building calculator in java

I need to build a calculator in java for calculations that have two options, one for + and -. and the second for * and / ...
the user should choose one of the two options then enters a number then choose an operation then enters a number then an operation until the user enters "=" .. example : user choose first condition for + and -, then enters number 1 then enters + then 2 then - then 1 and when he enters = it shows the result which is 2.

conditions :
1 : throws exception when dividing on 0
2: throws exception when user enters 0 in condition 1 "+and -"