org.kiji.avro.mapreduce.AvroKeyValueOutputFormat.java Source code

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Here is the source code for org.kiji.avro.mapreduce.AvroKeyValueOutputFormat.java

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/**
 * Licensed to WibiData, Inc. under one or more contributor license
 * agreements.  See the NOTICE file distributed with this work for
 * additional information regarding copyright ownership.  WibiData, Inc.
 * 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.kiji.avro.mapreduce;

import java.io.IOException;

import org.apache.avro.hadoop.io.AvroDatumConverter;
import org.apache.avro.hadoop.io.AvroDatumConverterFactory;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

/**
 * FileOutputFormat for writing Avro container files of key/value pairs.
 *
 * <p>Since Avro container files can only contain records (not key/value pairs), this
 * output format puts the key and value into an Avro generic record with two fields, named
 * 'key' and 'value'.</p>
 *
 * <p>The keys and values given to this output format may be Avro objects wrapped in
 * <code>AvroKey</code> or <code>AvroValue</code> objects.  The basic Writable types are
 * also supported (e.g., IntWritable, Text); they will be converted to their corresponding
 * Avro types.</p>
 *
 * @param <K> The type of key. If an Avro type, it must be wrapped in an <code>AvroKey</code>.
 * @param <V> The type of value. If an Avro type, it must be wrapped in an <code>AvroValue</code>.
 */
public class AvroKeyValueOutputFormat<K, V> extends AvroOutputFormatBase<K, V> {
    /** {@inheritDoc} */
    @Override
    @SuppressWarnings("unchecked")
    public RecordWriter<K, V> getRecordWriter(TaskAttemptContext context) throws IOException {
        AvroDatumConverterFactory converterFactory = new AvroDatumConverterFactory(context.getConfiguration());

        AvroDatumConverter<K, ?> keyConverter = converterFactory.create((Class<K>) context.getOutputKeyClass());
        AvroDatumConverter<V, ?> valueConverter = converterFactory.create((Class<V>) context.getOutputValueClass());

        return new AvroKeyValueRecordWriter<K, V>(keyConverter, valueConverter, getCompressionCodec(context),
                getAvroFileOutputStream(context));
    }
}