/*
 * 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 spark

import spark.executor.TaskMetrics
import spark.serializer.Serializer


private[spark] abstract class ShuffleFetcher {
  /**
   * Fetch the shuffle outputs for a given ShuffleDependency.
   * @return An iterator over the elements of the fetched shuffle outputs.
   */
  def fetch[K, V](shuffleId: Int, reduceId: Int, metrics: TaskMetrics,
    serializer: Serializer = SparkEnv.get.serializerManager.default): Iterator[(K,V)]

  /** Stop the fetcher */
  def stop() {}
}