java - how to bind field to foreign key in bean vaadin -

I have my sister as this

  public class registration entity {Private long account Number; Private string first name; Private string middlename; Personal string last name; // Business Unit is another table, the professionalism of personal business; }   
 components are like this  
  first name = new textfield ("first name"); FirstName.setRequired (true); FirstName.setWidth (COMMON_FIELD_WIDTH); LastName = New TextField ("Last Name"); LastName.setRequired (true); LastName.setWidth (COMMON_FIELD_WIDTH); Business = new basic selection ("business:"); Occupation.setRequired (true); Occupation.setImmediate (true); Occupation.setWidth (COMMON_FIELD_WIDTH); Occupation.setNullSelectionItemId ("- Select--"); Occupation.addItem ("static");   
 As long as the first name and last name are assumed, this can be bound in such a way  
  fieldgroup.bind (first name, "first name ");   
 But how can I force business resident to occupationEntity ?????   
 
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 You can use  BeanFieldGroup  and Custom FieldGroupFieldFactory for this matter:    Binder = New Beanfield Group & lt; Registration Entity & gt; (RegistrationInternet.class); Binder.setFieldFactory (New FieldGroupFieldFactory () {Private DefaultFieldGroupFieldFactory defaultFactory = New DefaultFieldGroupFieldFactory (); @Override Public & lt; t createField (Class  TYPE; datatype, class  fieldType) { If ("OccupationEntity" T field is expanded gt. Equals (dataType.getName ()) {Binimum Container & quot; Occupation Entity> Capture Entity Container = New Bean Content Container & lt; Business Components & gt; ProfessionalAxA Category); ProfessionalismAncientContactor.Ad All (All Entity); Field Field = New Combat Box ("Business:", Occupational Antennor); (Explained) Area) .setItemCaptionPropertyId (- Insert Title Bean property here--), ((Combobox area) .setNullSelectionAllowed (false); FieldType.cast (region) return;} return defaultFactory.createField (datatype, fieldType);}}); Binder.setItemDataSource (item);