Language Rosetta

Every Mateu server emits the same wire model, so the concepts are identical across languages — only the declaration syntax changes. This page maps the idioms; the concept documentation (UX patterns, execution model, wire contract) applies to all three.

Declaring views and apps

Concept	Java	C# (.NET)	Python
Routed view	`@UI("/route")`	`[UI("route")]`	`@ui("route")`
Title	`@Title("...")`	`[Title("...")]`	`@title("...")`
App shell	`@UI` class with `@Menu` fields	`[App("...")]` class with `[MenuItem]` methods	`@app("...")` class with `@menu_item` methods
CRUD	`extends AutoCrud<T>` + `repository()`	`class X : Crud<T>` + `Fetch(...)`	`class X(Crud[Thing])` + `fetch(...)`
Wizard	`extends Wizard` + step fields	`Wizard` + `[Step]`	`Wizard` + `Step()`

Fields

Concept	Java	C#	Python
Required	`@NotNull` / `@NotEmpty`	`[Required]`	`Annotated[str, Required()]`
Label	`@Label("...")`	`[Label("...")]`	`Annotated[str, Label("...")]`
Section	`@Section("...")`	`[Section("...")]`	`Annotated[str, Section("...")]`
Explicit stereotype	`@Stereotype(...)`	`[Stereotype("...")]`	`Annotated[str, Stereotype("...")]`
Multiline	`@Multiline`	`[Multiline]`	`Annotated[str, Multiline()]`
Password	stereotype `password`	`[Password]`	`Annotated[str, Password()]`
Money	`@Stereotype(money)`	`[Money]`	`Annotated[str, Money()]`
Plain text (read-only)	`@PlainText`	`[PlainText]`	`Annotated[str, PlainText()]`
Radio group	`@UseRadioButtons`	`[UseRadioButtons]`	`Annotated[MyEnum, UseRadioButtons()]`
Nav link	`@LinkTo("/x/${state.id}")` / `LinkSupplier`	`[LinkTo("...")]` / `ILinkSupplier`	`Annotated[str, LinkTo("...")]` / `link(member_name)`
Signature capture	`@Signature`	`[Signature]`	`Annotated[str, Signature()]`
Photo capture	`@PhotoCapture`	`[PhotoCapture]`	`Annotated[str, PhotoCapture()]`
Tree select	`@TreeSelect(leavesOnly=…)`	`[TreeSelect(leavesOnly: …)]`	`Annotated[str, TreeSelect(leaves_only=…)]`
Numeric range filter (crud listing)	`@RangeFilter`	`[RangeFilter]`	`Annotated[float, RangeFilter()]`
Static options	class implements `OptionsSupplier`	class implements `IOptionsSupplier`	the view’s `options(field_name)` method

Actions & page features

Concept	Java	C#	Python
Button	`@Button` method	`[Button]` method	`@button()` method
Toast message	return `Message`	return `Message`	return `Message`
KPI	`@KPI` field	`[Kpi("Open tickets")]` method	`@kpi("Open tickets")` method
FAB	`@Fab(icon=…)` method	`[Fab("icon")]` method	`@fab("icon")` method
Keyboard shortcut	`@Action(shortcut="ctrl+s")`	`[Shortcut("ctrl+s")]`	`@shortcut("ctrl+s")`
Compact mode	`@Compact`	`[Compact]`	`@compact`
Adaptive layout	(default heuristics)	`[AutoLayout]`	`@auto_layout`
Banner	`@Banner(theme=…)` method	`[Banner(BannerTheme.Info, "…")]` method	`@banner(BannerTheme.INFO, "…")` method
Header badge	`@BadgeInHeader` field	`[HeaderBadge("success")]`	`Annotated[..., HeaderBadge(color="success")]`
App context selector	`@AppContext` field	`[AppContext]` member	`@app_context` method
Emit event	`UICommand.dispatchEvent` / `@Emits(name=…)`	`[Emits("order-created")]`	`@emits("order-created")`
Subscribe to event	`@SubscribeTo(event=…, action=…)`	`[SubscribeTo("event", "action")]`	`@subscribe_to("event", "action")`
Unsaved-changes guard	`@ConfirmOnNavigationIfDirty`	`[ConfirmOnNavigationIfDirty]`	`@confirm_on_navigation_if_dirty`
i18n	`Translator`	`ITranslator`	`Translator`

Exact signatures can drift — the per-language manuals (C#, Python) and each backend’s golden tests (backend/dotnet/test, backend/python/tests) are the source of truth.

What stays identical

The wire: POST /{baseUrl}/mateu/v3/sync/{route} → UIIncrement JSON.
The renderers: web (Vaadin, Redwood, SAP UI5, PatternFly) and native (JavaFX, Compose, React Native) render any server without client changes.
The concepts: everything under UX Patterns and the execution model.

For what each server supports today, see the feature parity matrix.