code: @Override
      public Integer parameterFromPathAsInteger(String key) {
          String parameter = parameterFromPath(key);
          if (parameter == null) {
              return null;
          } else {
              return Integer.parseInt(parameter);
          }
      }
docs: Get the path parameter for the given key and convert it to Integer.
  <p>
  The parameter will be decoded based on the RFCs.
  <p>
  Check out http://docs.oracle.com/javase/6/docs/api/java/net/URI.html for
  more information.
  
  @param key the key of the path parameter
  @return the numeric path parameter, or null of no such path parameter is
  defined, or if it cannot be parsed to int