org.apache.avro.mapreduce.AvroKeyInputFormat Maven / Gradle / Ivy
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* 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
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
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*/
package org.apache.avro.mapreduce;
import java.io.IOException;
import org.apache.avro.Schema;
import org.apache.avro.mapred.AvroKey;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import com.facebook.presto.hive.$internal.org.slf4j.Logger;
import com.facebook.presto.hive.$internal.org.slf4j.LoggerFactory;
/**
* A MapReduce InputFormat that can handle Avro container files.
*
*
* Keys are AvroKey wrapper objects that contain the Avro data. Since Avro
* container files store only records (not key/value pairs), the value from this
* InputFormat is a NullWritable.
*
*/
public class AvroKeyInputFormat extends FileInputFormat, NullWritable> {
private static final Logger LOG = LoggerFactory.getLogger(AvroKeyInputFormat.class);
/** {@inheritDoc} */
@Override
public RecordReader, NullWritable> createRecordReader(InputSplit split, TaskAttemptContext context)
throws IOException, InterruptedException {
Schema readerSchema = AvroJob.getInputKeySchema(context.getConfiguration());
if (null == readerSchema) {
LOG.warn("Reader schema was not set. Use AvroJob.setInputKeySchema() if desired.");
LOG.info("Using a reader schema equal to the writer schema.");
}
return new AvroKeyRecordReader<>(readerSchema);
}
}