IllegalArgumentException = hard to catch it.. (help)

Question

Hi there,
I've got little problem catching the "IllegalArgumentException", if you guys know how to solve this problem that'd help me a lot..
The code works, but if I type something else than what's assigned in Enum it shows IllegalArgumentException...
TIA
       public Options paper, rock, scissors;
     //assign variables
       paper = Options.paper;
       rock = Options.rock;
       scissors = Options.scissors;
     String Playing;
//here comes the code.... = problem................................
//Select one of these only!
while(     !(Options.valueOf(thePlay) == Options.rock) && !(Options.valueOf(thePlay) == Options.paper) && !(Options.valueOf(thePlay) == Options.scissors)  )
         System.out.println("\n It's your turn select ONE:  rock,  paper,  scissors ");
     try{
      catch (IllegalArgumentException e)
          Playing = scan.next().toLowerCase();
.......Error:
Exception in thread "main" java.lang.IllegalArgumentException: No enum const class...

Answer 1

I see.
A few ways occur to me. Given this:
enum Stuff {dog, cat, monkey}You could do this:
Stuff s = null;
do {
  try {
    s = Stuff.valueOf(Input.getString());
  } catch (IllegalArgumentException e) {
    System.err.println("that's not a valid Stuff: " + e);
} while(s == null);
System.out.println("s is: " + s);which works, but is ugly.
Or you could do this:
Stuff s = null;
ASKUSER: while(true) {
  String in = Input.getString();
  for(Stuff t : Stuff.values()) {
    if (t.name().equals(in)) {
      s = t;
      break ASKUSER;
  System.err.println("That's not a valid value: " + in);
System.out.println("s is: " + s);Or you could do this:
Map<String, Stuff> vals = new HashMap<String, Stuff>();
for(Stuff t : Stuff.values())
  vals.put(t.name(), t);
// then later:
Stuff s = null;
do {
  s = vals.get(Input.getString());
  if (s == null)
    System.err.println("That's not a valid value");
} while(s == null);
System.out.println("s is: " + s);which might be worthwhile if you're doing a lot of lookups and there are a lot of values in the enum.
Another way which may be best is the following. First, define your enum like this:
enum Stuff {
  dog, cat, monkey;
  public static Stuff niceValueOf(String s) {
    for(Stuff t : values())
      if (t.name().equals(s))
        return t;
    return null;
}Then you could just do this;Stuff s = null;
do {
  s = Stuff.niceValueOf(Input.getString());
  if (s == null)
    System.err.println("That's not a valid value");
} while(s == null);
System.out.println("s is: " + s);I haven't used enums a whole lot myself, so maybe there's a better approach I'm not familiar with.