reverse formatter in ui5

Hi Guys,

I have learned UI5 for a few weeks, and have one questions about ui5.  

there is Formatter that could be used as transformer of data format from model property to ui element property.  but is there a type of formatter used in the reverse direction, that is from UI element property to model property.

if there is no one, could you please tell me any workaround. cause this way, I don't need to access ui element to get the value.

Thanks,

Torren