code: String buildUrl(String relativePath)
      {
          return String.format("%s://%s:%s%s%s", this.protocol, this.hostname, this.port, this.uriPrefix, relativePath);
      }
docs: Build the URL from the protocol://hostname:port + uriPrefix + relativePath
  @param relativePath The path of the resource (should always start with a "/")
  @return The URL to call