Package edu.caltech.nanodb.transactions

Class TransactionState

java.lang.Object

edu.caltech.nanodb.transactions.TransactionState

public class TransactionState
extends java.lang.Object

This class manages the transaction state associated with every client session. The transaction state for the current session can be retrieved like this:

    TransactionState txnState = SessionState.get().getTransactionState()

The transaction state should generally not be managed directly! Rather, the operations provided by the TransactionManager should be used.

Field Summary

Fields

Modifier and Type	Field	Description
private LogSequenceNumber	lastLSN
private boolean	loggedTxnStart	This value indicates whether the current transaction has been logged to the write-ahead log yet.
static int	NO_TRANSACTION
private boolean	performedWrites
private int	transactionID
private boolean	userStartedTxn

Constructor Summary

Constructors

Constructor	Description
TransactionState()

Method Summary

Modifier and Type	Method	Description
void	clear()
LogSequenceNumber	getLastLSN()
int	getTransactionID()
boolean	getUserStartedTxn()
boolean	hasLoggedTxnStart()
boolean	hasPerformedWrites()
boolean	isTxnInProgress()
void	setLastLSN(LogSequenceNumber lsn)
void	setLoggedTxnStart(boolean b)
void	setPerformedWrites(boolean b)
void	setTransactionID(int transactionID)
void	setUserStartedTxn(boolean b)
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

NO_TRANSACTION

public static final int NO_TRANSACTION

See Also:

Constant Field Values

transactionID

private int transactionID

userStartedTxn

private boolean userStartedTxn

performedWrites

private boolean performedWrites

loggedTxnStart

private boolean loggedTxnStart

This value indicates whether the current transaction has been logged to the write-ahead log yet. We don't write the "T_i: start" record until the transaction performs its first write operation.

lastLSN

private LogSequenceNumber lastLSN

Constructor Detail

TransactionState

public TransactionState()

Method Detail

getTransactionID

public int getTransactionID()

setTransactionID

public void setTransactionID(int transactionID)

getUserStartedTxn

public boolean getUserStartedTxn()

setUserStartedTxn

public void setUserStartedTxn(boolean b)

hasPerformedWrites

public boolean hasPerformedWrites()

setPerformedWrites

public void setPerformedWrites(boolean b)

hasLoggedTxnStart

public boolean hasLoggedTxnStart()

setLoggedTxnStart

public void setLoggedTxnStart(boolean b)

getLastLSN

public LogSequenceNumber getLastLSN()

setLastLSN

public void setLastLSN(LogSequenceNumber lsn)

clear

public void clear()

isTxnInProgress

public boolean isTxnInProgress()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object