Myujth

Suppose there are two nodes, Alice and Bob. Alice has a state she wants to make Bob aware of. How can Alice send the state to Bob and get him to store it in his vault?

You will need both an initiator and a responder flow:

• The initiator will retrieve the state from its vault, retrieve the transaction that created this state, and send the transaction to the counterparty to be recorded


• The responder will record the transaction, storing all its states

Initiator flow

@InitiatingFlow
@StartableByRPC
public class Initiator extends FlowLogic<Void> 
 private final UUID stateId;
 private final Party otherParty;

 private final ProgressTracker progressTracker = new ProgressTracker();

 public Initiator(UUID stateId, Party otherParty) 
 this.stateId = stateId;
 this.otherParty = otherParty;
 

 @Override
 public ProgressTracker getProgressTracker() 
 return progressTracker;
 

 @Suspendable
 @Override
 public Void call() throws FlowException 
 // Find the correct state.
 LinearStateQueryCriteria criteria = new LinearStateQueryCriteria(null, Collections.singletonList(stateId));
 Vault.Page<IOUState> queryResults = getServiceHub().getVaultService().queryBy(IOUState.class, criteria);
 if (queryResults.getStates().size() != 1)
 throw new IllegalStateException("Not exactly one match for the provided ID.");
 StateAndRef<IOUState> stateAndRef = queryResults.getStates().get(0);

 // Find the transaction that created this state.
 SecureHash creatingTransactionHash = stateAndRef.getRef().getTxhash();
 SignedTransaction creatingTransaction = getServiceHub().getValidatedTransactions().getTransaction(creatingTransactionHash);

 // Send the transaction to the counterparty.
 final FlowSession counterpartySession = initiateFlow(otherParty);
 subFlow(new SendTransactionFlow(counterpartySession, creatingTransaction));

 return null;
 

Responder flow

@InitiatedBy(Initiator.class)
public class Responder extends FlowLogic<Void> 
 private final FlowSession counterpartySession;

 public Responder(FlowSession counterpartySession) 
 this.counterpartySession = counterpartySession;
 

 @Suspendable
 @Override
 public Void call() throws FlowException 
 // Receive the transaction and store all its states.
 // If we don't pass `ALL_VISIBLE`, only the states for which the node is one of the `participants` will be stored.
 subFlow(new ReceiveTransactionFlow(counterpartySession, true, StatesToRecord.ALL_VISIBLE));

 return null;