         out.writeInt(count);
         out.writeInt(indexCount);
-        out.writeCollection(scriptLangs, StreamOutput::writeString);
+        out.writeStringCollection(scriptLangs);
         out.writeLong(scriptLessCount);
         out.writeLong(shadowedCount);
         fieldScriptStats.writeTo(out);

diff --git a/server/src/main/java/org/elasticsearch/action/admin/cluster/stats/SearchUsageStats.java b/server/src/main/java/org/elasticsearch/action/admin/cluster/stats/SearchUsageStats.java
@@ -58,8 +58,8 @@ public SearchUsageStats(StreamInput in) throws IOException {
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeMap(queries, StreamOutput::writeString, StreamOutput::writeLong);
-        out.writeMap(sections, StreamOutput::writeString, StreamOutput::writeLong);
+        out.writeMap(queries, StreamOutput::writeLong);
+        out.writeMap(sections, StreamOutput::writeLong);
         out.writeVLong(totalSearchCount);
     }
 

diff --git a/...er/src/main/java/org/elasticsearch/action/admin/indices/alias/get/GetAliasesResponse.java b/...er/src/main/java/org/elasticsearch/action/admin/indices/alias/get/GetAliasesResponse.java
@@ -45,8 +45,8 @@ public Map<String, List<DataStreamAlias>> getDataStreamAliases() {
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeMap(aliases, StreamOutput::writeString, (streamOutput1, list1) -> streamOutput1.writeCollection(list1));
-        out.writeMap(dataStreamAliases, StreamOutput::writeString, (streamOutput, list) -> streamOutput.writeCollection(list));
+        out.writeMap(aliases, StreamOutput::writeCollection);
+        out.writeMap(dataStreamAliases, StreamOutput::writeCollection);
     }
 
     @Override

diff --git a/...src/main/java/org/elasticsearch/action/admin/indices/analyze/ReloadAnalyzersResponse.java b/...src/main/java/org/elasticsearch/action/admin/indices/analyze/ReloadAnalyzersResponse.java
@@ -125,7 +125,7 @@ public static ReloadAnalyzersResponse fromXContent(XContentParser parser) {
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
-        out.writeMap(reloadDetails, StreamOutput::writeString, (stream, details) -> details.writeTo(stream));
+        out.writeMap(reloadDetails, (stream, details) -> details.writeTo(stream));
     }
 
     @Override

diff --git a/.../java/org/elasticsearch/action/admin/indices/diskusage/AnalyzeIndexDiskUsageResponse.java b/.../java/org/elasticsearch/action/admin/indices/diskusage/AnalyzeIndexDiskUsageResponse.java
@@ -40,7 +40,7 @@ public final class AnalyzeIndexDiskUsageResponse extends BroadcastResponse {
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
-        out.writeMap(stats, StreamOutput::writeString, (o, v) -> v.writeTo(o));
+        out.writeMap(stats, (o, v) -> v.writeTo(o));
     }
 
     Map<String, IndexDiskUsageStats> getStats() {

diff --git a/...r/src/main/java/org/elasticsearch/action/admin/indices/diskusage/IndexDiskUsageStats.java b/...r/src/main/java/org/elasticsearch/action/admin/indices/diskusage/IndexDiskUsageStats.java
@@ -61,7 +61,7 @@ public IndexDiskUsageStats(StreamInput in) throws IOException {
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeMap(fields, StreamOutput::writeString, (o, v) -> v.writeTo(o));
+        out.writeMap(fields, (o, v) -> v.writeTo(o));
         out.writeVLong(indexSizeInBytes);
     }
 

diff --git a/server/src/main/java/org/elasticsearch/action/admin/indices/get/GetIndexResponse.java b/server/src/main/java/org/elasticsearch/action/admin/indices/get/GetIndexResponse.java
@@ -173,10 +173,10 @@ public String getSetting(String index, String setting) {
     public void writeTo(StreamOutput out) throws IOException {
         out.writeStringArray(indices);
         MappingMetadata.writeMappingMetadata(out, mappings);
-        out.writeMap(aliases, StreamOutput::writeString, (streamOutput, list) -> streamOutput.writeCollection(list));
-        out.writeMap(settings, StreamOutput::writeString, (o, v) -> v.writeTo(o));
-        out.writeMap(defaultSettings, StreamOutput::writeString, (o, v) -> v.writeTo(o));
-        out.writeMap(dataStreams, StreamOutput::writeString, StreamOutput::writeOptionalString);
+        out.writeMap(aliases, StreamOutput::writeCollection);
+        out.writeMap(settings, (o, v) -> v.writeTo(o));
+        out.writeMap(defaultSettings, (o, v) -> v.writeTo(o));
+        out.writeMap(dataStreams, StreamOutput::writeOptionalString);
     }
 
     @Override

diff --git a/...ain/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java b/...ain/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java
@@ -153,12 +153,12 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeMap(mappings, StreamOutput::writeString, (outpt, map) -> {
+        out.writeMap(mappings, (outpt, map) -> {
             if (outpt.getTransportVersion().before(TransportVersion.V_8_0_0)) {
                 outpt.writeVInt(1);
                 outpt.writeString(MapperService.SINGLE_MAPPING_NAME);
             }
-            outpt.writeMap(map, StreamOutput::writeString, (o, v) -> {
+            outpt.writeMap(map, (o, v) -> {
                 o.writeString(v.fullName());
                 o.writeBytesReference(v.source);
             });

diff --git a/server/src/main/java/org/elasticsearch/action/admin/indices/rollover/RolloverConditions.java b/server/src/main/java/org/elasticsearch/action/admin/indices/rollover/RolloverConditions.java
@@ -115,9 +115,8 @@ public boolean hasMinConditions() {
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeCollection(
-            conditions.values().stream().filter(c -> c.includedInVersion(out.getTransportVersion())).toList(),
-            StreamOutput::writeNamedWriteable
+        out.writeNamedWriteableCollection(
+            conditions.values().stream().filter(c -> c.includedInVersion(out.getTransportVersion())).toList()
         );
     }
 

diff --git a/.../src/main/java/org/elasticsearch/action/admin/indices/rollover/RolloverConfiguration.java b/.../src/main/java/org/elasticsearch/action/admin/indices/rollover/RolloverConfiguration.java
@@ -71,7 +71,7 @@ public RolloverConfiguration(StreamInput in) throws IOException {
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         out.writeWriteable(concreteConditions);
-        out.writeCollection(automaticConditions, StreamOutput::writeString);
+        out.writeStringCollection(automaticConditions);
     }
 
     @Override

diff --git a/server/src/main/java/org/elasticsearch/action/admin/indices/rollover/RolloverInfo.java b/server/src/main/java/org/elasticsearch/action/admin/indices/rollover/RolloverInfo.java
@@ -88,7 +88,7 @@ public static Diff<RolloverInfo> readDiffFrom(StreamInput in) throws IOException
     public void writeTo(StreamOutput out) throws IOException {
         out.writeString(alias);
         out.writeVLong(time);
-        out.writeNamedWriteableList(metConditions);
+        out.writeNamedWriteableCollection(metConditions);
     }
 
     @Override

diff --git a/server/src/main/java/org/elasticsearch/action/admin/indices/rollover/RolloverResponse.java b/server/src/main/java/org/elasticsearch/action/admin/indices/rollover/RolloverResponse.java
@@ -120,7 +120,7 @@ public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         out.writeString(oldIndex);
         out.writeString(newIndex);
-        out.writeMap(conditionStatus, StreamOutput::writeString, StreamOutput::writeBoolean);
+        out.writeMap(conditionStatus, StreamOutput::writeBoolean);
         out.writeBoolean(dryRun);
         out.writeBoolean(rolledOver);
         out.writeBoolean(shardsAcknowledged);

diff --git a/...rc/main/java/org/elasticsearch/action/admin/indices/settings/get/GetSettingsResponse.java b/...rc/main/java/org/elasticsearch/action/admin/indices/settings/get/GetSettingsResponse.java
@@ -79,8 +79,8 @@ public String getSetting(String index, String setting) {
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeMap(indexToSettings, StreamOutput::writeString, (o, v) -> v.writeTo(o));
-        out.writeMap(indexToDefaultSettings, StreamOutput::writeString, (o, v) -> v.writeTo(o));
+        out.writeMap(indexToSettings, (o, v) -> v.writeTo(o));
+        out.writeMap(indexToDefaultSettings, (o, v) -> v.writeTo(o));
     }
 
     private static void parseSettingsField(

diff --git a/...c/main/java/org/elasticsearch/action/admin/indices/shards/IndicesShardStoresResponse.java b/...c/main/java/org/elasticsearch/action/admin/indices/shards/IndicesShardStoresResponse.java
@@ -267,11 +267,7 @@ public List<Failure> getFailures() {
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        out.writeMap(
-            storeStatuses,
-            StreamOutput::writeString,
-            (o, v) -> o.writeMap(v, StreamOutput::writeInt, StreamOutput::writeCollection)
-        );
+        out.writeMap(storeStatuses, (o, v) -> o.writeMap(v, StreamOutput::writeInt, StreamOutput::writeCollection));
         out.writeCollection(failures);
     }
 

diff --git a/...r/src/main/java/org/elasticsearch/action/admin/indices/stats/FieldUsageStatsResponse.java b/...r/src/main/java/org/elasticsearch/action/admin/indices/stats/FieldUsageStatsResponse.java
@@ -41,7 +41,7 @@ public class FieldUsageStatsResponse extends ChunkedBroadcastResponse {
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
-        out.writeMap(stats, StreamOutput::writeString, (streamOutput, list) -> streamOutput.writeCollection(list));
+        out.writeMap(stats, StreamOutput::writeCollection);
     }
 
     public Map<String, List<FieldUsageShardResponse>> getStats() {

diff --git a/server/src/main/java/org/elasticsearch/action/admin/indices/stats/IndicesStatsResponse.java b/server/src/main/java/org/elasticsearch/action/admin/indices/stats/IndicesStatsResponse.java
@@ -172,8 +172,8 @@ public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         out.writeArray(shards);
         if (out.getTransportVersion().onOrAfter(TransportVersion.V_8_1_0)) {
-            out.writeMap(indexHealthMap, StreamOutput::writeString, (o, s) -> s.writeTo(o));
-            out.writeMap(indexStateMap, StreamOutput::writeString, (o, s) -> s.writeTo(o));
+            out.writeMap(indexHealthMap, (o, s) -> s.writeTo(o));
+            out.writeMap(indexStateMap, (o, s) -> s.writeTo(o));
         }
     }
 

diff --git a/.../java/org/elasticsearch/action/admin/indices/template/get/GetComponentTemplateAction.java b/.../java/org/elasticsearch/action/admin/indices/template/get/GetComponentTemplateAction.java
@@ -148,7 +148,7 @@ public RolloverConfiguration getRolloverConfiguration() {
 
         @Override
         public void writeTo(StreamOutput out) throws IOException {
-            out.writeMap(componentTemplates, StreamOutput::writeString, (o, v) -> v.writeTo(o));
+            out.writeMap(componentTemplates, (o, v) -> v.writeTo(o));
             if (out.getTransportVersion().onOrAfter(TransportVersion.V_8_500_010)) {
                 out.writeOptionalWriteable(rolloverConfiguration);
             }

diff --git a/...org/elasticsearch/action/admin/indices/template/get/GetComposableIndexTemplateAction.java b/...org/elasticsearch/action/admin/indices/template/get/GetComposableIndexTemplateAction.java
@@ -146,7 +146,7 @@ public Map<String, ComposableIndexTemplate> indexTemplates() {
 
         @Override
         public void writeTo(StreamOutput out) throws IOException {
-            out.writeMap(indexTemplates, StreamOutput::writeString, (o, v) -> v.writeTo(o));
+            out.writeMap(indexTemplates, (o, v) -> v.writeTo(o));
             if (out.getTransportVersion().onOrAfter(TransportVersion.V_8_500_010)) {
                 out.writeOptionalWriteable(rolloverConfiguration);
             }

diff --git a/server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilities.java b/server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilities.java
@@ -264,7 +264,7 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeOptionalStringArray(nonDimensionIndices);
             out.writeOptionalStringArray(metricConflictsIndices);
         }
-        out.writeMap(meta, StreamOutput::writeString, (o, set) -> o.writeCollection(set, StreamOutput::writeString));
+        out.writeMap(meta, StreamOutput::writeStringCollection);
     }
 
     @Override

diff --git a/server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilitiesIndexResponse.java b/server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilitiesIndexResponse.java
@@ -60,7 +60,7 @@ final class FieldCapabilitiesIndexResponse implements Writeable {
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         out.writeString(indexName);
-        out.writeMap(responseMap, StreamOutput::writeString, (valueOut, fc) -> fc.writeTo(valueOut));
+        out.writeMap(responseMap, (valueOut, fc) -> fc.writeTo(valueOut));
         out.writeBoolean(canMatch);
         if (out.getTransportVersion().onOrAfter(MAPPING_HASH_VERSION)) {
             out.writeOptionalString(indexMappingHash);
@@ -78,7 +78,7 @@ private record GroupByMappingHash(List<String> indices, String indexMappingHash,
         public void writeTo(StreamOutput out) throws IOException {
             out.writeStringCollection(indices);
             out.writeString(indexMappingHash);
-            out.writeMap(responseMap, StreamOutput::writeString, (valueOut, fc) -> fc.writeTo(valueOut));
+            out.writeMap(responseMap, (valueOut, fc) -> fc.writeTo(valueOut));
         }
 
         Stream<FieldCapabilitiesIndexResponse> getResponses() {

diff --git a/server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilitiesResponse.java b/server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilitiesResponse.java
@@ -147,13 +147,13 @@ private static Map<String, FieldCapabilities> readField(StreamInput in) throws I
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         out.writeStringArray(indices);
-        out.writeMap(responseMap, StreamOutput::writeString, FieldCapabilitiesResponse::writeField);
+        out.writeMap(responseMap, FieldCapabilitiesResponse::writeField);
         FieldCapabilitiesIndexResponse.writeList(out, indexResponses);
         out.writeCollection(failures);
     }
 
     private static void writeField(StreamOutput out, Map<String, FieldCapabilities> map) throws IOException {
-        out.writeMap(map, StreamOutput::writeString, (valueOut, fc) -> fc.writeTo(valueOut));
+        out.writeMap(map, (valueOut, fc) -> fc.writeTo(valueOut));
     }
 
     @Override

diff --git a/server/src/main/java/org/elasticsearch/action/fieldcaps/IndexFieldCapabilities.java b/server/src/main/java/org/elasticsearch/action/fieldcaps/IndexFieldCapabilities.java
@@ -89,7 +89,7 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeBoolean(isDimension);
             out.writeOptionalEnum(metricType);
         }
-        out.writeMap(meta, StreamOutput::writeString, StreamOutput::writeString);
+        out.writeMap(meta, StreamOutput::writeString);
     }
 
     public String getName() {