public static <E extends Enum<E>> E getEnum(final Attributes attributes, final String name,
      final Class<E> clazz) {
    return getEnum(attributes, name, clazz, null);
  }
@return Enum value for named attribute or null if attribute not defined.
@since GemFire 8.1
geode-core/src/main/java/org/apache/geode/internal/cache/xmlcache/CacheXml.java