Interface StateMachine

All Superinterfaces:

AutoCloseable

All Known Implementing Classes:

LegacyStateMachine

public interface StateMachine
extends AutoCloseable

Canonical state-machine contract driving a single Restate invocation.

This is shaped after the restate-sdk-shared-core VM trait.

It is implemented twice, selected at runtime by StateMachineFactory:

• a Panama/FFM implementation calling the native restate-sdk-shared-core library, used on JDK 23+ — the path that supports the latest Restate features;
• a pure-Java implementation (the legacy state machine) used on JDK < 23, or when the native library is unavailable/disabled — a deprecated fallback that will be removed in a future release.

Instances of this interface are not thread-safe.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	StateMachine.AwaitResult
static final record	StateMachine.Awakeable
static final record	StateMachine.CallHandle
static final record	StateMachine.Input
static enum	StateMachine.InvocationState
static interface	StateMachine.NotificationValue
static final record	StateMachine.RunResultHandle

Method Summary

Modifier and Type	Method	Description
int	attachInvocation(String invocationId)
StateMachine.Awakeable	awakeable()
StateMachine.CallHandle	call(Target target, Slice payload, @Nullable String idempotencyKey, @Nullable String scope, @Nullable String limitKey, @Nullable Collection<Map.Entry<String,String>> headers)
void	cancelInvocation(String targetInvocationId)
void	close()
void	completeAwakeable(String awakeableId, Slice value)
void	completeAwakeable(String awakeableId, TerminalException exception)
void	completeSignal(String targetInvocationId, String signalName, Slice value)
void	completeSignal(String targetInvocationId, String signalName, TerminalException exception)
int	createSignalHandle(String signalName)
StateMachine.AwaitResult	doAwait(UnresolvedFuture future)	Make progress on the still-uncompleted await tree rooted at future, or return null when nothing is left to await (every node already resolved).
void	end()
int	getInvocationOutput(String invocationId)
String	getResponseContentType()
StateMachine.Input	input()
boolean	isReadyToExecute()
void	notifyError(Throwable throwable)
void	notifyInput(Slice bytes)	Feed the next chunk of wire input.
void	notifyInputClosed()
int	promiseComplete(String key, Slice value)
int	promiseComplete(String key, TerminalException exception)
int	promiseGet(String key)
int	promisePeek(String key)
void	proposeRunCompletion(int handle, Slice value)
void	proposeRunCompletion(int handle, TerminalException terminalException)
void	proposeRunCompletion(int handle, Throwable exception, Duration attemptDuration, @Nullable RetryPolicy retryPolicy)
StateMachine.RunResultHandle	run(String name)
int	send(Target target, Slice payload, @Nullable String idempotencyKey, @Nullable String scope, @Nullable String limitKey, @Nullable Collection<Map.Entry<String,String>> headers, @Nullable Duration delay)
int	sleep(Duration duration, @Nullable String name)
StateMachine.InvocationState	state()
void	stateClear(String key)
void	stateClearAll()
int	stateGet(String key)
int	stateGetKeys()
void	stateSet(String key, Slice bytes)
@Nullable StateMachine.NotificationValue	takeNotification(int handle)
Slice	takeOutput()	Drain the next chunk of serialized output ready for the wire, or Slice.EMPTY when nothing is buffered.
void	writeOutput(Slice value)
void	writeOutput(TerminalException exception)

Method Details

getResponseContentType

String getResponseContentType()

notifyInput

void notifyInput(Slice bytes)

Feed the next chunk of wire input.

notifyInputClosed

void notifyInputClosed()

notifyError

void notifyError(Throwable throwable)

takeOutput

Slice takeOutput()

Drain the next chunk of serialized output ready for the wire, or Slice.EMPTY when nothing is buffered.

isReadyToExecute

boolean isReadyToExecute()

doAwait

StateMachine.AwaitResult doAwait(UnresolvedFuture future)

Make progress on the still-uncompleted await tree rooted at future, or return null when nothing is left to await (every node already resolved).

On suspension this does not return a value: it sneaky-throws AbortedExecutionException, which should be treated as a clean abort of the user code, not a failure to re-report.

takeNotification

@Nullable StateMachine.NotificationValue takeNotification(int handle)

input

StateMachine.Input input()

stateGet

int stateGet(String key)

stateGetKeys

int stateGetKeys()

stateSet

void stateSet(String key,
 Slice bytes)

stateClear

void stateClear(String key)

stateClearAll

void stateClearAll()

sleep

int sleep(Duration duration,
 @Nullable String name)

call

StateMachine.CallHandle call(Target target,
 Slice payload,
 @Nullable String idempotencyKey,
 @Nullable String scope,
 @Nullable String limitKey,
 @Nullable Collection<Map.Entry<String,String>> headers)

send

int send(Target target,
 Slice payload,
 @Nullable String idempotencyKey,
 @Nullable String scope,
 @Nullable String limitKey,
 @Nullable Collection<Map.Entry<String,String>> headers,
 @Nullable Duration delay)

awakeable

StateMachine.Awakeable awakeable()

completeAwakeable

void completeAwakeable(String awakeableId,
 Slice value)

completeAwakeable

void completeAwakeable(String awakeableId,
 TerminalException exception)

createSignalHandle

int createSignalHandle(String signalName)

completeSignal

void completeSignal(String targetInvocationId,
 String signalName,
 Slice value)

completeSignal

void completeSignal(String targetInvocationId,
 String signalName,
 TerminalException exception)

promiseGet

int promiseGet(String key)

promisePeek

int promisePeek(String key)

promiseComplete

int promiseComplete(String key,
 Slice value)

promiseComplete

int promiseComplete(String key,
 TerminalException exception)

run

StateMachine.RunResultHandle run(String name)

proposeRunCompletion

void proposeRunCompletion(int handle,
 Slice value)

proposeRunCompletion

void proposeRunCompletion(int handle,
 TerminalException terminalException)

proposeRunCompletion

void proposeRunCompletion(int handle,
 Throwable exception,
 Duration attemptDuration,
 @Nullable RetryPolicy retryPolicy)

cancelInvocation

void cancelInvocation(String targetInvocationId)

attachInvocation

int attachInvocation(String invocationId)

getInvocationOutput

int getInvocationOutput(String invocationId)

writeOutput

void writeOutput(Slice value)

writeOutput

void writeOutput(TerminalException exception)

end

void end()

close

void close()

Specified by:

close in interface AutoCloseable

state

StateMachine.InvocationState state()