Add missing interface file

core/src/main/scala/org/apache/spark/shuffle/sort/SortShuffleSorter.scala

@@ -0,0 +1,44 @@
+/*
+ * 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.shuffle.sort
+
+import java.io.File
+
+import org.apache.spark.TaskContext
+import org.apache.spark.storage.BlockId
+
+trait SortShuffleSorter[K, V] {
+
+  def insertAll(records: Iterator[_ <: Product2[K, V]]): Unit
+
+    /**
+   * Write all the data added into this shuffle sorter into a file in the disk store. This is
+   * called by the SortShuffleWriter and can go through an efficient path of just concatenating
+   * binary files if we decided to avoid merge-sorting.
+   *
+   * @param blockId block ID to write to. The index file will be blockId.name + ".index".
+   * @param context a TaskContext for a running Spark task, for us to update shuffle metrics.
+   * @return array of lengths, in bytes, of each partition of the file (used by map output tracker)
+   */
+  def writePartitionedFile(
+    blockId: BlockId,
+    context: TaskContext,
+    outputFile: File): Array[Long]
+
+  def stop(): Unit
+}