sdk-core/dev.restate.sdk.core/StateMachine

StateMachine

interface StateMachine : 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.

Inheritors

LegacyStateMachine

Types

AwaitResult

interface AwaitResult

Awakeable

class Awakeable : Record

CallHandle

class CallHandle : Record

Input

class Input : Record

InvocationState

enum InvocationState

NotificationValue

interface NotificationValue

RunResultHandle

class RunResultHandle : Record

Functions

attachInvocation

abstract fun attachInvocation(invocationId: String): Int

awakeable

abstract fun awakeable(): StateMachine.Awakeable

call

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

cancelInvocation

abstract fun cancelInvocation(targetInvocationId: String)

abstract fun close()

completeAwakeable

abstract fun completeAwakeable(awakeableId: String, value: Slice)

abstract fun completeAwakeable(awakeableId: String, exception: TerminalException)

completeSignal

abstract fun completeSignal(targetInvocationId: String, signalName: String, value: Slice)

abstract fun completeSignal(targetInvocationId: String, signalName: String, exception: TerminalException)

createSignalHandle

abstract fun createSignalHandle(signalName: String): Int

doAwait

abstract fun doAwait(future: UnresolvedFuture): StateMachine.AwaitResult

Make progress on the still-uncompleted await tree rooted at future, or return


null

when nothing is left to await (every node already resolved).

end

abstract fun end()

getInvocationOutput

abstract fun getInvocationOutput(invocationId: String): Int

getResponseContentType

abstract fun getResponseContentType(): String

input

abstract fun input(): StateMachine.Input

isReadyToExecute

abstract fun isReadyToExecute(): Boolean

notifyError

abstract fun notifyError(throwable: Throwable)

notifyInput

abstract fun notifyInput(bytes: Slice)

Feed the next chunk of wire input.

notifyInputClosed

abstract fun notifyInputClosed()

promiseComplete

abstract fun promiseComplete(key: String, value: Slice): Int

abstract fun promiseComplete(key: String, exception: TerminalException): Int

promiseGet

abstract fun promiseGet(key: String): Int

promisePeek

abstract fun promisePeek(key: String): Int

proposeRunCompletion

abstract fun proposeRunCompletion(handle: Int, value: Slice)

abstract fun proposeRunCompletion(handle: Int, terminalException: TerminalException)

abstract fun proposeRunCompletion(handle: Int, exception: Throwable, attemptDuration: Duration, @Nullable retryPolicy: @Nullable RetryPolicy)

run

abstract fun run(name: String): StateMachine.RunResultHandle

send

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

sleep