TransferLandTitleFlow_Qry.java

@InitiatingFlow
@StartableByRPC
public class TransferLandTitleFlow implements Flow<SignedTransactionDigest> {
  
  // Constructor
  
  @CordaInject
  private PersistenceService persistenceService;
  
  // Inject other services
  
  @Suspendable
  public SignedTransactionDigest call() {
    
    // Fetch the parameters passed to the flow.
  
    //Query the landState
    Map <String, Object> namedParameters = new LinkedHashMap<>();
    namedParameters.put("stateStatus", StateStatus.UNCONSUMED);
    Cursor<StateAndRef<LandTitleState>> cursor = persistenceService.query(
            "VaultState.findByStateStatus",
            namedParameters,
            new SetBasedVaultQueryFilter.Builder()
                    .withContractStateClassNames(Set.of(LandTitleState.class.getName()))
                    .build(),
            "Corda.IdentityStateAndRefPostProcessor"
    );

    List<StateAndRef<LandTitleState>> inputLandStateStateAndRefList =
            cursor.poll(100, Duration.ofSeconds(20)).getValues();
    
    // Filter the states to find the state in question
    StateAndRef<LandTitleState> inputLandStateStateAndRef =
                inputLandStateStateAndRefList.stream().filter(stateAndRef -> {
            LandTitleState landTitleState = stateAndRef.getState().getData();
            return landTitleState.getPlotNumber().equals(plotNumber);
        }).findAny().orElseThrow(() -> new FlowException("Land Not Found"));  
    
    // Build, Verify, Collect Signature and Commit Transaction.
  }

}