Avoid creating an extra buffer when saving a stream of values as DISK_ONLY

core/src/main/scala/spark/storage/BlockStore.scala

 package spark.storage
 
-import java.io.{File, RandomAccessFile}
+import java.io.{File, FileOutputStream, RandomAccessFile}
 import java.nio.ByteBuffer
 import java.nio.channels.FileChannel.MapMode
 import java.util.{LinkedHashMap, UUID}
@@ -8,12 +8,14 @@ import java.util.concurrent.{ArrayBlockingQueue, ConcurrentHashMap}
 
 import scala.collection.mutable.ArrayBuffer
 
+import it.unimi.dsi.fastutil.io.FastBufferedOutputStream
+
 import spark.{Utils, Logging, Serializer, SizeEstimator}
 
 /**
  * Abstract class to store blocks
  */
-abstract class BlockStore(blockManager: BlockManager) extends Logging {
+abstract class BlockStore(val blockManager: BlockManager) extends Logging {
   initLogging()
 
   def putBytes(blockId: String, bytes: ByteBuffer, level: StorageLevel) 
@@ -217,25 +219,28 @@ class DiskStore(blockManager: BlockManager, rootDirs: String)
     logDebug("Attempting to put block " + blockId)
     val startTime = System.currentTimeMillis
     val file = createFile(blockId)
-    if (file != null) {
-      val channel = new RandomAccessFile(file, "rw").getChannel()
-      val buffer = channel.map(MapMode.READ_WRITE, 0, bytes.limit)
-      buffer.put(bytes)
-      channel.close()
-      val finishTime = System.currentTimeMillis
-      logDebug("Block %s stored to file of %d bytes to disk in %d ms".format(
-        blockId, bytes.limit, (finishTime - startTime)))
-    } else {
-      logError("File not created for block " + blockId)
-    }
+    val channel = new RandomAccessFile(file, "rw").getChannel()
+    val buffer = channel.map(MapMode.READ_WRITE, 0, bytes.limit)
+    buffer.put(bytes)
+    channel.close()
+    val finishTime = System.currentTimeMillis
+    logDebug("Block %s stored to file of %d bytes to disk in %d ms".format(
+      blockId, bytes.limit, (finishTime - startTime)))
   }
 
   def putValues(blockId: String, values: Iterator[Any], level: StorageLevel)
-  : Either[Iterator[Any], ByteBuffer] = {
-    val bytes = dataSerialize(values) 
-    logDebug("Converted block " + blockId + " to " + bytes.limit + " bytes")
-    putBytes(blockId, bytes, level)
-    return Right(bytes)
+      : Either[Iterator[Any], ByteBuffer] = {
+
+    logDebug("Attempting to write values for block " + blockId)
+    val file = createFile(blockId)
+    val fileOut = new FastBufferedOutputStream(new FileOutputStream(file))
+    val objOut = blockManager.serializer.newInstance().serializeStream(fileOut)
+    objOut.writeAll(values)
+    objOut.close()
+
+    // Return a byte buffer for the contents of the file
+    val channel = new RandomAccessFile(file, "rw").getChannel()
+    Right(channel.map(MapMode.READ_WRITE, 0, channel.size()))
   }
 
   def getBytes(blockId: String): Option[ByteBuffer] = {
@@ -267,8 +272,7 @@ class DiskStore(blockManager: BlockManager, rootDirs: String)
       newFile.getParentFile.mkdirs()
       return newFile 
     } else {
-      logError("File for block " + blockId + " already exists on disk, " + file)
-      return null
+      throw new Exception("File for block " + blockId + " already exists on disk, " + file)
     }
   }