// like Integer, but can be modified; I use it to pass a number "by reference"
class MutableInteger {
    public int num;
}

class SampleData {
    //meh, in C++, this class would have a std::string (which is mutable) and
    //an int I can then pass by pointer, instead of this mess :)
    public StringBuilder string;
    public MutableInteger num;
}

class NumberHandler extends XMLHandler {
    public NumberHandler(MutableInteger result) {
        this.result = result;
    }
    public void characterData(char[] data) {
        int i;
        for (i=0; i<data.length; ++i) {
            if ('0' <= data[i] && data[i] <= '9') {
                result.num *= 10;
                result.num += data[i] - '0';
            } else {
                throw new XMLException("Non-digit found in <data>");
            }
        }
    }
    private MutableInteger result;
}

class DataHandler extends XMLHandler {
    public DataHandler(SampleData data) {
        this.data = data;
        inData = false;
        inString = false;
    }
    public void startElement(String name) {
        if (name.equals("data")) {
            inData = true;
        } else if (name.equals("string") && inData) {
            inString = true;
        } else if (name.equals("num") && inData) {
            pushHandler(new NumberHandler(data.num));
        }
    }
    public void endElement(String name) {
        if (name.equals("data")) {
            if (inData) {
                inData = false;
            } else {
                throw new XMLException("end of data but we weren't in data");
            }
        } else if (name.equals("string")) {
            if (inString) {
                inString = false;
            } else {
                throw new XMLException("end of string but we weren't in string");
            }
        }
    }
    public void characterData(char[] s) {
        if (inString) {
            data.string.append(s);
        }
    }

    private SampleData data;
    private boolean inData, inString;
};

class MainTest {
    public static void main(String args[]) {
        String xml = "<data><string>foobarbaz</string><num>12345</num></data>";
        SampleData data = new SampleData();

        XMLParser parser = new XMLParser();
        parser.pushHandler(new DataHandler(data));

        try {
            parser.parse(xml);
        } catch(XMLException e) {
            System.err.println("Parse error: " + e.getMessage());
            System.exit(1);
        }

        if (!data.string.equals("foobarbaz")) {
            System.err.println("Parsed string doesn't match");
            System.exit(1);
        }
        if (data.num != 12345) {
            System.err.println("Parsed number doesn't match");
            System.exit(1);
        }
    }
}
/* vim: set ts=4 sw=4 et: */