org.basex.io
Class TableDiskAccess

java.lang.Object
  org.basex.io.TableAccess
      org.basex.io.TableDiskAccess

public final class TableDiskAccess
extends TableAccess

This class stores the table on disk and reads it block-wise.

Author:

Workgroup DBIS, University of Konstanz 2005-10, ISC License, Christian Gruen, Tim Petrowsky

Field Summary

RandomAccessFile

data File storing all blocks.

Constructor Summary

TableDiskAccess(MetaData md, String pf)
Constructor.

Method Summary

int	blocks() Returns the number of used blocks; needed for JUnit tests.
void	close() Closes the table access.
void	delete(int first, int nr) Deletes the specified number of entries from the database.
void	flush() Flushes the table contents.
void	insert(int pre, byte[] entries) Inserts the specified entries into the database.
int	read1(int pre, int off) Reads a byte value and returns it as an integer value.
int	read2(int pre, int off) Reads a short value and returns it as an integer value.
int	read4(int pre, int off) Reads an integer value.
long	read5(int pre, int off) Reads a 5-byte value and returns it as a long value.
void	set(int pre, byte[] entries) Copies the specified entry into the database.
int	size() Returns the number of entries; needed for JUnit tests.
void	write1(int pre, int off, int v) Writes a byte value to the specified position.
void	write2(int pre, int off, int v) Writes a short value to the specified position.
void	write4(int pre, int off, int v) Writes an integer value to the specified position.
void	write5(int pre, int off, long v) Writes a 5-byte value to the specified position.

Methods inherited from class java.lang.Object

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

Field Detail

data

public final RandomAccessFile data

File storing all blocks.

Constructor Detail

TableDiskAccess

public TableDiskAccess(MetaData md,
                       String pf)
                throws IOException

Constructor.

Parameters:

md - meta data

pf - file prefix

Throws:

IOException - I/O exception

Method Detail

flush

public void flush()
           throws IOException

Description copied from class: TableAccess

Flushes the table contents.

Specified by:

flush in class TableAccess

Throws:

IOException - I/O exception

close

public void close()
           throws IOException

Description copied from class: TableAccess

Closes the table access.

Specified by:

close in class TableAccess

Throws:

IOException - I/O exception

read1

public int read1(int pre,
                 int off)

Description copied from class: TableAccess

Reads a byte value and returns it as an integer value.

Specified by:

read1 in class TableAccess

Parameters:

pre - pre value

off - offset

Returns:

integer value

read2

public int read2(int pre,
                 int off)

Description copied from class: TableAccess

Reads a short value and returns it as an integer value.

Specified by:

read2 in class TableAccess

Parameters:

pre - pre value

off - offset

Returns:

integer value

read4

public int read4(int pre,
                 int off)

Description copied from class: TableAccess

Reads an integer value.

Specified by:

read4 in class TableAccess

Parameters:

pre - pre value

off - offset

Returns:

integer value

read5

public long read5(int pre,
                  int off)

Description copied from class: TableAccess

Reads a 5-byte value and returns it as a long value.

Specified by:

read5 in class TableAccess

Parameters:

pre - pre value

off - offset

Returns:

integer value

write1

public void write1(int pre,
                   int off,
                   int v)

Description copied from class: TableAccess

Writes a byte value to the specified position.

Specified by:

write1 in class TableAccess

Parameters:

pre - pre value

off - offset

v - value to be written

write2

public void write2(int pre,
                   int off,
                   int v)

Description copied from class: TableAccess

Writes a short value to the specified position.

Specified by:

write2 in class TableAccess

Parameters:

pre - pre value

off - offset

v - value to be written

write4

public void write4(int pre,
                   int off,
                   int v)

Description copied from class: TableAccess

Writes an integer value to the specified position.

Specified by:

write4 in class TableAccess

Parameters:

pre - pre value

off - offset

v - value to be written

write5

public void write5(int pre,
                   int off,
                   long v)

Description copied from class: TableAccess

Writes a 5-byte value to the specified position.

Specified by:

write5 in class TableAccess

Parameters:

pre - pre value

off - offset

v - value to be written

delete

public void delete(int first,
                   int nr)

Description copied from class: TableAccess

Deletes the specified number of entries from the database.

Specified by:

delete in class TableAccess

Parameters:

first - pre value of the first node to delete

nr - number of entries to be deleted

insert

public void insert(int pre,
                   byte[] entries)

Description copied from class: TableAccess

Inserts the specified entries into the database.

Specified by:

insert in class TableAccess

Parameters:

pre - pre value

entries - array of bytes containing the entries to insert

set

public void set(int pre,
                byte[] entries)

Description copied from class: TableAccess

Copies the specified entry into the database.

Specified by:

set in class TableAccess

Parameters:

pre - pre value

entries - array of bytes containing the entries to insert

size

public int size()

Returns the number of entries; needed for JUnit tests.

Returns:

number of used blocks

blocks

public int blocks()

Returns the number of used blocks; needed for JUnit tests.

Returns:

number of used blocks