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The Microsoft Azure IoT Device SDK for Java
// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.
package com.microsoft.azure.iothub;
import com.microsoft.azure.iothub.transport.amqps.AmqpsTransport;
import com.microsoft.azure.iothub.transport.https.HttpsTransport;
import com.microsoft.azure.iothub.transport.IotHubReceiveTask;
import com.microsoft.azure.iothub.transport.IotHubSendTask;
import com.microsoft.azure.iothub.transport.IotHubTransport;
import com.microsoft.azure.iothub.transport.mqtt.MqttTransport;
import java.io.Closeable;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URISyntaxException;
import java.net.URLDecoder;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
/**
*
* The public-facing API. Allows a single logical or physical device to connect
* to an IoT Hub. The IoT Hub client supports sending events to and receiving
* messages from an IoT Hub.
*
*
* To support these workflows, the client library will provide the following
* abstractions: a message, with its payload and associated properties; and a
* client, which sends and receives messages.
*
*
* The client buffers messages while the network is down, and re-sends them when
* the network comes back online. It also batches messages to improve
* communication efficiency (HTTPS only).
*
* The client supports HTTPS 1.1 and AMQPS 1.0 transports.
*/
public final class DeviceClient implements Closeable
{
/** The state of the IoT Hub client's connection with the IoT Hub. */
protected enum IotHubClientState
{
OPEN, CLOSED
}
/**
* The number of milliseconds the transport will wait between
* sending out messages.
*/
public static long SEND_PERIOD_MILLIS = 10l;
/**
* The number of milliseconds the transport will wait between
* polling for messages.
*/
public static long RECEIVE_PERIOD_MILLIS_AMQPS = 10l;
public static long RECEIVE_PERIOD_MILLIS_MQTT = 10l;
public static long RECEIVE_PERIOD_MILLIS_HTTPS = 25*60*1000; /*25 minutes*/
/** The hostname attribute name in a connection string. */
public static final String HOSTNAME_ATTRIBUTE = "HostName=";
/** The device ID attribute name in a connection string. */
public static final String DEVICE_ID_ATTRIBUTE = "DeviceId=";
/** The shared access key attribute name in a connection string. */
public static final String SHARED_ACCESS_KEY_ATTRIBUTE = "SharedAccessKey=";
/**
* The charset used for URL-encoding the device ID in the connection
* string.
*/
public static final Charset CONNECTION_STRING_CHARSET = StandardCharsets.UTF_8;
protected DeviceClientConfig config;
protected IotHubTransport transport;
protected ScheduledExecutorService taskScheduler;
protected IotHubClientState state;
protected long RECEIVE_PERIOD_MILLIS;
/**
* Constructor that takes a connection string as an argument.
*
* @param connString the connection string. The connection string is a set
* of key-value pairs that are separated by ';', with the keys and values
* separated by '='. It should contain values for the following keys:
* {@code HostName}, {@code DeviceId}, and {@code SharedAccessKey}.
* @param protocol the communication protocol used (i.e. HTTPS).
*
* @throws IllegalArgumentException if any of {@code connString} or
* {@code protocol} are {@code null}; or if {@code connString} is missing
* one of the following attributes:{@code HostName}, {@code DeviceId}, or
* {@code SharedAccessKey}.
* @throws URISyntaxException if the IoT hub hostname does not conform to
* RFC 3986.
*/
public DeviceClient(String connString, IotHubClientProtocol protocol)
throws URISyntaxException
{
// Codes_SRS_DEVICECLIENT_11_047: [If the connection string is null, the function shall throw an IllegalArgumentException.]
if (connString == null)
{
throw new IllegalArgumentException(
"IoT Hub connection string cannot be null.");
}
// Codes_SRS_DEVICECLIENT_11_042: [The constructor shall interpret the connection string as a set of key-value pairs delimited by ';', with keys and values separated by '='.]
String[] connStringAttrs = connString.split(";");
String hostname = null;
String deviceId = null;
String sharedAccessKey = null;
for (String attr : connStringAttrs)
{
// Codes_SRS_DEVICECLIENT_11_043: [The constructor shall save the IoT Hub hostname as the value of 'HostName' in the connection string.]
if (attr.startsWith(HOSTNAME_ATTRIBUTE))
{
hostname = attr.substring(HOSTNAME_ATTRIBUTE.length());
}
// Codes_SRS_DEVICECLIENT_11_044: [The constructor shall save the device ID as the UTF-8 URL-decoded value of 'DeviceId' in the connection string.]
else if (attr.startsWith(DEVICE_ID_ATTRIBUTE))
{
String urlEncodedDeviceId = attr.substring(DEVICE_ID_ATTRIBUTE.length());
try
{
deviceId = URLDecoder.decode(urlEncodedDeviceId,CONNECTION_STRING_CHARSET.name());
}
catch (UnsupportedEncodingException e)
{
// should never happen, since the encoding is hard-coded.
throw new IllegalStateException(e);
}
}
// Codes_SRS_DEVICECLIENT_11_045: [The constructor shall save the device key as the value of 'SharedAccessKey' in the connection string.]
else if (attr.startsWith(SHARED_ACCESS_KEY_ATTRIBUTE))
{
sharedAccessKey = attr.substring(SHARED_ACCESS_KEY_ATTRIBUTE.length());
}
}
initIotHubClient(hostname, deviceId, sharedAccessKey, protocol);
}
/**
* Starts asynchronously sending and receiving messages from an IoT Hub. If
* the client is already open, the function shall do nothing.
*
* @throws IOException if a connection to an IoT Hub is cannot be
* established.
*/
public void open() throws IOException
{
// Codes_SRS_DEVICECLIENT_11_028: [If the client is already open, the function shall do nothing.]
if (this.state == IotHubClientState.OPEN)
{
return;
}
// Codes_SRS_DEVICECLIENT_11_035: [The function shall open the transport to communicate with an IoT Hub.]
// Codes_SRS_DEVICECLIENT_11_036: [If an error occurs in opening the transport, the function shall throw an IOException.]
this.transport.open();
IotHubSendTask sendTask = new IotHubSendTask(this.transport);
IotHubReceiveTask receiveTask = new IotHubReceiveTask(this.transport);
this.taskScheduler = Executors.newScheduledThreadPool(2);
// the scheduler waits until each execution is finished before
// scheduling the next one, so executions of a given task
// will never overlap.
// Codes_SRS_DEVICECLIENT_11_023: [The function shall schedule send tasks to run every SEND_PERIOD_MILLIS milliseconds.]
this.taskScheduler.scheduleAtFixedRate(sendTask, 0,
SEND_PERIOD_MILLIS, TimeUnit.MILLISECONDS);
// Codes_SRS_DEVICECLIENT_11_024: [The function shall schedule receive tasks to run every RECEIVE_PERIOD_MILLIS milliseconds.]
this.taskScheduler.scheduleAtFixedRate(receiveTask, 0,
RECEIVE_PERIOD_MILLIS, TimeUnit.MILLISECONDS);
this.state = IotHubClientState.OPEN;
}
/**
* Completes all current outstanding requests and closes the IoT Hub client.
* Must be called to terminate the background thread that is sending data to
* IoT Hub. After {@code close()} is called, the IoT Hub client is no longer
* usable. If the client is already closed, the function shall do nothing.
*
* @throws IOException if the connection to an IoT Hub cannot be closed.
*/
public void close() throws IOException
{
// Codes_SRS_DEVICECLIENT_11_031: [If the client is already closed, the function shall do nothing.]
if (this.state == IotHubClientState.CLOSED)
{
return;
}
// Codes_SRS_DEVICECLIENT_11_010: [The function shall finish all ongoing tasks.]
// Codes_SRS_DEVICECLIENT_11_011: [The function shall cancel all recurring tasks.]
while (!this.transport.isEmpty())
{
}
this.taskScheduler.shutdown();
// Codes_SRS_DEVICECLIENT_11_037: [The function shall close the transport.]
this.transport.close();
this.state = IotHubClientState.CLOSED;
}
/**
* Asynchronously sends an event message to the IoT Hub.
*
* @param message the message to be sent.
* @param callback the callback to be invoked when a response is received.
* Can be {@code null}.
* @param callbackContext a context to be passed to the callback. Can be
* {@code null} if no callback is provided.
*
* @throws IllegalArgumentException if the message provided is {@code null}.
* @throws IllegalStateException if the client has not been opened yet or is
* already closed.
*/
public void sendEventAsync(Message message,
IotHubEventCallback callback,
Object callbackContext)
{
// Codes_SRS_DEVICECLIENT_11_039: [If the client is closed, the function shall throw an IllegalStateException.]
if (this.state == IotHubClientState.CLOSED)
{
throw new IllegalStateException(
"Cannot send event from "
+ "an IoT Hub client that is closed.");
}
// Codes_SRS_DEVICECLIENT_11_033: [If the message given is null, the function shall throw an IllegalArgumentException.]
if (message == null)
{
throw new IllegalArgumentException("Cannot send message 'null'.");
}
// Codes_SRS_DEVICECLIENT_11_006: [The function shall add the message, with its associated callback and callback context, to the transport.]
transport.addMessage(message, callback, callbackContext);
}
/**
* Sets the message callback.
*
* @param callback the message callback. Can be {@code null}.
* @param context the context to be passed to the callback. Can be {@code null}.
*
* @return itself, for fluent setting.
*
* @throws IllegalArgumentException if the callback is {@code null} but a context is
* passed in.
* @throws IllegalStateException if the callback is set after the client is
* closed.
*/
public DeviceClient setMessageCallback(
MessageCallback callback,
Object context)
{
// Codes_SRS_DEVICECLIENT_11_032: [If the callback is null but the context is non-null, the function shall throw an IllegalArgumentException.]
if (callback == null && context != null)
{
throw new IllegalArgumentException(
"Cannot give non-null context for a null callback.");
}
// Codes_SRS_DEVICECLIENT_11_012: [The function shall set the message callback, with its associated context.]
this.config.setMessageCallback(callback, context);
return this;
}
/**
* Initializes an IoT Hub device client with the given parameters.
*
* @param iotHubHostname the IoT Hub hostname.
* @param deviceId the device ID.
* @param deviceKey the device key.
* @param protocol the communication protocol used (i.e. HTTPS).
*
* @throws IllegalArgumentException if any of {@code iotHubHostname}, {@code deviceId},
* {@code deviceKey}, or {@code protocol} are {@code null}; or if {@code iotHubHostname}
* does not contain a valid IoT Hub name as its prefix.
* @throws URISyntaxException if the IoT Hub hostname does not conform to
* RFC 3986.
*/
protected void initIotHubClient(String iotHubHostname, String deviceId,
String deviceKey, IotHubClientProtocol protocol)
throws URISyntaxException
{
// Codes_SRS_DEVICECLIENT_11_048: [If no value for 'HostName' is found in the connection string, the function shall throw an IllegalArgumentException.]
// Codes_SRS_DEVICECLIENT_11_025: [If iotHubHostname is null, the constructor shall throw an IllegalArgumentException.]
if (iotHubHostname == null)
{
throw new IllegalArgumentException(
"IoT Hub hostname cannot be null.");
}
// Codes_SRS_DEVICECLIENT_11_049: [If no value for 'DeviceId' is found in the connection string, the function shall throw an IllegalArgumentException.]
// Codes_SRS_DEVICECLIENT_11_026: [If deviceId is null, the constructor shall throw an IllegalArgumentException.]
if (deviceId == null)
{
throw new IllegalArgumentException("Device ID cannot be null.");
}
// Codes_SRS_DEVICECLIENT_11_050: [If no argument for 'SharedAccessKey' is found in the connection string, the function shall throw an IllegalArgumentException.]
// Codes_SRS_DEVICECLIENT_11_027: [If deviceKey is null, the constructor shall throw an IllegalArgumentException.]
if (deviceKey == null)
{
throw new IllegalArgumentException("Device key cannot be null.");
}
// Codes_SRS_DEVICECLIENT_11_051: [If protocol is null, the function shall throw an IllegalArgumentException.]
// Codes_SRS_DEVICECLIENT_11_034: [If protocol is null, the constructor shall throw an IllegalArgumentException.]
if (protocol == null)
{
throw new IllegalArgumentException("Protocol cannot be null.");
}
// Codes_SRS_DEVICECLIENT_11_052: [The constructor shall save the IoT Hub hostname, device ID, and device key as configuration parameters.]
this.config = new DeviceClientConfig(iotHubHostname, deviceId, deviceKey);
// Codes_SRS_DEVICECLIENT_11_046: [The constructor shall initialize the IoT Hub transport that uses the protocol specified.]
// Codes_SRS_DEVICECLIENT_11_004: [The constructor shall initialize the IoT Hub transport that uses the protocol specified.]
switch (protocol)
{
case HTTPS:
this.transport = new HttpsTransport(this.config);
RECEIVE_PERIOD_MILLIS = RECEIVE_PERIOD_MILLIS_HTTPS;
break;
case AMQPS:
case AMQPS_WS:
this.transport = new AmqpsTransport(this.config, protocol);
RECEIVE_PERIOD_MILLIS = RECEIVE_PERIOD_MILLIS_AMQPS;
break;
case MQTT:
this.transport = new MqttTransport(this.config);
RECEIVE_PERIOD_MILLIS = RECEIVE_PERIOD_MILLIS_MQTT;
break;
default:
// should never happen.
throw new IllegalStateException(
"Invalid client protocol specified.");
}
this.state = IotHubClientState.CLOSED;
}
protected DeviceClient()
{
this.config = null;
this.transport = null;
this.taskScheduler = null;
}
/**
* Sets a runtime option identified by parameter {@code optionName}
* to {@code value}.
*
* The options that can be set via this API are:
* - SetMinimumPollingInterval - this option is applicable only
* when the transport configured with this client is HTTP. This
* option specifies the interval in milliseconds between calls to
* the service checking for availability of new messages. The value
* is expected to be of type {@code long}.
*
* @param optionName the option name to modify
* @param value an object of the appropriate type for the option's value
*/
public void setOption(String optionName, Object value)
{
// Codes_SRS_DEVICECLIENT_02_001: [If optionName is null or not an option handled by the client, then it shall throw IllegalArgumentException.]
if(optionName == null)
{
throw new IllegalArgumentException("optionName is null");
}
else
{
// Codes_SRS_DEVICECLIENT_02_003: [Available only for HTTP.]
if(this.transport.getClass() == HttpsTransport.class)
{
if(optionName.equals("SetMinimumPollingInterval"))
{
if(this.state!=IotHubClientState.CLOSED)
{
throw new IllegalStateException("setOption only works when the transport is closed");
}
else
{
// Codes_SRS_DEVICECLIENT_02_004: [Value needs to have type long].
if (value instanceof Long)
{
this.RECEIVE_PERIOD_MILLIS = (long) value;
}
else
{
throw new IllegalArgumentException("value is not long = " + value);
}
}
}
else
{
// Codes_SRS_DEVICECLIENT_02_001: [If optionName is null or not an option handled by the client, then it shall throw IllegalArgumentException.]
throw new IllegalArgumentException("optionName is unknown = "+optionName);
}
}
else
{
throw new IllegalArgumentException("AMQP does not have setOption");
}
}
}
}
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