Field Detail

• LOG

  private static final org.apache.commons.logging.Log LOG

• conf

  protected org.apache.hadoop.conf.Configuration conf

• fs

  protected org.apache.hadoop.fs.FileSystem fs

• path

  protected org.apache.hadoop.fs.Path path

• edit

  protected long edit

• fileLength

  protected long fileLength

• compressionContext

  protected CompressionContext compressionContext

  Compression context to use reading. Can be null if no compression.

• emptyCompressionContext

  protected boolean emptyCompressionContext

Constructor Detail

• ReaderBase

  public ReaderBase()

  Default constructor.

Method Detail

• init

  public void init(org.apache.hadoop.fs.FileSystem fs,
          org.apache.hadoop.fs.Path path,
          org.apache.hadoop.conf.Configuration conf,
          org.apache.hadoop.fs.FSDataInputStream stream)
            throws IOException

  Specified by:

  init in interface DefaultWALProvider.Reader

  Parameters:

  fs - File system.

  path - Path.

  conf - Configuration.

  stream - Input stream that may have been pre-opened by the caller; may be null.

  Throws:

  IOException

• next

  public WAL.Entry next()
                 throws IOException

  Specified by:

  next in interface WAL.Reader

  Throws:

  IOException

• next

  public WAL.Entry next(WAL.Entry reuse)
                 throws IOException

  Specified by:

  next in interface WAL.Reader

  Throws:

  IOException

• seek

  public void seek(long pos)
            throws IOException

  Specified by:

  seek in interface WAL.Reader

  Throws:

  IOException

• initReader

  protected abstract String initReader(org.apache.hadoop.fs.FSDataInputStream stream)
                                throws IOException

  Initializes the log reader with a particular stream (may be null). Reader assumes ownership of the stream if not null and may use it. Called once.

  Returns:

  the class name of cell Codec, null if such information is not available

  Throws:

  IOException

• initAfterCompression

  protected abstract void initAfterCompression()
                                        throws IOException

  Initializes the compression after the shared stuff has been initialized. Called once.

  Throws:

  IOException

• initAfterCompression

  protected abstract void initAfterCompression(String cellCodecClsName)
                                        throws IOException

  Initializes the compression after the shared stuff has been initialized. Called once.

  Parameters:

  cellCodecClsName - class name of cell Codec

  Throws:

  IOException

• hasCompression

  protected abstract boolean hasCompression()

  Returns:

  Whether compression is enabled for this log.

• hasTagCompression

  protected abstract boolean hasTagCompression()

  Returns:

  Whether tag compression is enabled for this log.

• readNext

  protected abstract boolean readNext(WAL.Entry e)
                               throws IOException

  Read next entry.

  Parameters:

  e - The entry to read into.

  Returns:

  Whether there was anything to read.

  Throws:

  IOException

• seekOnFs

  protected abstract void seekOnFs(long pos)
                            throws IOException

  Performs a filesystem-level seek to a certain position in an underlying file.

  Throws:

  IOException