branch-2.0.4-alpha/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/protocolrecords/StartContainerResponse.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.yarn.api.protocolrecords;

import java.nio.ByteBuffer;
import java.util.Map;

import org.apache.hadoop.classification.InterfaceAudience.Public;
import org.apache.hadoop.classification.InterfaceStability.Stable;
import org.apache.hadoop.yarn.api.ContainerManager;

/**
 * <p>The response sent by the <code>NodeManager</code> to the 
 * <code>ApplicationMaster</code> when asked to <em>start</em> an
 * allocated container.</p>
 * 
 * @see ContainerManager#startContainer(StartContainerRequest)
 */
@Public
@Stable
public interface StartContainerResponse {
  /**
   * <p>Get the responses from all auxiliary services running on the 
   * <code>NodeManager</code>.</p>
   * <p>The responses are returned as a Map between the auxiliary service names
   * and their corresponding opaque blob <code>ByteBuffer</code>s</p> 
   * @return a Map between the auxiliary service names and their outputs
   */
  Map<String, ByteBuffer> getAllServiceResponse();

  /**
   * Get the response from a single auxiliary service running on the
   * <code>NodeManager</code>
   * 
   * @param key The auxiliary service name whose response is desired.
   * @return The opaque blob <code>ByteBuffer</code> returned by the auxiliary
   * service.
   */
  ByteBuffer getServiceResponse(String key);

  /**
   * Add to the list of auxiliary services which have been started on the
   * <code>NodeManager</code>. This is done only once when the
   * <code>NodeManager</code> starts up
   * @param serviceResponse A map from auxiliary service names to the opaque
   * blob <code>ByteBuffer</code>s for that auxiliary service
   */
  void addAllServiceResponse(Map<String, ByteBuffer> serviceResponse);

  /**
   * Add to the list of auxiliary services which have been started on the
   * <code>NodeManager</code>. This is done only once when the
   * <code>NodeManager</code> starts up
   * 
   * @param key The auxiliary service name
   * @param value The opaque blob <code>ByteBuffer</code> managed by the
   * auxiliary service
   */
  void setServiceResponse(String key, ByteBuffer value);

  /**
   * Remove a single auxiliary service from the StartContainerResponse object
   * @param key The auxiliary service to remove
   */
  void removeServiceResponse(String key);
  
  /**
   * Remove all the auxiliary services from the StartContainerResponse object
   */
  void clearServiceResponse();
}