net.corda.confidential.SwapIdentitiesFlow;

Question

Console output of gradlew.bat clean deployNodesJava

My project does not work after I used SwapIdentitiesFlow(owner) in my flow class(code below). I have re-imported my project using Gradle to no benefit. I still get: "error: package net.corda.confidential does not exist import net.corda.confidential.SwapIdentitiesFlow;"

Interestingly, the external library has a file with a similar sounding name(Gradle: net.corda:corda-confidential-identities:corda-3.0) This and the import statement also exists.

Other similar issues did not help as I mentioned re-importing the project does not work. Initially, I get a red squiggly line in that class. I am prompted to add the classpath for it. Build gives no errors but the gradlew.bat.... does.

Thanks for the help.

package java_bootcamp;

import co.paralleluniverse.fibers.Suspendable;
import com.google.common.collect.ImmutableList;
import net.corda.confidential.SwapIdentitiesFlow;
import net.corda.core.contracts.StateAndRef;
import net.corda.core.flows.*;
import net.corda.core.identity.AbstractParty;
import net.corda.core.identity.AnonymousParty;
import net.corda.core.identity.Party;
import net.corda.core.transactions.SignedTransaction;
import net.corda.core.transactions.TransactionBuilder;
import net.corda.core.utilities.ProgressTracker;

import java.security.PublicKey;
import java.util.HashMap;
import java.util.List;

@InitiatingFlow
@StartableByRPC
public class BallotTransferFlow extends FlowLogic<SignedTransaction> {
private final Party owner;

public BallotTransferFlow(Party owner)
{
    this.owner = owner;
}

private final ProgressTracker progressTracker = new ProgressTracker();

@Override
public ProgressTracker getProgressTracker() {
    return progressTracker;
}


@Suspendable
public SignedTransaction call() throws FlowException {
    // We get a reference to our own identity.
    AbstractParty issuer = getOurIdentity();

    // We extract all the `VoteStates from the vault.
    List<StateAndRef<VoteState>> voteStateAndRefs = getServiceHub().getVaultService().queryBy(VoteState.class).getStates();

    // We find the `VoteState` of the issuer.
    StateAndRef<VoteState> inputVoteStateAndRef = voteStateAndRefs
            .stream().filter(voteStateAndRef -> {
                VoteState voteState = voteStateAndRef.getState().getData();
                return voteState.getOwner().equals(issuer) && voteState.getVote()==1;
            }).findAny().orElseThrow(() -> new IllegalArgumentException("The Ballot State for this owner was not found."));
    VoteState inputVoteState = inputVoteStateAndRef.getState().getData();


    // We find the `VoteState` of the candidate.
    StateAndRef<VoteState> inputVoteStateAndRef1 = voteStateAndRefs
            .stream().filter(voteStateAndRef -> {
                VoteState voteState = voteStateAndRef.getState().getData();
                return voteState.getOwner().equals(owner);
            }).findAny().orElseThrow(() -> new IllegalArgumentException("The Candidate State for this owner was not found."));
    VoteState oldCandidateState = inputVoteStateAndRef1.getState().getData();


    // We throw an exception if the flow was not started by the ballot's current owner.
    if (!(issuer.equals(inputVoteState.getOwner())))
        throw new IllegalStateException("This flow must be started by the current owner.");

    // We use the notary used by the input state.
    Party notary = inputVoteStateAndRef1.getState().getNotary();

    // We build a transaction using a `TransactionBuilder`.
    TransactionBuilder txBuilder = new TransactionBuilder(notary);


    VoteContract.Commands.Transfer commandData = new VoteContract.Commands.Transfer();
    final HashMap<Party, AnonymousParty> txKeys = subFlow(new SwapIdentitiesFlow(owner));
    if (txKeys.size() != 2) {
        throw new IllegalStateException("Something went wrong when generating confidential identities.");
    } else if (!txKeys.containsKey(getOurIdentity())) {
        throw new FlowException("Couldn't create our conf. identity.");
    } else if (!txKeys.containsKey(owner)) {
        throw new FlowException("Couldn't create lender's conf. identity.");
    }

    final AnonymousParty anonymousMe = txKeys.get(getOurIdentity());
    final AnonymousParty anonymousLender = txKeys.get(owner);

    // New Candidate State
    VoteState newCandidateState = new VoteState(oldCandidateState.getVote()+1, anonymousLender, anonymousMe);

    txBuilder.addInputState(inputVoteStateAndRef);
    txBuilder.addOutputState(newCandidateState, VoteContract.ID );
    List<PublicKey> requiredSigners = ImmutableList.of(inputVoteState.getOwner().getOwningKey());

    txBuilder.addCommand(commandData, requiredSigners);

    // We check that the transaction builder we've created meets the
    // contracts of the input and output states.
    txBuilder.verify(getServiceHub());


    // We sign the transaction with our private key, making it immutable.
    SignedTransaction signedTransaction = getServiceHub().signInitialTransaction(txBuilder);

    // We get the transaction notarised and recorded automatically by the platform.
    return subFlow(new FinalityFlow(signedTransaction));
}
}

Answer 1

As of Corda 3, you can fix this by adding the following cordaCompile dependency to the dependencies block of your build.gradle file:

cordaCompile "$corda_release_group:corda-confidential-identities:$corda_release_version"