org.neo4j.kernel.impl.transaction
Class TxLog

java.lang.Object
  org.neo4j.kernel.impl.transaction.TxLog

public class TxLog
extends Object

This class is made public for testing purposes only, do not use.

The TxManager uses this class to keep a transaction log for transaction recovery.

Nested Class Summary

static class

TxLog.Record Made public for testing only.

Field Summary

static byte	BRANCH_ADD
static byte	MARK_COMMIT
static byte	TX_DONE
static byte	TX_START

Constructor Summary

TxLog(String fileName)
Initializes a transaction log using filename.

Method Summary

void	addBranch(byte[] globalId, byte[] branchId) Writes a BRANCH_ADD record to the file.
void	close() Closes the file representing the transaction log.
void	force() Forces the log file (with metadata).
Iterator<List<TxLog.Record>>	getDanglingRecords() Returns an array of lists, each list contains dangling records (transactions that han't been completed yet) grouped after global by transaction id.
String	getName() Returns the name of the transaction log.
int	getRecordCount() Returns the number of records (one of TX_START,BRANCH_ADD,MARK_COMMIT or TX_DONE) written since this instance was created or truncated.
void	markAsCommitting(byte[] globalId) Writes a MARK_COMMIT record to the file and forces the file to disk.
void	switchToLogFile(String newFile) Switches log file.
void	truncate() Truncates the file to zero size and sets the record count to zero.
void	txDone(byte[] globalId) Writes a TX_DONE record to the file.
void	txStart(byte[] globalId) Writes a TX_START record to the file.

Methods inherited from class java.lang.Object

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

Field Detail

TX_START

public static final byte TX_START

See Also:

Constant Field Values

BRANCH_ADD

public static final byte BRANCH_ADD

See Also:

Constant Field Values

MARK_COMMIT

public static final byte MARK_COMMIT

See Also:

Constant Field Values

TX_DONE

public static final byte TX_DONE

See Also:

Constant Field Values

Constructor Detail

TxLog

public TxLog(String fileName)
      throws IOException

Initializes a transaction log using filename. If the file isn't empty the position will be set to size of file so new records will be appended.

Parameters:

fileName - Filename of file to use

Throws:

IOException - If unable to open file

Method Detail

getName

public String getName()

Returns the name of the transaction log.

getRecordCount

public int getRecordCount()

Returns the number of records (one of TX_START,BRANCH_ADD,MARK_COMMIT or TX_DONE) written since this instance was created or truncated.

close

public void close()
           throws IOException

Closes the file representing the transaction log.

Throws:

IOException

force

public void force()
           throws IOException

Forces the log file (with metadata). Useful when switching log.

Throws:

IOException

truncate

public void truncate()
              throws IOException

Truncates the file to zero size and sets the record count to zero.

Throws:

IOException

txStart

public void txStart(byte[] globalId)
             throws IOException

Writes a TX_START record to the file.

Parameters:

globalId - The global id of the new transaction

Throws:

IOException - If unable to write

addBranch

public void addBranch(byte[] globalId,
                      byte[] branchId)
               throws IOException

Writes a BRANCH_ADD record to the file.

Parameters:

globalId - The global id of the transaction

branchId - The branch id for the enlisted resource

Throws:

IOException - If unable to write

markAsCommitting

public void markAsCommitting(byte[] globalId)
                      throws IOException

Writes a MARK_COMMIT record to the file and forces the file to disk.

Parameters:

globalId - The global id of the transaction

Throws:

IOException - If unable to write

txDone

public void txDone(byte[] globalId)
            throws IOException

Writes a TX_DONE record to the file.

Parameters:

globalId - The global id of the transaction completed

Throws:

IOException - If unable to write

getDanglingRecords

public Iterator<List<TxLog.Record>> getDanglingRecords()
                                                throws IOException

Returns an array of lists, each list contains dangling records (transactions that han't been completed yet) grouped after global by transaction id.

Throws:

IOException

switchToLogFile

public void switchToLogFile(String newFile)
                     throws IOException

Switches log file. Copies the dangling records in current log file to the newFile and the makes the switch closing the old log file.

Parameters:

newFile - The filename of the new file to switch to

Throws:

IOException - If unable to switch log file