IssueEvolvableTokenFlow

IssueEvolvableTokenFlow.java

/**
*  Issue a token for an existing house asset. Fetch the house from ledger using uuid, and issue a token against it.
*  call built in IssueTokens Flow to issue tokens
*  IssueTokens flow is a flow for issuing fungible or non-fungible tokens which initiates its own participantSessions. 
*  This is the case when called from the node rpc or in a unit test. However, in the case where you already
*  have a session with another [Party]
*  and you wish to issue tokens as part of a wider workflow, then use [IssueTokensFlow].
*/
@StartableByRPC
    public static class IssueEvolvableTokenFlow extends FlowLogic<SignedTransaction>{
        private final String evolvableTokenId;
        private final Party recipient;

        public IssueEvolvableTokenFlow(String evolvableTokenId, Party recipient) {
            this.evolvableTokenId = evolvableTokenId;
            this.recipient = recipient;
        }

        @Override
        @Suspendable
        public SignedTransaction call() throws FlowException {
            // uuid column in vault_linear_states contains the uuid of the created asset on ledger
            UUID uuid = UUID.fromString(evolvableTokenId);
            // construct queryCriteria to get the created asset on ledger by using LinearStateCriteria
            // get all the unconsumed states from vault_linear_states having uuid
            QueryCriteria queryCriteria = new QueryCriteria.LinearStateQueryCriteria(null, ImmutableList.of(uuid), null,
                    Vault.StateStatus.UNCONSUMED, null);
            // use vaultservice to hit the vault using the query criteria
            StateAndRef<RealEstateEvolvableTokenType> stateAndRef = getServiceHub().getVaultService().
                    queryBy(RealEstateEvolvableTokenType.class, queryCriteria).getStates().get(0);
            // get the state from StateAndRef returned by the query
            RealEstateEvolvableTokenType evolvableTokenType = stateAndRef.getState().getData();
            LinearPointer linearPointer = new LinearPointer(evolvableTokenType.getLinearId(), RealEstateEvolvableTokenType.class);
            // token pointer is a linear pointer to created real estate asset
            TokenPointer token = new TokenPointer(linearPointer, evolvableTokenType.getFractionDigits());
            // issue token stating issuer who is getOurIdentity() for this example, recipient will be the holder of the token
            return (SignedTransaction) subFlow(new IssueTokens(token, this.getOurIdentity(), recipient));
        }
    }