branch-2.0.4-alpha/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/main/java/org/apache/hadoop/mapreduce/v2/api/MRDelegationTokenIdentifier.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.mapreduce.v2.api;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceAudience.Private;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.security.token.Token;
import org.apache.hadoop.security.token.TokenIdentifier;
import org.apache.hadoop.security.token.delegation.AbstractDelegationTokenIdentifier;

/**
 * {@link TokenIdentifier} that identifies delegation tokens 
 * issued by JobHistoryServer to delegate
 * MR tasks talking to the JobHistoryServer.
 */
@Private
// TODO Move to a different package.
public class MRDelegationTokenIdentifier extends AbstractDelegationTokenIdentifier {

  public static final Text KIND_NAME = new Text("MR_DELEGATION_TOKEN");

 
  public MRDelegationTokenIdentifier() {
  }
  
  /**
   * Create a new delegation token identifier
   * @param owner the effective username of the token owner
   * @param renewer the username of the renewer
   * @param realUser the real username of the token owner
   */
  public MRDelegationTokenIdentifier(Text owner, Text renewer, Text realUser) {
    super(owner, renewer, realUser);
  }

 
  @Override
  public Text getKind() {
    return KIND_NAME;
  }

  @InterfaceAudience.Private
  public static class Renewer extends Token.TrivialRenewer {
    @Override
    protected Text getKind() {
      return KIND_NAME;
    }
  }
}