Command constraints

    fun verifyCommandConstraints(tx: LedgerTransaction){

        val command = tx.commands.requireSingleCommand<AgreementContract.Commands>()

        when (command.value){
            is Commands.Propose -> {
            }
            is Commands.Reject -> {
                // Path Constraints have already checked there is only one input and one output
                val inputState = tx.inputsOfType<AgreementState>().single()
                val outputState = tx.outputsOfType<AgreementState>().single()

                // Note, to check the majority of properties haven't change the code copies the outputstate but sets the changing properties to that of the input state. if all the other properties are the same, the copy should match the input state.
                requireThat {"When the command is Reject no properties can change except status, rejectionReason and rejectedBy." using (outputState.copy(
                        status = inputState.status,
                        rejectionReason = inputState.rejectionReason,
                        rejectedBy = inputState.rejectedBy) == inputState)}
            }
            is Commands.Repropose -> {
            }
            is Commands.Agree -> {
                requireThat {
                    // Path Constraints have already checked there is only one input and one output
                    val inputState = tx.inputsOfType<AgreementState>().single()
                    val outputState = tx.outputsOfType<AgreementState>().single()
                    requireThat {"When the command is Agree no properties can change except status." using (outputState.copy(status = inputState.status) == inputState)}
                }
            }
            is Commands.Complete -> {}
        }
    }