Vaadin binding objects - vaadin

Question

I am trying to bind a textfield to an object. I've done some research and I have found this answer.
public class Person {
String name;
String surname;
Address address;
// assume getters and setters
}
public class Address {
String street;
// assume getter and setters
}
Then, you could bind the street address like this:
Binder<Person> binder = new Binder<>();
TextField streetAddressField = new TextField();
// bind using lambda expressions
binder.bind(streetAddressField,
person -> person.getAddress().getStreet(),
(person, street) -> person.getAddress().setStreet(street));
What value do I instantiate street as (in the last line of code)?
The above was the example I found. My code is as follows - I have a contact class:
#Entity
public class Contact {
#Id
#GeneratedValue
private Long id;
private String firstName;
private String lastName;
private String phoneNumber;
#ManyToOne (cascade = {CascadeType.ALL})
#JoinColumn(name="phoneType_typeId")
private PhoneType phoneType;
public Contact(){
}
public Contact(String firstName, String lastName, String phoneNumber, PhoneType type) {
this.firstName = firstName;
this.lastName = lastName;
this.phoneNumber = phoneNumber;
this.phoneType = type;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getPhoneNumber() {
return phoneNumber;
}
public void setPhoneNumber(String phoneNumber) {
this.phoneNumber = phoneNumber;
}
public PhoneType getPhoneType() {
return phoneType;
}
public void setPhoneType(PhoneType phoneType) {
this.phoneType = phoneType;
}
#Override
public String toString() {
return String.format("Contact[firstName='%s', lastName='%s', phoneNumber='%s', phoneType = '%s']",
firstName, lastName, phoneNumber, phoneType);
}
}
Then I have a phoneType class:
#Entity
#Table(name="phoneType")
public class PhoneType {
#Id
#GeneratedValue
#Column(name = "typeId")
private Long id;
private String type;
public PhoneType(String type){
this.type = type;
}
public PhoneType(){}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
#Override
public String toString() {
return type;
}
}
Then in a Contact Editor I am trying to bind the phoneType to a textfield:
#SpringComponent
#UIScope
public class ContactEditor extends VerticalLayout {
private final ContactRepository repository;
private Contact contact;
TextField firstName = new TextField("First name");
TextField lastName = new TextField("Last name");
TextField phoneNumber = new TextField("Phone number");
TextField phoneType = new TextField( "Phone type");
Button save = new Button("Save", VaadinIcons.CHECK);
Button cancel = new Button("Cancel");
Button delete = new Button("Delete", VaadinIcons.TRASH);
CssLayout actions = new CssLayout(save, cancel, delete);
Binder<Contact> binder = new Binder<>(Contact.class);
#Autowired
public ContactEditor(ContactRepository repository, Contact contact) {
this.repository = repository;
this.contact = contact;
String type = contact.getPhoneType().getType();
addComponents(firstName, lastName, phoneNumber, phoneType, actions);
// bind using naming convention
**binder.bind(phoneType, contact.getPhoneType().getType(), contact.getPhoneType().setType(type));**
binder.bindInstanceFields(this);
// Configure and style components
setSpacing(true);
actions.setStyleName(ValoTheme.LAYOUT_COMPONENT_GROUP);
save.setStyleName(ValoTheme.BUTTON_PRIMARY);
save.setClickShortcut(ShortcutAction.KeyCode.ENTER);
// wire action buttons to save, delete and reset
save.addClickListener(e -> repository.save(contact));
delete.addClickListener(e -> repository.delete(contact));
cancel.addClickListener(e -> editContact(contact));
setVisible(false);
}
public interface ChangeHandler {
void onChange();
}
public final void editContact(Contact c) {
if (c == null) {
setVisible(false);
return;
}
final boolean persisted = c.getId() != null;
if (persisted) {
// Find fresh entity for editing
contact = repository.findById(c.getId()).get();
}
else {
contact = c;
}
cancel.setVisible(persisted);
// Bind customer properties to similarly named fields
// Could also use annotation or "manual binding" or programmatically
// moving values from fields to entities before saving
binder.setBean(contact);
setVisible(true);
// A hack to ensure the whole form is visible
save.focus();
// Select all text in firstName field automatically
firstName.selectAll();
}
public void setChangeHandler(ChangeHandler h) {
// ChangeHandler is notified when either save or delete
// is clicked
save.addClickListener(e -> h.onChange());
delete.addClickListener(e -> h.onChange());
}
}
The line enclosed in ** in Contact Editor (i.e. binder.bind(phoneType, contact.getPhoneType().getType(), contact.getPhoneType().setType(type))) is giving me an error - "no instance of type variable FIELDVALUE exist so that string conforms to ValueProvider .

Answer 1

The line
binder.bind(phoneType, contact.getPhoneType().getType(), contact.getPhoneType().setType(type));
does not compile because the method arguments do not match to any of the bind methods, and there is an illegal Java expression in the 3rd argument. According to your question, you have simply forgotten to use lambdas. Try:
binder.bind(phoneType, c -> c.getPhoneType().getType(), (c, t) -> c.getPhoneType().setType(t));
Have a look at the method signature:
public <FIELDVALUE> Binder.Binding<BEAN,FIELDVALUE> bind(HasValue<FIELDVALUE> field,
ValueProvider<BEAN,FIELDVALUE> getter,
Setter<BEAN,FIELDVALUE> setter)
It expects ValueProvider and Setter as 2nd and 3rd argument. These interfaces have only one method to be implemented, therefore you can use lambdas to pass them to bind.

Answer 2

I don't know if this is what you'r asking, but what I see as missing is that you haven't binded your binder to any bean.
You have created the binder, and you've told your textfield which property is binded to, but now you need to tell the binder which is his bean.
Something like:
Person yourPerson = new Person(); //or get person from database somehow
yourPerson.setAddress(new Address());
yourPerson.getAddress().setStreet("Road cool code, 404");
binder.setBean(yourPerson);
This should do the trick... if not, please explain better what you need. ;)