ProtobufLogReader (Apache HBase 1.4.11 API)

java.lang.Object
- org.apache.hadoop.hbase.regionserver.wal.ReaderBase
- - org.apache.hadoop.hbase.regionserver.wal.ProtobufLogReader

All Implemented Interfaces:

Closeable, AutoCloseable, DefaultWALProvider.Reader, WAL.Reader

Direct Known Subclasses:

SecureProtobufLogReader
```
@InterfaceAudience.LimitedPrivate(value={"Coprocesssor","Phoenix","Configuration"})
public class ProtobufLogReader
extends ReaderBase
```
A Protobuf based WAL has the following structure:
<PB_WAL_MAGIC><WALHeader><WALEdits>...<WALEdits><Trailer> <TrailerSize> <PB_WAL_COMPLETE_MAGIC>
The Reader reads meta information (WAL Compression state, WALTrailer, etc) in ProtobufLogReader#initReader(FSDataInputStream). A WALTrailer is an extensible structure which is appended at the end of the WAL. This is empty for now; it can contain some meta information such as Region level stats, etc in future.

Field Summary

Fields
Modifier and Type	Field and Description
`protected WALCellCodec.ByteStringUncompressor`	`byteStringUncompressor`
`protected Codec.Decoder`	`cellDecoder`
`protected boolean`	`hasCompression`
`protected boolean`	`hasTagCompression`
`protected org.apache.hadoop.fs.FSDataInputStream`	`inputStream`
`static byte[]`	`PB_WAL_COMPLETE_MAGIC`
`static byte[]`	`PB_WAL_MAGIC`
`protected org.apache.hadoop.hbase.protobuf.generated.WALProtos.WALTrailer`	`trailer`
`protected int`	`trailerWarnSize`

Fields inherited from class org.apache.hadoop.hbase.regionserver.wal.ReaderBase
compressionContext, conf, edit, emptyCompressionContext, fileLength, fs, path

Constructor Summary

Constructors
Constructor and Description

ProtobufLogReader()

Constructors
Constructor and Description
`ProtobufLogReader()`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`close()`
`protected WALCellCodec`	`getCodec(org.apache.hadoop.conf.Configuration conf, String cellCodecClsName, CompressionContext compressionContext)`
`String`	`getCodecClsName()`
`long`	`getPosition()`
`List<String>`	`getWriterClsNames()`
`protected boolean`	`hasCompression()`
`protected boolean`	`hasTagCompression()`
`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)`
`protected void`	`initAfterCompression()` Initializes the compression after the shared stuff has been initialized.
`protected void`	`initAfterCompression(String cellCodecClsName)` Initializes the compression after the shared stuff has been initialized.
`protected String`	`initReader(org.apache.hadoop.fs.FSDataInputStream stream)` Initializes the log reader with a particular stream (may be null).
`protected org.apache.hadoop.hbase.regionserver.wal.ProtobufLogReader.WALHdrContext`	`readHeader(org.apache.hadoop.hbase.protobuf.generated.WALProtos.WALHeader.Builder builder, org.apache.hadoop.fs.FSDataInputStream stream)`
`protected boolean`	`readNext(WAL.Entry entry)` Read next entry.
`void`	`reset()`
`protected void`	`seekOnFs(long pos)` Performs a filesystem-level seek to a certain position in an underlying file.
`long`	`trailerSize()`

Methods inherited from class org.apache.hadoop.hbase.regionserver.wal.ReaderBase
next, next, seek

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PB_WAL_MAGIC

@InterfaceAudience.Private
public static final byte[] PB_WAL_MAGIC

PB_WAL_COMPLETE_MAGIC

@InterfaceAudience.Private
public static final byte[] PB_WAL_COMPLETE_MAGIC

inputStream

protected org.apache.hadoop.fs.FSDataInputStream inputStream

cellDecoder
```
protected Codec.Decoder cellDecoder
```

byteStringUncompressor

protected WALCellCodec.ByteStringUncompressor byteStringUncompressor

hasCompression
```
protected boolean hasCompression
```

hasTagCompression
```
protected boolean hasTagCompression
```

trailer

protected org.apache.hadoop.hbase.protobuf.generated.WALProtos.WALTrailer trailer

trailerWarnSize
```
protected int trailerWarnSize
```

Constructor Detail
- ProtobufLogReader
```
public ProtobufLogReader()
```

Method Detail
- trailerSize
```
@InterfaceAudience.Private
public long trailerSize()
```
- close
```
public void close()
           throws IOException
```
  Throws:
  
  IOException
- getPosition
```
public long getPosition()
                 throws IOException
```
  Throws:
  
  IOException
- reset
```
public void reset()
           throws IOException
```
  Throws:
  
  IOException
- 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
  
  Overrides:
  
  init in class ReaderBase
  
  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
- initReader
```
protected String initReader(org.apache.hadoop.fs.FSDataInputStream stream)
                     throws IOException
```
  Description copied from class: ReaderBase
  
  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.
  
  Specified by:
  
  initReader in class ReaderBase
  
  Returns:
  the class name of cell Codec, null if such information is not available
  
  Throws:
  
  IOException
- getWriterClsNames
```
public List<String> getWriterClsNames()
```
- getCodecClsName
```
public String getCodecClsName()
```
- readHeader
```
protected org.apache.hadoop.hbase.regionserver.wal.ProtobufLogReader.WALHdrContext readHeader(org.apache.hadoop.hbase.protobuf.generated.WALProtos.WALHeader.Builder builder,
                                                                                  org.apache.hadoop.fs.FSDataInputStream stream)
                                                                                       throws IOException
```
  Throws:
  
  IOException
- getCodec
```
protected WALCellCodec getCodec(org.apache.hadoop.conf.Configuration conf,
                    String cellCodecClsName,
                    CompressionContext compressionContext)
                         throws IOException
```
  Throws:
  
  IOException
- initAfterCompression
```
protected void initAfterCompression()
                             throws IOException
```
  Description copied from class: ReaderBase
  
  Initializes the compression after the shared stuff has been initialized. Called once.
  
  Specified by:
  
  initAfterCompression in class ReaderBase
  
  Throws:
  
  IOException
- initAfterCompression
```
protected void initAfterCompression(String cellCodecClsName)
                             throws IOException
```
  Description copied from class: ReaderBase
  
  Initializes the compression after the shared stuff has been initialized. Called once.
  
  Specified by:
  
  initAfterCompression in class ReaderBase
  
  Parameters:
  cellCodecClsName - class name of cell Codec
  
  Throws:
  
  IOException
- hasCompression
```
protected boolean hasCompression()
```
  Specified by:
  
  hasCompression in class ReaderBase
  
  Returns:
  Whether compression is enabled for this log.
- hasTagCompression
```
protected boolean hasTagCompression()
```
  Specified by:
  
  hasTagCompression in class ReaderBase
  
  Returns:
  Whether tag compression is enabled for this log.
- readNext
```
protected boolean readNext(WAL.Entry entry)
                    throws IOException
```
  Description copied from class: ReaderBase
  
  Read next entry.
  
  Specified by:
  
  readNext in class ReaderBase
  
  Parameters:
  entry - The entry to read into.
  
  Returns:
  Whether there was anything to read.
  
  Throws:
  
  IOException
- seekOnFs
```
protected void seekOnFs(long pos)
                 throws IOException
```
  Description copied from class: ReaderBase
  
  Performs a filesystem-level seek to a certain position in an underlying file.
  
  Specified by:
  
  seekOnFs in class ReaderBase
  
  Throws:
  
  IOException

Class ProtobufLogReader

Field Summary

Fields inherited from class org.apache.hadoop.hbase.regionserver.wal.ReaderBase

Constructor Summary

Method Summary

Methods inherited from class org.apache.hadoop.hbase.regionserver.wal.ReaderBase

Methods inherited from class java.lang.Object

Field Detail

PB_WAL_MAGIC

PB_WAL_COMPLETE_MAGIC

inputStream

cellDecoder

byteStringUncompressor

hasCompression

hasTagCompression

trailer

trailerWarnSize

Constructor Detail

ProtobufLogReader

Method Detail

trailerSize

close

getPosition

reset

init

initReader

getWriterClsNames

getCodecClsName

readHeader

getCodec

initAfterCompression

initAfterCompression

hasCompression

hasTagCompression

readNext

seekOnFs