Metacat

import java.io.BufferedInputStream;

import java.util.Enumeration;

import java.util.Hashtable;

import java.util.Random;

import java.util.PropertyResourceBundle;

import java.net.URL;

 * <p>Valid parameters are:<br>

 * action=query -- query the values of all elements and attributes

 *                     and return a result set of nodes<br>

 * action= -- export a zip format for data packadge<br>

 * action=read -- read any metadata/data file from Metacat and from Internet<br>

 * action=insert -- insert an XML document into the database store<br>

 * action=getprincipals -- retrieve a list of principals in XML<br>

 * datadoc -- data document name (id)<br>

 * <p>

 * particular action value is quite specific.  This documentation

 * will be reorganized to reflect this information.

 */

  private String resultStyleURL = null;

  private String xmlcatalogfile = null;

  private String saxparser = null;

  private File dataDirectory = null;

  private PropertyResourceBundle options = null;

  private MetaCatUtil util = null;

  private DBConnectionPool connPool = null;

    try {

      super.init( config );

      this.config = config;

      System.out.println("MetaCatServlet Initialize");

      util = new MetaCatUtil();

      //initial DBConnection pool

      connPool = DBConnectionPool.getInstance();

   * Close all db connections from the pool

   */

  public void destroy() {

      connPool.release();

  }

  /**

   * Control servlet response depending on the action parameter specified

   */

  {

    if ( util == null ) {

    }

    /*MetaCatUtil.debugMessage("Connection pool size: "

                                     +connPool.getSizeOfDBConnectionPool(),10);

    MetaCatUtil.debugMessage("Free DBConnection number: "

                                  +connPool.getFreeDBConnectionNumber(), 10);*/

    //size to initial value

    DBConnectionPool.shrinkDBConnectionPoolSize();

    //Debug message to print out the method which have a busy DBConnection

    connPool.printMethodNameHavingBusyDBConnection();

    String ctype = request.getContentType();

    if (ctype != null && ctype.startsWith("multipart/form-data")) {

      handleMultipartForm(request, response);

    } else {

      String name = null;

      String[] value = null;

      String[] docid = new String[3];

      Hashtable params = new Hashtable();

      Enumeration paramlist = request.getParameterNames();

      while (paramlist.hasMoreElements()) {

        name = (String)paramlist.nextElement();

        value = request.getParameterValues(name);

        // Decode the docid and mouse click information

        if (name.endsWith(".y")) {

          docid[0] = name.substring(0,name.length()-2);

        }

        if (name.endsWith(".x")) {

          name = "xpos";

      //handle param is emptpy

      if (params.isEmpty() || params == null)

      {

      }

      //if the user clicked on the input images, decode which image

      //was clicked then set the action.

      util.debugMessage("Line 230: Action is: " + action, 1);

      // This block handles session management for the servlet

      // by looking up the current session information for all actions

      // other than "login" and "logout"

      String password = null;

      String[] groupnames = null;

      String sess_id = null;

      // handle login action

      if (action.equals("login")) {

        PrintWriter out = response.getWriter();

        handleLoginAction(out, params, request, response);

        out.close();

      } else if (action.equals("logout")) {

        PrintWriter out = response.getWriter();

        handleLogoutAction(out, params, request, response);

        out.close();

      // handle shrink DBConnection request

      } else if (action.equals("shrink")) {

        PrintWriter out = response.getWriter();

        boolean success = false;

        //size to initial value

        success = DBConnectionPool.shrinkConnectionPoolSize();

        if (success)

        }

       //close out put

        out.close();

        HttpSession sess = request.getSession(true);

          // session expired or has not been stored b/w user requests

          username = "public";

          sess.setAttribute("username", username);

            sess_id = (String)sess.getId();

          } catch(IllegalStateException ise) {

            System.out.println("error in handleGetOrPost: this shouldn't " +

                               ise.getMessage());

          }

       // Now that we know the session is valid, we can delegate the request

      // to a particular action handler

      if(action.equals("query")) {

          out.close();

        }

      } else if (action.equals("export")) {

        handleExportAction(params, response, username, groupnames, password);

      } else if (action.equals("read")) {

        handleReadAction(params, response, username,password, groupnames);

        PrintWriter out = response.getWriter();

        if ( (username != null) &&  !username.equals("public") ) {

          handleInsertOrUpdateAction(out,params,response,username,groupnames);

          out.println("Permission denied for " + action);

        }

        out.close();

        PrintWriter out = response.getWriter();

        if ( (username != null) &&  !username.equals("public") ) {

          handleDeleteAction(out, params, response, username, groupnames);

          out.println("Permission denied for " + action);

        }

        out.close();

        out.println("</error>");

        out.close();

      }

      //util.closeConnections();

      // Close the stream to the client

      //out.close();

    }

  }

  // LOGIN & LOGOUT SECTION

   * Handle the login request. Create a new session object.

   * Do user authentication through the session.

   */

               HttpServletRequest request, HttpServletResponse response) {

    AuthSession sess = null;

    String pw = ((String[])params.get("password"))[0];

    String action = ((String[])params.get("action"))[0];

    String qformat = ((String[])params.get("qformat"))[0];

    try {

      sess = new AuthSession();

    } catch (Exception e) {

    // format and transform the output

    if (qformat.equals("xml")) {

      response.setContentType("text/xml");

    } else {

      try {

        DBTransform trans = new DBTransform();

        response.setContentType("text/html");

        trans.transformXMLDocument(sess.getMessage(), "-//NCEAS//login//EN",

                                   "-//W3C//HTML//EN", qformat, out);

      } catch(Exception e) {

        MetaCatUtil.debugMessage("Error in MetaCatServlet.handleLoginAction: "

                                +e.getMessage(), 30);

    }

   * Handle the logout request. Close the connection.

   */

               HttpServletRequest request, HttpServletResponse response) {

    String qformat = ((String[])params.get("qformat"))[0];

    // close the connection

    HttpSession sess = request.getSession(false);

    // produce output

    StringBuffer output = new StringBuffer();

    //format and transform the output

    if (qformat.equals("xml")) {

      response.setContentType("text/xml");

    } else {

      try {

        DBTransform trans = new DBTransform();

        response.setContentType("text/html");

                                   "-//W3C//HTML//EN", qformat, out);

      } catch(Exception e) {

        MetaCatUtil.debugMessage("Error in MetaCatServlet.handleLogoutAction"

                                  +e.getMessage(), 30);

    }

  }

  // END OF LOGIN & LOGOUT SECTION

  // SQUERY & QUERY SECTION

   * Retreive the squery xml, execute it and display it

   *

   * @param out the output stream to the client

   * @param params the Hashtable of parameters that should be included

   * in the squery.

   * @param response the response object linked to the client

   */

                 HttpServletResponse response, String user, String[] groups)

    String xmlquery = ((String[])params.get("query"))[0];

    String qformat = ((String[])params.get("qformat"))[0];

    String resultdoc = null;

    MetaCatUtil.debugMessage("xmlquery: "+xmlquery, 30);

    double startTime = System.currentTimeMillis()/1000;

    Hashtable doclist = runQuery(xmlquery, user, groups);

    MetaCatUtil.debugMessage("Time for getting doc list: "

                                            +(docListTime-startTime), 30);

    resultdoc = createResultDocument(doclist, transformQuery(xmlquery));

    double toStringTime = System.currentTimeMillis()/1000;

    MetaCatUtil.debugMessage("Time to create xml string: "

                              +(toStringTime-docListTime), 30);

    //format and transform the results

    if(qformat.equals("xml")) {

      response.setContentType("text/xml");

      out.println(resultdoc);

    * @param params the Hashtable of parameters that should be included

    * in the squery.

    * @param response the response object linked to the client

                 HttpServletResponse response, String user, String[] groups)

  {

    //create the query and run it

    Hashtable doclist = runQuery(xmlquery, user, groups);

    String qformat = ((String[])params.get("qformat"))[0];

    String resultdoc = null;

    resultdoc = createResultDocument(doclist, transformQuery(params));

    if(qformat.equals("xml")) {

      response.setContentType("text/xml");

      out.println(resultdoc);

      transformResultset(resultdoc, response, out, qformat);

    }

  }

  /**

   * Removes the <?xml version="x"?> tag from the beginning of xmlquery

   * so it can properly be placed in the <query> tag of the resultset.

   * This method is overwritable so that other applications can customize

   * the structure of what is in the <query> tag.

   * @param xmlquery is the query to remove the <?xml version="x"?> tag from.

   */

  protected String transformQuery(Hashtable params)

  {

    //function but it is necessary

    //so that overriding methods have access to the params hashtable

    String xmlquery = DBQuery.createSQuery(params);

    int index = xmlquery.indexOf("?>");

    return xmlquery.substring(index + 2, xmlquery.length());

  }

  /**

   * removes the <?xml version="1.0"?> tag from the beginning.  This takes a

   * string as a param instead of a hashtable.

   * @param xmlquery a string representing a query.

   */

  protected String transformQuery(String xmlquery)

    int index = xmlquery.indexOf("?>");

    return xmlquery.substring(index + 2, xmlquery.length());

  }

  /**

   * Run the query and return a hashtable of results.

   *

  private Hashtable runQuery(String xmlquery, String user, String[] groups)

  {

    Hashtable doclist=null;

    try

    {

      DBQuery queryobj = new DBQuery(saxparser);

      doclist = queryobj.findDocuments(new StringReader(xmlquery),user,groups);

      return doclist;

    {

                                                      + e.getMessage(), 30);

      doclist = null;

      return doclist;

  }

  /**

   * Transorms an xml resultset document to html and sends it to the browser

   *

   * @param response the HttpServletResponse object bound to the client.

   * @param out the output stream to the client

   * @param qformat the name of the style-set to use for transformations

                                    HttpServletResponse response,

                                    PrintWriter out, String qformat)

  {

    try {

      DBTransform trans = new DBTransform();

      response.setContentType("text/html");

                                 "-//W3C//HTML//EN", qformat, out);

    }

    catch(Exception e)

    {

      MetaCatUtil.debugMessage("Error in MetaCatServlet.transformResultset:"

                                +e.getMessage(), 30);

  }

  /**

   * Transforms a hashtable of documents to an xml or html result.

   *

  {

    // Create a buffer to hold the xml result

    StringBuffer resultset = new StringBuffer();

    String docid = null;

    String document = null;

    resultset.append("<?xml version=\"1.0\"?>\n");

    resultset.append("<resultset>\n");

    if(doclist != null)

    {

      {

        docid = (String)doclistkeys.nextElement();

        document = (String)doclist.get(docid);

    return resultset.toString();

  }

  // END OF SQUERY & QUERY SECTION

 //Exoport section

 /**

   * Handle the "export" request of data package from Metacat in zip format

   * @param user the username sent the request

   * @param groups the user's groupnames

   */

    HttpServletResponse response, String user, String[] groups, String passWord)

  {

    // Output stream

    ZipOutputStream zOut = null;

    DocumentImpl docImpls=null;

    DBQuery queryObj=null;

    String[] docs = new String[10];

    String docId = "";

    try

    {

      // read the params

      {

        docs = (String[])params.get("docid");

      }//if

        pw.println("<error>");

        pw.println("You didn't specify requested docid");

        pw.println("</error>");

        pw.close();

        return;

      }//if

      zOut =queryObj.getZippedPackage(docId, out, user, groups, passWord);

      zOut.finish(); //terminate the zip file

      zOut.close();  //close the zip stream

    catch (Exception e)

    {

      try

            // Close output stream

            out.close();

        }//if

        if ( zOut != null )

        {

          zOut.close();

      MetaCatUtil.debugMessage("Error in MetacatServlet.handleExportAction: " +

                         e.getMessage(), 30);

      e.printStackTrace(System.out);

    }//catch

  }//handleExportAction

  // READ SECTION

   * Handle the "read" request of metadata/data files from Metacat

   * or any files from Internet;

   * transformed metadata XML document into HTML presentation if requested;

   * @param groups the user's groupnames

   */

  private void handleReadAction(Hashtable params, HttpServletResponse response,

  {

    ServletOutputStream out = null;

    ZipOutputStream zout = null;

    PrintWriter pw = null;

    boolean zip = false;

    try {

      String[] docs = new String[0];

      String docid = "";

      String qformat = "";

      String abstrpath = null;

      // read the params

      if (params.containsKey("docid")) {

        docs = (String[])params.get("docid");

          URL murl = new URL(docs[i]);

          Hashtable murlQueryStr = util.parseQuery(murl.getQuery());

          // or docid="metacat://.../?docid=bbb"

          if (murlQueryStr.containsKey("docid")) {

            // get only docid, eliminate the rest

                            user, groups, zip, zout);

          }

        }

      } /* end for */

      if ( zip ) {

        zout.finish(); //terminate the zip file

        zout.close();  //close the zip stream

      }

    }

    // To handle doc not found exception

    catch (McdbDocNotFoundException notFoundE)

        {

          out.close();

        }

      }//try

      catch ( Exception exc)

      {

                                      exc.getMessage(), 30);

        try

        {

          {

            response.setContentType("text/xml");

            // Send back error message by printWriter

            pw.println("</error>");

            pw.close();

            out.close();

          }

          else

          {

           pw.close();

        }

        // close zout

        }

        }//try

        catch (IOException ie)

        }//cathch

      }//catch

    }// catch McdbDocNotFoundException

    {

      try {

        if (out != null) {

            response.setContentType("text/xml"); //MIME type

            pw = new PrintWriter(out);

           pw.println(e.getMessage());

           pw.println("</error>");

           pw.close();

        }

        // Close zip output stream

        if ( zout != null ) { zout.close(); }

      } catch (IOException ioe) {

        MetaCatUtil.debugMessage("Problem with the servlet output " +

                           "in MetacatServlet.handleReadAction: " +

                           ioe.getMessage(), 30);

        ioe.printStackTrace(System.out);

      }

      System.out.println("Error in MetacatServlet.handleReadAction: " +

                         e.getMessage());

      e.printStackTrace(System.out);

    }

  }

  // read metadata or data from Metacat

  private void readFromMetacat(HttpServletResponse response, String docid,

                               String qformat, String abstrpath, String user,

                             String[] groups, boolean zip, ZipOutputStream zout)

                      McdbException, Exception

  {

    try {

      DocumentImpl doc = new DocumentImpl(docid);

      //check the permission for read

      if (!doc.hasReadPermission(user, groups, docid))

      {

        Exception e = new Exception("User " + user + " does not have permission"

                       +" to read the document with the docid " + docid);

        throw e;

      }

      if ( doc.getRootNodeID() == 0 ) {

        // this is data file

        String filepath = util.getOption("datafilepath");

        String filename = filepath + docid;

        FileInputStream fin = null;

        fin = new FileInputStream(filename);

        //MIME type

        String contentType = getServletContext().getMimeType(filename);

        if (contentType == null) {

        response.setContentType(contentType);

        // if we decide to use "application/octet-stream" for all data returns

        // response.setContentType("application/octet-stream");

        try {

          byte[] buf = new byte[4 * 1024]; // 4K buffer

          int b = fin.read(buf);

          while (b != -1) {

      } else {

        // this is metadata doc

          // set content type first

          response.setContentType("text/xml");   //MIME type

          PrintWriter out = response.getWriter();

        } else {

          response.setContentType("text/html");  //MIME type

          PrintWriter out = response.getWriter();

          // Look up the document type

          String doctype = doc.getDoctype();

          // Transform the document to the new doctype

          dbt.transformXMLDocument(doc.toString(),

                                   doctype,"-//W3C//HTML//EN", qformat, out);

        }

      }

    }

    {

      throw except;

    }

  }

  // read data from URLConnection

  private void readFromURLConnection(HttpServletResponse response, String docid)

               throws IOException, MalformedURLException

  {

    String contentType = getServletContext().getMimeType(docid); //MIME type

    if (contentType == null) {

      if (docid.endsWith(".xml")) {

    } finally {

      if (bis != null) bis.close();

    }

  }

  // read file/doc and write to ZipOutputStream

                              String user, String[] groups)

                      McdbException, Exception

  {

    byte[] bytestring = null;

      zout.closeEntry();

    } catch (MalformedURLException mue) {

      // this is metacat doc (data file or metadata doc)

      try {

        DocumentImpl doc = new DocumentImpl(docid);

        //check the permission for read

        if (!doc.hasReadPermission(user, groups, docid))

        {

          Exception e = new Exception("User " + user + " does not have "

                    +"permission to read the document with the docid " + docid);

          throw e;

        if ( doc.getRootNodeID() == 0 ) {

          // this is data file; add file to zip

          String filepath = util.getOption("datafilepath");

          FileInputStream fin = null;

          fin = new FileInputStream(filename);

          try {

            zentry = new ZipEntry(docid);

            zout.putNextEntry(zentry);

            byte[] buf = new byte[4 * 1024]; // 4K buffer

        }

      } catch (Exception except) {

        throw except;

      }

    }

  }

  // view abstract within document

  private void viewAbstract(HttpServletResponse response,

                            String abstractpath, String docid)

               throws ClassNotFoundException, IOException, SQLException,

                      McdbException, Exception

  {

    PrintWriter out =null;

    try {

      response.setContentType("text/html");  //MIME type

      out = response.getWriter();

      Object[] abstracts = DBQuery.getNodeContent(abstractpath, docid);

       out.println("<error>");

       out.println(e.getMessage());

       out.println("</error>");

    }

  }

  /**

   * If metacat couldn't find a data file or document locally, it will read this

   * docid from its home server. This is for the replication feature

   */

                     ServletOutputStream out, boolean zip, ZipOutputStream zout)

                        throws Exception

 {

   // Create a object of RemoteDocument, "" is for zipEntryPath

                        new RemoteDocument (docid, rev,user, password, "");

   String docType = remoteDoc.getDocType();

   // Only read data file

    if (zip)

    {

      remoteDoc.readDocumentFromRemoteServerByZip(zout);

    else

    {

      if (out == null)

      response.setContentType("application/octet-stream");

      remoteDoc.readDocumentFromRemoteServer(out);

    }//else (not zip)

   else

   {

     throw new Exception("Docid: "+docid+"."+rev+" couldn't find");

 }//readFromRemoteMetaCat

  // END OF READ SECTION

  // INSERT/UPDATE SECTION

   * to the database connection

   */

               HttpServletResponse response, String user, String[] groups) {

    DBConnection dbConn = null;

          }

        } catch (NullPointerException npe) {}

      }

      StringReader xml = null;

      boolean validate = false;

      try {

        // in order to decide whether to use validation parser

        validate = validateXML(doctext[0]);

        xml = new StringReader(doctext[0]);

        } else if (action[0].equals("update")) {

          doAction = "UPDATE";

        }

        {

          // get a connection from the pool

          dbConn=DBConnectionPool.

                  getDBConnection("MetaCatServlet.handleInsertOrUpdateAction");

          serialNumber=dbConn.getCheckOutSerialNumber();

          // write the document to the database

          {

            String accNumber = docid[0];

            MetaCatUtil.debugMessage(""+ doAction + " " + accNumber +"...", 10);

            {

              accNumber = null;

            }//if

            newdocid = DocumentImpl.write(dbConn, xml, pub, dtd, doAction,

                                          accNumber, user, groups, validate);

          {

            newdocid = DocumentImpl.write(dbConn, xml, pub, dtd, doAction,

                                          null, user, groups, validate);

          }//catch

        {

          // Return db connection

          DBConnectionPool.returnDBConnection(dbConn, serialNumber);

        // set content type and other response header fields first

        response.setContentType("text/xml");

        out.println("<?xml version=\"1.0\"?>");

        out.println("<success>");

        out.println("</success>");

      } catch (NullPointerException npe) {

        response.setContentType("text/xml");

        out.println("<?xml version=\"1.0\"?>");

        out.println("<error>");

        out.println("</error>");

      }

    } catch (Exception e) {

      response.setContentType("text/xml");

      out.println("<?xml version=\"1.0\"?>");

      out.println("<error>");

      if (e instanceof SAXException) {

        Exception e2 = ((SAXException)e).getException();

        out.println("<error>");

    }

  }

   * in order to decide whether to use validation parser

   */

  private static boolean validateXML(String xmltext) throws IOException {

    StringReader xmlreader = new StringReader(xmltext);

    StringBuffer cbuff = new StringBuffer();

    java.util.Stack st = new java.util.Stack();

    boolean validate = false;

    int c;

    int inx;

    // read from the stream until find the keywords

    while ( (st.empty() || st.size()<4) && ((c = xmlreader.read()) != -1) ) {

      cbuff.append((char)c);

        st.push("SYSTEM");

      }

      // ">" character is found; put it in the stack

      // and second from <!DOCTYPE ... >

      if ( (inx = cbuff.toString().indexOf(">")) != -1 ) {

        cbuff = new StringBuffer();

  // END OF INSERT/UPDATE SECTION

  // DELETE SECTION

   * from the database connection

   */

               HttpServletResponse response, String user, String[] groups) {

    String[] docid = (String[])params.get("docid");

    // delete the document from the database

    try {

                                      // NOTE -- NEED TO TEST HERE

                                      // FOR EXISTENCE OF DOCID PARAM

                                      // BEFORE ACCESSING ARRAY

        DocumentImpl.delete(docid[0], user, groups);

        response.setContentType("text/xml");

        out.println("<?xml version=\"1.0\"?>");

        out.println("<success>");

        out.println("</success>");

      } catch (AccessionNumberException ane) {

        response.setContentType("text/xml");

        out.println("<?xml version=\"1.0\"?>");

        out.println("<error>");

        out.println("Error deleting document!!!");

        out.println("</error>");

      }

    } catch (Exception e) {

      response.setContentType("text/xml");

      out.println("<?xml version=\"1.0\"?>");

      out.println("<error>");

      out.println("</error>");

  }

  // END OF DELETE SECTION

  // VALIDATE SECTION

   * Handle the validation request and return the results to the requestor

   */

  private void handleValidateAction(PrintWriter out, Hashtable params) {

    String valtext = null;

    DBConnection dbConn = null;

    int serialNumber = -1;

    try {

      valtext = ((String[])params.get("valtext"))[0];

    } catch (Exception nullpe) {

      String docid = null;

      try {

        // Find the document id number

        // Get the document indicated from the db

        DocumentImpl xmldoc = new DocumentImpl(docid);

        valtext = xmldoc.toString();

      } catch (NullPointerException npe) {

        out.println("<error>Error getting document ID: " + docid + "</error>");

        //if ( conn != null ) { util.returnConnection(conn); }

        return;

      } catch (Exception e) {

    }

    try {

      // get a connection from the pool

      dbConn=DBConnectionPool.

      boolean valid = valobj.validateString(valtext);

      // set content type and other response header fields first

      out.println(valobj.returnErrors());

    } catch (NullPointerException npe2) {

      // set content type and other response header fields first

    } catch (Exception e) {

    } finally {

      // Return db connection

      DBConnectionPool.returnDBConnection(dbConn, serialNumber);

  }

  // END OF VALIDATE SECTION

  // OTHER ACTION HANDLERS

  /**

   * Handle "getrevsionanddoctype" action

   * Given a docid, return it's current revision and doctype from data base

   * The output is String look like "rev;doctype"

   */

                                                              Hashtable params)

  {

    // To store doc parameter

    // Store a single doc id

    String givenDocId = null;

    // Get docid from parameters

    {

      docs = (String[])params.get("docid");

    }

    // Get first docid form string array

    givenDocId = docs[0];

    {

      // Make sure there is a docid

      if (givenDocId == null || givenDocId.equals(""))

      {

        throw new Exception("User didn't specify docid!");

      }//if

      // Create a DBUtil object

      DBUtil dbutil = new DBUtil();

      // Get a rev and doctype

                dbutil.getCurrentRevisionAndDocTypeForGivenDocument(givenDocId);

      out.println(revAndDocType);

    {

      // Handle exception

      out.println("<?xml version=\"1.0\"?>");

      out.println("<error>");

      out.println(e.getMessage());

      out.println("</error>");

  }//handleGetRevisionAndDocTypeAction

   * Handle "getaccesscontrol" action.

   * Read Access Control List from db connection in XML format

   */

                                       String username, String[] groupnames) {

    DBConnection dbConn = null;

    int serialNumber = -1;

    String docid = ((String[])params.get("docid"))[0];

    try {

        // get connection from the pool

    } finally {

      // Retrun db connection to pool

      DBConnectionPool.returnDBConnection(dbConn, serialNumber);

  }

   * Handle the "getprincipals" action.

   * Read all principals from authentication scheme in XML format

   */

  private void handleGetPrincipalsAction(PrintWriter out, String user,

                                         String password) {

    try {

        AuthSession auth = new AuthSession();

        String principals = auth.getPrincipals(user, password);

        out.println(principals);

      out.println("<error>");

      out.println(e.getMessage());

      out.println("</error>");

  }

   * Handle "getdoctypes" action.

   * Read all doctypes from db connection in XML format

   */

                                       HttpServletResponse response) {

    try {

        DBUtil dbutil = new DBUtil();

        String doctypes = dbutil.readDoctypes();

        out.println(doctypes);

      out.println("<error>");

      out.println(e.getMessage());

      out.println("</error>");

  }

   * Handle the "getdtdschema" action.

   * Read DTD or Schema file for a given doctype from Metacat catalog system

   */

  private void handleGetDTDSchemaAction(PrintWriter out, Hashtable params,

                                        HttpServletResponse response) {

    String doctype = null;

    String[] doctypeArr = (String[])params.get("doctype");

    // get only the first doctype specified in the list of doctypes

    // it could be done for all doctypes in that list

    if (doctypeArr != null) {

    }

    try {

        DBUtil dbutil = new DBUtil();

        String dtdschema = dbutil.readDTDSchema(doctype);

        out.println(dtdschema);

      out.println("<error>");

      out.println(e.getMessage());

      out.println("</error>");

  }