Class LobStorageMap

java.lang.Object

org.h2.mvstore.db.LobStorageMap

All Implemented Interfaces:

LobStorageInterface

public final class LobStorageMap
extends Object
implements LobStorageInterface

This class stores LOB objects in the database, in maps. This is the back-end i.e. the server side of the LOB storage.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	LobStorageMap.BlobMeta
static final class	LobStorageMap.BlobReference
private final class	LobStorageMap.LobInputStream

Field Summary

Fields

Modifier and Type	Field	Description
private final Database	database
private final MVMap<Long, LobStorageMap.BlobMeta>	lobMap	The lob metadata map.
(package private) final MVStore	mvStore
private final AtomicLong	nextLobId
private final MVMap<LobStorageMap.BlobReference, Value>	refMap	The reference map.
private final StreamStore	streamStore
private final MVMap<Long,byte[]>	tempLobMap	The lob metadata map for temporary lobs.
private static final boolean	TRACE

Constructor Summary

Constructors

Constructor	Description
LobStorageMap(Database database)

Method Summary

Modifier and Type	Method	Description
ValueLob	copyLob(ValueLob old, int tableId)	Copy a lob.
private ValueBlob	createBlob(InputStream in)
ValueBlob	createBlob(InputStream in, long maxLength)	Create a BLOB object.
ValueClob	createClob(Reader reader, long maxLength)	Create a CLOB object.
private long	generateLobId()
InputStream	getInputStream(long lobId, int tableId, long byteCount)	Get the input stream for the given lob
InputStream	getInputStream(long lobId, long byteCount)	Get the input stream for the given lob, only called on server side of a TCP connection.
boolean	isReadOnly()	Whether the storage is read-only
private static boolean	isTemporaryLob(int tableId)
static MVMap<Long,byte[]>	openLobDataMap(TransactionStore txStore)	Open map used to store LOB data
static MVMap<Long, LobStorageMap.BlobMeta>	openLobMap(TransactionStore txStore)	Open map used to store LOB metadata
void	removeAllForTable(int tableId)	Remove all LOBs for this table.
private void	removeLob(int tableId, long lobId)
void	removeLob(ValueLob lob)	Delete a LOB (from the database, if it is stored there).
private static void	trace(String op)

Methods inherited from class Object

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

Field Details

TRACE

private static final boolean TRACE

See Also:

• Constant Field Values

database

private final Database database

mvStore

final MVStore mvStore

nextLobId

private final AtomicLong nextLobId

lobMap

private final MVMap<Long, LobStorageMap.BlobMeta> lobMap

The lob metadata map. It contains the mapping from the lob id (which is a long) to the blob metadata, including stream store id (which is a byte array).

tempLobMap

private final MVMap<Long,byte[]> tempLobMap

The lob metadata map for temporary lobs. It contains the mapping from the lob id (which is a long) to the stream store id (which is a byte array). Key: lobId (long) Value: streamStoreId (byte[])

refMap

private final MVMap<LobStorageMap.BlobReference, Value> refMap

The reference map. It is used to remove data from the stream store: if no more entries for the given streamStoreId exist, the data is removed from the stream store.

streamStore

private final StreamStore streamStore

Constructor Details

LobStorageMap

public LobStorageMap(Database database)

Method Details

openLobMap

public static MVMap<Long, LobStorageMap.BlobMeta> openLobMap(TransactionStore txStore)

Open map used to store LOB metadata

Parameters:

txStore - containing map

Returns:

MVMap instance

openLobDataMap

public static MVMap<Long,byte[]> openLobDataMap(TransactionStore txStore)

Open map used to store LOB data

Parameters:

txStore - containing map

Returns:

MVMap instance

createBlob

public ValueBlob createBlob(InputStream in,
 long maxLength)

Description copied from interface: LobStorageInterface

Create a BLOB object.

Specified by:

createBlob in interface LobStorageInterface

Parameters:

in - the input stream

maxLength - the maximum length (-1 if not known)

Returns:

the LOB

createClob

public ValueClob createClob(Reader reader,
 long maxLength)

Description copied from interface: LobStorageInterface

Create a CLOB object.

Specified by:

createClob in interface LobStorageInterface

Parameters:

reader - the reader

maxLength - the maximum length (-1 if not known)

Returns:

the LOB

createBlob

private ValueBlob createBlob(InputStream in)
                      throws IOException

Throws:

IOException

generateLobId

private long generateLobId()

isReadOnly

public boolean isReadOnly()

Description copied from interface: LobStorageInterface

Whether the storage is read-only

Specified by:

isReadOnly in interface LobStorageInterface

Returns:

true if yes

copyLob

public ValueLob copyLob(ValueLob old,
 int tableId)

Description copied from interface: LobStorageInterface

Copy a lob.

Specified by:

copyLob in interface LobStorageInterface

Parameters:

old - the old lob

tableId - the new table id

Returns:

the new lob

getInputStream

public InputStream getInputStream(long lobId,
 long byteCount)
                           throws IOException

Description copied from interface: LobStorageInterface

Get the input stream for the given lob, only called on server side of a TCP connection.

Specified by:

getInputStream in interface LobStorageInterface

Parameters:

lobId - the lob id

byteCount - the number of bytes to read, or -1 if not known

Returns:

the stream

Throws:

IOException - on failure

getInputStream

public InputStream getInputStream(long lobId,
 int tableId,
 long byteCount)
                           throws IOException

Description copied from interface: LobStorageInterface

Get the input stream for the given lob

Specified by:

getInputStream in interface LobStorageInterface

Parameters:

lobId - the lob id

tableId - the able id

byteCount - the number of bytes to read, or -1 if not known

Returns:

the stream

Throws:

IOException - on failure

removeAllForTable

public void removeAllForTable(int tableId)

Description copied from interface: LobStorageInterface

Remove all LOBs for this table.

Specified by:

removeAllForTable in interface LobStorageInterface

Parameters:

tableId - the table id

removeLob

public void removeLob(ValueLob lob)

Description copied from interface: LobStorageInterface

Delete a LOB (from the database, if it is stored there).

Specified by:

removeLob in interface LobStorageInterface

Parameters:

lob - the lob

removeLob

private void removeLob(int tableId,
 long lobId)

isTemporaryLob

private static boolean isTemporaryLob(int tableId)

trace

private static void trace(String op)