Represents an iterator component that can be used to create
a form of containing a dynamic hierarchy.
To create a dynamic hierarchy field, call FormOptions.createDynamicHierarchyField().
An iterator component which embeds a switcher containing a GROUP and ATTRIBUTE facet
is generated with default values for attribute values.
You can optionally specify alternative values for selected attributes by calling
the set methods on this class.
To create a form that contain dynamic hierachy,
call FormOptions.setFields() with a list that contains a dynamic hierarchy field
and call FormPattern.create() to create the form.