org.apache.hadoop.hbase.mapreduce.MultiTableInputFormat 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.hbase.mapreduce;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.yetus.audience.InterfaceAudience;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.client.Scan;
/**
* Convert HBase tabular data from multiple scanners into a format that
* is consumable by Map/Reduce.
*
*
* Usage example
*
*
*
* List<Scan> scans = new ArrayList<Scan>();
*
* Scan scan1 = new Scan();
* scan1.setStartRow(firstRow1);
* scan1.setStopRow(lastRow1);
* scan1.setAttribute(Scan.SCAN_ATTRIBUTES_TABLE_NAME, table1);
* scans.add(scan1);
*
* Scan scan2 = new Scan();
* scan2.setStartRow(firstRow2);
* scan2.setStopRow(lastRow2);
* scan1.setAttribute(Scan.SCAN_ATTRIBUTES_TABLE_NAME, table2);
* scans.add(scan2);
*
* TableMapReduceUtil.initTableMapperJob(scans, TableMapper.class, Text.class,
* IntWritable.class, job);
*
*/
@InterfaceAudience.Public
public class MultiTableInputFormat extends MultiTableInputFormatBase implements
Configurable {
/** Job parameter that specifies the scan list. */
public static final String SCANS = "hbase.mapreduce.scans";
/** The configuration. */
private Configuration conf = null;
/**
* Returns the current configuration.
*
* @return The current configuration.
* @see org.apache.hadoop.conf.Configurable#getConf()
*/
@Override
public Configuration getConf() {
return conf;
}
/**
* Sets the configuration. This is used to set the details for the tables to
* be scanned.
*
* @param configuration The configuration to set.
* @see org.apache.hadoop.conf.Configurable#setConf(
* org.apache.hadoop.conf.Configuration)
*/
@Override
public void setConf(Configuration configuration) {
this.conf = configuration;
String[] rawScans = conf.getStrings(SCANS);
if (rawScans.length <= 0) {
throw new IllegalArgumentException("There must be at least 1 scan configuration set to : "
+ SCANS);
}
List scans = new ArrayList<>();
for (int i = 0; i < rawScans.length; i++) {
try {
scans.add(TableMapReduceUtil.convertStringToScan(rawScans[i]));
} catch (IOException e) {
throw new RuntimeException("Failed to convert Scan : " + rawScans[i] + " to string", e);
}
}
this.setScans(scans);
}
}