LobFile.java 文件源码

@Override
/** {@inheritDoc} */
public InputStream readBlobRecord() throws IOException {
  if (!isRecordAvailable()) {
    // we're not currently aligned on a record-start.
    // Try to get the next one.
    if (!next()) {
      // No more records available.
      throw new EOFException("End of file reached.");
    }
  }

  // Ensure any previously-open user record stream is closed.
  closeUserStream();

  // Mark this record as consumed.
  this.isAligned = false;

  // The length of the stream we can return to the user is
  // the indexRecordLen minus the length of any per-record headers.
  // That includes the RecordStartMark, the entryId, and the claimedLen.
  long streamLen = this.indexRecordLen - RecordStartMark.START_MARK_LENGTH
      - WritableUtils.getVIntSize(this.curEntryId)
      - WritableUtils.getVIntSize(this.claimedRecordLen);
  LOG.debug("Yielding stream to user with length " + streamLen);
  this.userInputStream = new FixedLengthInputStream(this.dataIn, streamLen);
  if (this.codec != null) {
    // The user needs to decompress the data; wrap the InputStream.
    decompressor.reset();
    this.userInputStream = new DecompressorStream(
        this.userInputStream, decompressor);
  }
  return this.userInputStream;
}