Working integer list example

P/Sda1/Jpa/Company/companyJpa1/src/main/java/de/hdm_stuttgart/mi/company/ui/HelloUi.java

 package de.hdm_stuttgart.mi.company.ui;
 
+import java.util.SortedSet;
+import java.util.TreeSet;
+
 import javax.servlet.annotation.WebServlet;
 
 import com.vaadin.annotations.Theme;
 import com.vaadin.annotations.Title;
 import com.vaadin.annotations.VaadinServletConfiguration;
+import com.vaadin.data.Property;
+import com.vaadin.data.Property.ValueChangeEvent;
+import com.vaadin.data.util.ObjectProperty;
 import com.vaadin.server.VaadinRequest;
 import com.vaadin.server.VaadinServlet;
+import com.vaadin.ui.GridLayout;
 import com.vaadin.ui.HorizontalLayout;
 import com.vaadin.ui.Label;
+import com.vaadin.ui.TextField;
 import com.vaadin.ui.UI;
 import com.vaadin.ui.VerticalLayout;
 
@@ -20,51 +28,67 @@ import com.vaadin.ui.VerticalLayout;
 @Theme("valo")
 public class HelloUi  extends UI {
 
-   private static final long serialVersionUID = -307591917714387247L;
-
-   @Override
-   protected void init(VaadinRequest request) {
-   // The root of the component hierarchy
-      VerticalLayout content = new VerticalLayout();
-      content.setSizeFull(); // Use entire window
-      setContent(content);   // Attach to the UI
-      
-      // Add some component
-      content.addComponent(new Label("Hello!"));
-      
-      // Layout inside layout
-      HorizontalLayout hor = new HorizontalLayout();
-      hor.setSizeFull(); // Use all available space
-
-//      // Couple of horizontally laid out components
-//      Tree tree = new Tree("My Tree",
-//              TreeExample.createTreeContent());
-//      hor.addComponent(tree);
-//
-//      Table table = new Table("My Table",
-//              TableExample.generateContent());
-//      table.setSizeFull();
-//      hor.addComponent(table);
-//      hor.setExpandRatio(table, 1); // Expand to fill
-
-      content.addComponent(hor);
-      content.setExpandRatio(hor, 1); // Expand to fill
-      
-   }
-   
-   /**  Deployed as a Servlet or Portlet.
-   *
-   *  You can specify additional servlet parameters like the URI and UI
-   *  class name and turn on production mode when you have finished developing the application.
-   */
-  @WebServlet(urlPatterns = "/*")
-  @VaadinServletConfiguration(ui = HelloUi.class, productionMode = false)
-  public static class MyUIServlet extends VaadinServlet {
-
-    /**
-     * 
-     */
-    private static final long serialVersionUID = -2771410633323765889L;
-  }
+	private static final long serialVersionUID = -307591917714387247L;
+
+	static String convert(final SortedSet<Integer> values) {
+		if (0 == values.size()) {
+			return "";
+		} else {
+			final StringBuffer ret = new StringBuffer(values.first().toString());
+			final Integer v[] = values.toArray(new Integer[values.size()]);
+			for (int i = 1; i < v.length; i++) {
+				ret.append(", " + v[i]);
+			}
+			return ret.toString();
+		}		
+	}
+
+	final SortedSet<Integer> values = new TreeSet<Integer>();
+
+	@Override
+	protected void init(VaadinRequest request) {
+
+		final GridLayout grid = new GridLayout(2, 3);
+
+		setContent(grid);   // Attach to the UI
+
+		// Add or remove value
+		final ObjectProperty<Integer>
+		addInteger = new ObjectProperty<Integer>(0),
+		removeInteger = new ObjectProperty<Integer>(0);
+
+		final TextField 
+		addEditor = new TextField(addInteger),
+		removeEditor = new TextField(removeInteger);
+
+		final Label output = new Label();
+
+		grid.addComponents(
+				new Label("Add value:"), addEditor, 
+				new Label("Remove value:"), removeEditor,
+				new Label("Numbers:"), output);
+
+		addEditor.addValueChangeListener(event -> {
+			final Integer i = addInteger.getValue();
+			if (null != i && values.add(i)) {
+				output.setValue(convert(values));
+			}
+		});
+
+		removeEditor.addValueChangeListener(event -> {
+			final Integer i = removeInteger.getValue();
+			if (null != i && values.remove(i)) {
+				output.setValue(convert(values));
+			}
+		});
+	}
 
+	/**  Deployment description .
+	 *
+	 */
+	@WebServlet(urlPatterns = "/*")
+	@VaadinServletConfiguration(ui = HelloUi.class, productionMode = false)
+	public static class MyUIServlet extends VaadinServlet {
+		private static final long serialVersionUID = -2771410633323765889L;
+	}
 }