code: private String getURI(Map<String, Object> props) {
          if (props == null)
              return null;
          if (props.keySet().contains(URI)) {
              return (props.get(URI).toString());
          } else {
              return null;
          }
      }
docs: find the uri parameter which we will key off of
  
  @param props
  @return value of uri param within props, or null if no uri param