net.corda.core.flows

Class CollectSignaturesFlow

net.corda.core.flows.FlowLogic<T>

net.corda.core.flows.CollectSignaturesFlow

public class CollectSignaturesFlow
extends FlowLogic<T>

The class CollectSignaturesFlow is used to automate the collection of counterparty signatures for a given transaction.

You would typically use this flow after you have built a transaction with the TransactionBuilder and signed it with your key pair. If there are additional signatures to collect then they can be collected using this flow. Signatures are collected based upon the WireTransaction.requiredSigningKeys property which contains the union of all the PublicKeys listed in the transaction's commands as well as a notary's public key, if required. This flow returns a class SignedTransaction which can then be passed to the class FinalityFlow for notarisation. The other side of this flow is the class SignTransactionFlow.

WARNING: This flow ONLY works with ServiceHub.legalIdentityKeys and WILL break if used with randomly generated keys by the ServiceHub.keyManagementService.

Usage:

• Call the class CollectSignaturesFlow flow as a subFlow and pass it a class SignedTransaction which has at least been signed by the transaction creator (and possibly an oracle, if required)

• The flow expects that the calling node has signed the provided transaction, if not the flow will fail

• The flow will also fail if:

1. The provided transaction is invalid

2. Any of the required signing parties cannot be found in the ServiceHub.networkMapCache of the initiator

3. If the wrong key has been used by a counterparty to sign the transaction

4. The counterparty rejects the provided transaction

• The flow will return a class SignedTransaction with all the counterparty signatures (but not the notary's!)

• If the provided transaction has already been signed by all counterparties then this flow simply returns the provided transaction without contacting any counterparties

• Call the class FinalityFlow with the return value of this flow

Example - issuing a multi-lateral agreement which requires N signatures:

    val builder = TransactionBuilder(notaryRef)
    val issueCommand = Command(Agreement.Commands.Issue(), state.participants)

    builder.withItems(state, issueCommand)
    builder.toWireTransaction().toLedgerTransaction(serviceHub).verify()

    // Transaction creator signs transaction.
    val ptx = serviceHub.signInitialTransaction(builder)

    // Call to CollectSignaturesFlow.
    // The returned signed transaction will have all signatures appended apart from the notary's.
    val stx = subFlow(CollectSignaturesFlow(ptx))

See Also:

class CollectSignaturesFlow, WireTransaction.requiredSigningKeys, class SignedTransaction, class FinalityFlow, class SignTransactionFlow, ServiceHub.keyManagementService, class CollectSignaturesFlow, subFlow, class SignedTransaction, ServiceHub.networkMapCache, class SignedTransaction, class FinalityFlow

Field Detail

Companion

public static net.corda.core.flows.CollectSignaturesFlow.Companion Companion

Constructor Detail

CollectSignaturesFlow

@JvmOverloads
public CollectSignaturesFlow(@NotNull
                                           SignedTransaction partiallySignedTx,
                                           @NotNull
                                           java.util.Collection<? extends net.corda.core.flows.FlowSession> sessionsToCollectFrom,
                                           @Nullable
                                           java.lang.Iterable<? extends java.security.PublicKey> myOptionalKeys,
                                           @NotNull
                                           ProgressTracker progressTracker)

The class CollectSignaturesFlow is used to automate the collection of counterparty signatures for a given transaction.

You would typically use this flow after you have built a transaction with the TransactionBuilder and signed it with your key pair. If there are additional signatures to collect then they can be collected using this flow. Signatures are collected based upon the WireTransaction.requiredSigningKeys property which contains the union of all the PublicKeys listed in the transaction's commands as well as a notary's public key, if required. This flow returns a class SignedTransaction which can then be passed to the class FinalityFlow for notarisation. The other side of this flow is the class SignTransactionFlow.

WARNING: This flow ONLY works with ServiceHub.legalIdentityKeys and WILL break if used with randomly generated keys by the ServiceHub.keyManagementService.

Usage:

• Call the class CollectSignaturesFlow flow as a subFlow and pass it a class SignedTransaction which has at least been signed by the transaction creator (and possibly an oracle, if required)

• The flow expects that the calling node has signed the provided transaction, if not the flow will fail

• The flow will also fail if:

1. The provided transaction is invalid

2. Any of the required signing parties cannot be found in the ServiceHub.networkMapCache of the initiator

3. If the wrong key has been used by a counterparty to sign the transaction

4. The counterparty rejects the provided transaction

• The flow will return a class SignedTransaction with all the counterparty signatures (but not the notary's!)

• If the provided transaction has already been signed by all counterparties then this flow simply returns the provided transaction without contacting any counterparties

• Call the class FinalityFlow with the return value of this flow

Example - issuing a multi-lateral agreement which requires N signatures:

    val builder = TransactionBuilder(notaryRef)
    val issueCommand = Command(Agreement.Commands.Issue(), state.participants)

    builder.withItems(state, issueCommand)
    builder.toWireTransaction().toLedgerTransaction(serviceHub).verify()

    // Transaction creator signs transaction.
    val ptx = serviceHub.signInitialTransaction(builder)

    // Call to CollectSignaturesFlow.
    // The returned signed transaction will have all signatures appended apart from the notary's.
    val stx = subFlow(CollectSignaturesFlow(ptx))

Parameters:

partiallySignedTx - Transaction to collect the remaining signatures for

sessionsToCollectFrom - A session for every party we need to collect a signature from. Must be an exact match.

myOptionalKeys - set of keys in the transaction which are owned by this node. This includes keys used on commands, notjust in the states. If null, the default well known identity of the node is used.

progressTracker -

Override this to provide a class ProgressTracker. If one is provided and stepped, the framework will do something helpful with the progress reports e.g record to the audit service. 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.

Note that this has to return a tracker before the flow is invoked. You can't change your mind half way through.

See Also:

class CollectSignaturesFlow, WireTransaction.requiredSigningKeys, class SignedTransaction, class FinalityFlow, class SignTransactionFlow, ServiceHub.keyManagementService, class CollectSignaturesFlow, subFlow, class SignedTransaction, ServiceHub.networkMapCache, class SignedTransaction, class FinalityFlow

CollectSignaturesFlow

@JvmOverloads
public CollectSignaturesFlow(@NotNull
                                           SignedTransaction partiallySignedTx,
                                           @NotNull
                                           java.util.Collection<? extends net.corda.core.flows.FlowSession> sessionsToCollectFrom,
                                           @Nullable
                                           java.lang.Iterable<? extends java.security.PublicKey> myOptionalKeys)

The class CollectSignaturesFlow is used to automate the collection of counterparty signatures for a given transaction.

You would typically use this flow after you have built a transaction with the TransactionBuilder and signed it with your key pair. If there are additional signatures to collect then they can be collected using this flow. Signatures are collected based upon the WireTransaction.requiredSigningKeys property which contains the union of all the PublicKeys listed in the transaction's commands as well as a notary's public key, if required. This flow returns a class SignedTransaction which can then be passed to the class FinalityFlow for notarisation. The other side of this flow is the class SignTransactionFlow.

WARNING: This flow ONLY works with ServiceHub.legalIdentityKeys and WILL break if used with randomly generated keys by the ServiceHub.keyManagementService.

Usage:

• Call the class CollectSignaturesFlow flow as a subFlow and pass it a class SignedTransaction which has at least been signed by the transaction creator (and possibly an oracle, if required)

• The flow expects that the calling node has signed the provided transaction, if not the flow will fail

• The flow will also fail if:

1. The provided transaction is invalid

2. Any of the required signing parties cannot be found in the ServiceHub.networkMapCache of the initiator

3. If the wrong key has been used by a counterparty to sign the transaction

4. The counterparty rejects the provided transaction

• The flow will return a class SignedTransaction with all the counterparty signatures (but not the notary's!)

• If the provided transaction has already been signed by all counterparties then this flow simply returns the provided transaction without contacting any counterparties

• Call the class FinalityFlow with the return value of this flow

Example - issuing a multi-lateral agreement which requires N signatures:

    val builder = TransactionBuilder(notaryRef)
    val issueCommand = Command(Agreement.Commands.Issue(), state.participants)

    builder.withItems(state, issueCommand)
    builder.toWireTransaction().toLedgerTransaction(serviceHub).verify()

    // Transaction creator signs transaction.
    val ptx = serviceHub.signInitialTransaction(builder)

    // Call to CollectSignaturesFlow.
    // The returned signed transaction will have all signatures appended apart from the notary's.
    val stx = subFlow(CollectSignaturesFlow(ptx))

Parameters:

partiallySignedTx - Transaction to collect the remaining signatures for

sessionsToCollectFrom - A session for every party we need to collect a signature from. Must be an exact match.

myOptionalKeys - set of keys in the transaction which are owned by this node. This includes keys used on commands, notjust in the states. If null, the default well known identity of the node is used.

See Also:

class CollectSignaturesFlow, WireTransaction.requiredSigningKeys, class SignedTransaction, class FinalityFlow, class SignTransactionFlow, ServiceHub.keyManagementService, class CollectSignaturesFlow, subFlow, class SignedTransaction, ServiceHub.networkMapCache, class SignedTransaction, class FinalityFlow

CollectSignaturesFlow

@JvmOverloads
public CollectSignaturesFlow(@NotNull
                                           SignedTransaction partiallySignedTx,
                                           @NotNull
                                           java.util.Collection<? extends net.corda.core.flows.FlowSession> sessionsToCollectFrom,
                                           @NotNull
                                           ProgressTracker progressTracker)

CollectSignaturesFlow

@JvmOverloads
public CollectSignaturesFlow(@NotNull
                                           SignedTransaction partiallySignedTx,
                                           @NotNull
                                           java.util.Collection<? extends net.corda.core.flows.FlowSession> sessionsToCollectFrom)

Method Detail

call

@Suspendable
 @NotNull
public SignedTransaction call()

This is where you fill out your business logic.

getPartiallySignedTx

@NotNull
public SignedTransaction getPartiallySignedTx()

Transaction to collect the remaining signatures for

getSessionsToCollectFrom

@NotNull
public java.util.Collection<net.corda.core.flows.FlowSession> getSessionsToCollectFrom()

A session for every party we need to collect a signature from.

Must be an exact match.

getMyOptionalKeys

@Nullable
public java.lang.Iterable<java.security.PublicKey> getMyOptionalKeys()

set of keys in the transaction which are owned by this node.

This includes keys used on commands, notjust in the states. If null, the default well known identity of the node is used.

getProgressTracker

@NotNull
public ProgressTracker getProgressTracker()

Override this to provide a class ProgressTracker. If one is provided and stepped, the framework will do something helpful with the progress reports e.g record to the audit service. 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.

Note that this has to return a tracker before the flow is invoked. You can't change your mind half way through.

See Also:

class ProgressTracker

tracker

@JvmStatic
 @NotNull
public static ProgressTracker tracker()