public void validateAccountStatus()

in fineract-loan/src/main/java/org/apache/fineract/portfolio/loanaccount/serialization/LoanDownPaymentTransactionValidator.java [77:223]
145 lines of code
42 McCabe index (conditional complexity)

    public void validateAccountStatus(final Loan loan, final LoanEvent event) {
        final List<ApiParameterError> dataValidationErrors = new ArrayList<>();

        switch (event) {
            case LOAN_APPROVED -> {
                if (!loan.isSubmittedAndPendingApproval()) {
                    final String defaultUserMessage = "Loan Account Approval is not allowed. Loan Account is not in submitted and pending approval state.";
                    final ApiParameterError error = ApiParameterError
                            .generalError("error.msg.loan.approve.account.is.not.submitted.and.pending.state", defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case LOAN_APPROVAL_UNDO -> {
                if (!loan.isApproved()) {
                    final String defaultUserMessage = "Loan Account Undo Approval is not allowed. Loan Account is not in approved state.";
                    final ApiParameterError error = ApiParameterError.generalError("error.msg.loan.undo.approval.account.is.not.approved",
                            defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case LOAN_DISBURSED -> {
                if ((!(loan.isApproved() && loan.isNotDisbursed()) && !loan.getLoanProduct().isMultiDisburseLoan())
                        || (loan.getLoanProduct().isMultiDisburseLoan() && !loan.isAllTranchesNotDisbursed())) {
                    final String defaultUserMessage = "Loan Disbursal is not allowed. Loan Account is not in approved and not disbursed state.";
                    final ApiParameterError error = ApiParameterError
                            .generalError("error.msg.loan.disbursal.account.is.not.approve.not.disbursed.state", defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case LOAN_DISBURSAL_UNDO -> {
                if (!loan.isOpen()) {
                    final String defaultUserMessage = "Loan Undo disbursal is not allowed. Loan Account is not active.";
                    final ApiParameterError error = ApiParameterError.generalError("error.msg.loan.undo.disbursal.account.is.not.active",
                            defaultUserMessage);
                    dataValidationErrors.add(error);
                }
                if (loan.isOpen() && loan.isTopup()) {
                    final String defaultUserMessage = "Loan Undo disbursal is not allowed on Topup Loans";
                    final ApiParameterError error = ApiParameterError
                            .generalError("error.msg.loan.undo.disbursal.not.allowed.on.topup.loan", defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case LOAN_REPAYMENT_OR_WAIVER -> {
                if (!loan.isOpen()) {
                    final String defaultUserMessage = "Loan Repayment (or its types) or Waiver is not allowed. Loan Account is not active.";
                    final ApiParameterError error = ApiParameterError
                            .generalError("error.msg.loan.repayment.or.waiver.account.is.not.active", defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case WRITE_OFF_OUTSTANDING -> {
                if (!loan.isOpen()) {
                    final String defaultUserMessage = "Loan Written off is not allowed. Loan Account is not active.";
                    final ApiParameterError error = ApiParameterError.generalError("error.msg.loan.writtenoff.account.is.not.active",
                            defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case WRITE_OFF_OUTSTANDING_UNDO -> {
                if (!loan.isClosedWrittenOff()) {
                    final String defaultUserMessage = "Loan Undo Written off is not allowed. Loan Account is not Written off.";
                    final ApiParameterError error = ApiParameterError
                            .generalError("error.msg.loan.undo.writtenoff.account.is.not.written.off", defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case LOAN_CHARGE_PAYMENT -> {
                if (!loan.isOpen()) {
                    final String defaultUserMessage = "Charge payment is not allowed. Loan Account is not Active.";
                    final ApiParameterError error = ApiParameterError.generalError("error.msg.loan.charge.payment.account.is.not.active",
                            defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case LOAN_CLOSED -> {
                if (!loan.isOpen()) {
                    final String defaultUserMessage = "Closing Loan Account is not allowed. Loan Account is not Active.";
                    final ApiParameterError error = ApiParameterError.generalError("error.msg.loan.close.account.is.not.active",
                            defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case LOAN_EDIT_MULTI_DISBURSE_DATE -> {
                if (loan.isClosed()) {
                    final String defaultUserMessage = "Edit disbursement is not allowed. Loan Account is not active.";
                    final ApiParameterError error = ApiParameterError.generalError("error.msg.loan.edit.disbursement.account.is.not.active",
                            defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case LOAN_RECOVERY_PAYMENT -> {
                if (!loan.isClosedWrittenOff()) {
                    final String defaultUserMessage = "Recovery repayments may only be made on loans which are written off";
                    final ApiParameterError error = ApiParameterError.generalError("error.msg.loan.account.is.not.written.off",
                            defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case LOAN_REFUND -> {
                if (!loan.isOpen()) {
                    final String defaultUserMessage = "Loan Refund is not allowed. Loan Account is not active.";
                    final ApiParameterError error = ApiParameterError.generalError("error.msg.loan.refund.account.is.not.active",
                            defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case LOAN_DISBURSAL_UNDO_LAST -> {
                if (!loan.isOpen()) {
                    final String defaultUserMessage = "Loan Undo last disbursal is not allowed. Loan Account is not active.";
                    final ApiParameterError error = ApiParameterError
                            .generalError("error.msg.loan.undo.last.disbursal.account.is.not.active", defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case LOAN_FORECLOSURE -> {
                if (!loan.isOpen()) {
                    final String defaultUserMessage = "Loan foreclosure is not allowed. Loan Account is not active.";
                    final ApiParameterError error = ApiParameterError.generalError("error.msg.loan.foreclosure.account.is.not.active",
                            defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case LOAN_CREDIT_BALANCE_REFUND -> {
                if (!loan.getStatus().isOverpaid()) {
                    final String defaultUserMessage = "Loan Credit Balance Refund is not allowed. Loan Account is not Overpaid.";
                    final ApiParameterError error = ApiParameterError
                            .generalError("error.msg.loan.credit.balance.refund.account.is.not.overpaid", defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            case LOAN_CHARGE_ADJUSTMENT -> {
                if (!(loan.getStatus().isActive() || loan.getStatus().isClosedObligationsMet() || loan.getStatus().isOverpaid())) {
                    final String defaultUserMessage = "Loan Charge Adjustment is not allowed. Loan Account must be either Active, Fully repaid or Overpaid.";
                    final ApiParameterError error = ApiParameterError
                            .generalError("error.msg.loan.charge.adjustment.account.is.not.in.valid.state", defaultUserMessage);
                    dataValidationErrors.add(error);
                }
            }
            default -> {
            }
        }

        if (!dataValidationErrors.isEmpty()) {
            throw new PlatformApiDataValidationException(dataValidationErrors);
        }
    }