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 * and open the template in the editor.
 */
package servlets;

import com.saxonica.xqj.SaxonXQDataSource;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.xquery.XQConnection;
import javax.xml.xquery.XQDataSource;
import javax.xml.xquery.XQException;
import javax.xml.xquery.XQExpression;
import javax.xml.xquery.XQSequence;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

/**
 *
 * @author Marcin
 */
public class BooksServlet extends HttpServlet {

    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
     * methods.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response, String param1, String param2)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        try (PrintWriter out = response.getWriter()) {
            /* TODO output your page here. You may use following sample code. */
            out.println("<!DOCTYPE html>");
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Servlet BooksServlet</title>");
            out.println("</head>");
            out.println("<body>");
            out.println("<h1>Servlet - BooksServlet at " + request.getContextPath() + "</h1>");

            out.println("<form method='post'>");
            out.println("<input type='text' name='n1'>");
            out.println("<input type='text' name='n2'>");
            out.println("<input type='submit' value='search'>");
            out.println("</form>");


            XQDataSource ds = new SaxonXQDataSource(); //źródło xml
            XQConnection conn;
            try {
                conn = ds.getConnection(); //połaczenie ze źródłem
                XQExpression exp = conn.createExpression();
                //XQSequence seq = exp.executeQuery("for $n in 1 to 10 return $n*$n"); //wykonanie zapytania na pliku xml

                XQSequence seq;
                String seqs;

                seqs = "for $x in doc('https://mstepniak.ii.uph.edu.pl/air/lab06/books.xml')/catalog/book \n";
                if(param1 != null && !param1.equals("")){
                    seqs += "where $x/title = \"" + param1 + "\"\n";
                }
                if(param2 != null && !param2.equals("")){
                    seqs += "let $rok :=(substring($x/publish_date, 1, 4)) \n";
                    seqs += "where $rok = " + "\"" + param2 + "\""  + "\n";
                }

                seqs += "return $x ";
                seq = exp.executeQuery( seqs);
                //poruszanie się po zbiorze
                while (seq.next()) {
                    Element book = (Element)seq.getNode();
                    out.println(book.getElementsByTagName("title").item(0).getTextContent());
                    out.println("<br/>");
                }

            } catch (XQException ex) {
                ex.printStackTrace(out);
            }

            out.println("</body>");
            out.println("</html>");
        }
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response, null, null);
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String s1 = request.getParameter("n1");
        String s2 = request.getParameter("n2");
        processRequest(request, response, s1, s2);

    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}