SendResult sendMessage()

in iothub/device/iot-device-client/src/main/java/com/microsoft/azure/sdk/iot/device/transport/amqps/AmqpsSessionHandler.java [350:436]
51 lines of code
12 McCabe index (conditional complexity)

    SendResult sendMessage(Message message)
    {
        if (!this.clientConfiguration.getDeviceId().equals(message.getConnectionDeviceId()))
        {
            // This should never happen since this session handler was chosen from a map of device Id -> session handler
            // so it should have the same device Id as in the map it was grabbed from.
            log.warn("Failed to send the message because this session belongs to a different device");
            return SendResult.WRONG_DEVICE;
        }

        MessageType messageType = message.getMessageType();
        if (messageType == null)
        {
            // Twin and method messages have a message type assigned to them when they are constructed by this SDK
            // (users can't construct twin/method messages directly), but telemetry messages don't necessarily have this
            // type assigned since users may create telemetry messages. By default, assume any messages with an
            // unassigned type are telemetry messages.
            messageType = DEVICE_TELEMETRY;
        }

        // Check if the message being sent is a subscription change message. If so, open the corresponding links.
        if (message instanceof IotHubTransportMessage)
        {
            IotHubTransportMessage transportMessage = (IotHubTransportMessage) message;
            DeviceOperations subscriptionType = transportMessage.getDeviceOperationType();

            if (subscriptionType == DEVICE_OPERATION_METHOD_SUBSCRIBE_REQUEST)
            {
                return handleMethodSubscriptionRequest(transportMessage);
            }

            if (subscriptionType == DEVICE_OPERATION_TWIN_SUBSCRIBE_DESIRED_PROPERTIES_REQUEST)
            {
                return handleTwinSubscriptionRequest(transportMessage);
            }
        }

        AmqpsSenderLinkHandler senderLinkHandler = this.senderLinkHandlers.get(messageType);

        if (senderLinkHandler == null)
        {
            // no sender link handler saved for this message type, so it can't be sent
            // Should never happen since telemetry links are always opened, and twin/method messages can't be sent
            // before their respective subscription messages have already opened their links.
            return SendResult.LINKS_NOT_OPEN;
        }

        if (messageType == DEVICE_TWIN)
        {
            if (explicitInProgressTwinSubscriptionMessage != null)
            {
                // When this variable is not null, it means there is a subscription on twin in progress. These are initiated
                // by the user when they call startTwin.
                //
                // Don't send any twin messages while a twin subscription is in progress. Wait until the subscription
                // has been acknowledged by the service before sending it.
                return SendResult.SUBSCRIPTION_IN_PROGRESS;
            }

            for (SubscriptionType subscriptionType : this.implicitInProgressSubscriptionMessages.values())
            {
                if (subscriptionType == SubscriptionType.DESIRED_PROPERTIES_SUBSCRIPTION)
                {
                    // When there is at least one desired properties subscription in the implicitInProgressSubscriptionMessages
                    // value set, then that means there is a desired properties subscription message that has been sent
                    // to the service, but has not been acknowledged yet. These implicit subscriptions happen when a
                    // session loses connectivity temporarily, and the session handler sends out subscription messages
                    // to the service to re-establish all subscritptions that were active prior to the disconnection.
                    //
                    // Don't send any twin messages while a twin subscription is in progress. Reject this message until
                    // the subscription has been acknowledged by the service. The connection layer will requeue this message
                    // and it will have another chance to send when the timer task that checks for outgoing queued messages
                    // executes again.
                    return SendResult.SUBSCRIPTION_IN_PROGRESS;
                }
            }
        }

        AmqpsSendResult amqpsSendResult = senderLinkHandler.sendMessageAndGetDeliveryTag(message);

        if (amqpsSendResult.isDeliverySuccessful())
        {
            return SendResult.SUCCESS;
        }

        return SendResult.UNKNOWN_FAILURE;
    }