code: private boolean isValid(String request) {
  
          String tmp = decodePercent(request);
          if(tmp.indexOf('<') != -1 ||
             tmp.indexOf('>') != -1 ) {
              return false;
          }
  
          return true;
      }
docs: Validates request string for not containing malicious characters.
  
  @param request a request string
  @return true - if request string is valid, false - otherwise