code: public static String generateRevisionNumber(final ContentSpec contentSpec) {
          final StringBuilder rev = new StringBuilder();
  
          rev.append(generateRevision(contentSpec));
  
          // Add the separator
          rev.append("-");
  
          // Build the pubsnumber part of the revision number.
          final Integer pubsnum = contentSpec.getPubsNumber();
          if (pubsnum == null) {
              rev.append(BuilderConstants.DEFAULT_PUBSNUMBER);
          } else {
              rev.append(pubsnum);
          }
  
          return rev.toString();
      }
docs: Generates the Revision Number to be used in a Revision_History.xml
  file using the Book Version, Edition and Pubsnumber values from a content
  specification.
  
  @param contentSpec the content specification to generate the revision number for.
  @return The generated revnumber value.