added mqtt adapter

streaming/src/main/scala/org/apache/spark/streaming/StreamingContext.scala

@@ -450,6 +450,21 @@ class StreamingContext private (
     inputStream
   }
 
+/**
+   * Create an input stream that receives messages pushed by a mqtt publisher.
+   * @param brokerUrl Url of remote mqtt publisher
+   * @param topic topic name to subscribe to
+   * @param storageLevel RDD storage level. Defaults to memory-only.
+   */
+
+  def mqttStream(
+    brokerUrl: String,
+    topic: String,
+    storageLevel: StorageLevel = StorageLevel.MEMORY_ONLY_SER_2): DStream[String] = {
+    val inputStream = new MQTTInputDStream[String](this, brokerUrl, topic, storageLevel)
+    registerInputStream(inputStream)
+    inputStream
+  }
   /**
    * Create a unified DStream from multiple DStreams of the same type and same interval
    */