How to disable prettyPrint xstream xml and still add stylesheet and prolog?

Question

I can remove prettyprint in xml (all newlines/carriage returns) by using CompactWriter() but how to keep my prolog and stylesheets?

Currently I am using Writer class to add prolog and stylesheet using write method.

Below is my function to serialize an object.

private void serializeData(DiagData diagData){  
        fileinfo=new HashMap<String,String>();
        XStream xstream = new XStream();
        xstream.processAnnotations(DiagData.class);

        FileOutputStream fileOutputStream=null;
        Writer writer=null;
        //CompactWriter writer=null;
        xstream.registerConverter(new MapConverter());

        try {
            String path = Constants.XML_PATH+File.separator+Constants.DIRECTORY_NAME;
            File diagnosticDir = new File(path);

            String serialNumber=null;

            IDataCollector dataCollector=new DataCollector();
            serialNumber=dataCollector.getSerialNumber();

            String fileName = new SimpleDateFormat("yyyyMMddhhmmss'.xml'").format(new Date());
            if(serialNumber!=null)fileName=serialNumber+Constants.UNDERSCORE+fileName;
            fileName=Constants.PHONEHOME+Constants.UNDERSCORE+fileName;

            fileOutputStream = new FileOutputStream(path+File.separator+fileName);

            writer = new OutputStreamWriter(fileOutputStream);
            //writer = new CompactWriter(new OutputStreamWriter(fileOutputStream));

            writer.write(Constants.PROLOG);
            writer.write(Constants.STYLESHEET);
            xstream.toXML(diagData, writer);
            //xstream.marshal(diagData, writer);

        } catch (FileNotFoundException e1) {

        } catch (Exception e) {

        } finally {
            try {
                fileOutputStream.close();
                writer.close();             
            } catch (IOException e) {
                // TODO Auto-generated catch block
            }
        }
    }

Answer 1

If you look at the XStream documentation, they clearly state that you have to add the XML prolog yourself:

Why does XStream not write an XML declaration?

XStream is designed to write XML snippets, so you can embed its output into 
an existing stream or string. You can write the XML declaration yourself into 
the Writer before using it to call XStream.toXML(writer).

The following code should work. I removed most of your code, so you have to put it back. The purpose is just to give you a rough working example:

private static void serializeData(Object diagData) throws Exception {
    XStream xstream = new XStream();
    xstream.processAnnotations(DiagData.class);

    FileOutputStream fileOutputStream = null;
    Writer writer = new PrintWriter(new File(your file));
    CompactWriter compactWriter = new CompactWriter(writer);

    try {
        writer.write(your xml prolog);
        writer.write(your stylesheet);
        xstream.marshal(diagData, compactWriter);
    } catch (FileNotFoundException e1) {

    } catch (Exception e) {

    } finally {
       release resources
   }
}