AdvancedCriteria Servlet String to AdvancedCriteria

[heiss12345]

Smart GWT Power Edition Ver. 4.1
I want to convert my AdvancedCriteria Json String which i send with Post Parmater to servlet to an AdvancedCriteria Objcet and use it to fetch from databank.

is there a function available to convert String => AdvancedCriteria Object in server side?

Regards
Alireza