The cat is out of the bag (so to speak), Scott blogs about ObjectGraphBuilder and DomainBuilder, both are brainchildren of his. The former is already available in Groovy 1.1-rc-3, the later will see the light of day on Grails 1.0

Both of them will let you build a complex object graph provided you follow the usual conventions for beans, but the best thing IMHO is that OGB extends from FactoryBuilderSupport, thus enabling new features as "factory sharing". Suppose that you have a domain model where some classes are observable, i.e, they will fire PropertyChangeEvents whenever one of their properties changes value, and you'd like to connect listeners at the same you build the graph, that sounds like a job for bind() but that factory is available in SwingBuilder only. Should you copy the code? no need to, just register the BindFactory into your instance of OGB and your done! This is possible because SwingBuilder inherits from FBS also, take a look at the following example and see for yourself
import groovy.swing.factory.BindFactory import java.beans.PropertyChangeSupport // base class for observable beans class ObservableBean extends GroovyObjectSupport { def PropertyChangeSupport pso ObservableBean(){ pso = new PropertyChangeSupport(this) } void setProperty( String name, Object value ){ def oldValue = getProperty(name) if( oldValue != value ){ super.setProperty(name,value) pso.firePropertyChange(name,oldValue,value) } } public void addPropertyChangeListener( l ){ pso.addPropertyChangeListener(l) } public void removePropertyChangeListener( l ){ pso.removePropertyChangeListener(l) } } // observable domain classes =) class Company extends ObservableBean { String name List employees = [] } class Employee { String name } def ogb = new ObjectGraphBuilder() // enable groovyConsole's classloader, else // ogb won't find the previously defined classes ogb.classLoader = getClass().classLoader // borrow bind() from SwingBuilder ogb.registerFactory( "bind", new BindFactory() ) ogb.addAttributeDelegate( BindFactory.&bindingAttributeDelegate ) // build a company with 2 employees def company = ogb.company( id: 'c', name: "ACME" ) { employee( name: bind(source: c, sourceProperty: 'name', converter: { n -> "Drone @ $n" }) ) employee( name: bind(source: c, sourceProperty: 'name', converter: { n -> "Worker @ $n" }) ) } assert ["Drone @ ACME","Worker @ ACME"] == company.employees.name company.name = company.name.reverse() assert ["Drone @ EMCA","Worker @ EMCA"] == company.employees.name
Not only did the names of the employees were changed as the company's name was updated, but the value was also transformed, thanks to the options available on bind(). In case you were wondering, GraphicsBuilder does the same to support binding on shapes.

Keep on Groovying!