Using state in fluent components

When embedding fluent components inside a declarative page, there are multiple ways to use ViewModel state.

1. Direct component field (static content)

Component header = new Badge("Static");

Use this when the content does not depend on runtime state.

2. Deferred component with Callable<?> (recommended)

Callable<?> headerStats = () -> new HorizontalLayout(
    new Avatar(name),
    new Badge("v" + version)
);

Use this when the fluent content depends on hydrated ViewModel state.

This is the most natural approach in Java, since evaluation happens after the ViewModel has been hydrated.

3. State expressions

Component headerStats = new HorizontalLayout(
    new Avatar("${state.name}"),
    new Badge("v${state.version}")
);

Use this when the component supports state-based expressions directly.

Mental model

• Component → static content
• Callable<?> → dynamic content based on state
• ${state...} → declarative binding inside components