/**
 * 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.security;

import java.io.IOException;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.security.authentication.util.KerberosName;

import sun.security.krb5.Config;
import sun.security.krb5.KrbException;

/**
 * This class implements parsing and handling of Kerberos principal names. In 
 * particular, it splits them apart and translates them down into local
 * operating system names.
 */
@SuppressWarnings("all")
@InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
@InterfaceStability.Evolving
public class HadoopKerberosName extends KerberosName {

  static {
    try {
      Config.getInstance().getDefaultRealm();
    } catch (KrbException ke) {
      if(UserGroupInformation.isSecurityEnabled())
        throw new IllegalArgumentException("Can't get Kerberos configuration",ke);
    }
  }

  /**
   * Create a name from the full Kerberos principal name.
   * @param name
   */
  public HadoopKerberosName(String name) {
    super(name);
  }
  /**
   * Set the static configuration to get the rules.
   * <p/>
   * IMPORTANT: This method does a NOP if the rules have been set already.
   * If there is a need to reset the rules, the {@link KerberosName#setRules(String)}
   * method should be invoked directly.
   * 
   * @param conf the new configuration
   * @throws IOException
   */
  public static void setConfiguration(Configuration conf) throws IOException {
    String ruleString = conf.get("hadoop.security.auth_to_local", "DEFAULT");
    setRules(ruleString);
  }

  public static void main(String[] args) throws Exception {
    setConfiguration(new Configuration());
    for(String arg: args) {
      HadoopKerberosName name = new HadoopKerberosName(arg);
      System.out.println("Name: " + name + " to " + name.getShortName());
    }
  }
}