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 org.apache.avro.Schema;
  import org.apache.avro.mapred.AvroKey;
  import org.apache.avro.mapred.AvroValue;
  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 org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * A MapReduce InputFormat that reads from Avro container files of key/value
   * generic records.
   *
   * <p>
   * Avro container files that container generic records with the two fields 'key'
   * and 'value' are expected. The contents of the 'key' field will be used as the
   * job input key, and the contents of the 'value' field will be used as the job
   * output value.
   * </p>
   *
   * @param <K> The type of the Avro key to read.
   * @param <V> The type of the Avro value to read.
   */
  public class AvroKeyValueInputFormat<K, V> extends FileInputFormat<AvroKey<K>, AvroValue<V>> {
    private static final Logger LOG = LoggerFactory.getLogger(AvroKeyValueInputFormat.class);
  
    /** {@inheritDoc} */
    @Override
    public RecordReader<AvroKey<K>, AvroValue<V>> createRecordReader(InputSplit split, TaskAttemptContext context)
        throws IOException, InterruptedException {
      Schema keyReaderSchema = AvroJob.getInputKeySchema(context.getConfiguration());
      if (null == keyReaderSchema) {
        LOG.warn("Key reader schema was not set. Use AvroJob.setInputKeySchema() if desired.");
        LOG.info("Using a key reader schema equal to the writer schema.");
      }
      Schema valueReaderSchema = AvroJob.getInputValueSchema(context.getConfiguration());
      if (null == valueReaderSchema) {
        LOG.warn("Value reader schema was not set. Use AvroJob.setInputValueSchema() if desired.");
        LOG.info("Using a value reader schema equal to the writer schema.");
      }
      return new AvroKeyValueRecordReader<>(keyReaderSchema, valueReaderSchema);
    }
  }
  