== Compliant Solution

----
public void evaluate(int operator) {
  switch (operator) {
    /* ... */
    case ADD: // Compliant
      evaluateAdd();
      break;
    /* ... */
  }
}

private void evaluateAdd() {
  int a = stack.pop();
  int b = stack.pop();
  int result = a + b;
  stack.push(result);
}
----