mqttinputdstream for mqttstreaming adapter

streaming/src/main/scala/org/apache/spark/streaming/dstream/MQTTInputDStream.scala

+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.streaming.dstream
+
+import org.apache.spark.Logging
+import org.apache.spark.storage.StorageLevel
+import org.apache.spark.streaming.{ Time, DStreamCheckpointData, StreamingContext }
+
+import java.util.Properties
+import java.util.concurrent.Executors
+import java.io.IOException;
+
+import org.eclipse.paho.client.mqttv3.MqttCallback;
+import org.eclipse.paho.client.mqttv3.MqttClient;
+import org.eclipse.paho.client.mqttv3.MqttClientPersistence;
+import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
+import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
+import org.eclipse.paho.client.mqttv3.MqttException;
+import org.eclipse.paho.client.mqttv3.MqttMessage;
+import org.eclipse.paho.client.mqttv3.MqttTopic;
+
+import scala.collection.Map
+import scala.collection.mutable.HashMap
+import scala.collection.JavaConversions._
+
+/**
+ * Input stream that subscribe messages from a Mqtt Broker.
+ * Uses eclipse paho as MqttClient http://www.eclipse.org/paho/
+ * @param brokerUrl Url of remote mqtt publisher
+ * @param topic topic name to subscribe to
+ * @param storageLevel RDD storage level.
+ */
+
+private[streaming] class MQTTInputDStream[T: ClassManifest](
+  @transient ssc_ : StreamingContext,
+  brokerUrl: String,
+  topic: String,
+
+  storageLevel: StorageLevel) extends NetworkInputDStream[T](ssc_) with Logging {
+
+  def getReceiver(): NetworkReceiver[T] = {
+    new MQTTReceiver(brokerUrl, topic, storageLevel)
+      .asInstanceOf[NetworkReceiver[T]]
+  }
+}
+
+private[streaming] class MQTTReceiver(brokerUrl: String,
+  topic: String,
+  storageLevel: StorageLevel) extends NetworkReceiver[Any] {
+
+  lazy protected val blockGenerator = new BlockGenerator(storageLevel)
+
+  def onStop() {
+    blockGenerator.stop()
+  }
+
+  def onStart() {
+
+    blockGenerator.start()
+
+    //Set up persistence for messages 
+   var peristance:MqttClientPersistence =new MemoryPersistence();
+
+    //Initializing Mqtt Client specifying brokerUrl, clientID and MqttClientPersistance
+    var client: MqttClient = new MqttClient(brokerUrl, "MQTTSub", peristance);
+
+    //Connect to MqttBroker    
+    client.connect();
+    
+    //Subscribe to Mqtt topic
+    client.subscribe(topic);
+    
+    //Callback automatically triggers as and when new message arrives on specified topic
+    var callback: MqttCallback = new MqttCallback() {
+
+      //Handles Mqtt message 
+      override def messageArrived(arg0: String, arg1: MqttMessage) {
+        blockGenerator += new String(arg1.getPayload())
+      }
+      
+      override def deliveryComplete(arg0: IMqttDeliveryToken) {
+      }
+
+      override def connectionLost(arg0: Throwable) {
+        System.err.println("Connection lost " + arg0)
+
+      }
+
+    };
+
+    //Set up callback for MqttClient
+    client.setCallback(callback);
+
+  }
+
+}