XML Document object access problem?

Question

Hi,
I have created a servlet,which will call .sh file, which will call java application.........
this java application is working as a search engine,which will do search in the XML document object...........This is working fine when only one user run this servlet...........But when more than servlet do the same it is not working......... But once first servlet create the Document object,which is main source for serching..........then second servlet will work fine.......same thing with third servlet and so on...... I used the thread.sleep()/synchronize but it is not working...bcoz i am accessing the same application.....Then instead of servlet i tried to run the java application from the Dos prompt..........But i am facing the same problem......So pl guide me bcoz everything is working excluding this..........Becoz this document object creation is taking some time........ i am creating the object shown below
Document doc =parseXmlFile("Article.xml", false);
Element docElem = doc.getDocumentElement();
public static org.w3c.dom.Document parseXmlFile(String filename, boolean validating)
               try {
     // Create a builder factory
     DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
     factory.setValidating(validating);
     // Create the builder and parse the file
     // org.w3c.dom.Document doc = factory.newDocumentBuilder().parse(filename);
     org.w3c.dom.Document doc = factory.newDocumentBuilder().parse(new File(filename));
     return doc;
} catch (SAXException e) {
// A parsing error occurred; the xml input is not valid
} catch (ParserConfigurationException e) {
} catch (IOException e) {
return null;
}

Answer 1

Hi,
This is my Servlet code..............
package PW.Feed;
import java.io.*;
import javax.xml.parsers.*;
import org.w3c.dom.*;
import org.xml.sax.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.StreamResult;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;
import java.util.*;
public class PrintDom extends HttpServlet
     Document doc;
     Element docElem;
     Connection Conn=null;
     Statement stmt=null,stmt1=null;
     ResultSet rs1=null,rs=null;
     PrintWriter out;
     Vector myVector1=new Vector();
     Vector myVector2=new Vector();
     String strSql="";
     public void doGet(HttpServletRequest req,HttpServletResponse res)throws ServletException,IOException
          res.setContentType("text/html");
          out=res.getWriter();
          try
               String pubtype=req.getParameter("PubType");
               String pubDate=req.getParameter("PubDate");
               String toDate=req.getParameter("ToDate");
               String fromDate=req.getParameter("FromDate");
               if(pubDate==null)pubDate="2";
               if(toDate==null)toDate="02/09/2005";
               if(fromDate==null)fromDate="02/08/2005";
               Class.forName("org.firebirdsql.jdbc.FBDriver");
               Conn = DriverManager.getConnection("jdbc:firebirdsql:192.168.0.15/3050:D:/FBDatabases/PW1.GDB","SYSDBA","cohezia");
               //Conn = DriverManager.getConnection("jdbc:firebirdsql:192.168.0.99/3050:/share/pw1.gdb","SYSDBA","cohezia");
               stmt = Conn.createStatement( );
               if(pubDate.equals("2"))
                    strSql="Select sh.ARTICLEID,sh.cuttingsdate,sh.READDATE,sh.headline,sh.SUMMARY,sh.AUTHOR,sh.PAGEFROM,sh.PUB_NAME,sh.READER_NAME,sh.PARENTTITLE,sh.CANMAIL,sh.PUBLICATION_ID,sh.JOURNALIST_ID,sh.ISPDF FROM SCANSHEADER sh,PUBLICATIONS p where sh.publication_id=p.publication_id and sh.readdate>'"+fromDate+"' and sh.readdate<'"+toDate+"' and p.pubtype='"+ pubtype +"' order by sh.ARTICLEID";
               else
                    strSql="Select sh.ARTICLEID,sh.cuttingsdate,sh.READDATE,sh.headline,sh.SUMMARY,sh.AUTHOR,sh.PAGEFROM,sh.PUB_NAME,sh.READER_NAME,sh.PARENTTITLE,sh.CANMAIL,sh.PUBLICATION_ID,sh.JOURNALIST_ID,sh.ISPDF FROM SCANSHEADER sh,PUBLICATIONS p where sh.publication_id=p.publication_id and sh.cuttingsdate>'"+fromDate+"' and sh.cuttingsdate<'"+toDate+"' and p.pubtype='"+ pubtype +"' order by sh.ARTICLEID";
               rs=stmt.executeQuery(strSql);
               DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
               doc = builder.newDocument();
               docElem = doc.createElement("RECORDLIST");
               doc.appendChild(docElem);
               Element rootElem = doc.createElement("RECORDS");
               docElem.appendChild(rootElem);
               String artid="";
               while(rs.next())
                         Element artElem = doc.createElement("RECORD");
                         if((rs.getString("ARTICLEID")).length()>0)artElem.setAttribute("id",rs.getString("ARTICLEID"));
                         rootElem.appendChild(artElem);
                         Element rootFieldElem = doc.createElement("FIELDS");
                         artElem.appendChild(rootFieldElem);
                         Element eleCuttingDate = doc.createElement("FIELD");
                         rootFieldElem.appendChild(eleCuttingDate);
                         eleCuttingDate.setAttribute("fieldName","CUTTINGSDATE");
                         if((rs.getString("CUTTINGSDATE")).length()>0) eleCuttingDate.appendChild(doc.createTextNode(rs.getString("CUTTINGSDATE")));
                         Element eleReadDate = doc.createElement("FIELD");
                         rootFieldElem.appendChild(eleReadDate);
                         eleReadDate.setAttribute("fieldName","READDATE");
                         if((rs.getString("READDATE")).length()>0) eleReadDate.appendChild(doc.createTextNode(rs.getString("READDATE")));
                         Element eleHeadLine = doc.createElement("FIELD");
                         rootFieldElem.appendChild(eleHeadLine);
                         eleHeadLine.setAttribute("fieldName","HEADLINE");
                         if((rs.getString("HEADLINE")).length()>0) eleHeadLine.appendChild(doc.createTextNode(rs.getString("HEADLINE")));
                         Element eleSummary = doc.createElement("FIELD");
                         rootFieldElem.appendChild(eleSummary);
                         eleSummary.setAttribute("fieldName","SUMMARY");
                         if(rs.getString("SUMMARY")==null){
                              //out.println("String is null");
                              else
                              {eleSummary.appendChild(doc.createTextNode(rs.getString("SUMMARY")));}
                         Element eleAuthor = doc.createElement("FIELD");
                         rootFieldElem.appendChild(eleAuthor);
                         eleAuthor.setAttribute("fieldName","AUTHOR");
                         if((rs.getString("AUTHOR")).length()>0) eleAuthor.appendChild(doc.createTextNode(rs.getString("AUTHOR")));
                         Element elePageFrom = doc.createElement("FIELD");
                         rootFieldElem.appendChild(elePageFrom);
                         elePageFrom.setAttribute("fieldName","PAGEFROM");
                         if((rs.getString("PAGEFROM")).length()>0) elePageFrom.appendChild(doc.createTextNode(rs.getString("PAGEFROM")));
                         Element elePubName = doc.createElement("FIELD");
                         rootFieldElem.appendChild(elePubName);
                         elePubName.setAttribute("fieldName","PUBNAME");
                         if((rs.getString("PUB_NAME")).length()>0) elePubName.appendChild(doc.createTextNode(rs.getString("PUB_NAME")));
                         Element eleReaderName = doc.createElement("FIELD");
                         rootFieldElem.appendChild(eleReaderName);
                         eleReaderName.setAttribute("fieldName","READER NAME");
                         if((rs.getString("READER_NAME")).length()>0) eleReaderName.appendChild(doc.createTextNode(rs.getString("READER_NAME")));
                         Element eleParentTitle = doc.createElement("FIELD");
                         rootFieldElem.appendChild(eleParentTitle);
                         eleParentTitle.setAttribute("fieldName","PARENTTITLE");
                         if((rs.getString("PARENTTITLE")).length()>0)eleParentTitle.appendChild(doc.createTextNode(rs.getString("PARENTTITLE")));
                         Element eleCanMail = doc.createElement("FIELD");
                         rootFieldElem.appendChild(eleCanMail);
                         eleCanMail.setAttribute("fieldName","CANMAIL");
                         if((rs.getString("CANMAIL")).length()>0) eleCanMail.appendChild(doc.createTextNode(rs.getString("CANMAIL")));
                         Element elePublicationID = doc.createElement("FIELD");
                         rootFieldElem.appendChild(elePublicationID);
                         elePublicationID.setAttribute("fieldName","PUBLICATION_ID");
                         if((rs.getString("PUBLICATION_ID")).length()>0) elePublicationID.appendChild(doc.createTextNode(rs.getString("PUBLICATION_ID")));
                         Element eleJournlistID = doc.createElement("FIELD");
                         rootFieldElem.appendChild(eleJournlistID);
                         eleJournlistID.setAttribute("fieldName","JOURNALIST_ID");
                         if((rs.getString("JOURNALIST_ID")).length()>0) eleJournlistID.appendChild(doc.createTextNode(rs.getString("JOURNALIST_ID")));
                         Element eleIspdf = doc.createElement("FIELD");
                         rootFieldElem.appendChild(eleIspdf);
                         eleIspdf.setAttribute("fieldName","ISPDF");
                         if((rs.getString("ISPDF")).length()>0) eleIspdf.appendChild(doc.createTextNode(rs.getString("ISPDF")));
                         Element rootKeyElem=doc.createElement("KEYWORDS_CODES");
                    String[] arrCodes=getKeyCodes(rs.getString("ARTICLEID"));
                    int count1 = myVector1.size();
                    String[] myArray1=new String[count1];
                    myVector1.copyInto(myArray1);
                    int count2 = myVector2.size();
                    String[] myArray2=new String[count2];
                    myVector2.copyInto(myArray2);
                    for(int j=0;j<arrCodes.length;j++)
                         Element eleKeyword= doc.createElement("KEYWORD_CODE");
                         eleKeyword.setAttribute("CodeId",arrCodes[j]);
                         eleKeyword.setAttribute("LongName",myArray1[j]);
                         eleKeyword.setAttribute("CodeType",myArray2[j]);
                         rootKeyElem.appendChild(eleKeyword);
                    artElem.appendChild(rootKeyElem);
               Source source = new DOMSource(docElem);
               //File file = new File("/share/PrintDom.xml");
               StringWriter rw=new StringWriter();
               Result result = new StreamResult(rw);
               //Result result = new DOMResult();
               // Write the DOM document to the file
               Transformer xformer = TransformerFactory.newInstance().newTransformer();
               xformer.transform(source, result);
               out.println(rw);
          catch (ClassNotFoundException e)
                    out.println("Unable to load Driver Class" + e);
                    return;
                    //fileLog.log(e,"PressWatchFrame1.PressWatchFrame1()");
          catch (SQLException se)
               out.println(se);
          catch (Exception e)
               out.println(e);
finally{
                    try{
                         if(Conn!=null) Conn.close();
                    catch(SQLException ignored){}
     public String[] getKeyCodes(String strArticleId)
          Vector myVector=new Vector();
          myVector1.removeAllElements();
          myVector2.removeAllElements();
     try{
          stmt1=Conn.createStatement( );
          //String strSql1="Select codeid FROM SCANSSUBJECT where articleid='"+ strArticleId +"'";
          String strSql1="Select ss.codeid,c.longname,c.codetype FROM SCANSSUBJECT ss,CODES c where ss.codeid=c.codeid and articleid='"+ strArticleId +"'";
          rs1=stmt1.executeQuery(strSql1);
          String strCodes="";
          while(rs1.next())
               myVector.add(rs1.getString("codeid"));
               myVector1.add(rs1.getString("longname"));
               myVector2.add(rs1.getString("codetype"));
          }catch (SQLException se)
                                   out.println(se);
          int count = myVector.size();
          String[] myArray = new String[count];
          myVector.copyInto(myArray);
          return myArray;
..................Thanx