com.cloudera.science.avro2parquet.CombinedAvroKeyInputFormat.java Source code

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Here is the source code for com.cloudera.science.avro2parquet.CombinedAvroKeyInputFormat.java

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/**
 * 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 com.cloudera.science.avro2parquet;

import java.io.IOException;

import org.apache.avro.Schema;
import org.apache.avro.mapred.AvroKey;
import org.apache.avro.mapreduce.AvroJob;
import org.apache.avro.mapreduce.AvroKeyRecordReader;
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.CombineFileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.CombineFileRecordReader;
import org.apache.hadoop.mapreduce.lib.input.CombineFileSplit;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;
import org.apache.log4j.Logger;

/**
 * A combined input format for reading Avro data.
 * 
 * @author "Matthew Hayes"
 *
 * @param <T> Type of data to be read
 */
public class CombinedAvroKeyInputFormat<T> extends CombineFileInputFormat<AvroKey<T>, NullWritable> {
    private final Logger LOG = Logger.getLogger(CombinedAvroKeyInputFormat.class);

    public static class CombinedAvroKeyRecordReader<T> extends AvroKeyRecordReader<T> {
        private CombineFileSplit inputSplit;
        private Integer idx;

        public CombinedAvroKeyRecordReader(CombineFileSplit inputSplit, TaskAttemptContext context, Integer idx) {
            super(AvroJob.getInputKeySchema(context.getConfiguration()));
            this.inputSplit = inputSplit;
            this.idx = idx;
        }

        @Override
        public void initialize(InputSplit inputSplit, TaskAttemptContext context)
                throws IOException, InterruptedException {
            this.inputSplit = (CombineFileSplit) inputSplit;

            FileSplit fileSplit = new FileSplit(this.inputSplit.getPath(idx), this.inputSplit.getOffset(idx),
                    this.inputSplit.getLength(idx), this.inputSplit.getLocations());

            super.initialize(fileSplit, context);
        }
    }

    @SuppressWarnings("unchecked")
    @Override
    public RecordReader<AvroKey<T>, NullWritable> createRecordReader(InputSplit inputSplit,
            TaskAttemptContext context) throws IOException {
        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.");
        }

        Object c = CombinedAvroKeyRecordReader.class;
        return new CombineFileRecordReader<AvroKey<T>, NullWritable>((CombineFileSplit) inputSplit, context,
                (Class<? extends RecordReader<AvroKey<T>, NullWritable>>) c);
    }

}