co.nubetech.hiho.mapreduce.lib.db.DBQueryInputFormat.java Source code

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Here is the source code for co.nubetech.hiho.mapreduce.lib.db.DBQueryInputFormat.java

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/**
 * Copyright 2010 Nube Technologies
 * 
 * Licensed 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 co.nubetech.hiho.mapreduce.lib.db;

import java.io.IOException;
import java.sql.SQLException;
import java.util.ArrayList;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.DefaultStringifier;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.log4j.Logger;

import co.nubetech.apache.hadoop.DBConfiguration;
import co.nubetech.apache.hadoop.DBInputFormat;
import co.nubetech.apache.hadoop.DataDrivenDBInputFormat;
import co.nubetech.hiho.common.HIHOConf;

public class DBQueryInputFormat extends DataDrivenDBInputFormat<GenericDBWritable> {

    final static Logger logger = Logger.getLogger(co.nubetech.hiho.mapreduce.lib.db.DBQueryInputFormat.class);

    @Override
    protected RecordReader<LongWritable, GenericDBWritable> createDBRecordReader(DBInputSplit split,
            Configuration conf) throws IOException {

        DBConfiguration dbConf = getDBConf();
        @SuppressWarnings("unchecked")
        // Class<T> inputClass = (Class<T>) (dbConf.getInputClass());
        String dbProductName = getDBProductName();

        logger.debug("Creating db record reader for db product: " + dbProductName);
        ArrayList params = null;
        try {
            if (conf.get(HIHOConf.QUERY_PARAMS) != null) {
                logger.debug("creating stringifier in DBQueryInputFormat");
                DefaultStringifier<ArrayList> stringifier = new DefaultStringifier<ArrayList>(conf,
                        ArrayList.class);
                logger.debug("created stringifier");

                params = stringifier.fromString(conf.get(HIHOConf.QUERY_PARAMS));
                logger.debug("created params");
            }
            // use database product name to determine appropriate record reader.
            if (dbProductName.startsWith("MYSQL")) {
                // use MySQL-specific db reader.
                return new MySQLQueryRecordReader(split, conf, getConnection(), dbConf, dbConf.getInputConditions(),
                        dbConf.getInputFieldNames(), dbConf.getInputTableName(), params);
            } else {
                // Generic reader.
                return new DBQueryRecordReader(split, conf, getConnection(), dbConf, dbConf.getInputConditions(),
                        dbConf.getInputFieldNames(), dbConf.getInputTableName(), dbProductName, params);
            }
        } catch (SQLException ex) {
            throw new IOException(ex.getMessage());
        }
    }

    // Configuration methods override superclass to ensure that the proper
    // DataDrivenDBInputFormat gets used.

    /**
     * Note that the "orderBy" column is called the "splitBy" in this version.
     * We reuse the same field, but it's not strictly ordering it -- just
     * partitioning the results.
     */
    public static void setInput(Job job, String tableName, String conditions, String splitBy, ArrayList params,
            String... fieldNames) throws IOException {
        DBInputFormat.setInput(job, GenericDBWritable.class, tableName, conditions, splitBy, fieldNames);
        if (params != null) {
            DefaultStringifier<ArrayList> stringifier = new DefaultStringifier<ArrayList>(job.getConfiguration(),
                    ArrayList.class);
            job.getConfiguration().set(HIHOConf.QUERY_PARAMS, stringifier.toString(params));
            logger.debug("Converted params and saved them into config");
        }
        job.setInputFormatClass(DBQueryInputFormat.class);
    }

    /**
     * setInput() takes a custom query and a separate "bounding query" to use
     * instead of the custom "count query" used by DBInputFormat.
     */
    public static void setInput(Job job, String inputQuery, String inputBoundingQuery, ArrayList params)
            throws IOException {
        DBInputFormat.setInput(job, GenericDBWritable.class, inputQuery, "");
        if (inputBoundingQuery != null) {
            job.getConfiguration().set(DBConfiguration.INPUT_BOUNDING_QUERY, inputBoundingQuery);
        }
        if (params != null) {
            DefaultStringifier<ArrayList> stringifier = new DefaultStringifier<ArrayList>(job.getConfiguration(),
                    ArrayList.class);
            job.getConfiguration().set(HIHOConf.QUERY_PARAMS, stringifier.toString(params));
            logger.debug("Converted params and saved them into config");
        }
        job.setInputFormatClass(DBQueryInputFormat.class);
    }

}