Delegate for Preference implementations; this is used instead of the Preference Bean implementation
in cases where we simply want to work with a preference object outside a transaction context, for example
when the Ajax implementation needs to create a clone of the object for marshalling into JSON.
Construct a delegate from a Preference bean
this.dkey = pref.getDkey();
this.dvalue = pref.getDvalue();
this.readOnly = pref.isReadOnly();
this.readOnly = readOnly;
This method is required for the IPreference interface, but in the case of this
delegate isn't meaningful as this object is not persisted, and
is only used in a transient fashion.