public void handleRequest()

in src/main/java/com/amazonaws/handler/CreateOrderHandler.java [62:143]
79 lines of code
10 McCabe index (conditional complexity)

    public void handleRequest(InputStream input, OutputStream output,
                              Context context) throws IOException {
        final JsonNode event;
        try {
            event = objectMapper.readTree(input);
        } catch (JsonMappingException e) {
            writeInvalidJsonInStreamResponse(objectMapper, output, e.getMessage());
            return;
        }

        if (event == null) {
            writeInvalidJsonInStreamResponse(objectMapper, output, "event was null");
            return;
        }
        JsonNode createOrderRequestBody = event.findValue("body");
        if (createOrderRequestBody == null) {
            objectMapper.writeValue(output,
                    new GatewayResponse<>(
                            objectMapper.writeValueAsString(
                                    new ErrorMessage("Body was null",
                                            SC_BAD_REQUEST)),
                            APPLICATION_JSON, SC_BAD_REQUEST));
            return;
        }
        final CreateOrderRequest request;
        try {
            request = objectMapper.treeToValue(
                    objectMapper.readTree(createOrderRequestBody.asText()),
                    CreateOrderRequest.class);
        } catch (JsonParseException | JsonMappingException e) {
            objectMapper.writeValue(output,
                    new GatewayResponse<>(
                            objectMapper.writeValueAsString(
                                    new ErrorMessage("Invalid JSON in body: "
                                            + e.getMessage(), SC_BAD_REQUEST)),
                            APPLICATION_JSON, SC_BAD_REQUEST));
            return;
        }

        if (request == null) {
            objectMapper.writeValue(output,
                    new GatewayResponse<>(
                            objectMapper.writeValueAsString(REQUEST_WAS_NULL_ERROR),
                            APPLICATION_JSON, SC_BAD_REQUEST));
            return;
        }

        if (isNullOrEmpty(request.getCustomerId())) {
            objectMapper.writeValue(output,
                    new GatewayResponse<>(
                            objectMapper.writeValueAsString(REQUIRE_CUSTOMER_ID_ERROR),
                            APPLICATION_JSON, SC_BAD_REQUEST));
            return;
        }
        if (request.getPreTaxAmount() == null) {
            objectMapper.writeValue(output,
                    new GatewayResponse<>(
                            objectMapper.writeValueAsString(REQUIRE_PRETAX_AMOUNT_ERROR),
                            APPLICATION_JSON, SC_BAD_REQUEST));
            return;
        }
        if (request.getPostTaxAmount() == null) {
            objectMapper.writeValue(output,
                    new GatewayResponse<>(
                            objectMapper.writeValueAsString(REQUIRE_POST_TAX_AMOUNT_ERROR),
                            APPLICATION_JSON, SC_BAD_REQUEST));
            return;
        }
        try {
            final Order order = orderDao.createOrder(request);
            objectMapper.writeValue(output,
                    new GatewayResponse<>(objectMapper.writeValueAsString(order),
                            APPLICATION_JSON, SC_CREATED)); //TODO redirect with a 303
        } catch (CouldNotCreateOrderException e) {
            objectMapper.writeValue(output,
                    new GatewayResponse<>(
                            objectMapper.writeValueAsString(
                                    new ErrorMessage(e.getMessage(),
                                            SC_INTERNAL_SERVER_ERROR)),
                            APPLICATION_JSON, SC_INTERNAL_SERVER_ERROR));
        }
    }