Vaadin 7 FieldGroup & Converter
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The document summarizes Nicolas Frankel's presentation on Vaadin 7 at a Paris Vaadin & GWT Meetup. It covered Vaadin 7 features like SASS, connectors, and client-side extensions. It also discussed the new FieldGroup API for handling fields and data binding, providing examples of how to implement FieldGroup and customize field types. Finally, it explained converters for converting between model values and string representations without side effects.
Vaadin 7 FieldGroup & Converter
- 1. Paris Vaadin & GWT Meetup
- 2. Bio @nicolas_frankel Software Architect http://blog.frankel.ch & http://morevaadin.com Learning Vaadin Main interests: GUI Software quality Build automation New things!
- 3. Vaadin 7 revolutions SASS Connectors Client-side extensions …
- 4. Vaadin 7 evolutions Window API Javascript API FieldGroup Converter …
- 5. FieldGroup Remember the old Form? It coupled display & field handling It is deprecated Use FieldGroup And set the layout you want!
- 6. Data binding levels 1. Property Single value Birthdate 2. Item Connected properties First name, last name, birthdate 3. Container Collection of items
- 7. Example Person person = new Person(1L); person.setFirstName("John"); person.setLastName("Doe"); person.setBirthdate(new Date(0)); BeanItem<Person> item = new BeanItem<Person>(person);
- 8. Naive implementation TextField id = new TextField (item.getItemProperty("id")); TextField firstName = new TextField(item.getItemProperty("firstName")); TextField lastName = new TextField(item.getItemProperty("lastName")); DateField birthdate = new DateField(item.getItemProperty("birthdate")); Layout layout = new FormLayout(id, firstName, lastName, birthdate);
- 9. Result
- 10. FieldGroup implementation FieldGroup group = new FieldGroup(item); Field<?> id = group.buildAndBind("id"); Field<?> firstName = group.buildAndBind("firstName"); Field<?> lastName = group.buildAndBind("lastName"); Field<?> birthdate = group.buildAndBind("birthdate"); Layout layout = new VerticalLayout(id, firstName, lastName, birthdate);
- 11. Result
- 13. Custom FieldGroupFieldFactory @Override public <T extends Field> T createField(Class<?> dataType, Class<T> fieldType) { if (dataType.isAssignableFrom(Date.class)) { return (T) new DateField(); } return delegate.createField(dataType, fieldType); }
- 14. Rework group.setFieldFactory(new CustomFieldGroupFieldFactory()); Layout layout = new FormLayout(id, firstName, lastName, birthdate);
- 15. Result
- 16. Final rework Field<?> id = group.buildAndBind(null, "id"); Field<?> firstName = group.buildAndBind("Given name", "firstName"); Field<?> lastName = group.buildAndBind("Family name", "lastName");
- 17. Result
- 18. Converters Separate model values from their String representations Provides ways to convert From String to model And back
- 20. Requirements No side-effects, including GUI changes Method implementation need to be symmetric
- 21. Implementation TextField tf = new TextField(); tf.setConverter(new StringToIntegerConverter()); int i = (Integer) tf.getConvertedValue();
- 22. @learnvaadin