de.lmu.ifi.dbs.elki.persistent

Interface PageHeader

All Known Implementing Classes:

DefaultPageHeader, MkTreeHeader, RdKNNTreeHeader, TreeIndexHeader

public interface PageHeader

Defines the requirements for a header of a persistent page file. A header must at least store the size of a page in Bytes.

Author:

Elke Achtert

Method Summary

Methods

Modifier and Type	Method and Description
byte[]	asByteArray() Return the header as byte array
int	getPageSize() Returns the size of a page in Bytes.
int	getReservedPages() Returns the number of pages necessary for the header
void	readHeader(byte[] data) Initializes this header from the specified file.
void	readHeader(RandomAccessFile file) Initializes this header from the specified file.
int	size() Returns the size of this header in Bytes.
void	writeHeader(RandomAccessFile file) Writes this header to the specified file.

Method Detail

size

int size()

Returns the size of this header in Bytes.

Returns:

the size of this header in Bytes

readHeader

void readHeader(RandomAccessFile file)
                throws IOException

Initializes this header from the specified file.

Parameters:

file - the file to which this header belongs

Throws:

IOException - if an I/O-error occurs during reading

readHeader

void readHeader(byte[] data)

Initializes this header from the specified file.

Parameters:

data - byte array with the page data.

writeHeader

void writeHeader(RandomAccessFile file)
                 throws IOException

Writes this header to the specified file.

Parameters:

file - the file to which this header belongs

Throws:

IOException - IOException if an I/O-error occurs during writing

asByteArray

byte[] asByteArray()

Return the header as byte array

Returns:

header as byte array

getPageSize

int getPageSize()

Returns the size of a page in Bytes.

Returns:

the size of a page in Bytes

getReservedPages

int getReservedPages()

Returns the number of pages necessary for the header

Returns:

the number of pages