protected void doAction()

in src/main/java/com/amazonaws/services/kinesis/aggregators/app/QueryByLabelServlet.java [91:170]
63 lines of code
15 McCabe index (conditional complexity)

    protected void doAction(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String namespace = request.getParameter(NAMESPACE_PARAM);
        String labelValue = request.getParameter(LABEL_VALUE_PARAM);
        String dateValue = request.getParameter(DATE_VALUE_PARAM);
        String operator = request.getParameter(OPERATOR_PARAM);

        // have to provide namespace and label
        if (namespace == null) {
            doError(response, String.format("Argument '%s' must not be null", NAMESPACE_PARAM));
            return;
        }
        if (labelValue == null || labelValue.equals("")) {
            doError(response, String.format("Argument '%s' must not be null", LABEL_VALUE_PARAM));
            return;
        }

        // if date value is provided, the so too must operator and granularity
        ComparisonOperator setOperator = null;
        if (dateValue != null && operator == null) {
            setOperator = ComparisonOperator.EQ;
        }

        if (operator != null) {
            try {
                setOperator = ComparisonOperator.fromValue(operator);
            } catch (Exception e) {
                doError(response, String.format("%s is an invalid Comparison Operator", operator));
                return;
            }
        }

        String streamName = (String) request.getServletContext().getAttribute(
                AggregatorsConstants.STREAM_NAME_PARAM);
        AggregatorGroup aggGroup = (AggregatorGroup) request.getServletContext().getAttribute(
                AggregatorsBeanstalkApp.AGGREGATOR_GROUP_PARAM);
        if (aggGroup == null) {
            doError(response, "Aggregator Application Not Initialised");
            return;
        } else {
            // initialise the aggregator group onto shard 'none' for this
            // operation
            // - it may already be initialised
            try {
                aggGroup.initialize("none");
            } catch (Exception e) {
                throw new ServletException(e);
            }
        }

        Date dateValueAsDate = null;
        if (dateValue != null) {
            try {
                dateValueAsDate = StreamAggregator.dateFormatter.parse(dateValue);
            } catch (ParseException e1) {
                throw new ServletException(e1);
            }
        }

        // put the initialised aggregator group back into the context
        request.getServletContext().setAttribute(AggregatorsBeanstalkApp.AGGREGATOR_GROUP_PARAM,
                aggGroup);

        // acquire the correct aggregator by namespace
        for (StreamAggregator agg : aggGroup.getAggregators()) {
            if (agg.getNamespace().equals(namespace)) {
                // run the query
                try {
                    respondWith(response, agg.queryValue(labelValue, dateValueAsDate, setOperator));
                    return;
                } catch (Exception e) {
                    throw new ServletException(e);
                }
            }
        }

        // shouldn't get here, so bail with a meaning error on namespace
        doError(response,
                String.format("Unable to acquire Aggregator with Namespace %s", namespace));
    }