title: Simplify switch expression that updates private member
body: <p>I want to simplify this logic:</p>
  
  <pre><code>  private String member_A;
    private String member_B;
    private String member_C;
    private String member_D;
  
   private void xyz(Object x, String s) {
   switch (s) {
      case "A":
        member_A = x.getInternalNumber();
        break;
      case "B":
        member_B = x.getInternalNumber();
        break;
      case "C":
        member_C = x.getInternalNumber();
        break;
      case "D":
        member_D = x.getInternalNumber();
        break;
      default:
      }
   }
  
  
   xyz(x, "A");
   ...
   xyz(x, "B");
   ...
   etc
  </code></pre>
  
  <p>The <code>switch</code> shall be replaced by a more elegant solution. Technically, the calls of xyz(...) shall update the correct field with some value. 
  Does anyone has an idea to improve this?</p>