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 java.io.IOException;
021    import java.util.concurrent.ConcurrentHashMap;
022    import java.util.concurrent.ConcurrentMap;
023    
024    import org.apache.hadoop.security.UserGroupInformation;
025    
026    public class UserGroupInformationService implements Service {
027    
028        private ConcurrentMap<String, UserGroupInformation> cache = new ConcurrentHashMap<String, UserGroupInformation>();
029    
030        @Override
031        public void init(Services services) throws ServiceException {
032        }
033    
034        @Override
035        public void destroy() {
036            cache.clear();
037        }
038    
039        @Override
040        public Class<? extends Service> getInterface() {
041            return UserGroupInformationService.class;
042        }
043    
044        public UserGroupInformation getProxyUser(String user) throws IOException {
045            if (!cache.containsKey(user)) {
046                cache.putIfAbsent(user, UserGroupInformation.createProxyUser(user, UserGroupInformation.getLoginUser()));
047            }
048            return cache.get(user);
049        }
050    
051    }