content: /*
   * 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
   *
   *     https://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.avro.mapreduce;
  
  import java.io.IOException;
  import java.io.OutputStream;
  
  import org.apache.avro.Schema;
  import org.apache.avro.file.CodecFactory;
  import org.apache.avro.generic.GenericData;
  import org.apache.avro.hadoop.io.AvroSerialization;
  import org.apache.avro.mapred.AvroKey;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.io.NullWritable;
  import org.apache.hadoop.mapreduce.RecordWriter;
  import org.apache.hadoop.mapreduce.TaskAttemptContext;
  
  /**
   * FileOutputFormat for writing Avro container files.
   *
   * <p>
   * Since Avro container files only contain records (not key/value pairs), this
   * output format ignores the value.
   * </p>
   *
   * @param <T> The (java) type of the Avro data to write.
   */
  public class AvroKeyOutputFormat<T> extends AvroOutputFormatBase<AvroKey<T>, NullWritable> {
    /** A factory for creating record writers. */
    private final RecordWriterFactory mRecordWriterFactory;
  
    /**
     * Constructor.
     */
    public AvroKeyOutputFormat() {
      this(new RecordWriterFactory());
    }
  
    /**
     * Constructor.
     *
     * @param recordWriterFactory A factory for creating record writers.
     */
    protected AvroKeyOutputFormat(RecordWriterFactory recordWriterFactory) {
      mRecordWriterFactory = recordWriterFactory;
    }
  
    /**
     * A factory for creating record writers.
     *
     * @param <T> The java type of the avro record to write.
     */
    protected static class RecordWriterFactory<T> {
      /**
       * Creates a new record writer instance.
       *
       * @param writerSchema     The writer schema for the records to write.
       * @param compressionCodec The compression type for the writer file.
       * @param outputStream     The target output stream for the records.
       * @param syncInterval     The sync interval for the writer file.
       */
      protected RecordWriter<AvroKey<T>, NullWritable> create(Schema writerSchema, GenericData dataModel,
          CodecFactory compressionCodec, OutputStream outputStream, int syncInterval) throws IOException {
        return new AvroKeyRecordWriter<>(writerSchema, dataModel, compressionCodec, outputStream, syncInterval);
      }
    }
  
    /** {@inheritDoc} */
    @Override
    @SuppressWarnings("unchecked")
    public RecordWriter<AvroKey<T>, NullWritable> getRecordWriter(TaskAttemptContext context) throws IOException {
      Configuration conf = context.getConfiguration();
      // Get the writer schema.
      Schema writerSchema = AvroJob.getOutputKeySchema(conf);
      boolean isMapOnly = context.getNumReduceTasks() == 0;
      if (isMapOnly) {
        Schema mapOutputSchema = AvroJob.getMapOutputKeySchema(conf);
        if (mapOutputSchema != null) {
          writerSchema = mapOutputSchema;
        }
      }
      if (null == writerSchema) {
        throw new IOException("AvroKeyOutputFormat requires an output schema. Use AvroJob.setOutputKeySchema().");
      }
  
      GenericData dataModel = AvroSerialization.createDataModel(conf);
  
      OutputStream out = getAvroFileOutputStream(context);
      try {
        return mRecordWriterFactory.create(writerSchema, dataModel, getCompressionCodec(context), out,
            getSyncInterval(context));
      } catch (IOException e) {
        out.close();
        throw e;
      }
    }
  }
  