com.orientechnologies.orient.core.storage.impl.local.paginated.base

Class ODurablePage

java.lang.Object

com.orientechnologies.orient.core.storage.impl.local.paginated.base.ODurablePage

Direct Known Subclasses:

CellBTreeMultiValueV2Bucket, CellBTreeMultiValueV2EntryPoint, CellBTreeMultiValueV2NullBucket, OBonsaiBucketAbstract, OClusterPage, OClusterPositionMapBucket, ODirectoryPage, OHashIndexBucket, OHashIndexFileLevelMetadataPage, ONullBucket, ONullBucket, OPaginatedClusterStateV0, OPaginatedClusterStateV1, OPrefixBTreeBucket, OSBTreeBucket, OSBTreeValuePage

public class ODurablePage
extends Object

Base page class for all durable data structures, that is data structures state of which can be consistently restored after system crash but results of last operations in small interval before crash may be lost.

This page has several booked memory areas with following offsets at the beginning:

1. from 0 to 7 - Magic number
2. from 8 to 11 - crc32 of all page content, which is calculated by cache system just before save
3. from 12 to 23 - LSN of last operation which was stored for given page

Developer which will extend this class should use all page memory starting from NEXT_FREE_POSITION offset. All data structures which use this kind of pages should be derived from ODurableComponent class.

Since:

16.08.13

Author:

Andrey Lomakin (a.lomakin-at-orientdb.com)

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	CRC32_OFFSET
static int	MAGIC_NUMBER_OFFSET
static int	MAX_PAGE_SIZE_BYTES
static int	NEXT_FREE_POSITION
static int	WAL_POSITION_OFFSET
static int	WAL_SEGMENT_OFFSET

Constructor Summary

Constructors

Constructor and Description
ODurablePage(OCacheEntry cacheEntry)

Method Summary

Modifier and Type	Method and Description
protected <T> T	deserializeFromDirectMemory(OBinarySerializer<T> binarySerializer, int offset)
protected byte[]	getBinaryValue(int pageOffset, int valLen)
protected byte	getByteValue(int pageOffset)
OWALChanges	getChanges()
protected int	getIntValue(int pageOffset)
static OLogSequenceNumber	getLogSequenceNumber(int offset, byte[] data) DO NOT DELETE THIS METHOD IT IS USED IN ENTERPRISE STORAGE
static OLogSequenceNumber	getLogSequenceNumberFromPage(ByteBuffer buffer)
protected long	getLongValue(int pageOffset)
OLogSequenceNumber	getLsn()
protected int	getObjectSizeInDirectMemory(OBinarySerializer binarySerializer, int offset)
static void	getPageData(ByteBuffer buffer, byte[] data, int offset, int length) DO NOT DELETE THIS METHOD IT IS USED IN ENTERPRISE STORAGE
protected short	getShortValue(int pageOffset)
protected void	moveData(int from, int to, int len)
void	restoreChanges(OWALChanges changes)
protected int	setBinaryValue(int pageOffset, byte[] value)
protected int	setByteValue(int pageOffset, byte value)
protected int	setIntValue(int pageOffset, int value)
protected int	setLongValue(int pageOffset, long value)
void	setLsn(OLogSequenceNumber lsn)
protected int	setShortValue(int pageOffset, short value)
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

MAGIC_NUMBER_OFFSET

public static final int MAGIC_NUMBER_OFFSET

See Also:

Constant Field Values

CRC32_OFFSET

protected static final int CRC32_OFFSET

See Also:

Constant Field Values

WAL_SEGMENT_OFFSET

public static final int WAL_SEGMENT_OFFSET

See Also:

Constant Field Values

WAL_POSITION_OFFSET

public static final int WAL_POSITION_OFFSET

See Also:

Constant Field Values

MAX_PAGE_SIZE_BYTES

public static final int MAX_PAGE_SIZE_BYTES

NEXT_FREE_POSITION

public static final int NEXT_FREE_POSITION

See Also:

Constant Field Values

Constructor Detail

ODurablePage

public ODurablePage(OCacheEntry cacheEntry)

Method Detail

getLogSequenceNumberFromPage

public static OLogSequenceNumber getLogSequenceNumberFromPage(ByteBuffer buffer)

getPageData

public static void getPageData(ByteBuffer buffer,
                               byte[] data,
                               int offset,
                               int length)

DO NOT DELETE THIS METHOD IT IS USED IN ENTERPRISE STORAGE

Copies content of page into passed in byte array.

Parameters:

buffer - Buffer from which data will be copied

data - Byte array to which data will be copied

offset - Offset of data inside page

length - Length of data to be copied

getLogSequenceNumber

public static OLogSequenceNumber getLogSequenceNumber(int offset,
                                                      byte[] data)

DO NOT DELETE THIS METHOD IT IS USED IN ENTERPRISE STORAGE

Get value of LSN from the passed in offset in byte array.

Parameters:

offset - Offset inside of byte array from which LSN value will be read.

data - Byte array from which LSN value will be read.

getIntValue

protected int getIntValue(int pageOffset)

getShortValue

protected short getShortValue(int pageOffset)

getLongValue

protected long getLongValue(int pageOffset)

getBinaryValue

protected byte[] getBinaryValue(int pageOffset,
                                int valLen)

getObjectSizeInDirectMemory

protected int getObjectSizeInDirectMemory(OBinarySerializer binarySerializer,
                                          int offset)

deserializeFromDirectMemory

protected <T> T deserializeFromDirectMemory(OBinarySerializer<T> binarySerializer,
                                            int offset)

getByteValue

protected byte getByteValue(int pageOffset)

setIntValue

protected int setIntValue(int pageOffset,
                          int value)

setShortValue

protected int setShortValue(int pageOffset,
                            short value)

setByteValue

protected int setByteValue(int pageOffset,
                           byte value)

setLongValue

protected int setLongValue(int pageOffset,
                           long value)

setBinaryValue

protected int setBinaryValue(int pageOffset,
                             byte[] value)

moveData

protected void moveData(int from,
                        int to,
                        int len)

getChanges

public OWALChanges getChanges()

restoreChanges

public void restoreChanges(OWALChanges changes)

setLsn

public void setLsn(OLogSequenceNumber lsn)

getLsn

public OLogSequenceNumber getLsn()

toString

public String toString()

Overrides:

toString in class Object