vaadin-framework/uitest/src/main/java/com/vaadin/tests/TestSetVisibleAndCaching.java

package com.vaadin.tests;

import com.vaadin.ui.Button;
import com.vaadin.ui.Component;
import com.vaadin.ui.Label;
import com.vaadin.ui.LegacyWindow;
import com.vaadin.ui.Panel;
import com.vaadin.ui.VerticalLayout;

public class TestSetVisibleAndCaching
        extends com.vaadin.server.LegacyApplication {

    Panel panelA = new Panel("Panel A");
    Panel panelB = new Panel("Panel B");
    Panel panelC = new Panel("Panel C");

    Button buttonNextPanel = new Button("Show next panel");

    int selectedPanel = 0;

    @Override
    public void init() {
        final LegacyWindow mainWindow = new LegacyWindow(
                "TestSetVisibleAndCaching");
        setMainWindow(mainWindow);

        panelA.setContent(wrapInPanelLayout(
                new Label("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA")));
        panelB.setContent(wrapInPanelLayout(
                new Label("BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB")));
        panelC.setContent(wrapInPanelLayout(
                new Label("CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC")));

        mainWindow.addComponent(
                new Label("Inspect transfered data from server to "
                        + "client using firebug (http request / response cycles)."
                        + " See how widgets are re-used,"
                        + " after each panel is once shown in GUI then"
                        + " their contents are not resend."));
        mainWindow.addComponent(buttonNextPanel);
        mainWindow.addComponent(panelA);
        mainWindow.addComponent(panelB);
        mainWindow.addComponent(panelC);

        selectPanel(selectedPanel);

        buttonNextPanel.addClickListener(event -> {
            selectedPanel++;
            if (selectedPanel > 2) {
                selectedPanel = 0;
            }
            selectPanel(selectedPanel);
        });
    }

    private VerticalLayout wrapInPanelLayout(Component component) {
        VerticalLayout layout = new VerticalLayout();
        layout.setMargin(true);
        layout.addComponent(component);
        return layout;
    }

    private void selectPanel(int selectedPanel) {
        System.err.println("Selecting panel " + selectedPanel);
        switch (selectedPanel) {
        case 0:
            panelA.setVisible(true);
            panelB.setVisible(false);
            panelC.setVisible(false);
            break;
        case 1:
            panelA.setVisible(false);
            panelB.setVisible(true);
            panelC.setVisible(false);
            break;
        case 2:
            panelA.setVisible(false);
            panelB.setVisible(false);
            panelC.setVisible(true);
            break;
        }
    }
}