private String nextToken()

in mailet/ai/src/main/java/org/apache/james/ai/classic/Tokenizer.java [78:146]
60 lines of code
24 McCabe index (conditional complexity)

    private String nextToken(Reader reader) throws java.io.IOException {
        StringBuilder token = new StringBuilder();
        int i;
        char ch;
        char ch2;
        boolean previousWasDigit = false;
        boolean tokenCharFound = false;

        if (!reader.ready()) {
            return null;
        }

        while ((i = reader.read()) != -1) {

            ch = (char) i;

            if (ch == ':') {
                String tokenString = token.toString() + ':';
                if (tokenString.equals("From:") || tokenString.equals("Return-Path:") || tokenString.equals("Subject:") || tokenString.equals("To:")) {
                    return tokenString;
                }
            }

            if (Character.isLetter(ch) || ch == '-' || ch == '$' || ch == '€'
                    || ch == '!' || ch == '\'') {
                tokenCharFound = true;
                previousWasDigit = false;
                token.append(ch);
            } else if (Character.isDigit(ch)) {
                tokenCharFound = true;
                previousWasDigit = true;
                token.append(ch);
            } else if (previousWasDigit && (ch == '.' || ch == ',')) {
                reader.mark(1);
                previousWasDigit = false;
                i = reader.read();
                if (i == -1) {
                    break;
                }
                ch2 = (char) i;
                if (Character.isDigit(ch2)) {
                    tokenCharFound = true;
                    previousWasDigit = true;
                    token.append(ch);
                    token.append(ch2);
                } else {
                    reader.reset();
                    break;
                }
            } else if (ch == '\r') { //NOPMD
                // cr found, ignore
            } else if (ch == '\n') {
                // eol found
                tokenCharFound = true;
                previousWasDigit = false;
                token.append(ch);
                break;
            } else if (tokenCharFound) {
                break;
            }
        }

        if (tokenCharFound) {
            // System.out.println("Token read: " + token);
            return token.toString();
        } else {
            return null;
        }
    }