[SPARK-6428] Turn on explicit type checking for public methods.

This builds on my earlier pull requests and turns on the explicit type checking in scalastyle.

Author: Reynold Xin <rxin@databricks.com>

Closes #5342 from rxin/SPARK-6428 and squashes the following commits:

7b531ab [Reynold Xin] import ordering
2d9a8a5 [Reynold Xin] jl
e668b1c [Reynold Xin] override
9b9e119 [Reynold Xin] Parenthesis.
82e0cf5 [Reynold Xin] [SPARK-6428] Turn on explicit type checking for public methods.

1 files changed, 5 insertions, 7 deletions

diff --git a/external/flume/src/main/scala/org/apache/spark/streaming/flume/FlumeInputDStream.scala b/external/flume/src/main/scala/org/apache/spark/streaming/flume/FlumeInputDStream.scala
index 2de2a7926b..60e2994431 100644
--- a/external/flume/src/main/scala/org/apache/spark/streaming/flume/FlumeInputDStream.scala
+++ b/external/flume/src/main/scala/org/apache/spark/streaming/flume/FlumeInputDStream.scala
@@ -37,8 +37,7 @@ import org.apache.spark.streaming.dstream._
 import org.apache.spark.streaming.StreamingContext
 import org.apache.spark.streaming.receiver.Receiver
 
-import org.jboss.netty.channel.ChannelPipelineFactory
-import org.jboss.netty.channel.Channels
+import org.jboss.netty.channel.{ChannelPipeline, ChannelPipelineFactory, Channels}
 import org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory
 import org.jboss.netty.handler.codec.compression._
 
@@ -187,8 +186,8 @@ class FlumeReceiver(
     logInfo("Flume receiver stopped")
   }
 
-  override def preferredLocation = Some(host)
-  
+  override def preferredLocation: Option[String] = Option(host)
+
   /** A Netty Pipeline factory that will decompress incoming data from 
     * and the Netty client and compress data going back to the client.
     *
@@ -198,13 +197,12 @@ class FlumeReceiver(
     */
   private[streaming]
   class CompressionChannelPipelineFactory extends ChannelPipelineFactory {
-
-    def getPipeline() = {
+    def getPipeline(): ChannelPipeline = {
       val pipeline = Channels.pipeline()
       val encoder = new ZlibEncoder(6)
       pipeline.addFirst("deflater", encoder)
       pipeline.addFirst("inflater", new ZlibDecoder())
       pipeline
+    }
   }
 }
-}