org.neo4j.causalclustering.core.state.machines

Interface StateMachine<Command>

All Known Implementing Classes:

ReplicatedIdAllocationStateMachine, ReplicatedLockTokenStateMachine, ReplicatedTokenStateMachine, ReplicatedTransactionStateMachine

public interface StateMachine<Command>

Method Summary

Modifier and Type	Method and Description
void	applyCommand(Command command, long commandIndex, Consumer<Result> callback) Apply command to state machine, modifying its internal state.
void	flush() Flushes state to durable storage.
long	lastAppliedIndex() Return the index of the last applied command by this state machine.

Method Detail

applyCommand

void applyCommand(Command command,
                  long commandIndex,
                  Consumer<Result> callback)

Apply command to state machine, modifying its internal state. Implementations should be idempotent, so that the caller is free to replay commands from any point in the log.

Parameters:

command - Command to the state machine.

commandIndex - The index of the command.

callback - To be called when a result is produced.

flush

void flush()
    throws IOException

Flushes state to durable storage.

Throws:

IOException

lastAppliedIndex

long lastAppliedIndex()

Return the index of the last applied command by this state machine.

Returns:

the last applied index for this state machine