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.security;
019    
020    import java.io.IOException;
021    import java.util.List;
022    
023    import org.apache.hadoop.classification.InterfaceAudience;
024    import org.apache.hadoop.classification.InterfaceStability;
025    import org.apache.hadoop.fs.CommonConfigurationKeysPublic;
026    
027    /**
028     * An interface for the implementation of <userId, userName> mapping
029     * and <groupId, groupName> mapping
030     */
031    @InterfaceAudience.Public
032    @InterfaceStability.Evolving
033    public interface IdMappingServiceProvider {
034    
035      // Return uid for given user name
036      public int getUid(String user) throws IOException;
037    
038      // Return gid for given group name
039      public int getGid(String group) throws IOException;
040    
041      // Return user name for given user id uid, if not found, return 
042      // <unknown> passed to this method
043      public String getUserName(int uid, String unknown);
044    
045      // Return group name for given groupd id gid, if not found, return 
046      // <unknown> passed to this method
047      public String getGroupName(int gid, String unknown);
048      
049      // Return uid for given user name.
050      // When can't map user, return user name's string hashcode
051      public int getUidAllowingUnknown(String user);
052    
053      // Return gid for given group name.
054      // When can't map group, return group name's string hashcode
055      public int getGidAllowingUnknown(String group);
056    }