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.oozie.service;
019    
020    import org.apache.hadoop.conf.Configuration;
021    import org.apache.oozie.util.XConfiguration;
022    
023    import java.io.IOException;
024    import java.util.List;
025    import java.util.Map;
026    
027    /**
028     * The GroupsService class delegates to the Hadoop's <code>org.apache.hadoop.security.Groups</code>
029     * to retrieve the groups a user belongs to.
030     */
031    public class GroupsService implements Service {
032        public static final String CONF_PREFIX = Service.CONF_PREFIX + "GroupsService.";
033    
034        private org.apache.hadoop.security.Groups hGroups;
035    
036        /**
037         * Returns the service interface.
038         * @return <code>GroupService</code>
039         */
040        @Override
041        public Class<? extends Service> getInterface() {
042            return GroupsService.class;
043        }
044    
045        /**
046         * Initializes the service.
047         *
048         * @param services services singleton initializing the service.
049         */
050        @Override
051        public void init(Services services) {
052            Configuration sConf = services.getConf();
053            Configuration gConf = new XConfiguration();
054            for (Map.Entry<String, String> entry : sConf) {
055                String name = entry.getKey();
056                if (name.startsWith(CONF_PREFIX)) {
057                    gConf.set(name.substring(CONF_PREFIX.length()), sConf.get(name));
058                }
059            }
060            hGroups = new org.apache.hadoop.security.Groups(gConf);
061        }
062    
063        /**
064         * Destroys the service.
065         */
066        @Override
067        public void destroy() {
068        }
069    
070        /**
071         * Returns the list of groups a user belongs to.
072         *
073         * @param user user name.
074         * @return the groups the given user belongs to.
075         * @throws IOException thrown if there was an error retrieving the groups of the user.
076         */
077        public List<String> getGroups(String user) throws IOException {
078            return hGroups.getGroups(user);
079        }
080    
081    }