</function>

  <function>
    <description>
      Returns formatted number from a given value.
    </description>
    <name>formatNumber</name>
    <function-class>org.codelibs.fess.taglib.FessFunctions</function-class>
    <function-signature>java.lang.String formatNumber(long, java.lang.String)</function-signature>
    <example>
      ${fe:formatNumber(doc.content_length, "###,###")}
    </example>
  </function>

        return DurationFormatUtils.formatDuration(durationMillis, "d 'days' HH:mm:ss.SSS").replace("0 days", StringUtil.EMPTY).trim();

    }

    public static String formatNumber(final long value, final String pattern) {
        final DecimalFormat df = (DecimalFormat) NumberFormat.getNumberInstance(getUserLocale());
        df.applyPattern(pattern);
        return df.format(value);
    }