The pattern that you want will be very similar. This is much eaiser. Write an applet that will convert dollars to and from your currency. Make it look pretty. This exercise just exercises defining a class.
Money is too important to be just an int or a double .
To keep it simple, let's assume the amount is not large. We won't worry about errors, at least yet. Your implementation will contain this amount in the class. It returns itself. Make it look pretty.