private static String buildScanRegionStateMalformedErrorMessage(final String requestValue) {
    return String.format(
      "Requested SCAN_REGION_STATE value '%s' cannot be parsed as a RegionState.", requestValue);
  }
Adds {@code value} to {@code encoder} under {@code paramName} when {@code value} is non-null.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/http/MetaBrowser.java