Internal refactoring stringRepresentation/convertId.

Original Pull Request #2312
Closes #2228

src/main/java/org/springframework/data/elasticsearch/core/AbstractElasticsearchTemplate.java

@@ -531,11 +531,7 @@ public abstract class AbstractElasticsearchTemplate implements ElasticsearchOper
 		Object id = entityOperations.forEntity(entity, elasticsearchConverter.getConversionService(), routingResolver)
 				.getId();
 
-		if (id != null) {
+		return convertId(id);
-			return stringIdRepresentation(id);
-		}
-
-		return null;
 	}
 
 	@Nullable

src/main/java/org/springframework/data/elasticsearch/core/ElasticsearchOperations.java

@@ -80,13 +80,28 @@ public interface ElasticsearchOperations extends DocumentOperations, SearchOpera
 	 * gets the String representation for an id.
 	 *
 	 * @param id
-	 * @return
+	 * @return String representation
 	 * @since 4.0
+	 * @deprecated since 5.0, use {@link ElasticsearchOperations#convertId(Object)}.
 	 */
+	@Deprecated
 	@Nullable
 	default String stringIdRepresentation(@Nullable Object id) {
 		return Objects.toString(id, null);
 	}
+
+	/**
+	 * Converts an idValue to a String representation. The default implementation calls
+	 * {@link ElasticsearchConverter#convertId(Object)}
+	 *
+	 * @param idValue the value to convert
+	 * @return the converted value or {@literal null} if idValue is null
+	 * @since 5.0
+	 */
+	@Nullable
+	default String convertId(@Nullable Object idValue) {
+		return idValue != null ? getElasticsearchConverter().convertId(idValue) : null;
+	}
 	// endregion
 
 	// region routing

src/main/java/org/springframework/data/elasticsearch/repository/support/SimpleElasticsearchRepository.java

@@ -313,7 +313,7 @@ public class SimpleElasticsearchRepository<T, ID> implements ElasticsearchReposi
 	}
 
 	protected @Nullable String stringIdRepresentation(@Nullable ID id) {
-		return operations.stringIdRepresentation(id);
+		return operations.convertId(id);
 	}
 
 	private IndexCoordinates getIndexCoordinates() {