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mqtt/org/eclipse/paho/mqttv5/client/MqttTopic.java

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+/*******************************************************************************
+ * Copyright (c) 2009, 2014 IBM Corp.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * and Eclipse Distribution License v1.0 which accompany this distribution.
+ *
+ * The Eclipse Public License is available at
+ *    https://www.eclipse.org/legal/epl-2.0
+ * and the Eclipse Distribution License is available at
+ *   https://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * Contributors:
+ *    Dave Locke - initial API and implementation and/or initial documentation
+ */
+package org.eclipse.paho.mqttv5.client;
+
+import org.eclipse.paho.mqttv5.client.internal.ClientComms;
+import org.eclipse.paho.mqttv5.common.MqttException;
+import org.eclipse.paho.mqttv5.common.MqttMessage;
+import org.eclipse.paho.mqttv5.common.MqttPersistenceException;
+import org.eclipse.paho.mqttv5.common.packet.MqttProperties;
+import org.eclipse.paho.mqttv5.common.packet.MqttPublish;
+
+/**
+ * Represents a topic destination, used for publish/subscribe messaging.
+ */
+public class MqttTopic {
+
+
+	private ClientComms comms;
+	private String name;
+
+	/**
+	 * @param name
+	 *            The Name of the topic
+	 * @param comms
+	 *            The {@link ClientComms}
+	 */
+	public MqttTopic(String name, ClientComms comms) {
+		this.comms = comms;
+		this.name = name;
+	}
+
+	/**
+	 * Publishes a message on the topic. This is a convenience method, which will
+	 * create a new {@link 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.
+	 * 
+	 * @param payload
+	 *            the byte array to use as the payload
+	 * @param qos
+	 *            the Quality of Service. Valid values are 0, 1 or 2.
+	 * @param retained
+	 *            whether or not this message should be retained by the server.
+	 * @return {@link MqttToken}
+	 * @throws MqttException
+	 *             If an error occurs publishing the message
+	 * @throws MqttPersistenceException
+	 *             If an error occurs persisting the message
+	 * @throws IllegalArgumentException
+	 *             if value of QoS is not 0, 1 or 2.
+	 * @see #publish(MqttMessage)
+	 * @see MqttMessage#setQos(int)
+	 * @see MqttMessage#setRetained(boolean)
+	 */
+	public MqttToken publish(byte[] payload, int qos, boolean retained)
+			throws MqttException, MqttPersistenceException {
+		MqttMessage message = new MqttMessage(payload);
+		message.setQos(qos);
+		message.setRetained(retained);
+		return this.publish(message);
+	}
+
+	/**
+	 * Publishes the specified message to this topic, but does not wait for delivery
+	 * of the message to complete. The returned {@link MqttToken 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.
+	 *
+	 * @param message
+	 *            the message to publish
+	 * @return an MqttToken for tracking the delivery of the message
+	 * @throws MqttException
+	 *             if an error occurs publishing the message
+	 * @throws MqttPersistenceException
+	 *             if an error occurs persisting the message
+	 */
+	public MqttToken publish(MqttMessage message) throws MqttException, MqttPersistenceException {
+		MqttToken token = new MqttToken(comms.getClient().getClientId());
+                token.internalTok.setDeliveryToken(true);
+		token.setMessage(message);
+		comms.sendNoWait(createPublish(message, new MqttProperties()), token);
+		token.internalTok.waitUntilSent();
+		return token;
+	}
+
+	/**
+	 * Returns the name of the queue or topic.
+	 *
+	 * @return the name of this destination.
+	 */
+	public String getName() {
+		return name;
+	}
+
+	/**
+	 * Create a PUBLISH packet from the specified message.
+	 */
+	private MqttPublish createPublish(MqttMessage message, MqttProperties properties) {
+		return new MqttPublish(this.getName(), message, properties);
+	}
+
+	/**
+	 * Returns a string representation of this topic.
+	 * 
+	 * @return a string representation of this topic.
+	 */
+	public String toString() {
+		return getName();
+	}
+
+}