Question

Recently I wrote something like this:

public void doSomething(boolean b1, boolean b2){
   while(true){
      if(b1){
         doThis();
      }
      if(b2){
         doThat();
      }
   }
}

But I really don’t like this solution, because in every iteration you will have to check the 2 booleans. So as possible solution I could imagine to write 4 while loops with the ifs before each loop, but for obvious reasons this sucks in maintainability. Do you have any suggestions to make this piece of code nice and effective?

Answer 1

I agree that this is premature optimization, but here’s another construct you might be able to use if your language has guarantees on short-circuit evaluation. Since java does not allow you to cast void return types to boolean, you would need to modify doThis() and doThat() to return boolean.

public void doSomething(boolean b1, boolean b2){
    while(true){
        b1 && doThis(),
        b2 && doThat();
    }
}

The (x && foo()) will only execute the function if the value of x is true, otherwise short-circuit evaluation will kick in.

You would have to be extremely careful that your compiler does not just optimize away this entire expression since no values are actually assigned.

A real, possible optimization that will avoid both comparisons in all cases is to use a switch statement in the inner loop.

public void doSomething(boolean b1, boolean b2){
    int state = (b1 ? 1 : 0) + (b2 ? 2 : 0);
    while(true){
        switch (state){
            case 1: doThis(); break;
            case 3: doThis();
            case 2: doThat();
            default:
        }
    }
}