Datatable

Question

I'm trying to create the following logic:

Step one : Check if the values have been stored more then x time, if so delete them.
Step two : Check if current value has been used before
Step Three : If used return False (and write value to Datatable), else return true (dont' write the value to the arraylist).

I thought this would be best if I create an DataTable. But how do i go about this?