Fire a typed custom event from a Composite to its parent

Hold an EventDispatcher inside the Composite, dispatch your event object from any internal handler, and expose onRatingChanged so callers register listeners without reaching into the component's internals. The RatingPicker owns its star buttons and recolors them itself when the value changes; the event simply carries the new rating.

import com.webforj.component.Composite;
import com.webforj.component.Theme;
import com.webforj.component.html.elements.Div;
import com.webforj.component.icons.IconButton;
import com.webforj.component.icons.TablerIcon;
import com.webforj.dispatcher.EventDispatcher;
import com.webforj.dispatcher.EventListener;
import com.webforj.dispatcher.ListenerRegistration;
import java.util.ArrayList;
import java.util.EventObject;
import java.util.List;

public class RatingPicker extends Composite<Div> {
  private final Div self = getBoundComponent();
  private final EventDispatcher dispatcher = new EventDispatcher();
  private final List<IconButton> stars = new ArrayList<>();
  private int value = 0;

  public RatingPicker() {
    for (int i = 1; i <= 5; i++) {
      int rating = i;
      IconButton star = new IconButton(TablerIcon.create("star"));
      star.setTheme(Theme.GRAY);
      star.onClick(e -> setValue(rating));
      stars.add(star);
      self.add(star);
    }
  }

  public void setValue(int newValue) {
    this.value = newValue;
    updateStars();
    dispatcher.dispatchEvent(new RatingChangedEvent(this, newValue));
  }

  public int getValue() {
    return value;
  }

  private void updateStars() {
    for (int i = 0; i < stars.size(); i++) {
      stars.get(i).setTheme(i < value ? Theme.PRIMARY : Theme.GRAY);
    }
  }

  public ListenerRegistration<RatingChangedEvent> onRatingChanged(
      EventListener<RatingChangedEvent> listener) {
    return dispatcher.addListener(RatingChangedEvent.class, listener);
  }

  public static class RatingChangedEvent extends EventObject {
    private final int value;

    public RatingChangedEvent(Object source, int value) {
      super(source);
      this.value = value;
    }

    public int getValue() {
      return value;
    }
  }
}

Any view that uses RatingPicker subscribes through onRatingChanged and reacts to the typed event. The parent reads the value from the event without touching the picker's stars:

import com.webforj.component.Composite;
import com.webforj.component.html.elements.Div;
import com.webforj.component.html.elements.Paragraph;
import com.webforj.router.annotation.Route;

@Route
public class RatingView extends Composite<Div> {
  private final Div self = getBoundComponent();
  private final RatingPicker ratingPicker = new RatingPicker();
  private final Paragraph summary = new Paragraph("No rating yet");

  public RatingView() {
    ratingPicker.onRatingChanged(e -> summary.setText("You rated: " + e.getValue() + " / 5"));
    self.add(ratingPicker, summary);
  }
}