State, actions and fields

Mateu UIs are built from a small set of concepts.

State (fields)

Fields represent UI state.

Actions

Actions represent behavior triggered by the user.

They can be defined as:

• methods annotated with @Toolbar
• methods annotated with @Button
• Runnable fields annotated with @Button

Buttons and placement

• @Toolbar → top toolbar
• @Button on methods → bottom form actions
• @Button on fields → inline buttons

Action behavior

Actions can be configured declaratively using @Action.

Validation

Bean validation is automatically enforced in the UI.

Reactions

Triggers define when actions run.

Dynamic behavior

Rules define how the UI changes dynamically in the browser.

UI effects

Actions can return:

• Message → user feedback
• UICommand → browser control

Mental model

• state → fields
• actions → methods or buttons
• action behavior → @Action
• reactions → triggers
• rules → dynamic behavior
• validation → bean validation
• effects → UI feedback