001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.hadoop.hdfs.web.resources;
019    
020    import org.apache.hadoop.security.UserGroupInformation;
021    
022    /** Represents delegation token used for authentication. */
023    public class DelegationParam extends StringParam {
024      /** Parameter name. */
025      public static final String NAME = "delegation";
026      /** Default parameter value. */
027      public static final String DEFAULT = "";
028    
029      private static final Domain DOMAIN = new Domain(NAME, null);
030    
031      /**
032       * Constructor.
033       * @param str a string representation of the parameter value.
034       */
035      public DelegationParam(final String str) {
036        super(DOMAIN, UserGroupInformation.isSecurityEnabled()
037            && str != null && !str.equals(DEFAULT)? str: null);
038      }
039    
040      @Override
041      public String getName() {
042        return NAME;
043      }
044    }