hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/RpcScheduler.java

/**
 * 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.hadoop.ipc;

/**
 * Implement this interface to be used for RPC scheduling and backoff.
 *
 */
public interface RpcScheduler {
  /**
   * Returns priority level greater than zero as a hint for scheduling.
   */
  int getPriorityLevel(Schedulable obj);

  boolean shouldBackOff(Schedulable obj);

  /**
   * Store a processing time value for an RPC call into this scheduler.
   *
   * @param callName The name of the call.
   * @param schedulable The schedulable representing the incoming call.
   * @param details The details of processing time.
   */
  void addResponseTime(String callName, Schedulable schedulable,
      ProcessingDetails details);

  void stop();
}