com.uber.hoodie.common.table.log.block.HoodieCommandBlock Maven / Gradle / Ivy

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/*
 * Copyright (c) 2016 Uber Technologies, Inc. ([email protected])
 *
 * 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.common.table.log.block;

import com.uber.hoodie.common.model.HoodieLogFile;
import org.apache.hadoop.fs.FSDataInputStream;

import java.util.HashMap;
import java.util.Map;
import java.util.Optional;

/**
 * Command block issues a specific command to the scanner
 */
public class HoodieCommandBlock extends HoodieLogBlock {

  private final HoodieCommandBlockTypeEnum type;

  public enum HoodieCommandBlockTypeEnum {ROLLBACK_PREVIOUS_BLOCK}

  public HoodieCommandBlock(Map header) {
    this(Optional.empty(), null, false, Optional.empty(), header, new HashMap<>());
  }

  private HoodieCommandBlock(Optional content, FSDataInputStream inputStream,
      boolean readBlockLazily, Optional blockContentLocation,
      Map header, Map footer) {
    super(header, footer, blockContentLocation, content, inputStream, readBlockLazily);
    this.type = HoodieCommandBlockTypeEnum.values()[Integer
        .parseInt(header.get(HeaderMetadataType.COMMAND_BLOCK_TYPE))];
  }

  public HoodieCommandBlockTypeEnum getType() {
    return type;
  }

  @Override
  public HoodieLogBlockType getBlockType() {
    return HoodieLogBlockType.COMMAND_BLOCK;
  }

  @Override
  public byte[] getContentBytes() {
    return new byte[0];
  }

  public static HoodieLogBlock getBlock(HoodieLogFile logFile,
      FSDataInputStream inputStream,
      Optional content,
      boolean readBlockLazily,
      long position,
      long blockSize,
      long blockEndpos,
      Map header,
      Map footer) {

    return new HoodieCommandBlock(content, inputStream, readBlockLazily,
        Optional.of(new HoodieLogBlockContentLocation(logFile, position, blockSize, blockEndpos)),
        header, footer);
  }
}