com.microsoft.azure.sdk.iot.device.transport.amqps

Class AmqpsTransport

java.lang.Object

com.microsoft.azure.sdk.iot.device.transport.amqps.AmqpsTransport

All Implemented Interfaces:

ServerListener, IotHubTransport, Closeable, AutoCloseable

public final class AmqpsTransport
extends Object
implements IotHubTransport, ServerListener

An AMQPS transport. Contains functionality for adding messages and sending messages to an IoT Hub. Buffers unsent messages until they are received by an IoT Hub. A transport is bound at construction to the following parameters: IoT Hub name, device ID and device key.

The transport also receives messages from IoT Hub and invokes a user-defined message callback if a message and callback are found.

Constructor Summary

Constructors

Constructor and Description
AmqpsTransport(DeviceClientConfig config, Boolean useWebSockets) Constructs an instance from the given DeviceClientConfig object.

Method Summary

Modifier and Type	Method and Description
void	addMessage(Message message, IotHubEventCallback callback, Object callbackContext) Adds a message to the transport queue.
void	close() Closes all resources used to communicate with an IoT Hub.
void	connectionLost() If the connection is lost, all the messages in progress are buffered to be sent again.
void	handleMessage() Invokes the message callback if a message is found and responds to the IoT Hub on how the processed message should be handled by the IoT Hub.
void	invokeCallbacks() Invokes the callbacks for all completed requests.
boolean	isEmpty() Returns true if the transport has no more messages to handle, and false otherwise.
void	messageReceived(AmqpsMessage message) When a message is received, it is added to the list of messages to be processed.
void	messageSent(Integer messageHash, Boolean deliveryState) When a message is acknowledged by IoTHub, it is removed from the list of in progress messages and its callback is added to the list of callbacks to be executed.
void	open() Establishes a communication channel with an IoT Hub.
void	sendMessages() Sends all messages from the waiting list, one at a time.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AmqpsTransport

public AmqpsTransport(DeviceClientConfig config,
                      Boolean useWebSockets)

Constructs an instance from the given DeviceClientConfig object.

Parameters:

config - configuration parameters for an AMQPS session with an IoT Hub

useWebSockets - whether the transport should use web sockets or not

Method Detail

open

public void open()
          throws IOException

Establishes a communication channel with an IoT Hub. If a channel is already open, the function shall do nothing.

Specified by:

open in interface IotHubTransport

Throws:

IOException - if a communication channel cannot be established.

close

public void close()
           throws IOException

Closes all resources used to communicate with an IoT Hub. Once close() is called, the transport is no longer usable. If the transport is already closed, the function shall do nothing.

Specified by:

close in interface IotHubTransport

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException - if an error occurs in closing the transport.

addMessage

public void addMessage(Message message,
                       IotHubEventCallback callback,
                       Object callbackContext)
                throws IllegalStateException

Adds a message to the transport queue.

Specified by:

addMessage in interface IotHubTransport

Parameters:

message - the message to be sent.

callback - the callback to be invoked when a response for the message is received.

callbackContext - the context to be passed in when the callback is invoked.

Throws:

IllegalStateException - if the transport is closed.

sendMessages

public void sendMessages()
                  throws IOException,
                         IllegalStateException

Sends all messages from the waiting list, one at a time. If a previous send attempt had failed, the function will attempt to resend the messages in the previous attempt.

Specified by:

sendMessages in interface IotHubTransport

Throws:

IOException - if the server could not be reached.

IllegalStateException - if the transport has not been opened or is already closed.

invokeCallbacks

public void invokeCallbacks()
                     throws IllegalStateException

Invokes the callbacks for all completed requests.

Specified by:

invokeCallbacks in interface IotHubTransport

Throws:

IllegalStateException - if the transport is closed.

handleMessage

public void handleMessage()
                   throws IllegalStateException

Invokes the message callback if a message is found and responds to the IoT Hub on how the processed message should be handled by the IoT Hub.

If no message callback is set, the function will do nothing.

Specified by:

handleMessage in interface IotHubTransport

Throws:

IllegalStateException - if the transport is closed.

messageSent

public void messageSent(Integer messageHash,
                        Boolean deliveryState)

When a message is acknowledged by IoTHub, it is removed from the list of in progress messages and its callback is added to the list of callbacks to be executed. If the message was not successfully delivered, it is buffered to be sent again.

Specified by:

messageSent in interface ServerListener

Parameters:

messageHash - The hash of the message.

deliveryState - The state of the delivery.

connectionLost

public void connectionLost()

If the connection is lost, all the messages in progress are buffered to be sent again.

Specified by:

connectionLost in interface ServerListener

messageReceived

public void messageReceived(AmqpsMessage message)

When a message is received, it is added to the list of messages to be processed.

Specified by:

messageReceived in interface ServerListener

Parameters:

message - The message received.

isEmpty

public boolean isEmpty()

Returns true if the transport has no more messages to handle, and false otherwise.

Specified by:

isEmpty in interface IotHubTransport

Returns:

true if the transport has no more messages to handle, and false otherwise.