---
title: Composite Fields with CustomField
order: 32
layout: page
---

[[components.customfield]]
= Composite Fields with [classname]#CustomField#

The [classname]#CustomField# is a way to create composite components like with
[classname]#CustomComponent#, except that it implements the
[interfacename]#Field# interface and inherit [classname]#AbstractField#,
described in
<<dummy/../../../framework/components/components-fields#components.fields,"Field
Components">>. A field allows editing a property value in the Vaadin data model,
and can be bound to data with field groups, as described in
<<dummy/../../../framework/datamodel/datamodel-itembinding#datamodel.itembinding,"Creating
Forms by Binding Fields to Items">>. The field values are buffered and can be
validated with validators.

A composite field class must implement the [methodname]#getType()# and
[methodname]#initContent()# methods. The latter should return the content
composite of the field. It is typically a layout component, but can be any
component.

It is also possible to override [methodname]#validate()#,
[methodname]#setInternalValue()#, [methodname]#commit()#,
[methodname]#setPropertyDataSource#, [methodname]#isEmpty()# and other methods
to implement different functionalities in the field. Methods overriding
[methodname]#setInternalValue()# should call the superclass method.