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

Class HttpsTransport

java.lang.Object

com.microsoft.azure.sdk.iot.device.transport.https.HttpsTransport

All Implemented Interfaces:

IotHubTransport, Closeable, AutoCloseable

public final class HttpsTransport
extends Object
implements IotHubTransport

An HTTPS transport. Contains functionality for adding messages and sending batched 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, device key, and message valid seconds.

The transport can also poll an IoT Hub for messages and invoke a user-defined message callback if a message and callback is found.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	HttpsTransport.HttpsTransportState The state of the HTTPS transport.

Field Summary

Fields

Modifier and Type	Field and Description
protected Queue<IotHubCallbackPacket>	callbackList Messages whose callbacks that are waiting to be invoked.
protected DeviceClientConfig	config
protected HttpsIotHubConnection	connection The underlying HTTPS connection.
protected Queue<IotHubOutboundPacket>	inProgressList Messages that are waiting for a response from an IoT Hub.
protected HttpsTransport.HttpsTransportState	state
protected Queue<IotHubOutboundPacket>	waitingList Messages waiting to be sent to an IoT Hub.

Constructor Summary

Constructors

Constructor and Description
HttpsTransport(DeviceClientConfig config) 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	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.
protected HttpsMessage	inProgressListToMessage() Generates the message, possibly batched, to be sent using the messages in the in-progress list.
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.
protected void	moveInProgressListToCallbackList(IotHubStatusCode status) Moves messages from the in progress list to the callback list, updating the message packets with the status code from the response.
protected void	moveWaitingListToInProgressList() Moves as many messages as can be sent in one HTTPS request from the waiting list to the in-progress list.
void	open() Establishes a communication channel with an IoT Hub.
void	sendMessages() Sends all messages on the transport queue as a batched request.

Methods inherited from class java.lang.Object

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

Field Detail

state

protected HttpsTransport.HttpsTransportState state

connection

protected HttpsIotHubConnection connection

The underlying HTTPS connection.

waitingList

protected final Queue<IotHubOutboundPacket> waitingList

Messages waiting to be sent to an IoT Hub.

inProgressList

protected final Queue<IotHubOutboundPacket> inProgressList

Messages that are waiting for a response from an IoT Hub.

callbackList

protected final Queue<IotHubCallbackPacket> callbackList

Messages whose callbacks that are waiting to be invoked.

config

protected final DeviceClientConfig config

Constructor Detail

HttpsTransport

public HttpsTransport(DeviceClientConfig config)

Constructs an instance from the given DeviceClientConfig object.

Parameters:

config - configuration parameters for an IoT Hub connection.

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)

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 has not been opened or is already closed.

sendMessages

public void sendMessages()
                  throws IOException

Sends all messages on the transport queue as a batched request.

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()

Invokes the callbacks for all completed requests.

Specified by:

invokeCallbacks in interface IotHubTransport

Throws:

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

handleMessage

public void handleMessage()
                   throws IOException

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:

IOException - if the server could not be reached, or if the response from sending the IoT Hub message result does not have status code IotHubStatusCode.OK_EMPTY.

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

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.

moveWaitingListToInProgressList

protected void moveWaitingListToInProgressList()

Moves as many messages as can be sent in one HTTPS request from the waiting list to the in-progress list. If a single message is moved to the in-progress list, this indicates that the message is to be sent in the un-batched message format.

inProgressListToMessage

protected HttpsMessage inProgressListToMessage()
                                        throws SizeLimitExceededException

Generates the message, possibly batched, to be sent using the messages in the in-progress list.

Returns:

the message to be sent.

Throws:

SizeLimitExceededException - if the messages in inProgressList exceed the service-bound message size limit of 255 kb.

NoSuchElementException - if inProgressList is empty.

moveInProgressListToCallbackList

protected void moveInProgressListToCallbackList(IotHubStatusCode status)

Moves messages from the in progress list to the callback list, updating the message packets with the status code from the response.

Parameters:

status - the status code returned by the IoT Hub.