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
   *
   * 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.apache.calcite.adapter.kafka;
  
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.rel.type.RelDataTypeFactory;
  import org.apache.calcite.rel.type.RelDataTypeSystem;
  import org.apache.calcite.sql.type.SqlTypeFactoryImpl;
  import org.apache.calcite.sql.type.SqlTypeName;
  
  import org.apache.kafka.clients.consumer.ConsumerRecord;
  
  /**
   * Default implementation of {@link KafkaRowConverter}, both key and value are byte[].
   */
  public class KafkaRowConverterImpl implements KafkaRowConverter<byte[], byte[]> {
    /**
     * Generates the row schema for a given Kafka topic.
     *
     * @param topicName Kafka topic name
     * @return row type
     */
    @Override public RelDataType rowDataType(final String topicName) {
      final RelDataTypeFactory typeFactory =
          new SqlTypeFactoryImpl(RelDataTypeSystem.DEFAULT);
      final RelDataTypeFactory.Builder fieldInfo = typeFactory.builder();
      fieldInfo.add("MSG_PARTITION", typeFactory.createSqlType(SqlTypeName.INTEGER)).nullable(false);
      fieldInfo.add("MSG_TIMESTAMP", typeFactory.createSqlType(SqlTypeName.BIGINT)).nullable(false);
      fieldInfo.add("MSG_OFFSET", typeFactory.createSqlType(SqlTypeName.BIGINT)).nullable(false);
      fieldInfo.add("MSG_KEY_BYTES", typeFactory.createSqlType(SqlTypeName.VARBINARY)).nullable(true);
      fieldInfo.add("MSG_VALUE_BYTES", typeFactory.createSqlType(SqlTypeName.VARBINARY))
          .nullable(false);
  
      return fieldInfo.build();
    }
  
    /**
     * Parses and reformats a Kafka message from the consumer, to align with the
     * row schema defined as {@link #rowDataType(String)}.
     *
     * @param message Raw Kafka message record
     * @return fields in the row
     */
    @Override public Object[] toRow(final ConsumerRecord<byte[], byte[]> message) {
      Object[] fields = new Object[5];
      fields[0] = message.partition();
      fields[1] = message.timestamp();
      fields[2] = message.offset();
      fields[3] = message.key();
      fields[4] = message.value();
  
      return fields;
    }
  }
  