import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext; //导入依赖的package包/类
FSReaderImpl(FSDataInputStreamWrapper stream, long fileSize, HFileSystem hfs, Path path,
    HFileContext fileContext) throws IOException {
  this.fileSize = fileSize;
  this.hfs = hfs;
  if (path != null) {
    this.pathName = path.toString();
  }
  this.fileContext = fileContext;
  this.hdrSize = headerSize(fileContext.isUseHBaseChecksum());

  this.streamWrapper = stream;
  // Older versions of HBase didn't support checksum.
  this.streamWrapper.prepareForBlockReader(!fileContext.isUseHBaseChecksum());
  defaultDecodingCtx = new HFileBlockDefaultDecodingContext(fileContext);
  encodedBlockDecodingCtx = defaultDecodingCtx;
}
 

import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext; //导入依赖的package包/类
@Override
public HFileBlockDecodingContext newDataBlockDecodingContext(HFileContext fileContext) {
  DataBlockEncoder encoder = encoding.getEncoder();
  if (encoder != null) {
    return encoder.newDataBlockDecodingContext(fileContext);
  }
  return new HFileBlockDefaultDecodingContext(fileContext);
}
 

import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext; //导入依赖的package包/类
public FSReaderImpl(FSDataInputStreamWrapper stream, long fileSize, HFileSystem hfs, Path path,
    HFileContext fileContext) throws IOException {
  super(fileSize, hfs, path, fileContext);
  this.streamWrapper = stream;
  // Older versions of HBase didn't support checksum.
  this.streamWrapper.prepareForBlockReader(!fileContext.isUseHBaseChecksum());
  defaultDecodingCtx = new HFileBlockDefaultDecodingContext(fileContext);
  encodedBlockDecodingCtx = defaultDecodingCtx;
}
 

import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext; //导入依赖的package包/类
public FSReaderV2(FSDataInputStreamWrapper stream, long fileSize, HFileSystem hfs, Path path,
    HFileContext fileContext) throws IOException {
  super(fileSize, hfs, path, fileContext);
  this.streamWrapper = stream;
  // Older versions of HBase didn't support checksum.
  this.streamWrapper.prepareForBlockReader(!fileContext.isUseHBaseChecksum());
  defaultDecodingCtx =
    new HFileBlockDefaultDecodingContext(fileContext);
  encodedBlockDecodingCtx =
      new HFileBlockDefaultDecodingContext(fileContext);
}
 

import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext; //导入依赖的package包/类
@Override
public HFileBlockDecodingContext newDataBlockDecodingContext(
    Algorithm compressionAlgorithm) {
  DataBlockEncoder encoder = encoding.getEncoder();
  if (encoder != null) {
    return encoder.newDataBlockDecodingContext(compressionAlgorithm);
  }
  return new HFileBlockDefaultDecodingContext(compressionAlgorithm);
}
 

import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext; //导入依赖的package包/类
public FSReaderV2(FSDataInputStreamWrapper stream, Algorithm compressAlgo, long fileSize,
    int minorVersion, HFileSystem hfs, Path path) throws IOException {
  super(compressAlgo, fileSize, minorVersion, hfs, path);
  this.streamWrapper = stream;
  // Older versions of HBase didn't support checksum.
  boolean forceNoHBaseChecksum = (this.getMinorVersion() < MINOR_VERSION_WITH_CHECKSUM);
  this.streamWrapper.prepareForBlockReader(forceNoHBaseChecksum);

  defaultDecodingCtx =
    new HFileBlockDefaultDecodingContext(compressAlgo);
  encodedBlockDecodingCtx =
      new HFileBlockDefaultDecodingContext(compressAlgo);
}
 

import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext; //导入依赖的package包/类
@Override
public HFileBlockDecodingContext newOnDiskDataBlockDecodingContext(
    Algorithm compressionAlgorithm) {
  if (onDisk != null) {
    DataBlockEncoder encoder = onDisk.getEncoder();
    if (encoder != null) {
      return encoder.newDataBlockDecodingContext(
          compressionAlgorithm);
    }
  }
  return new HFileBlockDefaultDecodingContext(compressionAlgorithm);
}
 

import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext; //导入依赖的package包/类
public FSReaderV2(FSDataInputStream istream, 
    FSDataInputStream istreamNoFsChecksum, Algorithm compressAlgo,
    long fileSize, int minorVersion, HFileSystem hfs, Path path) 
  throws IOException {
  super(istream, istreamNoFsChecksum, compressAlgo, fileSize, 
        minorVersion, hfs, path);

  if (hfs != null) {
    // Check the configuration to determine whether hbase-level
    // checksum verification is needed or not.
    useHBaseChecksum = hfs.useHBaseChecksum();
  } else {
    // The configuration does not specify anything about hbase checksum
    // validations. Set it to true here assuming that we will verify
    // hbase checksums for all reads. For older files that do not have 
    // stored checksums, this flag will be reset later.
    useHBaseChecksum = true;
  }

  // for older versions, hbase did not store checksums.
  if (getMinorVersion() < MINOR_VERSION_WITH_CHECKSUM) {
    useHBaseChecksum = false;
  }
  this.useHBaseChecksumConfigured = useHBaseChecksum;
  defaultDecodingCtx =
    new HFileBlockDefaultDecodingContext(compressAlgo);
  encodedBlockDecodingCtx =
      new HFileBlockDefaultDecodingContext(compressAlgo);
}
 

import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext; //导入依赖的package包/类
@Override
public HFileBlockDecodingContext newDataBlockDecodingContext(HFileContext meta) {
  return new HFileBlockDefaultDecodingContext(meta);
}
 

import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext; //导入依赖的package包/类
@Override
public HFileBlockDecodingContext newDataBlockDecodingContext(
    Algorithm compressionAlgorithm) {
  return new HFileBlockDefaultDecodingContext(compressionAlgorithm);
}
 

import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext; //导入依赖的package包/类
@Override
public HFileBlockDecodingContext newDataBlockDecodingContext(Algorithm compressionAlgorithm) {
  return new HFileBlockDefaultDecodingContext(compressionAlgorithm);
}
 

import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext; //导入依赖的package包/类
@Override
public HFileBlockDecodingContext newOnDiskDataBlockDecodingContext(
    Algorithm compressionAlgorithm) {
  return new HFileBlockDefaultDecodingContext(compressionAlgorithm);
}