UI & UISpec Annotations

@UI (Target: TYPE)

public @interface UI {
  String value();                                           // required: URL path
  String indexHtmlPath() default "/static/_index.html";
  String frontendComponentPath() default "/assets/mateu.js";
}

The foundational annotation of the Mateu framework. Registers a Java class as a UI endpoint accessible at the given URL path.

Attribute	Type	Default	Description
`value`	`String`	—	URL path where this UI is served (e.g. `/orders`)
`indexHtmlPath`	`String`	`/static/_index.html`	Path to the HTML shell page
`frontendComponentPath`	`String`	`/assets/mateu.js`	Path to the frontend JS component

How it works:

Mateu’s annotation processor scans for @UI at startup
Registers the class as a handler for the given path
When a request arrives, instantiates the class and generates the UIDL (UI Definition Language) response
The frontend renders the UIDL as an interactive UI

Example:

@UI("/orders")
public class Orders extends AutoCrud<Order> {
    @Override
    public CrudRepository<Order> repository() {
        return new OrderRepository();
    }
}

@Script (Target: TYPE)

@Repeatable(Scripts.class)
public @interface Script {
  String src();
  String type() default "";
  boolean crossorigin() default false;
  boolean defer() default false;
  boolean async() default false;
}

Injects a <script> tag into the <head> of the generated HTML page. Can be applied multiple times to the same class.

Attribute	Type	Default	Description
`src`	`String`	—	URL of the script file
`type`	`String`	`""`	Value for the `type` attribute (e.g. `"module"`). Omitted when empty
`crossorigin`	`boolean`	`false`	Adds the `crossorigin` attribute
`defer`	`boolean`	`false`	Adds the `defer` attribute
`async`	`boolean`	`false`	Adds the `async` attribute

@UI("/dashboard")
@Script(src = "/assets/charts.js", type = "module")
@Script(src = "/assets/analytics.js", defer = true)
public class Dashboard { ... }

The generated HTML will contain, before </head>:

<script type="module" src="/assets/charts.js"></script>
<script src="/assets/analytics.js" defer></script>

@Link (Target: TYPE)

@Repeatable(Links.class)
public @interface Link {
  String rel();
  String href();
  String type() default "";
  String as() default "";
  boolean crossorigin() default false;
}

Injects a <link> tag into the <head> of the generated HTML page. Typical uses include stylesheets, preloads, and web fonts. Can be applied multiple times.

Attribute	Type	Default	Description
`rel`	`String`	—	Value for the `rel` attribute (e.g. `"stylesheet"`, `"preload"`)
`href`	`String`	—	URL of the linked resource
`type`	`String`	`""`	Value for the `type` attribute. Omitted when empty
`as`	`String`	`""`	Value for the `as` attribute (used with `rel="preload"`). Omitted when empty
`crossorigin`	`boolean`	`false`	Adds the `crossorigin` attribute

@UI("/dashboard")
@Link(rel = "stylesheet", href = "/assets/custom-theme.css")
@Link(rel = "preload", href = "/assets/fonts/inter.woff2", as = "font", crossorigin = true)
public class Dashboard { ... }

The generated HTML will contain, before </head>:

<link rel="stylesheet" href="/assets/custom-theme.css">
<link rel="preload" href="/assets/fonts/inter.woff2" as="font" crossorigin>

@Meta (Target: TYPE)

@Repeatable(Metas.class)
public @interface Meta {
  String name() default "";
  String content();
  String httpEquiv() default "";
  String charset() default "";
}

Injects a <meta> tag into the <head> of the generated HTML page. Can be applied multiple times.

Attribute	Type	Default	Description
`content`	`String`	—	Value for the `content` attribute
`name`	`String`	`""`	Value for the `name` attribute (e.g. `"description"`, `"viewport"`). Omitted when empty
`httpEquiv`	`String`	`""`	Value for the `http-equiv` attribute. Omitted when empty
`charset`	`String`	`""`	Value for the `charset` attribute. Omitted when empty

@UI("/dashboard")
@Meta(name = "description", content = "Sales dashboard for the admin panel")
@Meta(name = "viewport", content = "width=device-width, initial-scale=1")
public class Dashboard { ... }

The generated HTML will contain, before </head>:

<meta name="description" content="Sales dashboard for the admin panel">
<meta name="viewport" content="width=device-width, initial-scale=1">

Complete example

The three annotations can be combined freely on the same @UI class:

@UI("/store")
@Meta(name = "description", content = "Online store powered by Mateu")
@Link(rel = "stylesheet", href = "/assets/store-theme.css")
@Link(rel = "preload", href = "/assets/fonts/brand.woff2", as = "font", crossorigin = true)
@Script(src = "https://cdn.example.com/analytics.js", defer = true)
public class Store extends AutoCrud<Product> { ... }

@UISpec (Target: TYPE)

public @interface UISpec {
  String value();  // path to YAML UI specification file
}

Alternative to code-based UI definition. Points to a YAML file that describes the UI structure declaratively without Java annotations.

Used when:

The UI is defined by a non-Java team
The UI structure changes frequently without code changes
Integrating with external tooling that generates YAML

Cross-reference: see the YAML UI Definition guide for the full YAML format.