Routing and parameters

Mateu binds URL parameters directly to ViewModel fields. There are no controllers, no manual parsing, and no mapping layer.

The URL is just another input to your UI state.

Path parameters

Define placeholders in the route using :name syntax. Mateu maps them to fields with matching names.

@Route("/products/:id")
public class ProductForm {

    String id;   // receives the value from the URL

}

Navigating to /products/abc-123 sets id = "abc-123" before any action runs.

Query parameters

Fields not covered by path parameters are populated from the query string automatically.

@Route("/products/:id")
public class ProductForm {

    String id;       // from path
    int version;     // from query string

}

Navigating to /products/abc-123?version=2 sets:

id = "abc-123"
version = 2

Mateu handles type conversion. A missing parameter uses the field’s default Java value.

Full example

@Route("/products/:id")
public class ProductForm {

    String id;
    int version;

    @NotBlank
    String name;

    @Stereotype(FieldStereotype.radio)
    Status status;

    @ReadOnly
    String audit;

    @Button
    void inspect() {
        audit = "id=" + id + ", version=" + version + ", name=" + name;
    }

}

URL:

http://localhost:8080/products/abc-123?version=2

Result before the user acts:

id = "abc-123"
version = 2
name and status are populated from whatever the browser sent as form state

What this enables

Traditional architectures require:

Controller receives request
Controller parses parameters
Controller maps to a DTO
DTO is passed to the UI layer

With Mateu:

URL maps directly to the ViewModel

No intermediate layer. No boilerplate.

Notes

Field names must match parameter names exactly (case-sensitive)
Type conversion is automatic for primitives and common types (String, int, long, boolean, LocalDate, etc.)
Missing parameters leave fields at their Java default value