revert: restore generated DerivedField.java to main state

The fix belongs in the OpenSearch API specification, not in generated
code. Submitted upstream: opensearch-project/opensearch-api-specification#1156

The java-codegen/opensearch-openapi.yaml change is kept here as a local
workaround until the upstream spec fix is pulled in by the weekly
code-generation workflow.

Signed-off-by: RadhaKrishnan Rajendran <gingeekrishna@gmail.com>
Signed-off-by: Radhakrishnan Pachyappan <gingeekrishna@gmail.com>

Author: radhakrishnan-op

java-client/src/generated/java/org/opensearch/client/opensearch/_types/DerivedField.java

@@ -68,6 +68,9 @@ public class DerivedField implements PlainJsonSerializable, ToCopyableBuilder<De
     @Nullable
     private final Boolean ignoreMalformed;
 
+    @Nonnull
+    private final String name;
+
     @Nullable
     private final String prefilterField;
 
@@ -85,6 +88,7 @@ public class DerivedField implements PlainJsonSerializable, ToCopyableBuilder<De
     private DerivedField(Builder builder) {
         this.format = builder.format;
         this.ignoreMalformed = builder.ignoreMalformed;
+        this.name = ApiTypeHelper.requireNonNull(builder.name, this, "name");
         this.prefilterField = builder.prefilterField;
         this.properties = ApiTypeHelper.unmodifiable(builder.properties);
         this.script = ApiTypeHelper.requireNonNull(builder.script, this, "script");
@@ -111,6 +115,14 @@ public final Boolean ignoreMalformed() {
         return this.ignoreMalformed;
     }
 
+    /**
+     * Required - API name: {@code name}
+     */
+    @Nonnull
+    public final String name() {
+        return this.name;
+    }
+
     /**
      * API name: {@code prefilter_field}
      */
@@ -164,6 +176,9 @@ protected void serializeInternal(JsonGenerator generator, JsonpMapper mapper) {
             generator.write(this.ignoreMalformed);
         }
 
+        generator.writeKey("name");
+        generator.write(this.name);
+
         if (this.prefilterField != null) {
             generator.writeKey("prefilter_field");
             generator.write(this.prefilterField);
@@ -207,6 +222,7 @@ public static class Builder extends ObjectBuilderBase implements CopyableBuilder
         private String format;
         @Nullable
         private Boolean ignoreMalformed;
+        private String name;
         @Nullable
         private String prefilterField;
         @Nullable
@@ -219,6 +235,7 @@ public Builder() {}
         private Builder(DerivedField o) {
             this.format = o.format;
             this.ignoreMalformed = o.ignoreMalformed;
+            this.name = o.name;
             this.prefilterField = o.prefilterField;
             this.properties = _mapCopy(o.properties);
             this.script = o.script;
@@ -228,6 +245,7 @@ private Builder(DerivedField o) {
         private Builder(Builder o) {
             this.format = o.format;
             this.ignoreMalformed = o.ignoreMalformed;
+            this.name = o.name;
             this.prefilterField = o.prefilterField;
             this.properties = _mapCopy(o.properties);
             this.script = o.script;
@@ -258,6 +276,15 @@ public final Builder ignoreMalformed(@Nullable Boolean value) {
             return this;
         }
 
+        /**
+         * Required - API name: {@code name}
+         */
+        @Nonnull
+        public final Builder name(String value) {
+            this.name = value;
+            return this;
+        }
+
         /**
          * API name: {@code prefilter_field}
          */
@@ -346,6 +373,7 @@ public DerivedField build() {
     protected static void setupDerivedFieldDeserializer(ObjectDeserializer<DerivedField.Builder> op) {
         op.add(Builder::format, JsonpDeserializer.stringDeserializer(), "format");
         op.add(Builder::ignoreMalformed, JsonpDeserializer.booleanDeserializer(), "ignore_malformed");
+        op.add(Builder::name, JsonpDeserializer.stringDeserializer(), "name");
         op.add(Builder::prefilterField, JsonpDeserializer.stringDeserializer(), "prefilter_field");
         op.add(Builder::properties, JsonpDeserializer.stringMapDeserializer(JsonData._DESERIALIZER), "properties");
         op.add(Builder::script, Script._DESERIALIZER, "script");
@@ -357,6 +385,7 @@ public int hashCode() {
         int result = 17;
         result = 31 * result + Objects.hashCode(this.format);
         result = 31 * result + Objects.hashCode(this.ignoreMalformed);
+        result = 31 * result + this.name.hashCode();
         result = 31 * result + Objects.hashCode(this.prefilterField);
         result = 31 * result + Objects.hashCode(this.properties);
         result = 31 * result + this.script.hashCode();
@@ -371,6 +400,7 @@ public boolean equals(Object o) {
         DerivedField other = (DerivedField) o;
         return Objects.equals(this.format, other.format)
             && Objects.equals(this.ignoreMalformed, other.ignoreMalformed)
+            && this.name.equals(other.name)
             && Objects.equals(this.prefilterField, other.prefilterField)
             && Objects.equals(this.properties, other.properties)
             && this.script.equals(other.script)