vaadin-framework/documentation/articles/CreatingACustomFieldForEditingTheAddressOfAPerson.asciidoc

---
title: Creating A Custom Field For Editing The Address Of A Person
order: 27
layout: page
---

[[creating-a-customfield-for-editing-the-address-of-a-person]]
= Creating a CustomField for editing the address of a person

A normal use case is that you want to create a form out a bean that the
user can edit. Often these beans contain references to other beans as
well, and you have to create a separate editor for those. This tutorial
goes through on how to edit an `Address` bean which is inside a `Person`
bean with the use of `CustomField` and `FieldGroup`.

Here are the `Person` and `Address` beans

[source,java]
....
public class Person {
  private String firstName;
  private String lastName;
  private Address address;
  private String phoneNumber;
  private String email;
  private Date dateOfBirth;
  private String comments;

  //Getters and setters
}
....

[source,java]
....
public class Address {
  private String street;
  private String zip;
  private String city;
  private String country;

  // Getters and setters
}
....

[[creating-a-new-field]]
Creating a new field
~~~~~~~~~~~~~~~~~~~~

The first step is to create a new field which represents the editor for
the address. In this case the field itself will be a button. The button
will open a window where you have all the address fields. The address
will be stored back when the user closes the window.

[source,java]
....
public class AddressPopup extends CustomField<Address> {
  @Override
  protected Component initContent() {
    return null;
  }

  @Override
  public Class<Address> getType() {
    return Address.class;
  }
}
....

CustomField requires that you implement two methods, `initContent()` and
`getType()`. `initContent()` creates the actual visual representation of
your field. `getType()` tells the field which type of data will be handled
by the field. In our case it is an `Address` object so we return
`Address.class` in the method.

[[creating-the-content]]
Creating the content
~~~~~~~~~~~~~~~~~~~~

Next up we create the actual button that will be visible in the person
editor when the CustomField is rendered. This button should open up a
new window where the user can edit the address.

[source,java]
....
@Override
protected Component initContent() {
  final Window window = new Window("Edit address");
  final Button button = new Button("Open address editor", new ClickListener() {
    public void buttonClick(ClickEvent event) {
      getUI().addWindow(window);
    }
  });
  return button;
}
....

This is enough to attach the field to the person editor, but the window
will be empty and it won't modify the data in any way.

[[creating-the-editable-fields]]
Creating the editable fields
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The address object contains four strings - street, zip, city and
country. For the three latter a `TextField` is good for editing, but the
street address can contain multiple row so a `TextArea` is better here.
All the fields have to be put into a layout and the layout has to be set
as the content of the window. `FormLayout` is a good choice here to nicely
align up the captions and fields of the window.

[source,java]
....
FormLayout layout = new FormLayout();
TextArea street = new TextArea("Street address:");
TextField zip = new TextField("Zip code:");
TextField city = new TextField("City:");
TextField country = new TextField("Country:");
layout.addComponent(street);
layout.addComponent(zip);
layout.addComponent(city);
layout.addComponent(country);
window.setContent(layout);
....

The field is now visually ready but it doesn't contain or affect any
data. You want to also modify the sizes as well to make it look a bit
nicer:

[source,java]
....
window.center();
window.setWidth(null);
layout.setWidth(null);
layout.setMargin(true);
....

[[binding-the-address-to-the-field]]
Binding the address to the field
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

A FieldGroup can be used to bind the data of an Address bean into the
fields. We create a member variable for a FieldGroup and initialize it
within the createContent() -method:

[source,java]
....
fieldGroup = new BeanFieldGroup<Address>(Address.class);
fieldGroup.bind(street, "street");
fieldGroup.bind(zip, "zip");
fieldGroup.bind(city, "city");
fieldGroup.bind(country, "country");
....

The `FieldGroup` of the person editor will call
`AddressPopup.setValue(person.getAddress())` when we start to edit our
person. We need to override `setInternalValue(Address)` to get the `Address`
object and pass it to the `FieldGroup` of the address editor.

[source,java]
....
@Override
protected void setInternalValue(Address address) {
  super.setInternalValue(address);
  fieldGroup.setItemDataSource(new BeanItem<Address>(address));
}
....

The last thing that has to be done is save the modifications made by the
user back into the `Address` bean. This is done with a `commit()` call to
the `FieldGroup`, which can be made for example when the window is closed:

[source,java]
....
window.addCloseListener(new CloseListener() {
  public void windowClose(CloseEvent e) {
    try {
      fieldGroup.commit();
    } catch (CommitException ex) {
      ex.printStackTrace();
    }
  }
});
....

Now you need to attach the `AddressPopup` custom field into the person
editor through it's `FieldGroup` and you have a working editor.

[[complete-code]]
Complete code
~~~~~~~~~~~~~

[source,java]
....
package com.example.addressforms.fields;

import com.example.addressforms.data.Address;
import com.vaadin.data.fieldgroup.BeanFieldGroup;
import com.vaadin.data.fieldgroup.FieldGroup;
import com.vaadin.data.fieldgroup.FieldGroup.CommitException;
import com.vaadin.data.util.BeanItem;
import com.vaadin.ui.Button;
import com.vaadin.ui.Button.ClickEvent;
import com.vaadin.ui.Button.ClickListener;
import com.vaadin.ui.Component;
import com.vaadin.ui.CustomField;
import com.vaadin.ui.FormLayout;
import com.vaadin.ui.TextArea;
import com.vaadin.ui.TextField;
import com.vaadin.ui.Window;
import com.vaadin.ui.Window.CloseEvent;
import com.vaadin.ui.Window.CloseListener;

public class AddressPopup extends CustomField<Address> {
  private FieldGroup fieldGroup;

  @Override
  protected Component initContent() {
    FormLayout layout = new FormLayout();
    final Window window = new Window("Edit address", layout);
    TextArea street = new TextArea("Street address:");
    TextField zip = new TextField("Zip code:");
    TextField city = new TextField("City:");
    TextField country = new TextField("Country:");
    layout.addComponent(street);
    layout.addComponent(zip);
    layout.addComponent(city);
    layout.addComponent(country);

    fieldGroup = new BeanFieldGroup<Address>(Address.class);
    fieldGroup.bind(street, "street");
    fieldGroup.bind(zip, "zip");
    fieldGroup.bind(city, "city");
    fieldGroup.bind(country, "country");
    Button button = new Button("Open address editor", new ClickListener() {
      public void buttonClick(ClickEvent event) {
        getUI().addWindow(window);
      }
    });
    window.addCloseListener(new CloseListener() {
      public void windowClose(CloseEvent e) {
        try {
          fieldGroup.commit();
        } catch (CommitException ex) {
          ex.printStackTrace();
        }
      }
    });

    window.center();
    window.setWidth(null);
    layout.setWidth(null);
    layout.setMargin(true);
    return button;
  }

  @Override
  public Class<Address> getType() {
    return Address.class;
  }

  @Override
  protected void setInternalValue(Address address) {
    super.setInternalValue(address);
    fieldGroup.setItemDataSource(new BeanItem<Address>(address));
  }
}
....

image:img/person%20editor.png[Address editor]

image:img/address%20editor.png[Address editor window]