I am using the googleJsonAPIService to manipulate users (CRUD). This is how I get the Directory instance:

def getBuilder() {
    def builder
    def httpTransport = googleJsonAPIService.makeTransport()
    def jsonFactory = googleJsonAPIService.makeJsonFactory()
    def requestInitialiser = googleJsonAPIService.getRequestInitialiser()

    builder = new Directory.Builder(httpTransport, jsonFactory, requestInitialiser);

    return builder
  }

  Directory getGoogleService() {
    Directory googleService = getBuilder().build()
    return googleService;
  }

Once I have this service, I use it to get a user's details (in my own service) for example:

def query = getGoogleService().users().get(id)
return handleException { query.execute() }

I manually populate a DTO with the result of that query, and this is where my question comes:

Is there an elegant way to have this mapping (object returned to DTO) done automatically so all I have to do is pass the class of the object to be returned?

This is the structure of the object returned by google :

["agreedToTerms":true,"changePasswordAtNextLogin":false,

"creationTime":"2013-11-04T04:33:35.000Z", "emails":[{"address":"[email protected]","primary":true}],...]