/**
* Get a topic object which can be used to publish messages.
*
* <p>There are two alternative methods that should be used in preference to this one when
* publishing a message:
*
* <ul>
* <li>{@link MqttAsyncClient#publish(String, MqttMessage, MqttDeliveryToken)} to publish a
* message in a non-blocking manner or
* <li>{@link MqttClient#publishBlock(String, MqttMessage, MqttDeliveryToken)} to publish a
* message in a blocking manner
* </ul>
*
* <p>When you build an application, the design of the topic tree should take into account the
* following principles of topic name syntax and semantics:
*
* <ul>
* <li>A topic must be at least one character long.
* <li>Topic names are case sensitive. For example, <em>ACCOUNTS</em> and <em>Accounts</em> are
* two different topics.
* <li>Topic names can include the space character. For example, <em>Accounts payable</em> is a
* valid topic.
* <li>A leading "/" creates a distinct topic. For example, <em>/finance</em> is different from
* <em>finance</em>. <em>/finance</em> matches "+/+" and "/+", but not "+".
* <li>Do not include the null character (Unicode<samp class="codeph"> \x0000</samp>) in any
* topic.
* </ul>
*
* <p>The following principles apply to the construction and content of a topic tree:
*
* <ul>
* <li>The length is limited to 64k but within that there are no limits to the number of levels
* in a topic tree.
* <li>There can be any number of root nodes; that is, there can be any number of topic trees.
* </ul>
*
* @param topic the topic to use, for example "finance/stock/ibm".
* @return an MqttTopic object, which can be used to publish messages to the topic.
* @throws IllegalArgumentException if the topic contains a '+' or '#' wildcard character.
*/
protected MqttTopic getTopic(String topic) {
MqttTopic.validate(topic, false /*wildcards NOT allowed*/);
MqttTopic result = (MqttTopic) topics.get(topic);
if (result == null) {
result = new MqttTopic(topic, comms);
topics.put(topic, result);
}
return result;
}
/* (non-Javadoc)
* @see org.eclipse.paho.client.mqttv3.IMqttAsyncClient#subscribe(java.lang.String[], int[], java.lang.Object, org.eclipse.paho.client.mqttv3.IMqttActionListener)
*/
public IMqttToken subscribe(
String[] topicFilters, int[] qos, Object userContext, IMqttActionListener callback)
throws MqttException {
final String methodName = "subscribe";
if (topicFilters.length != qos.length) {
throw new IllegalArgumentException();
}
// remove any message handlers for individual topics
for (int i = 0; i < topicFilters.length; ++i) {
this.comms.removeMessageListener(topicFilters[i]);
}
String subs = "";
for (int i = 0; i < topicFilters.length; i++) {
if (i > 0) {
subs += ", ";
}
subs += "topic=" + topicFilters[i] + " qos=" + qos[i];
// Check if the topic filter is valid before subscribing
MqttTopic.validate(topicFilters[i], true /*allow wildcards*/);
}
// @TRACE 106=Subscribe topicFilter={0} userContext={1} callback={2}
log.fine(CLASS_NAME, methodName, "106", new Object[] {subs, userContext, callback});
MqttToken token = new MqttToken(getClientId());
token.setActionCallback(callback);
token.setUserContext(userContext);
token.internalTok.setTopics(topicFilters);
MqttSubscribe register = new MqttSubscribe(topicFilters, qos);
comms.sendNoWait(register, token);
// @TRACE 109=<
log.fine(CLASS_NAME, methodName, "109");
return token;
}
/* (non-Javadoc)
* @see org.eclipse.paho.client.mqttv3.IMqttAsyncClient#unsubscribe(java.lang.String[], java.lang.Object, org.eclipse.paho.client.mqttv3.IMqttActionListener)
*/
public IMqttToken unsubscribe(
String[] topicFilters, Object userContext, IMqttActionListener callback)
throws MqttException {
final String methodName = "unsubscribe";
String subs = "";
for (int i = 0; i < topicFilters.length; i++) {
if (i > 0) {
subs += ", ";
}
subs += topicFilters[i];
// Check if the topic filter is valid before unsubscribing
// Although we already checked when subscribing, but invalid
// topic filter is meanless for unsubscribing, just prohibit it
// to reduce unnecessary control packet send to broker.
MqttTopic.validate(topicFilters[i], true /*allow wildcards*/);
}
// @TRACE 107=Unsubscribe topic={0} userContext={1} callback={2}
log.fine(CLASS_NAME, methodName, "107", new Object[] {subs, userContext, callback});
// remove message handlers from the list for this client
for (int i = 0; i < topicFilters.length; ++i) {
this.comms.removeMessageListener(topicFilters[i]);
}
MqttToken token = new MqttToken(getClientId());
token.setActionCallback(callback);
token.setUserContext(userContext);
token.internalTok.setTopics(topicFilters);
MqttUnsubscribe unregister = new MqttUnsubscribe(topicFilters);
comms.sendNoWait(unregister, token);
// @TRACE 110=<
log.fine(CLASS_NAME, methodName, "110");
return token;
}
/* (non-Javadoc)
* @see org.eclipse.paho.client.mqttv3.IMqttAsyncClient#publish(java.lang.String, org.eclipse.paho.client.mqttv3.MqttMessage, java.lang.Object, org.eclipse.paho.client.mqttv3.IMqttActionListener)
*/
public IMqttDeliveryToken publish(
String topic, MqttMessage message, Object userContext, IMqttActionListener callback)
throws MqttException, MqttPersistenceException {
final String methodName = "publish";
// @TRACE 111=< topic={0} message={1}userContext={1} callback={2}
log.fine(CLASS_NAME, methodName, "111", new Object[] {topic, userContext, callback});
// Checks if a topic is valid when publishing a message.
MqttTopic.validate(topic, false /*wildcards NOT allowed*/);
MqttDeliveryToken token = new MqttDeliveryToken(getClientId());
token.setActionCallback(callback);
token.setUserContext(userContext);
token.setMessage(message);
token.internalTok.setTopics(new String[] {topic});
MqttPublish pubMsg = new MqttPublish(topic, message);
comms.sendNoWait(pubMsg, token);
// @TRACE 112=<
log.fine(CLASS_NAME, methodName, "112");
return token;
}