package chap8;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.xml.transform.*;
import javax.xml.transform.stream.*;

/**
 * Allows any combination of English, Spanish, and Chinese XML
 * and XSLT.
 */
public class LanguageDemo extends HttpServlet {

    public void doPost(HttpServletRequest req, HttpServletResponse res)
            throws ServletException, IOException {
        ServletContext ctx = getServletContext();

        // these are all required parameters from the HTML form
        String xmlLang = req.getParameter("xmlLanguage");
        String xsltLang = req.getParameter("xsltLanguage");
        String charEnc = req.getParameter("charEnc");

        // convert to system-dependent path names
        String xmlFileName = ctx.getRealPath(
                "/WEB-INF/xml/numbers_" + xmlLang + ".xml");
        String xsltFileName = ctx.getRealPath(
                "/WEB-INF/xslt/numbers_" + xsltLang + ".xslt");

        // do this BEFORE calling HttpServletResponse.getWriter()
        res.setContentType("text/html; charset=" + charEnc);

        try {
            Source xmlSource = new StreamSource(new File(xmlFileName));
            Source xsltSource = new StreamSource(new File(xsltFileName));

            TransformerFactory transFact = TransformerFactory.newInstance();
            Transformer trans = transFact.newTransformer(xsltSource);

            trans.setOutputProperty(OutputKeys.ENCODING, charEnc);

            // note: res.getWriter() will use the encoding type that was
            //       specified earlier in the call to res.setContentType()
            trans.transform(xmlSource, new StreamResult(res.getWriter()));

        } catch (TransformerConfigurationException tce) {
            throw new ServletException(tce);
        } catch (TransformerException te) {
            throw new ServletException(te);
        }
    }
}