SnackOrder example using Holon-Platform and Vaadin

This is my another post in learning my Vaadin journey through Holon Platform. There is already an example here https://vaadin.com/learn/tutorials/dynamic-web-forms-with-validation-in-java explaining the concepts but I just want to mimic the same so that I can learn more about the Holon Platform APIs myself.

Here is the simplified code for the Dynamic WebForm example of SnackOrder

import com.holonplatform.core.property.PropertyBox;
import com.holonplatform.vaadin.flow.components.Components;
import com.holonplatform.vaadin.flow.components.PropertyInputForm;
import com.holonplatform.vaadin.flow.components.PropertyListing;
import com.holonplatform.vaadin.flow.components.SingleSelect;
import com.vaadin.flow.component.button.Button;
import com.vaadin.flow.component.combobox.ComboBox;
import com.vaadin.flow.component.orderedlayout.HorizontalLayout;
import com.vaadin.flow.component.orderedlayout.VerticalLayout;
import com.vaadin.flow.data.provider.ListDataProvider;
import com.vaadin.flow.router.Route;

import java.util.*;

@Route("Snack")
public class SnackOrderView extends VerticalLayout {

    private PropertyInputForm inputForm;
    private PropertyListing listing;

    public SnackOrderView() {

        initialize();


    }

    private void initialize() {

        Map<String, List<String>> snacks = new HashMap<>();
        snacks.put("Fruits", Arrays.asList("Banana", "Apple", "Orange", "Avocado"));
        snacks.put("Candy", Arrays.asList("Chocolate bar", "Gummy bears", "Granola bar"));
        snacks.put("Drinks", Arrays.asList("Soda", "Water", "Coffee", "Tea"));


        List<PropertyBox> snackOrders = new ArrayList<>();
        ListDataProvider<PropertyBox> gridDataProvider = new ListDataProvider<>(snackOrders);

        Button orderBtn = Components.button()
                .text("Order")
                .withThemeName("primary")
                .enabled(false)
                .onClick(event -> {
                    snackOrders.add(inputForm.getValue());
                    listing.refresh();
                })
                .build();

        SingleSelect<String> snackSelect = Components.input.singleSelect(String.class)
                .required()
                .enabled(false)
                .withValueChangeListener(event -> {
                    orderBtn.setEnabled(true);
                })
                .build();

        SingleSelect<String> snackTypeSelect = Components.input.singleSelect(String.class)
                .required()
                .items(snacks.keySet())
                .withValueChangeListener(event -> {
                    ((ComboBox<String>) snackSelect.getComponent()).setItems(snacks.get(event.getValue()));
                    ((ComboBox<String>) snackSelect.getComponent()).setEnabled(true);
                })
                .build();

        HorizontalLayout hl = Components.hl().build();

        inputForm = Components.input.form(hl, SnackOrder.PROPERTY_SET)
                .composer((content, source) -> {
                    source.getComponents().forEach(component -> {
                        content.add(component);
                    });
                    content.add(orderBtn);
                })
                .bind(SnackOrder.TYPE, snackTypeSelect)
                .bind(SnackOrder.SNACK, snackSelect)
                .initializer(content -> {
                    content.setSpacing(true);
                    content.setDefaultVerticalComponentAlignment(Alignment.BASELINE);
                })
                .withValueChangeListener(event -> {
                    orderBtn.setEnabled(inputForm.isValid());
                })
                .build();

        listing = Components.listing.properties(SnackOrder.PROPERTY_SET)
                .dataSource(gridDataProvider)
                .build();

        add(inputForm.getComponent(), listing.getComponent());

    }

}

Here is the screenprint showing the neat and simple web form