/**
* (c) Copyright 2012 WibiData, Inc.
*
* See the NOTICE file distributed with this work for additional
* information regarding copyright ownership.
*
* 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 org.kiji.mapreduce.input;
import java.io.IOException;
import java.util.Map;
import org.apache.hadoop.hbase.mapreduce.TableInputFormat;
import org.apache.hadoop.mapreduce.InputFormat;
import org.apache.hadoop.mapreduce.Job;
import org.kiji.annotations.ApiAudience;
import org.kiji.annotations.ApiStability;
import org.kiji.mapreduce.MapReduceJobInput;
import org.kiji.mapreduce.impl.HTableInputFormat;
import org.kiji.mapreduce.tools.framework.JobIOConfKeys;
/**
* The class HTableMapReduceJobInput is used to indicate the usage of a HBase table
* as input to a MapReduce job. Any MapReduce job configured to read from an HBase
* table should expect to receive an <code>ImmutableBytesWritable</code> as a key
* and a <code>Result</code> as a value.
*
* <h2>Configuring an input:</h2>
* <p>
* HTableMapReduceJobInput must be configured with the name of the input HBase table:
* </p>
* <pre>
* <code>
* final MapReduceJobInput htableJobInput =
* MapReduceJobInputs.newHTableMapReduceJobInput("mytable");
* </code>
* </pre>
*/
@ApiAudience.Public
@ApiStability.Evolving
public final class HTableMapReduceJobInput extends MapReduceJobInput {
/** The name of the HTable to use as job input. */
private String mTableName;
/** Default constructor. Used by {@link MapReduceJobInputs} */
HTableMapReduceJobInput() { }
/** {@inheritDoc} */
@Override
public void initialize(Map<String, String> params) throws IOException {
mTableName = params.get(JobIOConfKeys.HTABLE_NAME_KEY);
}
/**
* Creates a new <code>HTableMapReduceJobInput</code> instance. Accessible via
* {@link MapReduceJobInputs#newHTableMapReduceJobInput(String)}.
*
* @param tableName The name of the HBase table (HTable) to use as input for the job.
*/
HTableMapReduceJobInput(String tableName) {
mTableName = tableName;
}
/** {@inheritDoc} */
@Override
public void configure(Job job) throws IOException {
// Configure the input format class.
super.configure(job);
// Configure the input HTable name.
job.getConfiguration().set(TableInputFormat.INPUT_TABLE, mTableName);
}
/** {@inheritDoc} */
@Override
protected Class<? extends InputFormat<?, ?>> getInputFormatClass() {
return HTableInputFormat.class;
}
}