public IotHubTransportMessage receive()

in iothub/device/iot-device-client/src/main/java/com/microsoft/azure/sdk/iot/device/transport/mqtt/MqttDirectMethod.java [119:179]
48 lines of code
11 McCabe index (conditional complexity)

    public IotHubTransportMessage receive()
    {
        synchronized (this.receivedMessagesLock)
        {
            IotHubTransportMessage message = null;

            Pair<String, MqttMessage> messagePair = this.receivedMessages.peek();

            if (messagePair != null)
            {
                String topic = messagePair.getKey();

                if (topic != null && topic.length() > 0)
                {
                    MqttMessage mqttMessage = messagePair.getValue();
                    byte[] data = mqttMessage.getPayload();

                    if (topic.length() > METHOD.length() && topic.startsWith(METHOD))
                    {
                        if (topic.length() > POST.length() && topic.startsWith(POST))
                        {
                            //remove this message from the queue as this is the correct handler
                            this.receivedMessages.poll();

                            // Case for $iothub/methods/POST/{method name}/?$rid={request id}
                            TopicParser topicParser = new TopicParser(topic);

                            if (data != null && data.length > 0)
                            {
                                message = new IotHubTransportMessage(data, MessageType.DEVICE_METHODS);
                            }
                            else
                            {
                                message = new IotHubTransportMessage(new byte[0], MessageType.DEVICE_METHODS);
                            }

                            message.setDeviceOperationType(DeviceOperations.DEVICE_OPERATION_UNKNOWN);
                            message.setQualityOfService(mqttMessage.getQos());

                            String methodName = topicParser.getMethodName(METHOD_TOKEN);
                            message.setMethodName(methodName);

                            String reqId = topicParser.getRequestId(REQID_TOKEN);
                            if (reqId != null)
                            {
                                message.setRequestId(reqId);

                                message.setDeviceOperationType(DeviceOperations.DEVICE_OPERATION_METHOD_RECEIVE_REQUEST);
                            }
                            else
                            {
                                log.warn("Request ID cannot be null");
                            }
                        }
                    }
                }
            }

            return message;
        }
    }