Actions

Actions represent user interactions.

Example

@Button
Runnable save = () -> {};

Mateu renders a button.

Key idea

Methods = actions.

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ActionSupplier

Interface — io.mateu.uidl.fluent.ActionSupplier

When a ViewModel implements ActionSupplier, Mateu calls actions() to obtain the list of Action objects that define which named actions the component exposes. The default implementation returns a wildcard action (id = "*"), which means all actions are allowed.

public interface ActionSupplier {
    default List<Action> actions(HttpRequest httpRequest) {
        return List.of(Action.builder().id("*").build());
    }
}

Use this to restrict or dynamically configure the set of actions available on a component — for example, to expose only certain actions depending on user role or entity state.

Example

@UI("/orders/{id}")
public class OrderForm implements ActionSupplier {

    public String status;

    @Override
    public List<Action> actions(HttpRequest httpRequest) {
        if ("draft".equals(status)) {
            return List.of(
                Action.builder().id("submit").build(),
                Action.builder().id("discard").build());
        }
        if ("pending".equals(status)) {
            return List.of(
                Action.builder().id("approve").build(),
                Action.builder().id("reject").build());
        }
        return List.of();
    }
}

Note: ActionSupplier controls which actions are exposed at the component level. For hiding or disabling individual buttons in the UI, use VisibilitySupplier or DisabledSupplier instead.

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ButtonsSupplier

Interface — io.mateu.uidl.interfaces.ButtonsSupplier

When a ViewModel implements ButtonsSupplier, Mateu calls buttons() to obtain the full list of page buttons. This completely replaces annotation-based button discovery (fields and methods annotated with @Button).

public interface ButtonsSupplier {
    Collection<UserTrigger> buttons();
}

Use this when you need full programmatic control over which buttons are shown and how they are configured, including label, color, variant, icon, and shortcut.

Example

@UI("/orders/{id}")
public class OrderForm implements ButtonsSupplier {

    public String status;

    @Override
    public Collection<UserTrigger> buttons() {
        var buttons = new ArrayList<UserTrigger>();
        if ("draft".equals(status)) {
            buttons.add(Button.builder().label("Submit").actionId("submit")
                .color(ButtonColor.primary).build());
            buttons.add(Button.builder().label("Discard").actionId("discard").build());
        }
        if ("pending".equals(status)) {
            buttons.add(Button.builder().label("Approve").actionId("approve")
                .color(ButtonColor.success).build());
            buttons.add(Button.builder().label("Reject").actionId("reject")
                .color(ButtonColor.error).build());
        }
        return buttons;
    }

    public void submit() { ... }
    public void discard() { ... }
    public void approve() { ... }
    public void reject() { ... }
}

Note: ButtonsSupplier takes full control of buttons. If you only need to hide or disable individual buttons dynamically, use VisibilitySupplier or DisabledSupplier instead — they work alongside annotation-based discovery.

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ToolbarSupplier

Interface — io.mateu.uidl.interfaces.ToolbarSupplier

When a ViewModel implements ToolbarSupplier, Mateu calls toolbar() to obtain the full list of toolbar items. This completely replaces annotation-based toolbar discovery (fields and methods annotated with @Toolbar).

public interface ToolbarSupplier {
    Collection<UserTrigger> toolbar();
}

Same semantics as ButtonsSupplier but for the toolbar area of the page.