code: public OptionalLong extractRevision(String buildName) {
          // Gets the regex for the pattern
          String regex = getRegex();
          // Matching
          Matcher matcher = Pattern.compile(regex).matcher(buildName);
          if (matcher.matches()) {
              String token = matcher.group(1);
              return OptionalLong.of(
                      Long.parseLong(token, 10)
              );
          } else {
              return OptionalLong.empty();
          }
      }
docs: Extracts the revision from a build name.