org.apache.cassandra.io.compress

Class CompressionMetadata

java.lang.Object

org.apache.cassandra.io.compress.CompressionMetadata

public class CompressionMetadata
extends java.lang.Object

Holds metadata about compressed file

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CompressionMetadata.Chunk Holds offset and length of the file chunk
static class	CompressionMetadata.Writer

Field Summary

Fields

Modifier and Type	Field and Description
long	compressedFileLength
long	dataLength
java.lang.String	indexFilePath
CompressionParams	parameters

Constructor Summary

Constructors

Constructor and Description
CompressionMetadata(Descriptor desc, long compressedLength)
CompressionMetadata(java.lang.String filePath, CompressionParams parameters, Memory offsets, long offsetsSize, long dataLength, long compressedLength)
CompressionMetadata(java.lang.String indexFilePath, long compressedLength, boolean hasMaxCompressedSize)

Method Summary

Modifier and Type	Method and Description
void	addTo(Ref.IdentityCollection identities)
CompressionMetadata.Chunk	chunkFor(long position) Get a chunk of compressed data (offset, length) corresponding to given position
int	chunkLength()
void	close()
ICompressor	compressor()
static CompressionMetadata	create(java.lang.String dataFilePath) Create metadata about given compressed file including uncompressed data length, chunk size and list of the chunk offsets of the compressed data.
static CompressionMetadata	createWithLength(java.lang.String dataFilePath, long compressedLength)
CompressionMetadata.Chunk[]	getChunksForSections(java.util.Collection<SSTableReader.PartitionPositionBounds> sections)
long	getTotalSizeForSections(java.util.Collection<SSTableReader.PartitionPositionBounds> sections)
int	maxCompressedLength()
long	offHeapSize() Returns the amount of memory in bytes used off heap.

Methods inherited from class java.lang.Object

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

Field Detail

dataLength

public final long dataLength

compressedFileLength

public final long compressedFileLength

indexFilePath

public final java.lang.String indexFilePath

parameters

public final CompressionParams parameters

Constructor Detail

CompressionMetadata

public CompressionMetadata(Descriptor desc,
                           long compressedLength)

CompressionMetadata

public CompressionMetadata(java.lang.String indexFilePath,
                           long compressedLength,
                           boolean hasMaxCompressedSize)

CompressionMetadata

public CompressionMetadata(java.lang.String filePath,
                           CompressionParams parameters,
                           Memory offsets,
                           long offsetsSize,
                           long dataLength,
                           long compressedLength)

Method Detail

create

public static CompressionMetadata create(java.lang.String dataFilePath)

Create metadata about given compressed file including uncompressed data length, chunk size and list of the chunk offsets of the compressed data. This is an expensive operation! Don't create more than one for each sstable.

Parameters:

dataFilePath - Path to the compressed file

Returns:

metadata about given compressed file.

createWithLength

public static CompressionMetadata createWithLength(java.lang.String dataFilePath,
                                                   long compressedLength)

compressor

public ICompressor compressor()

chunkLength

public int chunkLength()

maxCompressedLength

public int maxCompressedLength()

offHeapSize

public long offHeapSize()

Returns the amount of memory in bytes used off heap.

Returns:

the amount of memory in bytes used off heap

addTo

public void addTo(Ref.IdentityCollection identities)

chunkFor

public CompressionMetadata.Chunk chunkFor(long position)

Get a chunk of compressed data (offset, length) corresponding to given position

Parameters:

position - Position in the file.

Returns:

pair of chunk offset and length.

getTotalSizeForSections

public long getTotalSizeForSections(java.util.Collection<SSTableReader.PartitionPositionBounds> sections)

Parameters:

sections - Collection of sections in uncompressed file. Should not contain sections that overlap each other.

Returns:

Total chunk size in bytes for given sections including checksum.

getChunksForSections

public CompressionMetadata.Chunk[] getChunksForSections(java.util.Collection<SSTableReader.PartitionPositionBounds> sections)

Parameters:

sections - Collection of sections in uncompressed file

Returns:

Array of chunks which corresponds to given sections of uncompressed file, sorted by chunk offset

close

public void close()