hadoop BlockResolver 源码

  • 2022-10-20
  • 浏览 (20)

haddop BlockResolver 代码

文件路径:/hadoop-tools/hadoop-fs2img/src/main/java/org/apache/hadoop/hdfs/server/namenode/BlockResolver.java

/**
 * 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.hadoop.hdfs.server.namenode;

import java.util.ArrayList;
import java.util.List;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.BlockProto;

/**
 * Given an external reference, create a sequence of blocks and associated
 * metadata.
 */
@InterfaceAudience.Public
@InterfaceStability.Unstable
public abstract class BlockResolver {

  protected BlockProto buildBlock(long blockId, long bytes) {
    return buildBlock(blockId, bytes, 1001);
  }

  protected BlockProto buildBlock(long blockId, long bytes, long genstamp) {
    BlockProto.Builder b = BlockProto.newBuilder()
        .setBlockId(blockId)
        .setNumBytes(bytes)
        .setGenStamp(genstamp);
    return b.build();
  }

  /**
   * @param s the external reference.
   * @return sequence of blocks that make up the reference.
   */
  public Iterable<BlockProto> resolve(FileStatus s) {
    List<Long> lengths = blockLengths(s);
    ArrayList<BlockProto> ret = new ArrayList<>(lengths.size());
    long tot = 0;
    for (long l : lengths) {
      tot += l;
      ret.add(buildBlock(nextId(), l));
    }
    if (tot != s.getLen()) {
      // log a warning?
      throw new IllegalStateException(
          "Expected " + s.getLen() + " found " + tot);
    }
    return ret;
  }

  /**
   * @return the next block id.
   */
  public abstract long nextId();

  /**
   * @return the maximum sequentially allocated block ID for this filesystem.
   */
  protected abstract long lastId();

  /**
   * @param status the external reference.
   * @return the lengths of the resultant blocks.
   */
  protected abstract List<Long> blockLengths(FileStatus status);


  /**
   * @param status the external reference.
   * @return the block size to assign to this external reference.
   */
  public long preferredBlockSize(FileStatus status) {
    return status.getBlockSize();
  }

  /**
   * @param status the external reference.
   * @return the replication to assign to this external reference.
   */
  public abstract int getReplication(FileStatus status);

}

相关信息

hadoop 源码目录

相关文章

hadoop FSTreeWalk 源码

hadoop FileSystemImage 源码

hadoop FixedBlockMultiReplicaResolver 源码

hadoop FixedBlockResolver 源码

hadoop FsUGIResolver 源码

hadoop ImageWriter 源码

hadoop NullBlockAliasMap 源码

hadoop SingleUGIResolver 源码

hadoop TreePath 源码

hadoop TreeWalk 源码

0  赞