How to iterate/navigate through each character in a character set (e.g., US-ASCII or IBM037, in proper sequence)?

Question

I want to iterate through each character in a character set (primarily US-ASCII and IBM037) and then print all alphanumeric characters (or all printable characters) in the proper character set sequence. Is it possible without creating static arrays?

Answer 1

Try the following to print all the valid characters in the order of the encoded values.

public static void main(String... args) {
    printCharactersFor("US-ASCII");
    printCharactersFor("IBM037");
}

private static void printCharactersFor(String charsetName) {
    System.out.println("Character set map for " + charsetName);
    Charset charset = Charset.forName(charsetName);
    SortedMap<BigInteger, String> charsInEncodedOrder = new TreeMap<BigInteger, String>();
    for (int i = Character.MIN_VALUE; i < Character.MAX_VALUE; i++) {
        String s = Character.toString((char) i);
        byte[] encoded = s.getBytes(charset);
        String decoded = new String(encoded, charset);
        if (s.equals(decoded))
            charsInEncodedOrder.put(new BigInteger(1, encoded), i + " " + s);
    }
    for (Map.Entry<BigInteger, String> entry : charsInEncodedOrder.entrySet()) {
        System.out.println(entry.getKey().toString(16) + " " + entry.getValue());
    }
}

and it produces something which matches http://www.fileformat.info/info/charset/IBM037/grid.htm