corda / net.corda.flows / AbstractStateReplacementFlow / Instigator

Instigator

abstract class Instigator<out S : ContractState, out T : ContractState, out M> : FlowLogic<StateAndRef<T>>

The Instigator assembles the transaction for state replacement and sends out change proposals to all participants (Acceptor) of that state. If participants agree to the proposed change, they each sign the transaction. Finally, Instigator sends the transaction containing all participants' signatures to the notary for signature, and then back to each participant so they can record it and use the new updated state for future transactions.

Parameters

S - the input contract state type

T - the output contract state type, this can be different from S. For example, in contract upgrade, the output state type can be different from the input state type after the upgrade process.

M - the type of a class representing proposed modification by the instigator.

Types

NOTARY object NOTARY : Step
SIGNING object SIGNING : Step

Constructors

<init> Instigator(originalState: StateAndRef<S>, modification: M, progressTracker: ProgressTracker = tracker())

The Instigator assembles the transaction for state replacement and sends out change proposals to all participants (Acceptor) of that state. If participants agree to the proposed change, they each sign the transaction. Finally, Instigator sends the transaction containing all participants' signatures to the notary for signature, and then back to each participant so they can record it and use the new updated state for future transactions.

Properties

modification val modification: M
originalState val originalState: StateAndRef<S>
progressTracker open val progressTracker: ProgressTracker

Override this to provide a ProgressTracker. If one is provided and stepped, the framework will do something helpful with the progress reports. If this flow is invoked as a subflow of another, then the tracker will be made a child of the current step in the parent. If it's null, this flow doesn't track progress.

Inherited Properties

logger val logger: Logger

This is where you should log things to.

runId val runId: StateMachineRunId

Returns a wrapped UUID object that identifies this state machine run (i.e. subflows have the same identifier as their parents).

serviceHub val serviceHub: ServiceHub

Provides access to big, heavy classes that may be reconstructed from time to time, e.g. across restarts. It is only available once the flow has started, which means it cannnot be accessed in the constructor. Either access this lazily or from inside call.

stateMachine var stateMachine: FlowStateMachine<*>

Internal only. Reference to the Fiber instance that is the top level controller for the entire flow. When inside a flow this is equivalent to Strand.currentStrand. This is public only because it must be accessed across module boundaries.

Functions

assembleTx abstract fun assembleTx(): Pair<SignedTransaction, Iterable<CompositeKey>>
call open fun call(): StateAndRef<T>

This is where you fill out your business logic. The returned object will usually be ignored, but can be helpful if this flow is meant to be used as a subflow.

Inherited Functions

getCounterpartyMarker open fun getCounterpartyMarker(party: Party): Class<*>

Return the marker Class which party has used to register the counterparty flow that is to execute on the other side. The default implementation returns the class object of this FlowLogic, but any Class instance will do as long as the other side registers with it.

receive open fun <R : Any> receive(receiveType: Class<R>, otherParty: Party): UntrustworthyData<R>

Suspends until the specified otherParty sends us a message of type receiveType.

fun <R : Any> receive(otherParty: Party): UntrustworthyData<R>

Suspends until the specified otherParty sends us a message of type R.

send open fun send(otherParty: Party, payload: Any): Unit

Queues the given payload for sending to the otherParty and continues without suspending.

sendAndReceive open fun <R : Any> sendAndReceive(receiveType: Class<R>, otherParty: Party, payload: Any): UntrustworthyData<R>

Serializes and queues the given payload object for sending to the otherParty. Suspends until a response is received, which must be of the given receiveType. Remember that when receiving data from other parties the data should not be trusted until it's been thoroughly verified for consistency and that all expectations are satisfied, as a malicious peer may send you subtly corrupted data in order to exploit your code.

fun <R : Any> sendAndReceive(otherParty: Party, payload: Any): UntrustworthyData<R>

Serializes and queues the given payload object for sending to the otherParty. Suspends until a response is received, which must be of the given R type.

subFlow open fun <R> subFlow(subLogic: FlowLogic<R>, shareParentSessions: Boolean = false): R

Invokes the given subflow. This function returns once the subflow completes successfully with the result returned by that subflows call method. If the subflow has a progress tracker, it is attached to the current step in this flow's progress tracker.

track fun track(): Pair<String, Observable<String>>?

Returns a pair of the current progress step, as a string, and an observable of stringified changes to the progressTracker.

waitForLedgerCommit fun waitForLedgerCommit(hash: SecureHash): SignedTransaction

Suspends the flow until the transaction with the specified ID is received, successfully verified and sent to the vault for processing. Note that this call suspends until the transaction is considered valid by the local node, but that doesn't imply the vault will consider it relevant.

Companion Object Functions

tracker fun tracker(): ProgressTracker

Inheritors

Instigator class Instigator<OldState : ContractState, out NewState : ContractState> : Instigator<OldState, NewState, Class<out UpgradedContract<OldState, NewState>>>
Instigator class Instigator<out T : ContractState> : Instigator<T, T, Party>