Dynamic value for CASE in java SWITCH

Question

I need to implement switch case statement with dynamic value for case as below.

int v1 = 5;
int key = xx.getKey();

switch (v1) {
   case key:
       .......
   case key+1:
       .......
   case key+2:
       .......
   default:
       .......
}

When using this, java complains "case expressions must be constant expressions". Is there a way to use dynamic values in case. (switch variable is also dynamic value)

Answer 1

You cannot have non-constant expressions as cases in your switch statement. However, you can make the cases constant by subtracting key from v1:

switch (v1 - key) {
   case 0:
       .......
   case 1:
       .......
   case 2:
       .......
   default:
       .......
}

However, this only works because you have simple cases. As @BorisTheSpider points out, in the more general case, you'd need to use if...else statements.