org.eclipse.paho.client.mqttv3

Class MqttTopic

java.lang.Object

org.eclipse.paho.client.mqttv3.MqttTopic

public class MqttTopic
extends java.lang.Object

Represents a topic destination, used for publish/subscribe messaging.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	MULTI_LEVEL_WILDCARD Multi-level wildcard The number sign (#) is a wildcard character that matches any number of levels within a topic.
static java.lang.String	MULTI_LEVEL_WILDCARD_PATTERN Multi-level wildcard pattern(/#)
static java.lang.String	SINGLE_LEVEL_WILDCARD Single-level wildcard The plus sign (+) is a wildcard character that matches only one topic level.
static java.lang.String	TOPIC_LEVEL_SEPARATOR The forward slash (/) is used to separate each level within a topic tree and provide a hierarchical structure to the topic space.
static java.lang.String	TOPIC_WILDCARDS Topic wildcards (#+)

Constructor Summary

Constructors

Constructor and Description
MqttTopic(java.lang.String name, ClientComms comms)

Method Summary

Modifier and Type	Method and Description
java.lang.String	getName() Returns the name of the queue or topic.
static boolean	isMatched(java.lang.String topicFilter, java.lang.String topicName) Check the supplied topic name and filter match
MqttDeliveryToken	publish(byte[] payload, int qos, boolean retained) Publishes a message on the topic.
MqttDeliveryToken	publish(MqttMessage message) Publishes the specified message to this topic, but does not wait for delivery of the message to complete.
java.lang.String	toString() Returns a string representation of this topic.
static void	validate(java.lang.String topicString, boolean wildcardAllowed) Validate the topic name or topic filter

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

TOPIC_LEVEL_SEPARATOR

public static final java.lang.String TOPIC_LEVEL_SEPARATOR

The forward slash (/) is used to separate each level within a topic tree and provide a hierarchical structure to the topic space. The use of the topic level separator is significant when the two wildcard characters are encountered in topics specified by subscribers.

See Also:

Constant Field Values

MULTI_LEVEL_WILDCARD

public static final java.lang.String MULTI_LEVEL_WILDCARD

Multi-level wildcard The number sign (#) is a wildcard character that matches any number of levels within a topic.

See Also:

Constant Field Values

SINGLE_LEVEL_WILDCARD

public static final java.lang.String SINGLE_LEVEL_WILDCARD

Single-level wildcard The plus sign (+) is a wildcard character that matches only one topic level.

See Also:

Constant Field Values

MULTI_LEVEL_WILDCARD_PATTERN

public static final java.lang.String MULTI_LEVEL_WILDCARD_PATTERN

Multi-level wildcard pattern(/#)

See Also:

Constant Field Values

TOPIC_WILDCARDS

public static final java.lang.String TOPIC_WILDCARDS

Topic wildcards (#+)

See Also:

Constant Field Values

Constructor Detail

MqttTopic

public MqttTopic(java.lang.String name,
                 ClientComms comms)

Method Detail

publish

public MqttDeliveryToken publish(byte[] payload,
                                 int qos,
                                 boolean retained)
                          throws MqttException,
                                 MqttPersistenceException

Publishes a message on the topic. This is a convenience method, which will create a new MqttMessage object with a byte array payload and the specified QoS, and then publish it. All other values in the message will be set to the defaults.

Parameters:

payload - the byte array to use as the payload

qos - the Quality of Service. Valid values are 0, 1 or 2.

retained - whether or not this message should be retained by the server.

Throws:

java.lang.IllegalArgumentException - if value of QoS is not 0, 1 or 2.

MqttException

MqttPersistenceException

See Also:

publish(MqttMessage), MqttMessage.setQos(int), MqttMessage.setRetained(boolean)

publish

public MqttDeliveryToken publish(MqttMessage message)
                          throws MqttException,
                                 MqttPersistenceException

Publishes the specified message to this topic, but does not wait for delivery of the message to complete. The returned token can be used to track the delivery status of the message. Once this method has returned cleanly, the message has been accepted for publication by the client. Message delivery will be completed in the background when a connection is available.

Parameters:

message - the message to publish

Returns:

an MqttDeliveryToken for tracking the delivery of the message

Throws:

MqttException

MqttPersistenceException

getName

public java.lang.String getName()

Returns the name of the queue or topic.

Returns:

the name of this destination.

toString

public java.lang.String toString()

Returns a string representation of this topic.

Overrides:

toString in class java.lang.Object

Returns:

a string representation of this topic.

validate

public static void validate(java.lang.String topicString,
                            boolean wildcardAllowed)
                     throws java.lang.IllegalStateException,
                            java.lang.IllegalArgumentException

Validate the topic name or topic filter

Parameters:

topicString - topic name or filter

wildcardAllowed - true if validate topic filter, false otherwise

Throws:

java.lang.IllegalArgumentException - if the topic is invalid

java.lang.IllegalStateException

isMatched

public static boolean isMatched(java.lang.String topicFilter,
                                java.lang.String topicName)
                         throws java.lang.IllegalStateException,
                                java.lang.IllegalArgumentException

Check the supplied topic name and filter match

Parameters:

topicFilter - topic filter: wildcards allowed

topicName - topic name: wildcards not allowed

Throws:

java.lang.IllegalArgumentException - if the topic name or filter is invalid

java.lang.IllegalStateException