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.generic.GenericRecord;
  import org.apache.avro.hadoop.io.AvroKeyValue;
  import org.apache.avro.mapred.AvroKey;
  import org.apache.avro.mapred.AvroValue;
  
  /**
   * Reads Avro generic records from an Avro container file, where the records
   * contain two fields: 'key' and 'value'.
   *
   * <p>
   * The contents of the 'key' field will be parsed into an AvroKey object. The
   * contents of the 'value' field will be parsed into an AvroValue object.
   * </p>
   *
   * @param <K> The type of the Avro key to read.
   * @param <V> The type of the Avro value to read.
   */
  public class AvroKeyValueRecordReader<K, V> extends AvroRecordReaderBase<AvroKey<K>, AvroValue<V>, GenericRecord> {
    /** The current key the reader is on. */
    private final AvroKey<K> mCurrentKey;
  
    /** The current value the reader is on. */
    private final AvroValue<V> mCurrentValue;
  
    /**
     * Constructor.
     *
     * @param keyReaderSchema   The reader schema for the key within the generic
     *                          record.
     * @param valueReaderSchema The reader schema for the value within the generic
     *                          record.
     */
    public AvroKeyValueRecordReader(Schema keyReaderSchema, Schema valueReaderSchema) {
      super(AvroKeyValue.getSchema(keyReaderSchema, valueReaderSchema));
      mCurrentKey = new AvroKey<>(null);
      mCurrentValue = new AvroValue<>(null);
    }
  
    /** {@inheritDoc} */
    @Override
    public boolean nextKeyValue() throws IOException, InterruptedException {
      boolean hasNext = super.nextKeyValue();
      if (hasNext) {
        AvroKeyValue<K, V> avroKeyValue = new AvroKeyValue<>(getCurrentRecord());
        mCurrentKey.datum(avroKeyValue.getKey());
        mCurrentValue.datum(avroKeyValue.getValue());
      } else {
        mCurrentKey.datum(null);
        mCurrentValue.datum(null);
      }
      return hasNext;
    }
  
    /** {@inheritDoc} */
    @Override
    public AvroKey<K> getCurrentKey() throws IOException, InterruptedException {
      return mCurrentKey;
    }
  
    /** {@inheritDoc} */
    @Override
    public AvroValue<V> getCurrentValue() throws IOException, InterruptedException {
      return mCurrentValue;
    }
  }
  