bftsmart.tom.server.defaultservices

Class DefaultSingleRecoverable

java.lang.Object

bftsmart.tom.server.defaultservices.DefaultSingleRecoverable

All Implemented Interfaces:

Executable, Recoverable, SingleExecutable

Direct Known Subclasses:

BFTMapServer

public abstract class DefaultSingleRecoverable
extends java.lang.Object
implements Recoverable, SingleExecutable

Author:

Marcel Santos

Field Summary

Fields

Modifier and Type	Field and Description
static int	CHECKPOINT_PERIOD

Constructor Summary

Constructors

Constructor and Description
DefaultSingleRecoverable()

Method Summary

Methods

Modifier and Type	Method and Description
abstract byte[]	appExecuteOrdered(byte[] command, MessageContext msgCtx)
byte[]	computeHash(byte[] data)
byte[]	executeOrdered(byte[] command, MessageContext msgCtx) Method called to execute a request totally ordered.
abstract byte[]	getSnapshot()
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)
int	setState(ApplicationState recvState) Sets the state to the representation obtained in the state transfer protocol

Methods inherited from class java.lang.Object

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

Methods inherited from interface bftsmart.tom.server.Recoverable

setReplicaContext

Methods inherited from interface bftsmart.tom.server.Executable

executeUnordered

Field Detail

CHECKPOINT_PERIOD

public static final int CHECKPOINT_PERIOD

See Also:

Constant Field Values

Constructor Detail

DefaultSingleRecoverable

public DefaultSingleRecoverable()

Method Detail

executeOrdered

public byte[] executeOrdered(byte[] command,
                    MessageContext msgCtx)

Description copied from interface: SingleExecutable

Method called to execute a request totally ordered. The message context contains a lot of information about the request, such as timestamp, nonces and sender. The code for this method MUST use the value of timestamp instead of relying on its own local clock, and nonces instead of trying to generated its own random values. This is important because this values are the same for all replicas, and therefore, ensure the determinism required in a replicated state machine.

Specified by:

executeOrdered in interface SingleExecutable

Parameters:

command - the command issue by the client

msgCtx - information related with the command

Returns:

the reply for the request issued by the client

computeHash

public final byte[] computeHash(byte[] data)

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:

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

installSnapshot

public abstract void installSnapshot(byte[] state)

getSnapshot

public abstract byte[] getSnapshot()

appExecuteOrdered

public abstract byte[] appExecuteOrdered(byte[] command,
                       MessageContext msgCtx)