bftsmart.tom.server.defaultservices.durability

Class DurabilityCoordinator

java.lang.Object

bftsmart.tom.server.defaultservices.durability.DurabilityCoordinator

All Implemented Interfaces:

BatchExecutable, Executable, Recoverable

public abstract class DurabilityCoordinator
extends java.lang.Object
implements Recoverable, BatchExecutable

Implements the Collaborative State Transfer protocol. In this protocol, instead of all replicas send the state and log, or state and hash of the log, the replicas are divided into three groups. One group sends the state, another group sends the lower half of the log and the third group sends the upper portion of the log. The replica that receives the state, logs and hashes validates the state and install it. The details of the protocol are described in the paper "On the Efficiency of Durable State Machine Replication".

Constructor Summary

Constructors

Constructor and Description
DurabilityCoordinator()

Method Summary

Methods

Modifier and Type	Method and Description
abstract byte[][]	appExecuteBatch(byte[][] commands, MessageContext[] msgCtxs)
byte[][]	executeBatch(byte[][] commands, MessageContext[] msgCtx) Execute a batch of requests.
byte[]	getCurrentStateHash()
abstract byte[]	getSnapshot()
CSTState	getState(CSTRequest cstRequest)
ApplicationState	getState(int eid, boolean sendState) This method should return a representation of the application state
StateManager	getStateManager() Recoverers implementing this interface will have to chose among different options of state managers like DurableStateManager or StandardStateManager.
abstract void	installSnapshot(byte[] state)
void	setReplicaContext(ReplicaContext replicaContext)
int	setState(ApplicationState recvState) Sets the state to the representation obtained in the state transfer protocol

Methods inherited from class java.lang.Object

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

Methods inherited from interface bftsmart.tom.server.Recoverable

noOp

Methods inherited from interface bftsmart.tom.server.Executable

executeUnordered

Constructor Detail

DurabilityCoordinator

public DurabilityCoordinator()

Method Detail

executeBatch

public byte[][] executeBatch(byte[][] commands,
                    MessageContext[] msgCtx)

Description copied from interface: BatchExecutable

Execute a batch of requests.

Specified by:

executeBatch in interface BatchExecutable

Returns:

getState

public ApplicationState getState(int eid,
                        boolean sendState)

Description copied from interface: Recoverable

This method should return a representation of the application state

Specified by:

getState in interface Recoverable

Parameters:

eid - Execution up to which the application should return an Application state

sendState - true if the replica should send a complete representation of the state instead of only the hash. False otherwise

Returns:

A representation of the application state

setState

public int setState(ApplicationState recvState)

Description copied from interface: Recoverable

Sets the state to the representation obtained in the state transfer protocol

Specified by:

setState in interface Recoverable

Parameters:

recvState - State obtained in the state transfer protocol

Returns:

getState

public CSTState getState(CSTRequest cstRequest)

setReplicaContext

public void setReplicaContext(ReplicaContext replicaContext)

Specified by:

setReplicaContext in interface Recoverable

getStateManager

public StateManager getStateManager()

Description copied from interface: Recoverable

Recoverers implementing this interface will have to chose among different options of state managers like DurableStateManager or StandardStateManager. The recoverer class can also define a new strategy to manage the state and return it in this method.

Specified by:

getStateManager in interface Recoverable

Returns:

the implementation of state manager that suplies the strategy defined

getCurrentStateHash

public byte[] getCurrentStateHash()

installSnapshot

public abstract void installSnapshot(byte[] state)

getSnapshot

public abstract byte[] getSnapshot()

appExecuteBatch

public abstract byte[][] appExecuteBatch(byte[][] commands,
                       MessageContext[] msgCtxs)