Added Javadoc to clear checkstyle error

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1588857 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/commons/lang3/time/DurationFormatUtils.java

@@ -457,7 +457,15 @@ static String format(final Token[] tokens, final long years, final long months,
         return buffer.toString();
     }
 
-    // Helper method to simplify repetive code in format method above
+    /**
+     * <p>Converts a {@code long} to a {@code String} with optional
+     * zero padding.</p>
+     *
+     * @param value the value to convert
+     * @param padWithZeros whether to pad with zeroes
+     * @param count the size to pad to (ignored if {@code padWithZeros} is false)
+     * @return the string result
+     */
     private static String paddedValue(final long value, final boolean padWithZeros, final int count) {
         final String longString = Long.toString(value);
         return padWithZeros ? StringUtils.leftPad(longString, count, '0') : longString;