This processor is used to expand terms so the query looks for the same term in different fields. It also boosts a query based on its field.
This processor looks for every IFieldableNode contained in the query node tree. If a IFieldableNode is found, it checks if there is a ConfigurationKeys.MULTI_FIELDS defined in the Core.Config.QueryConfigHandler. If there is, the IFieldableNode is cloned N times and the clones are added to a BooleanQueryNode together with the original node. N is defined by the number of fields that it will be expanded to. The BooleanQueryNode is returned.