code: public void validate() throws InvalidRequestException
      {
          // required
          if (!attrs.containsKey("strategy_class"))
              throw new InvalidRequestException("missing required argument \"strategy_class\"");
          strategyClass = attrs.get("strategy_class");
  
          // optional
          for (String key : attrs.keySet())
              if ((key.contains(":")) && (key.startsWith("strategy_options")))
                  strategyOptions.put(key.split(":")[1], attrs.get(key));
      }
docs: The <code>CqlParser</code> only goes as far as extracting the keyword arguments
  from these statements, so this method is responsible for processing and
  validating, and must be called prior to access.
  
  @throws InvalidRequestException if arguments are missing or unacceptable