code: public static final String updateFilenameHashCode(EnterpriseBean enterpriseBean, String oldName)
      {
          String newName = null;
          int len = oldName.length();
          int last_ = (len > 9 && (oldName.charAt(len - 9) == '_')) ? len - 9 : -1;
          // input file name must have a trailing "_" follows by 8 hex digits
          // and check to make sure the last 8 characters are all hex digits
          if (last_ != -1 && allHexDigits(oldName, ++last_, len))
          {
              String hashStr = getHashStr(enterpriseBean);
              newName = oldName.substring(0, last_) + BuzzHash.computeHashStringMid32Bit(hashStr, true);
          }
          return newName;
      }
docs: Attempts to find the new file name originated from input oldName using the
  the new modified BuzzHash algorithm.
  This method detects if the oldName contains a valid trailing hashcode and
  try to compute the new one. If the oldName has no valid hashcode in the
  input name, null is return.
  For ease of invocation regardless of the type of file passes in, this method
  only changes the hash value and will not recreate the complete file name from
  the EnterpriseBean.
  
  @return the new file name using the oldName but with a new hash code, or null if no
  new name can be constructed.