org.apache.hadoop.hbase.io.hfile

Interface HFileDataBlockEncoder

All Known Implementing Classes:

HFileDataBlockEncoderImpl, NoOpDataBlockEncoder

@InterfaceAudience.Private
public interface HFileDataBlockEncoder

Controls what kind of data block encoding is used. If data block encoding is not set or the given block is not a data block (encoded or not), methods should just return the unmodified block.

Field Summary

Fields

Modifier and Type	Field and Description
static byte[]	DATA_BLOCK_ENCODING Type of encoding used for data blocks in HFile.

Method Summary

Modifier and Type	Method and Description
int	encode(org.apache.hadoop.hbase.Cell cell, org.apache.hadoop.hbase.io.encoding.HFileBlockEncodingContext encodingCtx, DataOutputStream out) Encodes a KeyValue.
void	endBlockEncoding(org.apache.hadoop.hbase.io.encoding.HFileBlockEncodingContext encodingCtx, DataOutputStream out, byte[] uncompressedBytesWithHeader, org.apache.hadoop.hbase.io.hfile.BlockType blockType) Ends encoding for a block of KeyValues.
org.apache.hadoop.hbase.io.encoding.DataBlockEncoding	getDataBlockEncoding()
org.apache.hadoop.hbase.io.encoding.DataBlockEncoding	getEffectiveEncodingInCache(boolean isCompaction)
org.apache.hadoop.hbase.io.encoding.HFileBlockDecodingContext	newDataBlockDecodingContext(org.apache.hadoop.hbase.io.hfile.HFileContext fileContext) create a encoder specific decoding context for reading.
org.apache.hadoop.hbase.io.encoding.HFileBlockEncodingContext	newDataBlockEncodingContext(byte[] headerBytes, org.apache.hadoop.hbase.io.hfile.HFileContext fileContext) Create an encoder specific encoding context object for writing.
void	saveMetadata(HFile.Writer writer) Save metadata in HFile which will be written to disk
void	startBlockEncoding(org.apache.hadoop.hbase.io.encoding.HFileBlockEncodingContext encodingCtx, DataOutputStream out) Starts encoding for a block of KeyValues.
boolean	useEncodedScanner() Decides whether we should use a scanner over encoded blocks.

Field Detail

DATA_BLOCK_ENCODING

static final byte[] DATA_BLOCK_ENCODING

Type of encoding used for data blocks in HFile. Stored in file info.

Method Detail

startBlockEncoding

void startBlockEncoding(org.apache.hadoop.hbase.io.encoding.HFileBlockEncodingContext encodingCtx,
                        DataOutputStream out)
                 throws IOException

Starts encoding for a block of KeyValues. Call endBlockEncoding(HFileBlockEncodingContext, DataOutputStream, byte[], BlockType) to finish encoding of a block.

Parameters:

encodingCtx -

out -

Throws:

IOException

encode

int encode(org.apache.hadoop.hbase.Cell cell,
           org.apache.hadoop.hbase.io.encoding.HFileBlockEncodingContext encodingCtx,
           DataOutputStream out)
    throws IOException

Encodes a KeyValue.

Parameters:

cell -

encodingCtx -

out -

Returns:

unencoded kv size

Throws:

IOException

endBlockEncoding

void endBlockEncoding(org.apache.hadoop.hbase.io.encoding.HFileBlockEncodingContext encodingCtx,
                      DataOutputStream out,
                      byte[] uncompressedBytesWithHeader,
                      org.apache.hadoop.hbase.io.hfile.BlockType blockType)
               throws IOException

Ends encoding for a block of KeyValues. Gives a chance for the encoder to do the finishing stuff for the encoded block. It must be called at the end of block encoding.

Parameters:

encodingCtx -

out -

uncompressedBytesWithHeader -

blockType -

Throws:

IOException

useEncodedScanner

boolean useEncodedScanner()

Decides whether we should use a scanner over encoded blocks.

Returns:

Whether to use encoded scanner.

saveMetadata

void saveMetadata(HFile.Writer writer)
           throws IOException

Save metadata in HFile which will be written to disk

Parameters:

writer - writer for a given HFile

Throws:

IOException - on disk problems

getDataBlockEncoding

org.apache.hadoop.hbase.io.encoding.DataBlockEncoding getDataBlockEncoding()

Returns:

the data block encoding

getEffectiveEncodingInCache

org.apache.hadoop.hbase.io.encoding.DataBlockEncoding getEffectiveEncodingInCache(boolean isCompaction)

Returns:

the effective in-cache data block encoding, taking into account whether we are doing a compaction.

newDataBlockEncodingContext

org.apache.hadoop.hbase.io.encoding.HFileBlockEncodingContext newDataBlockEncodingContext(byte[] headerBytes,
                                                                                          org.apache.hadoop.hbase.io.hfile.HFileContext fileContext)

Create an encoder specific encoding context object for writing. And the encoding context should also perform compression if compressionAlgorithm is valid.

Parameters:

headerBytes - header bytes

fileContext - HFile meta data

Returns:

a new HFileBlockEncodingContext object

newDataBlockDecodingContext

org.apache.hadoop.hbase.io.encoding.HFileBlockDecodingContext newDataBlockDecodingContext(org.apache.hadoop.hbase.io.hfile.HFileContext fileContext)

create a encoder specific decoding context for reading. And the decoding context should also do decompression if compressionAlgorithm is valid.

Parameters:

fileContext - - HFile meta data

Returns:

a new HFileBlockDecodingContext object