Looking to associate strings to ints in a cleaner/more efficient way

Question

How can I improve this?

The relationship is one to one and continuous on [-1,5] so i was thinking of using enum, but I\'m not sure how to compare a string value to

Answer 1

Why do you need a (very subjective) "cleaner" way?

You could get more efficiency from using a hash lookup but you'd want to be certain it's called quite a bit to make the extra coding effort worthwhile. If it's something that happens infrequently (and, by that, I mean something like less than once a second), it's not worth doing (YAGNI).

One thing you might want to do for better looking code (if that's important) is to ditch the else bits, they're totally unnecessary:

private int evaluateWord(String sval) {
    if (sval.equals("program")) return 1;
    if (sval.equals("begin"))   return 2;
    if (sval.equals("end"))     return 3;
    if (sval.equals("int"))     return 4;
    if (sval.equals("if"))      return 5;
    System.exit(0);
}

Answer 2

Have you considered stuffing the mapping into a HashMap once, and then just querying the map?

For example, something like this:

 private static final Map<String,Integer> m_map = new HashMap<String,Integer>();
 static {
     m_map.put( "program", 1 );
     m_map.put( "begin", 2 );
     m_map.put( "end", 3 );
     m_map.put( "int", 4 );
     m_map.put( "if", 5 );
 }

 private int evaluateWord(String sval) {
     Integer value = m_map.get( sval );
     if ( null != value ) {
        return value;
     }
     else {
        System.exit(0);
     }
 }

By the way, it looks as if you're writing a parser. It can be reasonable to write a parser by hand. Another option to consider, unless you have a good reason to write it by hand, is a parser generator like ANTLR.