Grails data binding

Question

I'm trying to use DataBindingUtils.bindObjectToInstance(object, source) to copy properties from one object to another using this code (which can be run in the Grails console):

import org.codehaus.groovy.grails.web.binding.DataBindingUtils

class Source {

  String foo = 'foo'
  String bar = 'bar'
}

class Target {

  String foo
  String bar
}

def s = new Source()
def t = new Target()

def result = DataBindingUtils.bindObjectToInstance(t, s)

assert t.foo == 'foo'
assert t.bar == 'bar'

But the assertions are failing because the properties of t are null, why?

Answer 1

The data binder (below) in Grails has only implemented binding for a select subset of object types, namely Maps and Web Requests. So binding two arbitrary objects isn't implemented.

https://github.com/grails/grails-core/blob/master/grails-web/src/main/groovy/org/codehaus/groovy/grails/web/binding/DataBindingUtils.java