GOBL Java implementation

Early stage functionality

• parse Invoice from Json file
• make Invoice signature and save it as an Envelop
• save Invoice to file
• load and save JWK keys from/to file
• Invoice extract from Envelop
• signature verification when extract document from Envelop (only one signature is supported now)

Current limitation

• The only possible type of document that can be placed inside a signed Envelope is an Invoice. This decision is dictated by the simplification of implementation at this stage of the project.
• There is no tax calculation logic
• and much, much more — so help is more than welcome

Parse Invoice

public class Main {
    public static void main(String[] args) {
        Gobl gobl = new Gobl();
        Invoice invoice = gobl.parseInvoice("src/test/resources/invoice.json");
        System.out.println(invoice);
    }
}

Sign Invoice file

public class Main {

    public static void main(String[] args) {
        Gobl gobl = new Gobl();

        KeySupport keySupport = new KeySupport();
        val keys = keySupport.generate();

        val envelope = gobl.signInvoice("src/test/resources/invoice.json", keys.privateKey(), UUID.randomUUID());
        System.out.println(envelope);
    }
    
}

Sign Invoice with key from file

public class Main {

    public static void main(String[] args) {
        Gobl gobl = new Gobl();

        KeySupport keySupport = new KeySupport();
        Key key = keySupport.loadKey(Path.of("src/test/resources/id_es256.jwk"));

        val envelope = gobl.signInvoice("src/test/resources/invoice.json", (ECPrivateKey) key, UUID.randomUUID());
        System.out.println(envelope);
    }
    
}

Check signature and extract Invoice from Envelope

try{
    File file = new File("src/test/resources/invoice-signed.json");
    KeySupport keySupport = new KeySupport();
    Key publicKey = keySupport.loadKey(Path.of("src/test/resources/id_es256.pub.jwk"));
    
    Invoice invoice = gobl.extractFromEnvelope(file, Invoice.class, publicKey); 
    // validation OK
    System.out.println(invoice);
    } catch (SignatureException ex) {
        // validation failed
    }   

Create and Save Invoice

val invoice = new Invoice()
        .withCode("standard")
        .withIssueDate("2024-01-01")
        .withCustomer(new Party()
                .withName("Company INC")
                .withAddresses(List.of(new Address()
                        .withCountry("Poland")
                        .withCode("05-092")
                        .withStreet("Warszawska")))
                .withTaxId(new Identity()
                        .withCode("2222222222")
                        .withCountry("PL"))
        ).withCustomer(new Party()
                .withName("Customer sp. z o.o.")
                .withAddresses(List.of(new Address()
                        .withCountry("Poland")
                        .withCode("05-092")
                        .withStreet("Warszawska")))
                .withTaxId(new Identity()
                        .withCode("1111111111")
                        .withCountry("PL"))
        ).withLines(List.of(new Line()
                .withI(1)
                .withItem(new Item()
                        .withName("Myszka")
                        .withCurrency("PLN")
                        .withPrice("100"))));

Gobl gobl = new Gobl();
gobl.saveInvoice(invoice, System.out);

Maven dependency

<dependency>
    <groupId>io.alapierre.gobl</groupId>
    <artifactId>gobl-core</artifactId>
    <version>0.0.2</version>
</dependency>

Build requirements

The project can be built on JDK17+.

Building the API client library requires:

1. Java 17+
2. Maven