org.h2.engine

Class SessionRemote

java.lang.Object

org.h2.engine.SessionRemote

All Implemented Interfaces:

Closeable, AutoCloseable, SessionInterface, DataHandler

public class SessionRemote
extends Object
implements DataHandler

The client side part of a session when using the server mode. This object communicates with a Session on the server side.

Field Summary

Fields

Modifier and Type	Field and Description
static int	CHANGE_ID
static int	COMMAND_CLOSE
static int	COMMAND_COMMIT
static int	COMMAND_EXECUTE_QUERY
static int	COMMAND_EXECUTE_UPDATE
static int	COMMAND_GET_META_DATA
static int	RESULT_CLOSE
static int	RESULT_FETCH_ROWS
static int	RESULT_RESET
static int	SESSION_CANCEL_STATEMENT
static int	SESSION_CHECK_KEY
static int	SESSION_CLOSE
static int	SESSION_PREPARE
static int	SESSION_PREPARE_READ_PARAMS
static int	SESSION_SET_AUTOCOMMIT
static int	SESSION_SET_ID
protected ArrayList<String>	sessionState
protected boolean	sessionStateChanged
static int	STATUS_CLOSED
static int	STATUS_ERROR
static int	STATUS_OK
static int	STATUS_OK_STATE_CHANGED

Constructor Summary

Constructors

Constructor and Description
SessionRemote(ConnectionInfo ci)

Method Summary

Methods

Modifier and Type	Method and Description
void	afterWriting() Called after writing has ended.
void	autoCommitIfCluster() Calls COMMIT if the session is in cluster mode.
void	cancel() Cancel the current or next command (called when closing a connection).
void	cancelStatement(int id) Cancel the statement with the given id.
void	checkClosed() Check if this session is closed and throws an exception if so.
void	checkPowerOff() Check if the simulated power failure occurred.
void	checkWritingAllowed() Check if writing is allowed.
void	close() Roll back pending transactions and close the session.
SessionInterface	connectEmbeddedOrServer(boolean openNew) Open a new (remote or embedded) session.
void	done(Transfer transfer) Called to flush the output after data has been sent to the server and just before receiving data.
void	freeUpDiskSpace() Free up disk space if possible.
boolean	getAutoCommit() Check if this session is in auto-commit mode.
int	getCurrentId()
String	getDatabasePath() Get the database path.
DataHandler	getDataHandler() Get the data handler object.
int	getLastReconnect()
String	getLobCompressionAlgorithm(int type) Get the compression algorithm used for large objects.
Connection	getLobConnection() Get a database connection to be used for LOB access.
SmallLRUCache<String,String[]>	getLobFileListCache() Get the lob file list cache if it is used.
LobStorage	getLobStorage() Get the lob storage mechanism to use.
Object	getLobSyncObject() Get the synchronization object for lob operations.
int	getMaxLengthInplaceLob() Get the maximum length of a in-place large object
int	getNextId()
int	getPowerOffCount() Get the number of disk operations before power failure is simulated.
TempFileDeleter	getTempFileDeleter() Get the temp file deleter mechanism.
Trace	getTrace() Get the trace object
boolean	isClosed() Check if close was called.
boolean	isClustered() Returns true if the connection was opened in cluster mode.
boolean	isReconnectNeeded(boolean write) Check if the database changed and therefore reconnecting is required.
FileStore	openFile(String name, String mode, boolean mustExist) Open a file at the given location.
CommandInterface	prepareCommand(String sql, int fetchSize) Parse a command and prepare it for execution.
void	readSessionState() Read the session state if necessary.
SessionInterface	reconnect(boolean write) Close the connection and open a new connection.
protected void	recreateSessionState() Re-create the session state using the stored sessionState list.
void	removeServer(IOException e, int i, int count) Remove a server from the list of cluster nodes and disables the cluster mode.
void	setAutoCommit(boolean autoCommit) Set the auto-commit mode.
void	setAutoCommitFromServer(boolean autoCommit)
void	setPowerOffCount(int count) Set the number of disk operations before power failure is simulated.
void	traceOperation(String operation, int id) Write the operation to the trace system if debug trace is enabled.

Methods inherited from class java.lang.Object

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

Field Detail

SESSION_PREPARE

public static final int SESSION_PREPARE

See Also:

Constant Field Values

SESSION_CLOSE

public static final int SESSION_CLOSE

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Constant Field Values

COMMAND_EXECUTE_QUERY

public static final int COMMAND_EXECUTE_QUERY

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Constant Field Values

COMMAND_EXECUTE_UPDATE

public static final int COMMAND_EXECUTE_UPDATE

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Constant Field Values

COMMAND_CLOSE

public static final int COMMAND_CLOSE

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Constant Field Values

RESULT_FETCH_ROWS

public static final int RESULT_FETCH_ROWS

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Constant Field Values

RESULT_RESET

public static final int RESULT_RESET

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Constant Field Values

RESULT_CLOSE

public static final int RESULT_CLOSE

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Constant Field Values

COMMAND_COMMIT

public static final int COMMAND_COMMIT

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Constant Field Values

CHANGE_ID

public static final int CHANGE_ID

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Constant Field Values

COMMAND_GET_META_DATA

public static final int COMMAND_GET_META_DATA

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Constant Field Values

SESSION_PREPARE_READ_PARAMS

public static final int SESSION_PREPARE_READ_PARAMS

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Constant Field Values

SESSION_SET_ID

public static final int SESSION_SET_ID

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Constant Field Values

SESSION_CANCEL_STATEMENT

public static final int SESSION_CANCEL_STATEMENT

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Constant Field Values

SESSION_CHECK_KEY

public static final int SESSION_CHECK_KEY

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Constant Field Values

SESSION_SET_AUTOCOMMIT

public static final int SESSION_SET_AUTOCOMMIT

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Constant Field Values

STATUS_ERROR

public static final int STATUS_ERROR

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Constant Field Values

STATUS_OK

public static final int STATUS_OK

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Constant Field Values

STATUS_CLOSED

public static final int STATUS_CLOSED

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Constant Field Values

STATUS_OK_STATE_CHANGED

public static final int STATUS_OK_STATE_CHANGED

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Constant Field Values

sessionState

protected ArrayList<String> sessionState

sessionStateChanged

protected boolean sessionStateChanged

Constructor Detail

SessionRemote

public SessionRemote(ConnectionInfo ci)

Method Detail

cancel

public void cancel()

Description copied from interface: SessionInterface

Cancel the current or next command (called when closing a connection).

Specified by:

cancel in interface SessionInterface

cancelStatement

public void cancelStatement(int id)

Cancel the statement with the given id.

Parameters:

id - the statement id

getAutoCommit

public boolean getAutoCommit()

Description copied from interface: SessionInterface

Check if this session is in auto-commit mode.

Specified by:

getAutoCommit in interface SessionInterface

Returns:

true if the session is in auto-commit mode

setAutoCommit

public void setAutoCommit(boolean autoCommit)

Description copied from interface: SessionInterface

Set the auto-commit mode.

Specified by:

setAutoCommit in interface SessionInterface

Parameters:

autoCommit - the new value

setAutoCommitFromServer

public void setAutoCommitFromServer(boolean autoCommit)

autoCommitIfCluster

public void autoCommitIfCluster()

Calls COMMIT if the session is in cluster mode.

getPowerOffCount

public int getPowerOffCount()

Description copied from interface: SessionInterface

Get the number of disk operations before power failure is simulated. This is used for testing. If not set, 0 is returned

Specified by:

getPowerOffCount in interface SessionInterface

Returns:

the number of operations, or 0

setPowerOffCount

public void setPowerOffCount(int count)

Description copied from interface: SessionInterface

Set the number of disk operations before power failure is simulated. To disable the countdown, use 0.

Specified by:

setPowerOffCount in interface SessionInterface

Parameters:

count - the number of operations

connectEmbeddedOrServer

public SessionInterface connectEmbeddedOrServer(boolean openNew)

Open a new (remote or embedded) session.

Parameters:

openNew - whether to open a new session in any case

Returns:

the session

removeServer

public void removeServer(IOException e,
                int i,
                int count)

Remove a server from the list of cluster nodes and disables the cluster mode.

Parameters:

e - the exception (used for debugging)

i - the index of the server to remove

count - the retry count index

prepareCommand

public CommandInterface prepareCommand(String sql,
                              int fetchSize)

Description copied from interface: SessionInterface

Parse a command and prepare it for execution.

Specified by:

prepareCommand in interface SessionInterface

Parameters:

sql - the SQL statement

fetchSize - the number of rows to fetch in one step

Returns:

the prepared command

checkClosed

public void checkClosed()

Check if this session is closed and throws an exception if so.

Throws:

DbException - if the session is closed

close

public void close()

Description copied from interface: SessionInterface

Roll back pending transactions and close the session.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface SessionInterface

getTrace

public Trace getTrace()

Description copied from interface: SessionInterface

Get the trace object

Specified by:

getTrace in interface SessionInterface

Returns:

the trace object

getNextId

public int getNextId()

getCurrentId

public int getCurrentId()

done

public void done(Transfer transfer)
          throws IOException

Called to flush the output after data has been sent to the server and just before receiving data. This method also reads the status code from the server and throws any exception the server sent.

Parameters:

transfer - the transfer object

Throws:

DbException - if the server sent an exception

IOException - if there is a communication problem between client and server

isClustered

public boolean isClustered()

Returns true if the connection was opened in cluster mode.

Returns:

true if it is

isClosed

public boolean isClosed()

Description copied from interface: SessionInterface

Check if close was called.

Specified by:

isClosed in interface SessionInterface

Returns:

if the session has been closed

traceOperation

public void traceOperation(String operation,
                  int id)

Write the operation to the trace system if debug trace is enabled.

Parameters:

operation - the operation performed

id - the id of the operation

checkPowerOff

public void checkPowerOff()

Description copied from interface: DataHandler

Check if the simulated power failure occurred. This call will decrement the countdown.

Specified by:

checkPowerOff in interface DataHandler

checkWritingAllowed

public void checkWritingAllowed()

Description copied from interface: DataHandler

Check if writing is allowed.

Specified by:

checkWritingAllowed in interface DataHandler

freeUpDiskSpace

public void freeUpDiskSpace()

Description copied from interface: DataHandler

Free up disk space if possible. This method is called if more space is needed.

Specified by:

freeUpDiskSpace in interface DataHandler

getDatabasePath

public String getDatabasePath()

Description copied from interface: DataHandler

Get the database path.

Specified by:

getDatabasePath in interface DataHandler

Returns:

the database path

getLobCompressionAlgorithm

public String getLobCompressionAlgorithm(int type)

Description copied from interface: DataHandler

Get the compression algorithm used for large objects.

Specified by:

getLobCompressionAlgorithm in interface DataHandler

Parameters:

type - the data type (CLOB or BLOB)

Returns:

the compression algorithm, or null

getMaxLengthInplaceLob

public int getMaxLengthInplaceLob()

Description copied from interface: DataHandler

Get the maximum length of a in-place large object

Specified by:

getMaxLengthInplaceLob in interface DataHandler

Returns:

the maximum size

openFile

public FileStore openFile(String name,
                 String mode,
                 boolean mustExist)

Description copied from interface: DataHandler

Open a file at the given location.

Specified by:

openFile in interface DataHandler

Parameters:

name - the file name

mode - the mode

mustExist - whether the file must already exist

Returns:

the file

getDataHandler

public DataHandler getDataHandler()

Description copied from interface: SessionInterface

Get the data handler object.

Specified by:

getDataHandler in interface SessionInterface

Returns:

the data handler

getLobSyncObject

public Object getLobSyncObject()

Description copied from interface: DataHandler

Get the synchronization object for lob operations.

Specified by:

getLobSyncObject in interface DataHandler

Returns:

the synchronization object

getLobFileListCache

public SmallLRUCache<String,String[]> getLobFileListCache()

Description copied from interface: DataHandler

Get the lob file list cache if it is used.

Specified by:

getLobFileListCache in interface DataHandler

Returns:

the cache or null

getLastReconnect

public int getLastReconnect()

getTempFileDeleter

public TempFileDeleter getTempFileDeleter()

Description copied from interface: DataHandler

Get the temp file deleter mechanism.

Specified by:

getTempFileDeleter in interface DataHandler

Returns:

the temp file deleter

isReconnectNeeded

public boolean isReconnectNeeded(boolean write)

Description copied from interface: SessionInterface

Check if the database changed and therefore reconnecting is required.

Specified by:

isReconnectNeeded in interface SessionInterface

Parameters:

write - if the next operation may be writing

Returns:

true if reconnecting is required

reconnect

public SessionInterface reconnect(boolean write)

Description copied from interface: SessionInterface

Close the connection and open a new connection.

Specified by:

reconnect in interface SessionInterface

Parameters:

write - if the next operation may be writing

Returns:

the new connection

afterWriting

public void afterWriting()

Description copied from interface: SessionInterface

Called after writing has ended. It needs to be called after isReconnectNeeded(true) returned false.

Specified by:

afterWriting in interface SessionInterface

getLobStorage

public LobStorage getLobStorage()

Description copied from interface: DataHandler

Get the lob storage mechanism to use.

Specified by:

getLobStorage in interface DataHandler

Returns:

the lob storage mechanism

getLobConnection

public Connection getLobConnection()

Description copied from interface: DataHandler

Get a database connection to be used for LOB access.

Specified by:

getLobConnection in interface DataHandler

Returns:

the connection or null

recreateSessionState

protected void recreateSessionState()

Re-create the session state using the stored sessionState list.

readSessionState

public void readSessionState()

Read the session state if necessary.