hoodie-spark/src/main/java/com/uber/hoodie/OverwriteWithLatestAvroPayload.java

/*
 *  Copyright (c) 2017 Uber Technologies, Inc. (hoodie-dev-group@uber.com)
 *
 *  Licensed 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 com.uber.hoodie;

import com.uber.hoodie.common.model.HoodieRecordPayload;
import com.uber.hoodie.common.util.HoodieAvroUtils;
import java.io.IOException;
import java.util.Optional;
import org.apache.avro.Schema;
import org.apache.avro.generic.GenericRecord;
import org.apache.avro.generic.IndexedRecord;

/**
 * Default payload used for delta streamer.
 * <p>
 * 1. preCombine - Picks the latest delta record for a key, based on an ordering field 2.
 * combineAndGetUpdateValue/getInsertValue - Simply overwrites storage with latest delta record
 */
public class OverwriteWithLatestAvroPayload extends BaseAvroPayload implements
    HoodieRecordPayload<OverwriteWithLatestAvroPayload> {

  /**
   * @param record
   * @param orderingVal
   */
  public OverwriteWithLatestAvroPayload(GenericRecord record, Comparable orderingVal) {
    super(record, orderingVal);
  }

  public OverwriteWithLatestAvroPayload(Optional<GenericRecord> record) {
    this(record.get(), (record1) -> 0); // natural order
  }

  @Override
  public OverwriteWithLatestAvroPayload preCombine(OverwriteWithLatestAvroPayload another) {
    // pick the payload with greatest ordering value
    if (another.orderingVal.compareTo(orderingVal) > 0) {
      return another;
    } else {
      return this;
    }
  }

  @Override
  public Optional<IndexedRecord> combineAndGetUpdateValue(IndexedRecord currentValue, Schema schema)
      throws IOException {
    // combining strategy here trivially ignores currentValue on disk and writes this record
    return getInsertValue(schema);
  }

  @Override
  public Optional<IndexedRecord> getInsertValue(Schema schema) throws IOException {
    return Optional.of(HoodieAvroUtils.rewriteRecord(HoodieAvroUtils.bytesToAvro(recordBytes, Schema.parse(schemaStr)),
        schema));
  }
}