org.apache.hadoop.hbase.mapreduce.IdentityTableMapper 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 org.apache.yetus.audience.InterfaceAudience;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.mapreduce.Job;
/**
* Pass the given key and record as-is to the reduce phase.
*/
@InterfaceAudience.Public
public class IdentityTableMapper
extends TableMapper {
/**
* Use this before submitting a TableMap job. It will appropriately set up
* the job.
*
* @param table The table name.
* @param scan The scan with the columns to scan.
* @param mapper The mapper class.
* @param job The job configuration.
* @throws IOException When setting up the job fails.
*/
@SuppressWarnings("rawtypes")
public static void initJob(String table, Scan scan,
Class mapper, Job job) throws IOException {
TableMapReduceUtil.initTableMapperJob(table, scan, mapper,
ImmutableBytesWritable.class, Result.class, job);
}
/**
* Pass the key, value to reduce.
*
* @param key The current key.
* @param value The current value.
* @param context The current context.
* @throws IOException When writing the record fails.
* @throws InterruptedException When the job is aborted.
*/
public void map(ImmutableBytesWritable key, Result value, Context context)
throws IOException, InterruptedException {
context.write(key, value);
}
}