Creating a TextField for integer only input using a data source

A TextField is a component that always has a value of type String. When binding a property of another type to a text field, the value is automatically converted if the conversion between the two types is supported.

Java

  1. public class MyBean {
  2.   private int value;
  4.   public int getValue() {
  5.     return value;
  6.   }
  8.   public void setValue(int integer) {
  9.     value = integer;
  10.   }
  11. }

The property named “value” from a BeanItem constructed from MyBean will be of type Integer. Binding the property to a TextField will automatically make validation fail for texts that can not be converted to an Integer.

Java

  1. final MyBean myBean = new MyBean();
  2. BeanItem<MyBean> beanItem = new BeanItem<MyBean>(myBean);
  4. final Property<Integer> integerProperty = (Property<Integer>) beanItem
  5.     .getItemProperty("value");
  6. final TextField textField = new TextField("Text field", integerProperty);
  8. Button submitButton = new Button("Submit value", new ClickListener() {
  9.   public void buttonClick(ClickEvent event) {
  10.     String uiValue = textField.getValue();
  11.     Integer propertyValue = integerProperty.getValue();
  12.     int dataModelValue = myBean.getValue();
  14.     Notification.show("UI value (String): " + uiValue
  15.         + "\nProperty value (Integer): " + propertyValue
  16.         + "\nData model value (int): " + dataModelValue);
  17.    }
  18. });
  20. addComponent(new Label("Text field type: " + textField.getType()));
  21. addComponent(new Label("Text field type: " + integerProperty.getType()));
  22. addComponent(textField);
  23. addComponent(submitButton);

With this example, entering a number and pressing the button causes the value of the TextField to be a String, the property value will be an Integer representing the same value and the value in the bean will be the same int. If e.g. a letter is entered to the field and the button is pressed, the validation will fail. This causes a notice to be displayed for the field. The field value is still updated, but the property value and the bean value are kept at their previous values.