bftsmart.tom.server.defaultservices

Class StateLog

java.lang.Object

bftsmart.tom.server.defaultservices.StateLog

Direct Known Subclasses:

DiskStateLog, DurableStateLog

public class StateLog
extends java.lang.Object

This classes serves as a log for the state associated with the last checkpoint, and the message batches received since the same checkpoint until the present. The state associated with the last checkpoint together with all the batches of messages received so far, comprises this replica current state

Author:

Jo�o Sousa

Constructor Summary

Constructors

Constructor and Description
StateLog(byte[] initialState, byte[] initialHash)
StateLog(int k) Constructs a State log
StateLog(int k, byte[] initialState, byte[] initialHash) Constructs a State log

Method Summary

Methods

Modifier and Type	Method and Description
void	addMessageBatch(byte[][] commands, int round, int leader) Adds a message batch to the log.
DefaultApplicationState	getApplicationState(int eid, boolean setState) Constructs a TransferableState using this log information
int	getLastCheckpointEid() Retrieves the execution ID for the last checkpoint
int	getLastCheckpointLeader() Retrieves the leader for the last checkpoint
int	getLastCheckpointRound() Retrieves the decision round for the last checkpoint
int	getLastEid() Retrieves the execution ID for the last messages batch delivered to the application
CommandsInfo	getMessageBatch(int eid) Returns a batch of messages, given its correspondent execution ID
CommandsInfo[]	getMessageBatches() Retrieves all the stored batches kept since the last checkpoint
int	getNumBatches() Retrieves the total number of stored batches kept since the last checkpoint
byte[]	getState() Retrieves the state associated with the last checkpoint
byte[]	getStateHash() Retrieves the hash of the state associated with the last checkpoint
void	newCheckpoint(byte[] state, byte[] stateHash) Sets the state associated with the last checkpoint, and updates the execution ID associated with it
void	setLastCheckpointEid(int lastCheckpointEid) Sets the execution ID for the last checkpoint
void	setLastCheckpointLeader(int lastCheckpointLeader) Sets the leader for the last checkpoint
void	setLastCheckpointRound(int lastCheckpointRound) Sets the decision round for the last checkpoint
void	setLastEid(int lastEid) Sets the execution ID for the last messages batch delivered to the application
void	update(DefaultApplicationState transState) Updates this log, according to the information contained in the TransferableState object

Methods inherited from class java.lang.Object

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

Constructor Detail

StateLog

public StateLog(int k,
        byte[] initialState,
        byte[] initialHash)

Constructs a State log

Parameters:

k - The chekpoint period

StateLog

public StateLog(int k)

Constructs a State log

Parameters:

k - The chekpoint period

StateLog

public StateLog(byte[] initialState,
        byte[] initialHash)

Method Detail

newCheckpoint

public void newCheckpoint(byte[] state,
                 byte[] stateHash)

Sets the state associated with the last checkpoint, and updates the execution ID associated with it

Parameters:

state - State associated with the last checkpoint

setLastCheckpointEid

public void setLastCheckpointEid(int lastCheckpointEid)

Sets the execution ID for the last checkpoint

Parameters:

lastCheckpointEid - Execution ID for the last checkpoint

getLastCheckpointEid

public int getLastCheckpointEid()

Retrieves the execution ID for the last checkpoint

Returns:

Execution ID for the last checkpoint, or -1 if none was obtained

setLastCheckpointRound

public void setLastCheckpointRound(int lastCheckpointRound)

Sets the decision round for the last checkpoint

Parameters:

lastCheckpointRound - Decision round for the last checkpoint

getLastCheckpointRound

public int getLastCheckpointRound()

Retrieves the decision round for the last checkpoint

Returns:

Decision round for the last checkpoint, or -1 if none was obtained

setLastCheckpointLeader

public void setLastCheckpointLeader(int lastCheckpointLeader)

Sets the leader for the last checkpoint

Parameters:

lastCheckpointLeader - Leader for the last checkpoint

getLastCheckpointLeader

public int getLastCheckpointLeader()

Retrieves the leader for the last checkpoint

Returns:

Leader for the last checkpoint, or -1 if none was obtained

setLastEid

public void setLastEid(int lastEid)

Sets the execution ID for the last messages batch delivered to the application

Parameters:

lastEid - the execution ID for the last messages batch delivered to the application

getLastEid

public int getLastEid()

Retrieves the execution ID for the last messages batch delivered to the application

Returns:

Execution ID for the last messages batch delivered to the application

getState

public byte[] getState()

Retrieves the state associated with the last checkpoint

Returns:

State associated with the last checkpoint

getStateHash

public byte[] getStateHash()

Retrieves the hash of the state associated with the last checkpoint

Returns:

Hash of the state associated with the last checkpoint

addMessageBatch

public void addMessageBatch(byte[][] commands,
                   int round,
                   int leader)

Adds a message batch to the log. This batches should be added to the log in the same order in which they are delivered to the application. Only the 'k' batches received after the last checkpoint are supposed to be kept

Parameters:

batch - The batch of messages to be kept.

getMessageBatch

public CommandsInfo getMessageBatch(int eid)

Returns a batch of messages, given its correspondent execution ID

Parameters:

eid - Execution ID associated with the batch to be fetched

Returns:

The batch of messages associated with the batch correspondent execution ID

getMessageBatches

public CommandsInfo[] getMessageBatches()

Retrieves all the stored batches kept since the last checkpoint

Returns:

All the stored batches kept since the last checkpoint

getNumBatches

public int getNumBatches()

Retrieves the total number of stored batches kept since the last checkpoint

Returns:

The total number of stored batches kept since the last checkpoint

getApplicationState

public DefaultApplicationState getApplicationState(int eid,
                                          boolean setState)

Constructs a TransferableState using this log information

Parameters:

eid - Execution ID correspondent to desired state

Returns:

TransferableState Object containing this log information

update

public void update(DefaultApplicationState transState)

Updates this log, according to the information contained in the TransferableState object

Parameters:

transState - TransferableState object containing the information which is used to updated this log