IngestDocument readability improvements

server/src/main/java/org/elasticsearch/common/util/LocaleUtils.java

@@ -14,15 +14,15 @@
 import java.util.MissingResourceException;
 
 /**
- * Utilities for for dealing with {@link Locale} objects
+ * Utilities for dealing with {@link Locale} objects
  */
 public class LocaleUtils {
 
  /**
  * Parse the given locale as {@code language}, {@code language-country} or
  * {@code language-country-variant}.
- * Either underscores or hyphens may be used as separators, but consistently, ie.
- * you may not use an hyphen to separate the language from the country and an
+ * Either underscores or hyphens may be used as separators, but consistently, i.e.
+ * you may not use a hyphen to separate the language from the country and an
  * underscore to separate the country from the variant.
  * @throws IllegalArgumentException if there are too many parts in the locale string
  * @throws IllegalArgumentException if the language or country is not recognized

server/src/main/java/org/elasticsearch/ingest/ConfigurationUtils.java

@@ -543,18 +543,38 @@ public static TemplateScript.Factory compileTemplate(
  Script script = new Script(ScriptType.INLINE, DEFAULT_TEMPLATE_LANG, propertyValue, Map.of());
  return scriptService.compile(script, TemplateScript.CONTEXT);
  } else {
- return (params) -> new TemplateScript(params) {
- @Override
- public String execute() {
- return propertyValue;
- }
- };
+ return new ConstantTemplateScriptFactory(propertyValue);
  }
  } catch (Exception e) {
  throw ConfigurationUtils.newConfigurationException(processorType, processorTag, propertyName, e);
  }
  }
 
+ /**
+ * A 'template script' that ignores the model to which it is applied and just always returns a constant String.
+ * <p>
+ * Having a separate named class for this allows for some hot code paths to pre-apply the 'template script' statically,
+ * rather than bothering to invoke it per-document. Note that this is probably only useful if something expensive
+ * is being done with the result of calling the script, and the code can then avoid doing that thing per-document.
+ */
+ public static class ConstantTemplateScriptFactory implements TemplateScript.Factory {
+ final TemplateScript script;
+
+ private ConstantTemplateScriptFactory(String value) {
+ this.script = new TemplateScript(Map.of()) {
+ @Override
+ public String execute() {
+ return value;
+ }
+ };
+ }
+
+ @Override
+ public TemplateScript newInstance(Map<String, Object> params) {
+ return script;
+ }
+ }
+
  private static void addMetadataToException(
  ElasticsearchException exception,
  String processorType,