Query for an input state that has been consumed in the transaction

Question

Let say, I have defined two states StateA and StateB and executed the following actions.

• Create StateA with no inputs. (NoInput -> StateA-sa1)
• Change one of the parameter on StateA. (StateA-sa1 -> StateA-sa2)
• Create StateB with unconsumed StateA as input. (StateA-sa2 -> StateB-sb1)

Is it possible to construct a single query to get current unconsumed StateB (StateB-sb1) and inputs(StateA-sa2) that went into creating this state?

Answer 1

As of Corda 3.1, no. It's not possible to achieve this with a single query. You actually need to perform three steps:

1. Query the vault for the current unconsumed StateB

   val stateBStateAndRef = serviceHub.vaultService.queryBy<StateB>().states.single()
   

2. Use the StateRef of the retrieved state to load the corresponding transaction

   val stateBTransaction = serviceHub.validatedTransactions.getTransaction(stateBStateAndRef.ref.txhash)!!
   

3. Load the states corresponding to the inputs of the loaded transaction

   val consumedInputs = stateBTransaction.inputs.map { stateRef -> serviceHub.loadState(stateRef) }