[ML] Use LinkedHashMap to preserve order in job and datafeed fields (#36389)

Author: dimitris-athanasiou

client/rest-high-level/src/main/java/org/elasticsearch/client/ml/job/config/Job.java

@@ -31,7 +31,7 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Date;
-import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -94,7 +94,7 @@ public class Job implements ToXContentObject {
             TimeValue.parseTimeValue(val, BACKGROUND_PERSIST_INTERVAL.getPreferredName())), BACKGROUND_PERSIST_INTERVAL);
         PARSER.declareLong(Builder::setResultsRetentionDays, RESULTS_RETENTION_DAYS);
         PARSER.declareLong(Builder::setModelSnapshotRetentionDays, MODEL_SNAPSHOT_RETENTION_DAYS);
-        PARSER.declareField(Builder::setCustomSettings, (p, c) -> p.map(), CUSTOM_SETTINGS, ValueType.OBJECT);
+        PARSER.declareField(Builder::setCustomSettings, (p, c) -> p.mapOrdered(), CUSTOM_SETTINGS, ValueType.OBJECT);
         PARSER.declareStringOrNull(Builder::setModelSnapshotId, MODEL_SNAPSHOT_ID);
         PARSER.declareString(Builder::setResultsIndexName, RESULTS_INDEX_NAME);
         PARSER.declareBoolean(Builder::setDeleting, DELETING);
@@ -441,7 +441,7 @@ public Builder(Job job) {
             this.backgroundPersistInterval = job.getBackgroundPersistInterval();
             this.modelSnapshotRetentionDays = job.getModelSnapshotRetentionDays();
             this.resultsRetentionDays = job.getResultsRetentionDays();
-            this.customSettings = job.getCustomSettings() == null ? null : new HashMap<>(job.getCustomSettings());
+            this.customSettings = job.getCustomSettings() == null ? null : new LinkedHashMap<>(job.getCustomSettings());
             this.modelSnapshotId = job.getModelSnapshotId();
             this.resultsIndexName = job.getResultsIndexNameNoPrefix();
             this.deleting = job.getDeleting();

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/datafeed/DatafeedConfig.java

@@ -165,9 +165,9 @@ private static ObjectParser<Builder, Void> createParser(boolean ignoreUnknownFie
         parser.declareString((builder, val) ->
             builder.setFrequency(TimeValue.parseTimeValue(val, FREQUENCY.getPreferredName())), FREQUENCY);
         if (ignoreUnknownFields) {
-            parser.declareObject(Builder::setQuery, (p, c) -> p.map(), QUERY);
-            parser.declareObject(Builder::setAggregations, (p, c) -> p.map(), AGGREGATIONS);
-            parser.declareObject(Builder::setAggregations, (p, c) -> p.map(), AGGS);
+            parser.declareObject(Builder::setQuery, (p, c) -> p.mapOrdered(), QUERY);
+            parser.declareObject(Builder::setAggregations, (p, c) -> p.mapOrdered(), AGGREGATIONS);
+            parser.declareObject(Builder::setAggregations, (p, c) -> p.mapOrdered(), AGGS);
         } else {
             parser.declareObject(Builder::setParsedQuery, (p, c) -> AbstractQueryBuilder.parseInnerQueryBuilder(p), QUERY);
             parser.declareObject(Builder::setParsedAggregations, (p, c) -> AggregatorFactories.parseAggregators(p), AGGREGATIONS);

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/job/config/Job.java

@@ -32,8 +32,8 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Date;
-import java.util.HashMap;
 import java.util.HashSet;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -116,7 +116,7 @@ private static ObjectParser<Builder, Void> createParser(boolean ignoreUnknownFie
             TimeValue.parseTimeValue(val, BACKGROUND_PERSIST_INTERVAL.getPreferredName())), BACKGROUND_PERSIST_INTERVAL);
         parser.declareLong(Builder::setResultsRetentionDays, RESULTS_RETENTION_DAYS);
         parser.declareLong(Builder::setModelSnapshotRetentionDays, MODEL_SNAPSHOT_RETENTION_DAYS);
-        parser.declareField(Builder::setCustomSettings, (p, c) -> p.map(), CUSTOM_SETTINGS, ValueType.OBJECT);
+        parser.declareField(Builder::setCustomSettings, (p, c) -> p.mapOrdered(), CUSTOM_SETTINGS, ValueType.OBJECT);
         parser.declareStringOrNull(Builder::setModelSnapshotId, MODEL_SNAPSHOT_ID);
         parser.declareStringOrNull(Builder::setModelSnapshotMinVersion, MODEL_SNAPSHOT_MIN_VERSION);
         parser.declareString(Builder::setResultsIndexName, RESULTS_INDEX_NAME);
@@ -674,7 +674,7 @@ public Builder(Job job) {
             this.backgroundPersistInterval = job.getBackgroundPersistInterval();
             this.modelSnapshotRetentionDays = job.getModelSnapshotRetentionDays();
             this.resultsRetentionDays = job.getResultsRetentionDays();
-            this.customSettings = job.getCustomSettings() == null ? null : new HashMap<>(job.getCustomSettings());
+            this.customSettings = job.getCustomSettings() == null ? null : new LinkedHashMap<>(job.getCustomSettings());
             this.modelSnapshotId = job.getModelSnapshotId();
             this.modelSnapshotMinVersion = job.getModelSnapshotMinVersion();
             this.resultsIndexName = job.getResultsIndexNameNoPrefix();