Generate java objects from one single XML file

Question

Hi,
I want to create an XML file that describes a set of "messages" (see XML below).
I want to generate the objects "Message" with simple getters and setters for each <message> entry.
And a little bit more complicated, I need to generate an object "Action" that will parse an incoming message based on the fields and rules described in the XML.
XML file:
*<messages>*
*<message>*
*<name>PrivateMessage</name>*
*<fields>*
*<receiver maxlength="32" minlength="4"/>*
*<sender maxlength="32" minlength="4"/>*
*<content minlength="1"/>*
*</fields>*
*</message>*
*<message>*
*<name>MessageToAll</name>*
Message object:
Example:
public class MessagePrivateMessage extends Message {
     private String sender;
     private String receiver;
     private String message;
     /* all the getters and setters for the fields above */
Action object:
The Action will parse an incoming message based on the rules in the XML above, and create the Message object; e.g. :
<sender maxlength="32" minlength="4"/>
will result to
String sender = getNextField(fields);
if (sender == null || sender.trim().equals("")) {
     throw new InvalidMessageException("Sender username null");
if (sender.length() > 32 || sender.length() < 4) {
     throw new InvalidMessageException("Sender username exceeds 32 characters: " + sender);
Example:
public class ActionPrivateMessage extends ActionReceiveClient<MessagePrivateMessage> {
     public ActionPrivateMessage() {
     public void execute(LinkedList<String> fields, EndpointServer server, int idMessage, Object stream, Date dateRead)
               throws InvalidMessageException {
          MessagePrivateMessage dtoMessage = new MessagePrivateMessage();
          dtoMessage.setDateServerRead(dateRead);
          dtoMessage.setId(idMessage);
          dtoMessage.setStream(stream);
          parseMessage(fields, dtoMessage);
          dtoMessage.setDateServerParsed(new Date());
          server.sendPrivateMessage(dtoMessage);
     public void parseMessage(LinkedList<String> fields, MessagePrivateMessage dto)
               throws InvalidMessageException {
          super.parseMessage(fields, dto);
          String sender = getNextField(fields);
          if (sender == null || sender.trim().equals("")) {
               throw new InvalidMessageException("Sender username null");
          if (sender.length() > 32 || sender.length() < 4) {
               throw new InvalidMessageException("Sender username exceeds 32 characters: " + sender);
          String receiver = getNextField(fields);
          if (receiver == null || receiver.trim().equals("")) {
               throw new InvalidMessageException("Receiver username null");
          if (receiver.length() > 32 || receiver.length() < 4) {
               throw new InvalidMessageException("Receiver username exceeds 32 characters: " + receiver);
          String message = getNextField(fields);
          if (message == null || message.trim().equals("")) {
               throw new InvalidMessageException("Message null");
          if (message.length() < 1) {
               throw new InvalidMessageException("Message exceeds 200 characters: " + message);
          if (!fields.isEmpty()) {
               String remainingFields = "";
               while (!fields.isEmpty()) {
                    remainingFields += fields.remove(0) + " ";
               throw new InvalidMessageException("Fields remaining but everything has been parsed: " + remainingFields);
          dto.setSender(sender);
          dto.setReceiver(receiver);
          dto.setMessage(message);
First question, is it possible ?
Second one would be, how ? Any tips ?
Thank you for any help :)

Answer 1

matthew_be wrote:
First question, is it possible ?Sure, why not.
Second one would be, how ?Well, I think the standard way is to write the required code.
If you really can't come up with a way, then you probably shouldn't be trying to implement such a thing.
Any tips ?Before I would start writing my own framework for something like that, I'd take a look at all the existing Java/XML technologies out there (of which there are a bunch). Either an existing framework will solve your problem or it will prove to be helpful in your own implementation.