@Override
protected Object doInBackground(Object... params) {
log("create connection");
String mqttConnSpec = "tcp://" + brokerHostName + "@" + MQTT_BROKER_PORT_NUM;
// Create the client and connect
try {
mqttClient = MqttClient.createMqttClient(mqttConnSpec, MQTT_PERSISTENCE);
String clientID = MQTT_CLIENT_ID + "/" + mPrefs.getString(PREF_DEVICE_ID, "");
mqttClient.connect(clientID, MQTT_CLEAN_START, MQTT_KEEP_ALIVE);
// register this client app has being able to receive messages
mqttClient.registerSimpleHandler(this);
// Subscribe to an initial topic, which is combination of client
// ID
// and device ID.
initTopic = MQTT_CLIENT_ID + "/" + initTopic;
subscribeToTopic(initTopic);
} catch (MqttException e) {
e.printStackTrace();
}
log("Connection established to " + brokerHostName + " on topic " + initTopic);
// Save start time
mStartTime = System.currentTimeMillis();
// Star the keep-alives
startKeepAlives();
return null;
}
/*
* Sends a message to the message broker, requesting that it be
* published to the specified topic.
*/
private void publishToTopic(String topicName, String message) throws MqttException {
if ((mqttClient == null) || (mqttClient.isConnected() == false)) {
// quick sanity check - don't try and publish if we don't have
// a connection
log("No connection to public to");
} else {
mqttClient.publish(
topicName, message.getBytes(), MQTT_QUALITY_OF_SERVICE, MQTT_RETAINED_PUBLISH);
}
}
/*
* Send a request to the message broker to be sent messages published
* with the specified topic name. Wildcards are allowed.
*/
private void subscribeToTopic(String topicName) throws MqttException {
if ((mqttClient == null) || (mqttClient.isConnected() == false)) {
// quick sanity check - don't try and subscribe if we don't have
// a connection
log("Connection error" + "No connection");
} else {
String[] topics = {topicName};
mqttClient.subscribe(topics, MQTT_QUALITIES_OF_SERVICE);
}
}
// Disconnect
public void disconnect() {
try {
stopKeepAlives();
if (mqttClient != null) {
mqttClient.disconnect();
}
} catch (MqttPersistenceException e) {
log("MqttException" + (e.getMessage() != null ? e.getMessage() : " NULL"), e);
}
}