Fixed streaming examples docs to use run-example instead of spark-submit

Pretty self-explanatory

Author: Tathagata Das <tathagata.das1565@gmail.com>

Closes #722 from tdas/example-fix and squashes the following commits:

7839979 [Tathagata Das] Minor changes.
0673441 [Tathagata Das] Fixed java docs of java streaming example
e687123 [Tathagata Das] Fixed scala style errors.
9b8d112 [Tathagata Das] Fixed streaming examples docs to use run-example instead of spark-submit.

1 files changed, 35 insertions, 23 deletions

diff --git a/external/twitter/src/main/scala/org/apache/spark/streaming/twitter/TwitterInputDStream.scala b/external/twitter/src/main/scala/org/apache/spark/streaming/twitter/TwitterInputDStream.scala
index 7bca140711..5ea2e5549d 100644
--- a/external/twitter/src/main/scala/org/apache/spark/streaming/twitter/TwitterInputDStream.scala
+++ b/external/twitter/src/main/scala/org/apache/spark/streaming/twitter/TwitterInputDStream.scala
@@ -63,36 +63,48 @@ class TwitterReceiver(
     storageLevel: StorageLevel
   ) extends Receiver[Status](storageLevel) with Logging {
 
-  var twitterStream: TwitterStream = _
+  private var twitterStream: TwitterStream = _
 
   def onStart() {
-    twitterStream = new TwitterStreamFactory().getInstance(twitterAuth)
-    twitterStream.addListener(new StatusListener {
-      def onStatus(status: Status) = {
-        store(status)
-      }
-      // Unimplemented
-      def onDeletionNotice(statusDeletionNotice: StatusDeletionNotice) {}
-      def onTrackLimitationNotice(i: Int) {}
-      def onScrubGeo(l: Long, l1: Long) {}
-      def onStallWarning(stallWarning: StallWarning) {}
-      def onException(e: Exception) {
-        restart("Error receiving tweets", e)
-      }
-    })
+    try {
+      val newTwitterStream = new TwitterStreamFactory().getInstance(twitterAuth)
+      newTwitterStream.addListener(new StatusListener {
+        def onStatus(status: Status) = {
+          store(status)
+        }
+        // Unimplemented
+        def onDeletionNotice(statusDeletionNotice: StatusDeletionNotice) {}
+        def onTrackLimitationNotice(i: Int) {}
+        def onScrubGeo(l: Long, l1: Long) {}
+        def onStallWarning(stallWarning: StallWarning) {}
+        def onException(e: Exception) {
+          restart("Error receiving tweets", e)
+        }
+      })
 
-    val query = new FilterQuery
-    if (filters.size > 0) {
-      query.track(filters.toArray)
-      twitterStream.filter(query)
-    } else {
-      twitterStream.sample()
+      val query = new FilterQuery
+      if (filters.size > 0) {
+        query.track(filters.toArray)
+        newTwitterStream.filter(query)
+      } else {
+        newTwitterStream.sample()
+      }
+      setTwitterStream(newTwitterStream)
+      logInfo("Twitter receiver started")
+    } catch {
+      case e: Exception => restart("Error starting Twitter stream", e)
     }
-    logInfo("Twitter receiver started")
   }
 
   def onStop() {
-    twitterStream.shutdown()
+    setTwitterStream(null)
     logInfo("Twitter receiver stopped")
   }
+
+  private def setTwitterStream(newTwitterStream: TwitterStream) = synchronized {
+    if (twitterStream != null) {
+      twitterStream.shutdown()
+    }
+    twitterStream = newTwitterStream
+  }
 }