org.apache.hadoop.mapred.lib.db.DBOutputFormat Maven / Gradle / Ivy
/**
* 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.hadoop.mapred.lib.db;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.OutputFormat;
import org.apache.hadoop.mapred.RecordWriter;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapreduce.MRJobConfig;
import org.apache.hadoop.mapreduce.TaskAttemptID;
import org.apache.hadoop.mapreduce.task.TaskAttemptContextImpl;
import org.apache.hadoop.util.Progressable;
@InterfaceAudience.Public
@InterfaceStability.Stable
public class DBOutputFormat
extends org.apache.hadoop.mapreduce.lib.db.DBOutputFormat
implements OutputFormat {
/**
* A RecordWriter that writes the reduce output to a SQL table
*/
protected class DBRecordWriter extends
org.apache.hadoop.mapreduce.lib.db.DBOutputFormat.DBRecordWriter
implements RecordWriter {
protected DBRecordWriter(Connection connection,
PreparedStatement statement) throws SQLException {
super(connection, statement);
}
/** {@inheritDoc} */
public void close(Reporter reporter) throws IOException {
super.close(null);
}
}
/** {@inheritDoc} */
public void checkOutputSpecs(FileSystem filesystem, JobConf job)
throws IOException {
}
/** {@inheritDoc} */
public RecordWriter getRecordWriter(FileSystem filesystem,
JobConf job, String name, Progressable progress) throws IOException {
org.apache.hadoop.mapreduce.RecordWriter w = super.getRecordWriter(
new TaskAttemptContextImpl(job,
TaskAttemptID.forName(job.get(MRJobConfig.TASK_ATTEMPT_ID))));
org.apache.hadoop.mapreduce.lib.db.DBOutputFormat.DBRecordWriter writer =
(org.apache.hadoop.mapreduce.lib.db.DBOutputFormat.DBRecordWriter) w;
try {
return new DBRecordWriter(writer.getConnection(), writer.getStatement());
} catch(SQLException se) {
throw new IOException(se);
}
}
/**
* Initializes the reduce-part of the job with the appropriate output settings
*
* @param job The job
* @param tableName The table to insert data into
* @param fieldNames The field names in the table.
*/
public static void setOutput(JobConf job, String tableName, String... fieldNames) {
if(fieldNames.length > 0 && fieldNames[0] != null) {
DBConfiguration dbConf = setOutput(job, tableName);
dbConf.setOutputFieldNames(fieldNames);
} else {
if(fieldNames.length > 0)
setOutput(job, tableName, fieldNames.length);
else
throw new IllegalArgumentException("Field names must be greater than 0");
}
}
/**
* Initializes the reduce-part of the job with the appropriate output settings
*
* @param job The job
* @param tableName The table to insert data into
* @param fieldCount the number of fields in the table.
*/
public static void setOutput(JobConf job, String tableName, int fieldCount) {
DBConfiguration dbConf = setOutput(job, tableName);
dbConf.setOutputFieldCount(fieldCount);
}
private static DBConfiguration setOutput(JobConf job, String tableName) {
job.setOutputFormat(DBOutputFormat.class);
job.setReduceSpeculativeExecution(false);
DBConfiguration dbConf = new DBConfiguration(job);
dbConf.setOutputTableName(tableName);
return dbConf;
}
}