import ch.codeblock.qrinvoice.model.QrInvoice;
import ch.codeblock.qrinvoice.model.builder.QrInvoiceBuilder;
import ch.codeblock.qrinvoice.model.validation.ValidationException;
import ch.codeblock.qrinvoice.model.validation.ValidationResult;

import ch.codeblock.qrinvoice.model.billinformation.swicos1v12.SwicoS1v12;
import ch.codeblock.qrinvoice.model.billinformation.swicos1v12.builder.PaymentConditionBuilder;
import ch.codeblock.qrinvoice.model.billinformation.swicos1v12.builder.SwicoS1v12Builder;
import ch.codeblock.qrinvoice.model.billinformation.swicos1v12.builder.VatDetailsBuilder;

// ...
try {

    final SwicoS1v12 s1 = SwicoS1v12Builder
    .create()
    .invoiceReference("10201409") // Tag 10 - any string
    .invoiceDate(LocalDate.of(19, 5, 12)) // Tag 11 - 12.05.2019
    .customerReference("1400.000-53") // Tag 20 - any string
    .uidNumber("106017086") // Tag 30 - UID-Nr. without pre- and suffix or delimiteres - CHE-106.017.086 MWST
    .vatDateStart(LocalDate.of(2018,5,8)) // Tag 31 - 08.05.2018
    .vatDetails(
            // Tag 32 - 7.7% VAT
            VatDetailsBuilder.create().taxPercentage(7.7).build()
    )
    .paymentConditions(
            // Tag 40 - 2% cash discount when payed within 10 days (2% skonto), afterwards 0% and amount payable within 30 days
            PaymentConditionBuilder.create().cashDiscountPercentage(2).eligiblePaymentPeriodDays(10).build(),
            PaymentConditionBuilder.create().cashDiscountPercentage(0).eligiblePaymentPeriodDays(30).build()
    )
    .build();

    // contains: "//S1/10/10201409/11/190512/20/1400.000-53/30/106017086/31/180508/32/7.7/40/2:10;0:30"
    final String swicoBillInformation = s1.toBillInformationString();

    final QrInvoice qrInvoice = QrInvoiceBuilder
    .create()
    // ..
    .additionalInformation(a -> a
        .billInformation(swicoBillInformation)
    )
    .build();
} catch (ValidationException validationException) {
    final ValidationResult validationResult = validationException.getValidationResult();
    // handle exception...
}