public static String getReferencedRegionName(final String fileName) {
    Matcher m = REF_OR_HFILE_LINK_PATTERN.matcher(fileName);
    if (!m.matches()) {
      throw new IllegalArgumentException(fileName + " is not a valid HFileLink name!");
    }
    return (m.group(3));
  }
Get the Region name of the referenced link
@param fileName HFileLink file name
@return the name of the referenced Region
hbase-server/src/main/java/org/apache/hadoop/hbase/io/HFileLink.java