org.apache.hadoop.hbase.regionserver.wal

Class ReaderBase

java.lang.Object

org.apache.hadoop.hbase.regionserver.wal.ReaderBase

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, DefaultWALProvider.Reader, WAL.Reader

Direct Known Subclasses:

ProtobufLogReader, SequenceFileLogReader

@InterfaceAudience.LimitedPrivate(value={"Coprocesssor","Phoenix"})
public abstract class ReaderBase
extends java.lang.Object
implements DefaultWALProvider.Reader

Field Summary

Fields

Modifier and Type	Field and Description
protected CompressionContext	compressionContext Compression context to use reading.
protected Configuration	conf
protected long	edit
protected boolean	emptyCompressionContext
protected long	fileLength
protected FileSystem	fs
protected Path	path

Constructor Summary

Constructors

Constructor and Description
ReaderBase() Default constructor.

Method Summary

Modifier and Type	Method and Description
protected abstract boolean	hasCompression()
protected abstract boolean	hasTagCompression()
void	init(FileSystem fs, Path path, Configuration conf, FSDataInputStream stream)
protected abstract void	initAfterCompression() Initializes the compression after the shared stuff has been initialized.
protected abstract void	initAfterCompression(java.lang.String cellCodecClsName) Initializes the compression after the shared stuff has been initialized.
protected abstract java.lang.String	initReader(FSDataInputStream stream) Initializes the log reader with a particular stream (may be null).
WAL.Entry	next()
WAL.Entry	next(WAL.Entry reuse)
protected abstract boolean	readNext(WAL.Entry e) Read next entry.
void	seek(long pos)
protected abstract void	seekOnFs(long pos) Performs a filesystem-level seek to a certain position in an underlying file.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.hadoop.hbase.wal.WAL.Reader

getPosition, reset

Methods inherited from interface java.io.Closeable

close

Field Detail

conf

protected Configuration conf

fs

protected FileSystem fs

path

protected 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(FileSystem fs,
                 Path path,
                 Configuration conf,
                 FSDataInputStream stream)
          throws java.io.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:

java.io.IOException

next

public WAL.Entry next()
               throws java.io.IOException

Specified by:

next in interface WAL.Reader

Throws:

java.io.IOException

next

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

Specified by:

next in interface WAL.Reader

Throws:

java.io.IOException

seek

public void seek(long pos)
          throws java.io.IOException

Specified by:

seek in interface WAL.Reader

Throws:

java.io.IOException

initReader

protected abstract java.lang.String initReader(FSDataInputStream stream)
                                        throws java.io.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:

java.io.IOException

initAfterCompression

protected abstract void initAfterCompression()
                                      throws java.io.IOException

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

Throws:

java.io.IOException

initAfterCompression

protected abstract void initAfterCompression(java.lang.String cellCodecClsName)
                                      throws java.io.IOException

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

Parameters:

cellCodecClsName - class name of cell Codec

Throws:

java.io.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 java.io.IOException

Read next entry.

Parameters:

e - The entry to read into.

Returns:

Whether there was anything to read.

Throws:

java.io.IOException

seekOnFs

protected abstract void seekOnFs(long pos)
                          throws java.io.IOException

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

Throws:

java.io.IOException