Helper class for populating field data from an UnstructGridModel.
When creating a report, the user can specify a set of field values (key/value pairs) to be replaced in the generated report. For convenience, a base collection is provided using this helper class along with the requested UnstructGridModel. The user can freely add his own field values on top of these if required.
The field value are a map of keys and values both represented as strings.
See topic Field values for more information on the usage of field values.