diff --git a/modules/mapper-extras/src/main/java/org/elasticsearch/index/mapper/extras/ScaledFloatFieldMapper.java b/modules/mapper-extras/src/main/java/org/elasticsearch/index/mapper/extras/ScaledFloatFieldMapper.java
index ae088d5fed02e..46c3a478a33a5 100644
--- a/modules/mapper-extras/src/main/java/org/elasticsearch/index/mapper/extras/ScaledFloatFieldMapper.java
+++ b/modules/mapper-extras/src/main/java/org/elasticsearch/index/mapper/extras/ScaledFloatFieldMapper.java
@@ -136,8 +136,8 @@ public Builder(String name, boolean ignoreMalformedByDefault, boolean coerceByDe
 
             this.metric = TimeSeriesParams.metricParam(
                 m -> toType(m).metricType,
-                TimeSeriesParams.MetricType.gauge,
-                TimeSeriesParams.MetricType.counter
+                TimeSeriesParams.MetricType.GAUGE,
+                TimeSeriesParams.MetricType.COUNTER
             ).addValidator(v -> {
                 if (v != null && hasDocValues.getValue() == false) {
                     throw new IllegalArgumentException(
@@ -287,7 +287,7 @@ public IndexFieldData.Builder fielddataBuilder(FieldDataContext fieldDataContext
                 failIfNoDocValues();
             }
 
-            ValuesSourceType valuesSourceType = metricType == TimeSeriesParams.MetricType.counter
+            ValuesSourceType valuesSourceType = metricType == TimeSeriesParams.MetricType.COUNTER
                 ? TimeSeriesValuesSourceType.COUNTER
                 : IndexNumericFieldData.NumericType.LONG.getValuesSourceType();
             if ((operation == FielddataOperation.SEARCH || operation == FielddataOperation.SCRIPT) && hasDocValues()) {
diff --git a/server/src/internalClusterTest/java/org/elasticsearch/search/fieldcaps/FieldCapabilitiesIT.java b/server/src/internalClusterTest/java/org/elasticsearch/search/fieldcaps/FieldCapabilitiesIT.java
index 6656e0aa1f936..d1089fec66931 100644
--- a/server/src/internalClusterTest/java/org/elasticsearch/search/fieldcaps/FieldCapabilitiesIT.java
+++ b/server/src/internalClusterTest/java/org/elasticsearch/search/fieldcaps/FieldCapabilitiesIT.java
@@ -110,7 +110,7 @@ public void setUp() throws Exception {
             .endObject()
             .startObject("some_metric")
             .field("type", "long")
-            .field("time_series_metric", TimeSeriesParams.MetricType.counter)
+            .field("time_series_metric", TimeSeriesParams.MetricType.COUNTER)
             .endObject()
             .startObject("secret_soundtrack")
             .field("type", "alias")
@@ -153,7 +153,7 @@ public void setUp() throws Exception {
             .endObject()
             .startObject("some_metric")
             .field("type", "long")
-            .field("time_series_metric", TimeSeriesParams.MetricType.gauge)
+            .field("time_series_metric", TimeSeriesParams.MetricType.GAUGE)
             .endObject()
             .endObject()
             .endObject()
@@ -368,7 +368,7 @@ public void testFieldMetricsAndDimensions() {
         assertTrue(response.get().get("some_dimension").get("keyword").isDimension());
         assertNull(response.get().get("some_dimension").get("keyword").nonDimensionIndices());
         assertTrue(response.get().containsKey("some_metric"));
-        assertEquals(TimeSeriesParams.MetricType.counter, response.get().get("some_metric").get("long").getMetricType());
+        assertEquals(TimeSeriesParams.MetricType.COUNTER, response.get().get("some_metric").get("long").getMetricType());
         assertNull(response.get().get("some_metric").get("long").metricConflictsIndices());
 
         response = client().prepareFieldCaps("old_index", "new_index").setFields("some_dimension", "some_metric").get();
diff --git a/server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilities.java b/server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilities.java
index eec23999dedca..9888240021c37 100644
--- a/server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilities.java
+++ b/server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilities.java
@@ -211,7 +211,7 @@ public FieldCapabilities(
             isSearchable,
             isAggregatable,
             isDimension == null ? false : isDimension,
-            metricType != null ? Enum.valueOf(TimeSeriesParams.MetricType.class, metricType) : null,
+            metricType != null ? TimeSeriesParams.MetricType.fromString(metricType) : null,
             indices != null ? indices.toArray(new String[0]) : null,
             nonSearchableIndices != null ? nonSearchableIndices.toArray(new String[0]) : null,
             nonAggregatableIndices != null ? nonAggregatableIndices.toArray(new String[0]) : null,
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/AbstractGeometryFieldMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/AbstractGeometryFieldMapper.java
index a6db9824c756f..c481efeb3a23b 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/AbstractGeometryFieldMapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/AbstractGeometryFieldMapper.java
@@ -163,7 +163,7 @@ protected AbstractGeometryFieldMapper(
         MultiFields multiFields,
         CopyTo copyTo,
         Parser<T> parser,
-        String onScriptError
+        OnScriptError onScriptError
     ) {
         super(simpleName, mappedFieldType, multiFields, copyTo, true, onScriptError);
         this.ignoreMalformed = Explicit.EXPLICIT_FALSE;
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/AbstractPointGeometryFieldMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/AbstractPointGeometryFieldMapper.java
index 571f0d59a9f20..14db646d86849 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/AbstractPointGeometryFieldMapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/AbstractPointGeometryFieldMapper.java
@@ -54,7 +54,7 @@ protected AbstractPointGeometryFieldMapper(
         MultiFields multiFields,
         CopyTo copyTo,
         Parser<T> parser,
-        String onScriptError
+        OnScriptError onScriptError
     ) {
         super(simpleName, mappedFieldType, multiFields, copyTo, parser, onScriptError);
         this.nullValue = null;
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/AbstractScriptFieldType.java b/server/src/main/java/org/elasticsearch/index/mapper/AbstractScriptFieldType.java
index 684adb9ac124a..b84294168397c 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/AbstractScriptFieldType.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/AbstractScriptFieldType.java
@@ -225,7 +225,10 @@ abstract static class Builder<Factory> extends RuntimeField.Builder {
             Objects::toString
         ).setSerializerCheck((id, ic, v) -> ic);
 
-        private final FieldMapper.Parameter<String> onScriptError = FieldMapper.Parameter.onScriptErrorParam(m -> m.onScriptError, script);
+        private final FieldMapper.Parameter<OnScriptError> onScriptError = FieldMapper.Parameter.onScriptErrorParam(
+            m -> m.onScriptError,
+            script
+        );
 
         Builder(String name, ScriptContext<Factory> scriptContext) {
             super(name);
@@ -270,14 +273,7 @@ final RuntimeField createRuntimeField(Factory scriptFactory) {
         }
 
         final RuntimeField createRuntimeField(Factory scriptFactory, Version indexVersion) {
-            var fieldType = createFieldType(
-                name,
-                scriptFactory,
-                getScript(),
-                meta(),
-                indexVersion,
-                OnScriptError.fromString(onScriptError.get())
-            );
+            var fieldType = createFieldType(name, scriptFactory, getScript(), meta(), indexVersion, onScriptError.get());
             return new LeafRuntimeField(name, fieldType, getParameters());
         }
 
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/BooleanFieldMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/BooleanFieldMapper.java
index b69d698f0f38f..63d9fe5c6b2b2 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/BooleanFieldMapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/BooleanFieldMapper.java
@@ -96,7 +96,7 @@ public static class Builder extends FieldMapper.Builder {
         ).acceptsNull();
 
         private final Parameter<Script> script = Parameter.scriptParam(m -> toType(m).script);
-        private final Parameter<String> onScriptError = Parameter.onScriptErrorParam(m -> toType(m).onScriptError, script);
+        private final Parameter<OnScriptError> onScriptError = Parameter.onScriptErrorParam(m -> toType(m).onScriptError, script);
 
         private final Parameter<Map<String, String>> meta = Parameter.metaParam();
 
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/CompositeRuntimeField.java b/server/src/main/java/org/elasticsearch/index/mapper/CompositeRuntimeField.java
index 0669e43fe7a3b..d7b039dde1c25 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/CompositeRuntimeField.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/CompositeRuntimeField.java
@@ -47,7 +47,10 @@ public class CompositeRuntimeField implements RuntimeField {
             }
         });
 
-        private final FieldMapper.Parameter<String> onScriptError = FieldMapper.Parameter.onScriptErrorParam(m -> m.onScriptError, script);
+        private final FieldMapper.Parameter<OnScriptError> onScriptError = FieldMapper.Parameter.onScriptErrorParam(
+            m -> m.onScriptError,
+            script
+        );
 
         private final FieldMapper.Parameter<Map<String, Object>> fields = new FieldMapper.Parameter<Map<String, Object>>(
             "fields",
@@ -85,15 +88,12 @@ protected RuntimeField createChildRuntimeField(
         @Override
         protected RuntimeField createRuntimeField(MappingParserContext parserContext) {
             CompositeFieldScript.Factory factory = parserContext.scriptCompiler().compile(script.get(), CompositeFieldScript.CONTEXT);
-            Function<RuntimeField.Builder, RuntimeField> builder = b -> {
-                OnScriptError onScriptError = OnScriptError.fromString(this.onScriptError.get());
-                return b.createChildRuntimeField(
-                    parserContext,
-                    name,
-                    lookup -> factory.newFactory(name, script.get().getParams(), lookup, onScriptError),
-                    onScriptError
-                );
-            };
+            Function<RuntimeField.Builder, RuntimeField> builder = b -> b.createChildRuntimeField(
+                parserContext,
+                name,
+                lookup -> factory.newFactory(name, script.get().getParams(), lookup, onScriptError.get()),
+                onScriptError.get()
+            );
             Map<String, RuntimeField> runtimeFields = RuntimeField.parseRuntimeFields(
                 new HashMap<>(fields.getValue()),
                 parserContext,
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/DateFieldMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/DateFieldMapper.java
index 81174dc2ae775..1b0f8411912b5 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/DateFieldMapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/DateFieldMapper.java
@@ -245,7 +245,7 @@ public static class Builder extends FieldMapper.Builder {
         private final Parameter<Boolean> ignoreMalformed;
 
         private final Parameter<Script> script = Parameter.scriptParam(m -> toType(m).script);
-        private final Parameter<String> onScriptError = Parameter.onScriptErrorParam(m -> toType(m).onScriptError, script);
+        private final Parameter<OnScriptError> onScriptError = Parameter.onScriptErrorParam(m -> toType(m).onScriptError, script);
 
         private final Resolution resolution;
         private final Version indexCreatedVersion;
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java
index e3026baa536c5..3746285aacb40 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/FieldMapper.java
@@ -70,7 +70,7 @@ public abstract class FieldMapper extends Mapper implements Cloneable {
     protected final MultiFields multiFields;
     protected final CopyTo copyTo;
     protected final boolean hasScript;
-    protected final String onScriptError;
+    protected final OnScriptError onScriptError;
 
     /**
      * @param simpleName        the leaf name of the mapper
@@ -96,7 +96,7 @@ protected FieldMapper(
         MultiFields multiFields,
         CopyTo copyTo,
         boolean hasScript,
-        String onScriptError
+        OnScriptError onScriptError
     ) {
         super(simpleName);
         // could be blank but not empty on indices created < 8.6.0
@@ -247,7 +247,7 @@ public final void executeScript(
         try {
             indexScriptValues(searchLookup, readerContext, doc, documentParserContext);
         } catch (Exception e) {
-            if ("continue".equals(onScriptError)) {
+            if (onScriptError == OnScriptError.CONTINUE) {
                 documentParserContext.addIgnoredField(name());
             } else {
                 throw new MapperParsingException("Error executing script on field [" + name() + "]", e);
@@ -938,12 +938,12 @@ public static <T extends Enum<T>> Parameter<T> enumParam(
         /**
          * Defines a parameter that takes one of a restricted set of values from an enumeration.
          *
-         * @param name          the parameter name
-         * @param updateable    whether the parameter can be changed by a mapping update
-         * @param initializer   a function that reads the parameter value from an existing mapper
-         * @param defaultValue  the default value, to be used if the parameter is undefined in a mapping
-         * @param enumClass     the enumeration class the parameter takes values from
-         * @param values        the set of values that the parameter can take
+         * @param name            the parameter name
+         * @param updateable      whether the parameter can be changed by a mapping update
+         * @param initializer     a function that reads the parameter value from an existing mapper
+         * @param defaultValue    the default value, to be used if the parameter is undefined in a mapping
+         * @param enumClass       the enumeration class the parameter takes values from
+         * @param acceptedValues  the set of values that the parameter can take
          */
         public static <T extends Enum<T>> Parameter<T> restrictedEnumParam(
             String name,
@@ -951,23 +951,28 @@ public static <T extends Enum<T>> Parameter<T> restrictedEnumParam(
             Function<FieldMapper, T> initializer,
             T defaultValue,
             Class<T> enumClass,
-            Set<T> values
+            Set<T> acceptedValues
         ) {
-            assert values.size() > 0;
-            return new Parameter<T>(name, updateable, () -> defaultValue, (n, c, o) -> {
+            assert acceptedValues.size() > 0;
+            return new Parameter<>(name, updateable, () -> defaultValue, (n, c, o) -> {
                 if (o == null) {
                     return defaultValue;
                 }
-                try {
-                    @SuppressWarnings("unchecked")
-                    T enumValue = Enum.valueOf(enumClass, (String) o);
-                    return enumValue;
-                } catch (IllegalArgumentException e) {
-                    throw new MapperParsingException("Unknown value [" + o + "] for field [" + name + "] - accepted values are " + values);
+                EnumSet<T> enumSet = EnumSet.allOf(enumClass);
+                for (T t : enumSet) {
+                    // the string representation may differ from the actual name of the enum type (e.g. lowercase vs uppercase)
+                    if (t.toString().equals(o.toString())) {
+                        return t;
+                    }
                 }
+                throw new MapperParsingException(
+                    "Unknown value [" + o + "] for field [" + name + "] - accepted values are " + acceptedValues
+                );
             }, initializer, XContentBuilder::field, Objects::toString).addValidator(v -> {
-                if (v != null && values.contains(v) == false) {
-                    throw new MapperParsingException("Unknown value [" + v + "] for field [" + name + "] - accepted values are " + values);
+                if (v != null && acceptedValues.contains(v) == false) {
+                    throw new MapperParsingException(
+                        "Unknown value [" + v + "] for field [" + name + "] - accepted values are " + acceptedValues
+                    );
                 }
             });
         }
@@ -1069,29 +1074,12 @@ public static Parameter<Script> scriptParam(Function<FieldMapper, Script> initia
          * @param dependentScriptParam the corresponding required script parameter
          * @return a new on_error_script parameter
          */
-        public static Parameter<String> onScriptErrorParam(
-            Function<FieldMapper, String> initializer,
+        public static Parameter<OnScriptError> onScriptErrorParam(
+            Function<FieldMapper, OnScriptError> initializer,
             Parameter<Script> dependentScriptParam
         ) {
-            return new Parameter<>(
-                "on_script_error",
-                true,
-                () -> "fail",
-                (n, c, o) -> XContentMapValues.nodeStringValue(o),
-                initializer,
-                XContentBuilder::field,
-                Function.identity()
-            ).addValidator(v -> {
-                switch (v) {
-                    case "fail":
-                    case "continue":
-                        return;
-                    default:
-                        throw new MapperParsingException(
-                            "Unknown value [" + v + "] for field [on_script_error] - accepted values are [fail, continue]"
-                        );
-                }
-            }).requiresParameter(dependentScriptParam);
+            return Parameter.enumParam("on_script_error", true, initializer, OnScriptError.FAIL, OnScriptError.class)
+                .requiresParameter(dependentScriptParam);
         }
     }
 
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/GeoPointFieldMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/GeoPointFieldMapper.java
index 105edc769edec..3f076b975f36a 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/GeoPointFieldMapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/GeoPointFieldMapper.java
@@ -78,7 +78,7 @@ public static class Builder extends FieldMapper.Builder {
         final Parameter<Boolean> hasDocValues = Parameter.docValuesParam(m -> builder(m).hasDocValues.get(), true);
         final Parameter<Boolean> stored = Parameter.storeParam(m -> builder(m).stored.get(), false);
         private final Parameter<Script> script = Parameter.scriptParam(m -> builder(m).script.get());
-        private final Parameter<String> onScriptError = Parameter.onScriptErrorParam(m -> builder(m).onScriptError.get(), script);
+        private final Parameter<OnScriptError> onScriptError = Parameter.onScriptErrorParam(m -> builder(m).onScriptError.get(), script);
         final Parameter<Map<String, String>> meta = Parameter.metaParam();
 
         private final ScriptCompiler scriptCompiler;
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/IpFieldMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/IpFieldMapper.java
index f722808a76ff4..68b6fc55c7380 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/IpFieldMapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/IpFieldMapper.java
@@ -71,7 +71,7 @@ public static class Builder extends FieldMapper.Builder {
             .acceptsNull();
 
         private final Parameter<Script> script = Parameter.scriptParam(m -> toType(m).script);
-        private final Parameter<String> onScriptError = Parameter.onScriptErrorParam(m -> toType(m).onScriptError, script);
+        private final Parameter<OnScriptError> onScriptError = Parameter.onScriptErrorParam(m -> toType(m).onScriptError, script);
 
         private final Parameter<Map<String, String>> meta = Parameter.metaParam();
         private final Parameter<Boolean> dimension;
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/KeywordFieldMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/KeywordFieldMapper.java
index 879525c79c103..3e235175ae03e 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/KeywordFieldMapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/KeywordFieldMapper.java
@@ -173,7 +173,7 @@ public static class Builder extends FieldMapper.Builder {
         private final Parameter<Map<String, String>> meta = Parameter.metaParam();
 
         private final Parameter<Script> script = Parameter.scriptParam(m -> toType(m).script);
-        private final Parameter<String> onScriptError = Parameter.onScriptErrorParam(m -> toType(m).onScriptError, script);
+        private final Parameter<OnScriptError> onScriptError = Parameter.onScriptErrorParam(m -> toType(m).onScriptError, script);
         private final Parameter<Boolean> dimension;
 
         private final IndexAnalyzers indexAnalyzers;
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/NumberFieldMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/NumberFieldMapper.java
index fcb52d59c01e1..9febe374054d5 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/NumberFieldMapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/NumberFieldMapper.java
@@ -96,7 +96,7 @@ public static class Builder extends FieldMapper.Builder {
         private final Parameter<Number> nullValue;
 
         private final Parameter<Script> script = Parameter.scriptParam(m -> toType(m).script);
-        private final Parameter<String> onScriptError = Parameter.onScriptErrorParam(m -> toType(m).onScriptError, script);
+        private final Parameter<OnScriptError> onScriptError = Parameter.onScriptErrorParam(m -> toType(m).onScriptError, script);
 
         /**
          * Parameter that marks this field as a time series dimension.
@@ -178,7 +178,7 @@ public Builder(
                 }
             });
 
-            this.metric = TimeSeriesParams.metricParam(m -> toType(m).metricType, MetricType.gauge, MetricType.counter).addValidator(v -> {
+            this.metric = TimeSeriesParams.metricParam(m -> toType(m).metricType, MetricType.GAUGE, MetricType.COUNTER).addValidator(v -> {
                 if (v != null && hasDocValues.getValue() == false) {
                     throw new IllegalArgumentException(
                         "Field [" + TimeSeriesParams.TIME_SERIES_METRIC_PARAM + "] requires that [" + hasDocValues.name + "] is true"
@@ -1551,7 +1551,7 @@ public IndexFieldData.Builder fielddataBuilder(FieldDataContext fieldDataContext
                 failIfNoDocValues();
             }
 
-            ValuesSourceType valuesSourceType = metricType == TimeSeriesParams.MetricType.counter
+            ValuesSourceType valuesSourceType = metricType == TimeSeriesParams.MetricType.COUNTER
                 ? TimeSeriesValuesSourceType.COUNTER
                 : type.numericType.getValuesSourceType();
 
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/OnScriptError.java b/server/src/main/java/org/elasticsearch/index/mapper/OnScriptError.java
index a4d4b895bcf11..42c3d1386793e 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/OnScriptError.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/OnScriptError.java
@@ -9,7 +9,6 @@
 package org.elasticsearch.index.mapper;
 
 import java.util.Locale;
-import java.util.Objects;
 
 /**
  * Represents the behaviour when a runtime field or an index-time script fails: either fail and raise the error,
@@ -19,15 +18,8 @@ public enum OnScriptError {
     FAIL,
     CONTINUE;
 
-    /**
-     * Parses the on_script_error parameter from a string into its corresponding enum instance
-     */
-    public static OnScriptError fromString(final String str) {
-        Objects.requireNonNull(str, "input string is null");
-        return switch (str.toLowerCase(Locale.ROOT)) {
-            case "fail" -> FAIL;
-            case "continue" -> CONTINUE;
-            default -> throw new IllegalArgumentException("Unknown onScriptError [" + str + "]");
-        };
+    @Override
+    public final String toString() {
+        return name().toLowerCase(Locale.ROOT);
     }
 }
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/TimeSeriesParams.java b/server/src/main/java/org/elasticsearch/index/mapper/TimeSeriesParams.java
index 2ab6a5ad6859e..cb0b9ddd87f02 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/TimeSeriesParams.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/TimeSeriesParams.java
@@ -10,6 +10,7 @@
 
 import java.util.Arrays;
 import java.util.EnumSet;
+import java.util.Locale;
 import java.util.function.Function;
 
 /**
@@ -23,8 +24,8 @@ public final class TimeSeriesParams {
     private TimeSeriesParams() {}
 
     public enum MetricType {
-        gauge(new String[] { "max", "min", "value_count", "sum" }),
-        counter(new String[] { "last_value" });
+        GAUGE(new String[] { "max", "min", "value_count", "sum" }),
+        COUNTER(new String[] { "last_value" });
 
         private final String[] supportedAggs;
 
@@ -35,6 +36,20 @@ public enum MetricType {
         public String[] supportedAggs() {
             return supportedAggs;
         }
+
+        @Override
+        public final String toString() {
+            return name().toLowerCase(Locale.ROOT);
+        }
+
+        public static MetricType fromString(String value) {
+            for (MetricType metricType : values()) {
+                if (metricType.toString().equals(value)) {
+                    return metricType;
+                }
+            }
+            throw new IllegalArgumentException("No enum constant MetricType." + value);
+        }
     }
 
     public static FieldMapper.Parameter<MetricType> metricParam(Function<FieldMapper, MetricType> initializer, MetricType... values) {
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldMapper.java
index 6bd9700feb904..e5f1537813d13 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldMapper.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldMapper.java
@@ -48,6 +48,7 @@
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.time.ZoneId;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 import java.util.stream.Stream;
@@ -247,9 +248,9 @@ public void checkVectorBounds(float[] vector) {
             void checkVectorMagnitude(VectorSimilarity similarity, float[] vector, float squaredMagnitude) {
                 StringBuilder errorBuilder = null;
 
-                if (similarity == VectorSimilarity.cosine && Math.sqrt(squaredMagnitude) == 0.0f) {
+                if (similarity == VectorSimilarity.COSINE && Math.sqrt(squaredMagnitude) == 0.0f) {
                     errorBuilder = new StringBuilder(
-                        "The [" + VectorSimilarity.cosine.name() + "] similarity does not support vectors with zero magnitude."
+                        "The [" + VectorSimilarity.COSINE + "] similarity does not support vectors with zero magnitude."
                     );
                 }
 
@@ -302,13 +303,13 @@ public void checkVectorBounds(float[] vector) {
             void checkVectorMagnitude(VectorSimilarity similarity, float[] vector, float squaredMagnitude) {
                 StringBuilder errorBuilder = null;
 
-                if (similarity == VectorSimilarity.dot_product && Math.abs(squaredMagnitude - 1.0f) > 1e-4f) {
+                if (similarity == VectorSimilarity.DOT_PRODUCT && Math.abs(squaredMagnitude - 1.0f) > 1e-4f) {
                     errorBuilder = new StringBuilder(
-                        "The [" + VectorSimilarity.dot_product.name() + "] similarity can only be used with unit-length vectors."
+                        "The [" + VectorSimilarity.DOT_PRODUCT + "] similarity can only be used with unit-length vectors."
                     );
-                } else if (similarity == VectorSimilarity.cosine && Math.sqrt(squaredMagnitude) == 0.0f) {
+                } else if (similarity == VectorSimilarity.COSINE && Math.sqrt(squaredMagnitude) == 0.0f) {
                     errorBuilder = new StringBuilder(
-                        "The [" + VectorSimilarity.cosine.name() + "] similarity does not support vectors with zero magnitude."
+                        "The [" + VectorSimilarity.COSINE + "] similarity does not support vectors with zero magnitude."
                     );
                 }
 
@@ -393,15 +394,20 @@ StringBuilder appendErrorElements(StringBuilder errorBuilder, float[] vector) {
     );
 
     enum VectorSimilarity {
-        l2_norm(VectorSimilarityFunction.EUCLIDEAN),
-        cosine(VectorSimilarityFunction.COSINE),
-        dot_product(VectorSimilarityFunction.DOT_PRODUCT);
+        L2_NORM(VectorSimilarityFunction.EUCLIDEAN),
+        COSINE(VectorSimilarityFunction.COSINE),
+        DOT_PRODUCT(VectorSimilarityFunction.DOT_PRODUCT);
 
         public final VectorSimilarityFunction function;
 
         VectorSimilarity(VectorSimilarityFunction function) {
             this.function = function;
         }
+
+        @Override
+        public final String toString() {
+            return name().toLowerCase(Locale.ROOT);
+        }
     }
 
     private abstract static class IndexOptions implements ToXContent {
@@ -555,7 +561,7 @@ public KnnVectorQuery createKnnQuery(float[] queryVector, int numCands, Query fi
 
             elementType.checkVectorBounds(queryVector);
 
-            if (similarity == VectorSimilarity.dot_product || similarity == VectorSimilarity.cosine) {
+            if (similarity == VectorSimilarity.DOT_PRODUCT || similarity == VectorSimilarity.COSINE) {
                 float squaredMagnitude = 0.0f;
                 for (float e : queryVector) {
                     squaredMagnitude += e * e;
diff --git a/server/src/test/java/org/elasticsearch/action/fieldcaps/FieldCapabilitiesTests.java b/server/src/test/java/org/elasticsearch/action/fieldcaps/FieldCapabilitiesTests.java
index 9c354451c4090..9ea8de558e9c7 100644
--- a/server/src/test/java/org/elasticsearch/action/fieldcaps/FieldCapabilitiesTests.java
+++ b/server/src/test/java/org/elasticsearch/action/fieldcaps/FieldCapabilitiesTests.java
@@ -80,7 +80,7 @@ public void testBuilder() {
 
         builder = new FieldCapabilities.Builder("field", "type");
         builder.add(new String[] { "index1" }, false, false, true, true, null, Collections.emptyMap());
-        builder.add(new String[] { "index2" }, false, true, false, false, TimeSeriesParams.MetricType.counter, Collections.emptyMap());
+        builder.add(new String[] { "index2" }, false, true, false, false, TimeSeriesParams.MetricType.COUNTER, Collections.emptyMap());
         builder.add(new String[] { "index3" }, false, false, false, false, null, Collections.emptyMap());
         {
             FieldCapabilities cap1 = builder.build(false);
@@ -108,15 +108,15 @@ public void testBuilder() {
         }
 
         builder = new FieldCapabilities.Builder("field", "type");
-        builder.add(new String[] { "index1" }, false, true, true, true, TimeSeriesParams.MetricType.counter, Collections.emptyMap());
-        builder.add(new String[] { "index2" }, false, true, true, true, TimeSeriesParams.MetricType.counter, Map.of("foo", "bar"));
-        builder.add(new String[] { "index3" }, false, true, true, true, TimeSeriesParams.MetricType.counter, Map.of("foo", "quux"));
+        builder.add(new String[] { "index1" }, false, true, true, true, TimeSeriesParams.MetricType.COUNTER, Collections.emptyMap());
+        builder.add(new String[] { "index2" }, false, true, true, true, TimeSeriesParams.MetricType.COUNTER, Map.of("foo", "bar"));
+        builder.add(new String[] { "index3" }, false, true, true, true, TimeSeriesParams.MetricType.COUNTER, Map.of("foo", "quux"));
         {
             FieldCapabilities cap1 = builder.build(false);
             assertThat(cap1.isSearchable(), equalTo(true));
             assertThat(cap1.isAggregatable(), equalTo(true));
             assertThat(cap1.isDimension(), equalTo(true));
-            assertThat(cap1.getMetricType(), equalTo(TimeSeriesParams.MetricType.counter));
+            assertThat(cap1.getMetricType(), equalTo(TimeSeriesParams.MetricType.COUNTER));
             assertNull(cap1.indices());
             assertNull(cap1.nonSearchableIndices());
             assertNull(cap1.nonAggregatableIndices());
@@ -127,7 +127,7 @@ public void testBuilder() {
             assertThat(cap2.isSearchable(), equalTo(true));
             assertThat(cap2.isAggregatable(), equalTo(true));
             assertThat(cap2.isDimension(), equalTo(true));
-            assertThat(cap2.getMetricType(), equalTo(TimeSeriesParams.MetricType.counter));
+            assertThat(cap2.getMetricType(), equalTo(TimeSeriesParams.MetricType.COUNTER));
             assertThat(cap2.indices().length, equalTo(3));
             assertThat(cap2.indices(), equalTo(new String[] { "index1", "index2", "index3" }));
             assertNull(cap2.nonSearchableIndices());
@@ -137,9 +137,9 @@ public void testBuilder() {
         }
 
         builder = new FieldCapabilities.Builder("field", "type");
-        builder.add(new String[] { "index1" }, false, true, true, true, TimeSeriesParams.MetricType.counter, Collections.emptyMap());
-        builder.add(new String[] { "index2" }, false, true, true, true, TimeSeriesParams.MetricType.gauge, Map.of("foo", "bar"));
-        builder.add(new String[] { "index3" }, false, true, true, true, TimeSeriesParams.MetricType.counter, Map.of("foo", "quux"));
+        builder.add(new String[] { "index1" }, false, true, true, true, TimeSeriesParams.MetricType.COUNTER, Collections.emptyMap());
+        builder.add(new String[] { "index2" }, false, true, true, true, TimeSeriesParams.MetricType.GAUGE, Map.of("foo", "bar"));
+        builder.add(new String[] { "index3" }, false, true, true, true, TimeSeriesParams.MetricType.COUNTER, Map.of("foo", "quux"));
         {
             FieldCapabilities cap1 = builder.build(false);
             assertThat(cap1.isSearchable(), equalTo(true));
diff --git a/server/src/test/java/org/elasticsearch/action/fieldcaps/MergedFieldCapabilitiesResponseTests.java b/server/src/test/java/org/elasticsearch/action/fieldcaps/MergedFieldCapabilitiesResponseTests.java
index 7954543c17940..defeb0342698b 100644
--- a/server/src/test/java/org/elasticsearch/action/fieldcaps/MergedFieldCapabilitiesResponseTests.java
+++ b/server/src/test/java/org/elasticsearch/action/fieldcaps/MergedFieldCapabilitiesResponseTests.java
@@ -168,7 +168,7 @@ private static FieldCapabilitiesResponse createSimpleResponse() {
                 true,
                 false,
                 false,
-                TimeSeriesParams.MetricType.counter,
+                TimeSeriesParams.MetricType.COUNTER,
                 new String[] { "index1", "index2" },
                 null,
                 new String[] { "index1" },
diff --git a/server/src/test/java/org/elasticsearch/index/mapper/NumberFieldMapperTests.java b/server/src/test/java/org/elasticsearch/index/mapper/NumberFieldMapperTests.java
index 9bafe9673be63..5f0f0c7b38dfc 100644
--- a/server/src/test/java/org/elasticsearch/index/mapper/NumberFieldMapperTests.java
+++ b/server/src/test/java/org/elasticsearch/index/mapper/NumberFieldMapperTests.java
@@ -30,7 +30,7 @@
 
 import static org.hamcrest.Matchers.both;
 import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.matchesPattern;
 
 public abstract class NumberFieldMapperTests extends MapperTestCase {
@@ -70,7 +70,7 @@ protected void registerParameters(ParameterChecker checker) throws IOException {
                 minimalMapping(b);
                 b.field("script", "test");
                 b.field("on_script_error", "continue");
-            }, m -> assertThat((m).onScriptError, equalTo("continue")));
+            }, m -> assertThat((m).onScriptError, is(OnScriptError.CONTINUE)));
         }
     }
 
@@ -264,7 +264,7 @@ public void testDimension() throws IOException {
 
     public void testMetricType() throws IOException {
         // Test default setting
-        MapperService mapperService = createMapperService(fieldMapping(b -> minimalMapping(b)));
+        MapperService mapperService = createMapperService(fieldMapping(this::minimalMapping));
         NumberFieldMapper.NumberFieldType ft = (NumberFieldMapper.NumberFieldType) mapperService.fieldType("field");
         assertNull(ft.getMetricType());
 
diff --git a/server/src/test/java/org/elasticsearch/index/mapper/ParametrizedMapperTests.java b/server/src/test/java/org/elasticsearch/index/mapper/ParametrizedMapperTests.java
index e25ff342e43be..fcfa1e9dd0b8f 100644
--- a/server/src/test/java/org/elasticsearch/index/mapper/ParametrizedMapperTests.java
+++ b/server/src/test/java/org/elasticsearch/index/mapper/ParametrizedMapperTests.java
@@ -33,6 +33,7 @@
 import java.util.Collections;
 import java.util.EnumSet;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 
@@ -44,9 +45,14 @@
 public class ParametrizedMapperTests extends MapperServiceTestCase {
 
     public enum DummyEnumType {
-        name1,
-        name2,
-        name3
+        NAME1,
+        NAME2,
+        NAME3;
+
+        @Override
+        public final String toString() {
+            return name().toLowerCase(Locale.ROOT);
+        }
     }
 
     public static class TestPlugin extends Plugin implements MapperPlugin {
@@ -127,7 +133,7 @@ public static class Builder extends FieldMapper.Builder {
             "enum_field",
             true,
             m -> toType(m).enumField,
-            DummyEnumType.name1,
+            DummyEnumType.NAME1,
             DummyEnumType.class
         );
 
@@ -135,9 +141,9 @@ public static class Builder extends FieldMapper.Builder {
             "restricted_enum_field",
             true,
             m -> toType(m).restrictedEnumField,
-            DummyEnumType.name1,
+            DummyEnumType.NAME1,
             DummyEnumType.class,
-            EnumSet.of(DummyEnumType.name1, DummyEnumType.name2)
+            EnumSet.of(DummyEnumType.NAME1, DummyEnumType.NAME2)
         );
 
         protected Builder(String name) {
@@ -648,13 +654,13 @@ public void testEnumField() {
             String mapping = """
                 {"type":"test_mapper","required":"a","enum_field":"name3"}""";
             TestMapper mapper = fromMapping(mapping);
-            assertEquals(DummyEnumType.name3, mapper.enumField);
+            assertEquals(DummyEnumType.NAME3, mapper.enumField);
         }
         {
             String mapping = """
                 {"type":"test_mapper","required":"a"}""";
             TestMapper mapper = fromMapping(mapping);
-            assertEquals(DummyEnumType.name1, mapper.enumField);
+            assertEquals(DummyEnumType.NAME1, mapper.enumField);
         }
     }
 
@@ -675,13 +681,13 @@ public void testRestrictedEnumField() {
             String mapping = """
                 {"type":"test_mapper","required":"a","restricted_enum_field":"name2"}""";
             TestMapper mapper = fromMapping(mapping);
-            assertEquals(DummyEnumType.name2, mapper.restrictedEnumField);
+            assertEquals(DummyEnumType.NAME2, mapper.restrictedEnumField);
         }
         {
             String mapping = """
                 {"type":"test_mapper","required":"a"}""";
             TestMapper mapper = fromMapping(mapping);
-            assertEquals(DummyEnumType.name1, mapper.restrictedEnumField);
+            assertEquals(DummyEnumType.NAME1, mapper.restrictedEnumField);
         }
     }
 
@@ -699,5 +705,4 @@ public void testCustomMergeValidation() throws IOException {
         })));
         assertThat(e.getMessage(), containsString("int_value"));
     }
-
 }
diff --git a/server/src/test/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldMapperTests.java b/server/src/test/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldMapperTests.java
index d8ef71ee71cfb..e8ca7fb8b2063 100644
--- a/server/src/test/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldMapperTests.java
+++ b/server/src/test/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldMapperTests.java
@@ -223,7 +223,7 @@ public void testDefaults() throws Exception {
     public void testIndexedVector() throws Exception {
         VectorSimilarity similarity = RandomPicks.randomFrom(random(), VectorSimilarity.values());
         DocumentMapper mapper = createDocumentMapper(
-            fieldMapping(b -> b.field("type", "dense_vector").field("dims", 3).field("index", true).field("similarity", similarity.name()))
+            fieldMapping(b -> b.field("type", "dense_vector").field("dims", 3).field("index", true).field("similarity", similarity))
         );
 
         float[] vector = { -0.5f, 0.5f, 0.7071f };
@@ -245,7 +245,7 @@ public void testIndexedByteVector() throws Exception {
                 b -> b.field("type", "dense_vector")
                     .field("dims", 3)
                     .field("index", true)
-                    .field("similarity", similarity.name())
+                    .field("similarity", similarity)
                     .field("element_type", "byte")
             )
         );
@@ -270,7 +270,7 @@ public void testIndexedByteVector() throws Exception {
     public void testDotProductWithInvalidNorm() throws Exception {
         DocumentMapper mapper = createDocumentMapper(
             fieldMapping(
-                b -> b.field("type", "dense_vector").field("dims", 3).field("index", true).field("similarity", VectorSimilarity.dot_product)
+                b -> b.field("type", "dense_vector").field("dims", 3).field("index", true).field("similarity", VectorSimilarity.DOT_PRODUCT)
             )
         );
         float[] vector = { -12.1f, 2.7f, -4 };
@@ -285,7 +285,7 @@ public void testDotProductWithInvalidNorm() throws Exception {
 
         DocumentMapper mapperWithLargerDim = createDocumentMapper(
             fieldMapping(
-                b -> b.field("type", "dense_vector").field("dims", 6).field("index", true).field("similarity", VectorSimilarity.dot_product)
+                b -> b.field("type", "dense_vector").field("dims", 6).field("index", true).field("similarity", VectorSimilarity.DOT_PRODUCT)
             )
         );
         float[] largerVector = { -12.1f, 2.7f, -4, 1.05f, 10.0f, 29.9f };
@@ -303,7 +303,7 @@ public void testDotProductWithInvalidNorm() throws Exception {
     public void testCosineWithZeroVector() throws Exception {
         DocumentMapper mapper = createDocumentMapper(
             fieldMapping(
-                b -> b.field("type", "dense_vector").field("dims", 3).field("index", true).field("similarity", VectorSimilarity.cosine)
+                b -> b.field("type", "dense_vector").field("dims", 3).field("index", true).field("similarity", VectorSimilarity.COSINE)
             )
         );
         float[] vector = { -0.0f, 0.0f, 0.0f };
@@ -323,7 +323,7 @@ public void testCosineWithZeroByteVector() throws Exception {
                 b -> b.field("type", "dense_vector")
                     .field("dims", 3)
                     .field("index", true)
-                    .field("similarity", VectorSimilarity.cosine)
+                    .field("similarity", VectorSimilarity.COSINE)
                     .field("element_type", "byte")
             )
         );
@@ -534,7 +534,7 @@ public void testByteVectorIndexBoundaries() throws IOException {
                     .field("element_type", "byte")
                     .field("dims", 3)
                     .field("index", true)
-                    .field("similarity", VectorSimilarity.cosine)
+                    .field("similarity", VectorSimilarity.COSINE)
             )
         );
 
diff --git a/server/src/test/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldTypeTests.java b/server/src/test/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldTypeTests.java
index 9993bed3d94eb..6f7e7a477ccfc 100644
--- a/server/src/test/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldTypeTests.java
+++ b/server/src/test/java/org/elasticsearch/index/mapper/vectors/DenseVectorFieldTypeTests.java
@@ -36,7 +36,7 @@ private DenseVectorFieldType createFloatFieldType() {
             DenseVectorFieldMapper.ElementType.FLOAT,
             5,
             indexed,
-            VectorSimilarity.cosine,
+            VectorSimilarity.COSINE,
             Collections.emptyMap()
         );
     }
@@ -48,7 +48,7 @@ private DenseVectorFieldType createByteFieldType() {
             DenseVectorFieldMapper.ElementType.BYTE,
             5,
             true,
-            VectorSimilarity.cosine,
+            VectorSimilarity.COSINE,
             Collections.emptyMap()
         );
     }
@@ -113,7 +113,7 @@ public void testFloatCreateKnnQuery() {
             DenseVectorFieldMapper.ElementType.FLOAT,
             3,
             false,
-            VectorSimilarity.cosine,
+            VectorSimilarity.COSINE,
             Collections.emptyMap()
         );
         IllegalArgumentException e = expectThrows(
@@ -128,7 +128,7 @@ public void testFloatCreateKnnQuery() {
             DenseVectorFieldMapper.ElementType.FLOAT,
             3,
             true,
-            VectorSimilarity.dot_product,
+            VectorSimilarity.DOT_PRODUCT,
             Collections.emptyMap()
         );
         e = expectThrows(IllegalArgumentException.class, () -> dotProductField.createKnnQuery(new float[] { 0.3f, 0.1f, 1.0f }, 10, null));
@@ -140,7 +140,7 @@ public void testFloatCreateKnnQuery() {
             DenseVectorFieldMapper.ElementType.FLOAT,
             3,
             true,
-            VectorSimilarity.cosine,
+            VectorSimilarity.COSINE,
             Collections.emptyMap()
         );
         e = expectThrows(IllegalArgumentException.class, () -> cosineField.createKnnQuery(new float[] { 0.0f, 0.0f, 0.0f }, 10, null));
@@ -154,7 +154,7 @@ public void testByteCreateKnnQuery() {
             DenseVectorFieldMapper.ElementType.BYTE,
             3,
             false,
-            VectorSimilarity.cosine,
+            VectorSimilarity.COSINE,
             Collections.emptyMap()
         );
         IllegalArgumentException e = expectThrows(
@@ -169,7 +169,7 @@ public void testByteCreateKnnQuery() {
             DenseVectorFieldMapper.ElementType.BYTE,
             3,
             true,
-            VectorSimilarity.cosine,
+            VectorSimilarity.COSINE,
             Collections.emptyMap()
         );
         e = expectThrows(IllegalArgumentException.class, () -> cosineField.createKnnQuery(new float[] { 0.0f, 0.0f, 0.0f }, 10, null));
diff --git a/test/framework/src/main/java/org/elasticsearch/index/mapper/MapperTestCase.java b/test/framework/src/main/java/org/elasticsearch/index/mapper/MapperTestCase.java
index 5a66cf243eab5..d1eb4c17b40ce 100644
--- a/test/framework/src/main/java/org/elasticsearch/index/mapper/MapperTestCase.java
+++ b/test/framework/src/main/java/org/elasticsearch/index/mapper/MapperTestCase.java
@@ -354,7 +354,7 @@ protected <T> void assertMetricType(String metricType, Function<T, Enum<TimeSeri
 
         @SuppressWarnings("unchecked") // Syntactic sugar in tests
         T fieldType = (T) mapperService.fieldType("field");
-        assertThat(checker.apply(fieldType).name(), equalTo(metricType));
+        assertThat(checker.apply(fieldType).toString(), equalTo(metricType));
     }
 
     public final void testEmptyName() {
diff --git a/x-pack/plugin/analytics/src/test/java/org/elasticsearch/xpack/analytics/rate/TimeSeriesRateAggregatorTests.java b/x-pack/plugin/analytics/src/test/java/org/elasticsearch/xpack/analytics/rate/TimeSeriesRateAggregatorTests.java
index 9b7c0cf123c4a..65cfd05e6c5a3 100644
--- a/x-pack/plugin/analytics/src/test/java/org/elasticsearch/xpack/analytics/rate/TimeSeriesRateAggregatorTests.java
+++ b/x-pack/plugin/analytics/src/test/java/org/elasticsearch/xpack/analytics/rate/TimeSeriesRateAggregatorTests.java
@@ -136,7 +136,7 @@ private MappedFieldType counterField(String name) {
             Collections.emptyMap(),
             null,
             false,
-            TimeSeriesParams.MetricType.counter
+            TimeSeriesParams.MetricType.COUNTER
         );
     }
 
diff --git a/x-pack/plugin/mapper-aggregate-metric/src/main/java/org/elasticsearch/xpack/aggregatemetric/mapper/AggregateDoubleMetricFieldMapper.java b/x-pack/plugin/mapper-aggregate-metric/src/main/java/org/elasticsearch/xpack/aggregatemetric/mapper/AggregateDoubleMetricFieldMapper.java
index c1b9412f8cedc..460a498d707b1 100644
--- a/x-pack/plugin/mapper-aggregate-metric/src/main/java/org/elasticsearch/xpack/aggregatemetric/mapper/AggregateDoubleMetricFieldMapper.java
+++ b/x-pack/plugin/mapper-aggregate-metric/src/main/java/org/elasticsearch/xpack/aggregatemetric/mapper/AggregateDoubleMetricFieldMapper.java
@@ -168,7 +168,7 @@ public Builder(String name, Boolean ignoreMalformedByDefault, Version indexCreat
                 ignoreMalformedByDefault
             );
 
-            this.timeSeriesMetric = TimeSeriesParams.metricParam(m -> toType(m).metricType, MetricType.gauge);
+            this.timeSeriesMetric = TimeSeriesParams.metricParam(m -> toType(m).metricType, MetricType.GAUGE);
 
             this.indexCreatedVersion = Objects.requireNonNull(indexCreatedVersion);
         }
diff --git a/x-pack/plugin/mapper-unsigned-long/src/main/java/org/elasticsearch/xpack/unsignedlong/UnsignedLongFieldMapper.java b/x-pack/plugin/mapper-unsigned-long/src/main/java/org/elasticsearch/xpack/unsignedlong/UnsignedLongFieldMapper.java
index 97ff720c6c14e..3adec4e7ae2d3 100644
--- a/x-pack/plugin/mapper-unsigned-long/src/main/java/org/elasticsearch/xpack/unsignedlong/UnsignedLongFieldMapper.java
+++ b/x-pack/plugin/mapper-unsigned-long/src/main/java/org/elasticsearch/xpack/unsignedlong/UnsignedLongFieldMapper.java
@@ -125,7 +125,7 @@ public Builder(String name, boolean ignoreMalformedByDefault) {
                 }
             });
 
-            this.metric = TimeSeriesParams.metricParam(m -> toType(m).metricType, MetricType.gauge, MetricType.counter).addValidator(v -> {
+            this.metric = TimeSeriesParams.metricParam(m -> toType(m).metricType, MetricType.GAUGE, MetricType.COUNTER).addValidator(v -> {
                 if (v != null && hasDocValues.getValue() == false) {
                     throw new IllegalArgumentException(
                         "Field [" + TimeSeriesParams.TIME_SERIES_METRIC_PARAM + "] requires that [" + hasDocValues.name + "] is true"
@@ -298,7 +298,7 @@ public IndexFieldData.Builder fielddataBuilder(FieldDataContext fieldDataContext
                 failIfNoDocValues();
             }
 
-            ValuesSourceType valuesSourceType = metricType == TimeSeriesParams.MetricType.counter
+            ValuesSourceType valuesSourceType = metricType == TimeSeriesParams.MetricType.COUNTER
                 ? TimeSeriesValuesSourceType.COUNTER
                 : IndexNumericFieldData.NumericType.LONG.getValuesSourceType();
 
diff --git a/x-pack/plugin/rollup/src/main/java/org/elasticsearch/xpack/downsample/FieldValueFetcher.java b/x-pack/plugin/rollup/src/main/java/org/elasticsearch/xpack/downsample/FieldValueFetcher.java
index f3103374df0ce..75b21a9d0e057 100644
--- a/x-pack/plugin/rollup/src/main/java/org/elasticsearch/xpack/downsample/FieldValueFetcher.java
+++ b/x-pack/plugin/rollup/src/main/java/org/elasticsearch/xpack/downsample/FieldValueFetcher.java
@@ -55,8 +55,8 @@ public AbstractRollupFieldProducer rollupFieldProducer() {
     private AbstractRollupFieldProducer createRollupFieldProducer() {
         if (fieldType.getMetricType() != null) {
             return switch (fieldType.getMetricType()) {
-                case gauge -> new MetricFieldProducer.GaugeMetricFieldProducer(name());
-                case counter -> new MetricFieldProducer.CounterMetricFieldProducer(name());
+                case GAUGE -> new MetricFieldProducer.GaugeMetricFieldProducer(name());
+                case COUNTER -> new MetricFieldProducer.CounterMetricFieldProducer(name());
             };
         } else {
             // If field is not a metric, we downsample it as a label
diff --git a/x-pack/plugin/rollup/src/main/java/org/elasticsearch/xpack/downsample/TimeseriesFieldTypeHelper.java b/x-pack/plugin/rollup/src/main/java/org/elasticsearch/xpack/downsample/TimeseriesFieldTypeHelper.java
index 06bd2260198ba..691279187e1a9 100644
--- a/x-pack/plugin/rollup/src/main/java/org/elasticsearch/xpack/downsample/TimeseriesFieldTypeHelper.java
+++ b/x-pack/plugin/rollup/src/main/java/org/elasticsearch/xpack/downsample/TimeseriesFieldTypeHelper.java
@@ -42,7 +42,7 @@ public boolean isTimeSeriesLabel(final String field, final Map<String, ?> unused
     public boolean isTimeSeriesMetric(final String unused, final Map<String, ?> fieldMapping) {
         final String metricType = (String) fieldMapping.get(TIME_SERIES_METRIC_PARAM);
         return metricType != null
-            && List.of(TimeSeriesParams.MetricType.values()).contains(TimeSeriesParams.MetricType.valueOf(metricType));
+            && List.of(TimeSeriesParams.MetricType.values()).contains(TimeSeriesParams.MetricType.fromString(metricType));
     }
 
     public boolean isTimeSeriesDimension(final String unused, final Map<String, ?> fieldMapping) {
diff --git a/x-pack/plugin/rollup/src/main/java/org/elasticsearch/xpack/downsample/TransportRollupAction.java b/x-pack/plugin/rollup/src/main/java/org/elasticsearch/xpack/downsample/TransportRollupAction.java
index a793cddc8e421..1c52ef19dbbf4 100644
--- a/x-pack/plugin/rollup/src/main/java/org/elasticsearch/xpack/downsample/TransportRollupAction.java
+++ b/x-pack/plugin/rollup/src/main/java/org/elasticsearch/xpack/downsample/TransportRollupAction.java
@@ -477,10 +477,10 @@ private static void addTimestampField(final DownsampleConfig config, final XCont
 
     private static void addMetricFieldMapping(final XContentBuilder builder, final String field, final Map<String, ?> fieldProperties)
         throws IOException {
-        final TimeSeriesParams.MetricType metricType = TimeSeriesParams.MetricType.valueOf(
+        final TimeSeriesParams.MetricType metricType = TimeSeriesParams.MetricType.fromString(
             fieldProperties.get(TIME_SERIES_METRIC_PARAM).toString()
         );
-        if (TimeSeriesParams.MetricType.counter.equals(metricType)) {
+        if (metricType == TimeSeriesParams.MetricType.COUNTER) {
             // For counters, we keep the same field type, because they store
             // only one value (the last value of the counter)
             builder.startObject(field).field("type", fieldProperties.get("type")).field(TIME_SERIES_METRIC_PARAM, metricType).endObject();
diff --git a/x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/downsample/DownsampleActionSingleNodeTests.java b/x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/downsample/DownsampleActionSingleNodeTests.java
index f4d06397da0fd..5a34a95f74a2e 100644
--- a/x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/downsample/DownsampleActionSingleNodeTests.java
+++ b/x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/downsample/DownsampleActionSingleNodeTests.java
@@ -746,7 +746,7 @@ private void assertRollupIndex(String sourceIndex, String rollupIndex, Downsampl
         Map<String, String> labelFields = new HashMap<>();
         MappingVisitor.visitMapping(sourceIndexMappings, (field, fieldMapping) -> {
             if (helper.isTimeSeriesMetric(field, fieldMapping)) {
-                metricFields.put(field, TimeSeriesParams.MetricType.valueOf(fieldMapping.get(TIME_SERIES_METRIC_PARAM).toString()));
+                metricFields.put(field, TimeSeriesParams.MetricType.fromString(fieldMapping.get(TIME_SERIES_METRIC_PARAM).toString()));
             } else if (helper.isTimeSeriesLabel(field, fieldMapping)) {
                 labelFields.put(field, fieldMapping.get("type").toString());
             }
@@ -911,8 +911,8 @@ private void assertFieldMappings(
 
         metricFields.forEach((field, metricType) -> {
             switch (metricType) {
-                case counter -> assertEquals("double", mappings.get(field).get("type"));
-                case gauge -> assertEquals("aggregate_metric_double", mappings.get(field).get("type"));
+                case COUNTER -> assertEquals("double", mappings.get(field).get("type"));
+                case GAUGE -> assertEquals("aggregate_metric_double", mappings.get(field).get("type"));
                 default -> fail("Unsupported field type");
             }
             assertEquals(metricType.toString(), mappings.get(field).get("time_series_metric"));