net.sf.joafip.kvstore.record.service

Class HeapElementManager

java.lang.Object

net.sf.joafip.kvstore.record.service.HeapElementManager

All Implemented Interfaces:

IHeapElementManager

@NotStorableClass
public class HeapElementManager
extends Object
implements IHeapElementManager

Heap elements manager in heap file.
elements are one heap header and the heap records
see IHeapElementManager for role description
implement a cache for elements read and to write
data in the cache that was modified will be saved when closing transaction

cache mechanism:
record cache is in heapRecordToWriteMap and in readHeapRecordMap

#readHeapFileDataRecord(long, boolean) check if record already in cache, if not read it from file and put it in cache ( the record is marked not modified )

#newHeapFileRecord(long, long, long, boolean, boolean, int, int), create a new record and put it in the cache

delete(long) delete record from the cache

closeTransaction() write record marked changed from the cache to the files ( see crash safe mechanisms )

crash safe mechanism can be turned off

crash safe mechanism:

to be crash safe file is maintained open for reading, write are not done as soon they are ask but put in the read/write cache. records on the read/write cache marked changed are write to file when closeTransaction() is call, that close the file to be sure all is on disk before reopen file for reading

wasBadFileStableState() must be call before use files to restore stable file state if needed

FlagData : flag file indicating data file state stable
FlagBackup: flag file indicating backup data file state stable
FlagGlobal: flag file indicating backup and data file stable state


FlagGlobal present .===#...................#===
.......... absent .....#===================#...
.......................|...................|...
FlagData present ...=======#...#===============
.......... absent .....|...#===#...........|...
.......................|...|...|...........|...
FlagBackup present .===============#...#=======
.......... absent .....|...|...|...#===#...|...
.......................|...|...|...|...|...|...
..................... (1) (2) (3) (4) (5) (6) .

(1) starting of files access for write
(2) starting of data file modification (write)
(3) ending of data file modification
(4) starting of backup data file modification (write)
(5) ending of backup data file modification
(6)end of files access for write

if all flag file are present then all files are in stable state
if 'FlagGlobal' is absent there was a modification crash

• if both 'FlagData' and 'FlagBackup' are present then the files are not deteriorated, but backup data may not be up to date
• if 'FlagData' is absent then data file may be deteriorated, backup file is in stable state ( previous data before last interrupted modification)
• if 'FlagBackup' is absent then backup data file is deteriorated, data file is in stable state ( contains last modification )

Author:

luc peuvrier

Constructor Summary

Constructors

Constructor and Description
HeapElementManager(FileForStorable fileForStorable, File stateOkFlagFile, FileForStorable fileForStorableBackup, File stateBackupOkFlagFile, File globalStateFlagFile, boolean deleteRenaming, boolean clearResizeFile, int maxFileOperationRetry, int fileOperationRetryMsDelay, File openFileTraceFile) construction for crash safe mode enabled
HeapElementManager(IFileForStorable fileForStorable, boolean deleteRenaming, boolean clearResizeFile, int maxFileOperationRetry, int fileOperationRetryMsDelay, File openFileTraceFile) construction for crash safe mode disabled

Method Summary

Methods

Modifier and Type	Method and Description
void	appendHeapFileRecord(IFileStorable heapRecord) append an heap file record that will be to write in file
String	backup(long identifier, int maxBackup)
void	clear() clear heap content service must be started and transaction opened
void	clearReadCache()
void	closeTransaction() close the heap file transaction management committing the modifications to the file before
void	closeTransactionDiscardChange() close the heap file transaction management without commit modification in file
void	delete(long positionInFile)
IDataRecordKeyManager	getDataRecordKeyManager()
IFileForStorable	getFileForStorable()
long	getFileSize()
IFileStorable	getHeapFileRecordInReadCache(long positionInFile) FOR TEST ONLY
IFileStorable	getHeapFileRecordInWriteCache(long positionInFile) FOR TEST ONLY
IFileStorable	getHeapHeader()
IHeapRecordFactory	getHeapRecordFactory()
int	getNumberOfHeaprecordInMemory()
boolean	isCrashSafeMode()
boolean	isDataLost() the returned value is set by IHeapElementManager.wasBadFileStableState()
boolean	isServiceStarted()
boolean	isTransactionOpened()
void	openTransaction() open the heap file transaction management
IFileStorable	readHeapFileDataRecord(long positionInFile) read heap record in file
void	removeFiles() removes files containing heap data transaction must be closed and service stopped
void	setDataRecordKeyManager(IDataRecordKeyManager dataRecordKeyManager)
void	setHeapHeader(IFileStorable heapHeader) set heap header
void	setHeapRecordFactory(IHeapRecordFactory heapRecordFactory)
void	startService() start heap record management service
void	stopService() stop heap record management service
boolean	wasBadFileStableState() check file stable state, restore if possible service must not be started must be called before heap file access

Methods inherited from class java.lang.Object

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

Constructor Detail

HeapElementManager

public HeapElementManager(IFileForStorable fileForStorable,
                  boolean deleteRenaming,
                  boolean clearResizeFile,
                  int maxFileOperationRetry,
                  int fileOperationRetryMsDelay,
                  File openFileTraceFile)

construction for crash safe mode disabled

Parameters:

fileForStorable - data file

deleteRenaming -

clearResizeFile -

maxFileOperationRetry -

fileOperationRetryMsDelay -

openFileTraceFile -

HeapElementManager

public HeapElementManager(FileForStorable fileForStorable,
                  File stateOkFlagFile,
                  FileForStorable fileForStorableBackup,
                  File stateBackupOkFlagFile,
                  File globalStateFlagFile,
                  boolean deleteRenaming,
                  boolean clearResizeFile,
                  int maxFileOperationRetry,
                  int fileOperationRetryMsDelay,
                  File openFileTraceFile)

construction for crash safe mode enabled

Parameters:

fileForStorable - data file

stateOkFlagFile - flag file indicating data file state stable

fileForStorableBackup - data backup file

stateBackupOkFlagFile - flag file indicating backup data file state stable

globalStateFlagFile - flag file indicating backup and data file stable state

deleteRenaming -

clearResizeFile -

maxFileOperationRetry -

fileOperationRetryMsDelay -

openFileTraceFile -

Throws:

HeapException - no files in stable state

Method Detail

isCrashSafeMode

public boolean isCrashSafeMode()

Specified by:

isCrashSafeMode in interface IHeapElementManager

getFileForStorable

public IFileForStorable getFileForStorable()

Specified by:

getFileForStorable in interface IHeapElementManager

Returns:

file used by heap element manager

getFileSize

public long getFileSize()
                 throws HeapException

Specified by:

getFileSize in interface IHeapElementManager

Returns:

file for storage size

Throws:

HeapException

wasBadFileStableState

public boolean wasBadFileStableState()
                              throws HeapException

Description copied from interface: IHeapElementManager

check file stable state, restore if possible
service must not be started
must be called before heap file access

Specified by:

wasBadFileStableState in interface IHeapElementManager

Returns:

true if file restored ( from backup to data or data to backup )

Throws:

HeapException - no file in stable state, no files in stable state

isDataLost

public boolean isDataLost()

Description copied from interface: IHeapElementManager

the returned value is set by IHeapElementManager.wasBadFileStableState()

Specified by:

isDataLost in interface IHeapElementManager

Returns:

true if data loose detected by IHeapElementManager.wasBadFileStableState()

removeFiles

public void removeFiles()
                 throws HeapException

Description copied from interface: IHeapElementManager

removes files containing heap data
transaction must be closed and service stopped

Specified by:

removeFiles in interface IHeapElementManager

Throws:

HeapException

clear

public void clear()
           throws HeapException

Description copied from interface: IHeapElementManager

clear heap content
service must be started and transaction opened

Specified by:

clear in interface IHeapElementManager

Throws:

HeapException

startService

public void startService()
                  throws HeapException

Description copied from interface: IHeapElementManager

start heap record management service

Specified by:

startService in interface IHeapElementManager

Throws:

HeapException - file access error file data corrupted

stopService

public void stopService()
                 throws HeapException

Description copied from interface: IHeapElementManager

stop heap record management service

Specified by:

stopService in interface IHeapElementManager

Throws:

HeapException

isServiceStarted

public boolean isServiceStarted()

Specified by:

isServiceStarted in interface IHeapElementManager

Returns:

true if heap file management service is started

openTransaction

public void openTransaction()
                     throws HeapException

Description copied from interface: IHeapElementManager

open the heap file transaction management

Specified by:

openTransaction in interface IHeapElementManager

Throws:

HeapException

closeTransaction

public void closeTransaction()
                      throws HeapException

Description copied from interface: IHeapElementManager

close the heap file transaction management committing the modifications to the file before

Specified by:

closeTransaction in interface IHeapElementManager

Throws:

HeapException

closeTransactionDiscardChange

public void closeTransactionDiscardChange()
                                   throws HeapException

Description copied from interface: IHeapElementManager

close the heap file transaction management without commit modification in file

Specified by:

closeTransactionDiscardChange in interface IHeapElementManager

Throws:

HeapException

clearReadCache

public void clearReadCache()

Specified by:

clearReadCache in interface IHeapElementManager

isTransactionOpened

public boolean isTransactionOpened()

Specified by:

isTransactionOpened in interface IHeapElementManager

Returns:

true if heap file transaction opened

setHeapHeader

public void setHeapHeader(IFileStorable heapHeader)
                   throws HeapException

Description copied from interface: IHeapElementManager

set heap header

Specified by:

setHeapHeader in interface IHeapElementManager

Throws:

HeapException

getHeapHeader

public IFileStorable getHeapHeader()
                            throws HeapException

Specified by:

getHeapHeader in interface IHeapElementManager

Returns:

the heap header in file

Throws:

HeapException

readHeapFileDataRecord

public IFileStorable readHeapFileDataRecord(long positionInFile)
                                     throws HeapException

Description copied from interface: IHeapElementManager

read heap record in file

Specified by:

readHeapFileDataRecord in interface IHeapElementManager

Parameters:

positionInFile - heap record position in file

Returns:

heap file record

Throws:

HeapException

appendHeapFileRecord

public void appendHeapFileRecord(IFileStorable heapRecord)
                          throws HeapException

Description copied from interface: IHeapElementManager

append an heap file record that will be to write in file

Specified by:

appendHeapFileRecord in interface IHeapElementManager

Parameters:

heapRecord - the heap file record to append

Throws:

HeapException

delete

public void delete(long positionInFile)
            throws HeapException

Specified by:

delete in interface IHeapElementManager

Throws:

HeapException

getNumberOfHeaprecordInMemory

public int getNumberOfHeaprecordInMemory()

Specified by:

getNumberOfHeaprecordInMemory in interface IHeapElementManager

setHeapRecordFactory

public void setHeapRecordFactory(IHeapRecordFactory heapRecordFactory)

Specified by:

setHeapRecordFactory in interface IHeapElementManager

getHeapRecordFactory

public IHeapRecordFactory getHeapRecordFactory()

Specified by:

getHeapRecordFactory in interface IHeapElementManager

setDataRecordKeyManager

public void setDataRecordKeyManager(IDataRecordKeyManager dataRecordKeyManager)

Specified by:

setDataRecordKeyManager in interface IHeapElementManager

getDataRecordKeyManager

public IDataRecordKeyManager getDataRecordKeyManager()

Specified by:

getDataRecordKeyManager in interface IHeapElementManager

getHeapFileRecordInReadCache

@Fortest
public IFileStorable getHeapFileRecordInReadCache(long positionInFile)

FOR TEST ONLY

Parameters:

positionInFile - heap record position in file

Returns:

heap record in read cache for position in file, null if none

getHeapFileRecordInWriteCache

@Fortest
public IFileStorable getHeapFileRecordInWriteCache(long positionInFile)

FOR TEST ONLY

Parameters:

positionInFile - heap record position in file

Returns:

heap record in write cache for position in file, null if none. can be NULL_FILE_STORABLE

backup

public String backup(long identifier,
            int maxBackup)
              throws HeapException

Specified by:

backup in interface IHeapElementManager

Throws:

HeapException