org.apache.lens.server.user.DatabaseUserConfigLoader.java Source code

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Here is the source code for org.apache.lens.server.user.DatabaseUserConfigLoader.java

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/**
 * 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.lens.server.user;

import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;

import org.apache.lens.server.api.LensConfConstants;
import org.apache.lens.server.api.user.UserConfigLoader;
import org.apache.lens.server.api.user.UserConfigLoaderException;
import org.apache.lens.server.util.UtilityMethods;

import org.apache.commons.dbcp.BasicDataSource;
import org.apache.hadoop.hive.conf.HiveConf;

import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;

/**
 * The Class DatabaseUserConfigLoader.
 */
public class DatabaseUserConfigLoader implements UserConfigLoader {

    /** The query sql. */
    protected final String querySql;

    /** The keys. */
    protected final String[] keys;

    /** The cache. */
    protected final Cache<String, Map<String, String>> cache;
    private final HiveConf hiveConf;

    /** The ds. */
    protected BasicDataSource ds;

    /**
     * Instantiates a new database user config loader.
     *
     * @param conf the conf
     * @throws UserConfigLoaderException the user config loader exception
     */
    public DatabaseUserConfigLoader(HiveConf conf) throws UserConfigLoaderException {
        this.hiveConf = conf;
        querySql = conf.get(LensConfConstants.USER_RESOLVER_DB_QUERY);
        keys = conf.get(LensConfConstants.USER_RESOLVER_DB_KEYS).split("\\s*,\\s*", -1);
        cache = CacheBuilder.newBuilder()
                .expireAfterWrite(conf.getInt(LensConfConstants.USER_RESOLVER_CACHE_EXPIRY, 2), TimeUnit.HOURS)
                .maximumSize(conf.getInt(LensConfConstants.USER_RESOLVER_CACHE_MAX_SIZE, 100)).build();
    }

    /*
     * (non-Javadoc)
     *
     * @see org.apache.lens.server.user.UserConfigLoader#getUserConfig(java.lang.String)
     */
    @Override
    public Map<String, String> getUserConfig(final String loggedInUser) throws UserConfigLoaderException {
        try {
            return cache.get(loggedInUser, new Callable<Map<String, String>>() {
                @Override
                public Map<String, String> call() throws Exception {
                    try {
                        final String[] config = queryDatabase(querySql, false, loggedInUser);
                        if (config.length != keys.length) {
                            throw new UserConfigLoaderException(
                                    "size of columns retrieved by db query(" + config.length + ") "
                                            + "is not equal to the number of keys required(" + keys.length + ").");
                        }
                        return new HashMap<String, String>() {
                            {
                                for (int i = 0; i < keys.length; i++) {
                                    put(keys[i], config[i]);
                                }
                            }
                        };
                    } catch (SQLException e) {
                        throw new UserConfigLoaderException(e);
                    }
                }
            });
        } catch (ExecutionException e) {
            throw new UserConfigLoaderException(e);
        }
    }

    private BasicDataSource refreshDataSource() {
        if (ds == null || ds.isClosed()) {
            ds = UtilityMethods.getDataSourceFromConf(hiveConf);
        }
        return ds;
    }

    String[] queryDatabase(String querySql, boolean allowNull, Object... args) throws SQLException {
        return UtilityMethods.queryDatabase(refreshDataSource(), querySql, allowNull, args);
    }
}