Metacat

/**

 *    Purpose: A Class that handles the SAX XML events as they

 *             are generated from XML documents

 *  Copyright: 2000 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Matt Jones, Jivka Bojilova

 *     '$Date$'

 * '$Revision$'

import java.util.Stack;

import java.util.Enumeration;

import org.xml.sax.SAXException;

import org.xml.sax.helpers.DefaultHandler;

 * A database aware Class implementing callback bethods for the SAX parser to

 * call when processing the XML stream and generating events

 */

   private String 	systemid;

   private Vector   nodeIndex;

   private Connection	  conn = null;

   private String   docid = null;

   private String   user = null;

   private Thread   xmlIndex;

   private boolean endDocument = false;

    *

    * @param conn the JDBC connection to which information is written

    */

     // if it doesn't already exist

     if (!stackCreated) {

       nodeStack = new Stack();

     }

    *

    * @param conn the JDBC connection to which information is written

    * @param docid to be inserted or updated into JDBC connection

    * @param user the user connected to MetaCat servlet

   {

     this.action = action;

     this.docid = docid;

     //this.xmlIndex.setPriority(Thread.MIN_PRIORITY);

     // added as it is encountered

     nodeStack.push(rootNode);

   /** SAX Handler that receives notification of end of the document */

     // It calls the run method of the thread.

     try {

       xmlIndex.start();

     } catch (NullPointerException e) {

       xmlIndex = null;

       throw new

       SAXException("Problem with starting thread for writing XML Index. " +

                    e.getMessage());

     }

   public void startElement(String uri, String localName,

                            String qName, Attributes atts)

               throws SAXException {

     DBSAXNode currentNode = null;

     try {

       parentNode = (DBSAXNode)nodeStack.peek();

     } catch (EmptyStackException e) {

       atFirstElement = false;

       if (docname == null) {

         docname = localName;

         MetaCatUtil.debugMessage("DOCNAME-a: " + docname);

         MetaCatUtil.debugMessage("DOCTYPE-a: " + doctype);

         MetaCatUtil.debugMessage("DOCTYPE-b: " + doctype);

       rootNode.writeNodename(docname);

       try {

       }

       //rootNode.writeDocID(currentDocument.getDocID());

                                 currentDocument.getRootNodeID(),docid,

                                 currentDocument.getDoctype());

     for (int i=0; i<atts.getLength(); i++) {

     // added as it is encountered

     nodeStack.push(currentNode);

     nodeIndex.addElement(currentNode);

  // The run method of xmlIndex thread. It writes XML Index for the document.

  public void run () {

    DBSAXNode currNode = null;

    DBSAXNode prevNode = null;

    int step = 0;

    int counter = 0;

      // Opening separate db connection for writing XML Index

      MetaCatUtil util = new MetaCatUtil();

      Connection conn = util.getConnection();

      conn.setAutoCommit(false);

      // Going through the elements of the document and writing its Index

      Enumeration nodes = nodeIndex.elements();

      while ( nodes.hasMoreElements() ) {

        currNode = (DBSAXNode)nodes.nextElement();

        currNode.updateNodeIndex(conn, docid, currentDocument.getDoctype());

      }

      conn.commit();

      //if this is a package file then write the package info to

      //the xml_relation table. relationHandler checks to see

      //if it is a package file so you don't have to do it here.

      DocumentImpl xmldoc = new DocumentImpl(conn, docid);

      relationHandler rth = new relationHandler(xmldoc, conn);

      util.returnConnection(conn);

      try {

        conn.rollback();

        conn.close();

      } catch (SQLException sqle) {}

      System.out.println("Error writing XML Index. " + e.getMessage());

    }

  }

  public void characters(char[] cbuf, int start, int len) throws SAXException {

     int leftover = len;

     int offset = start;

     boolean moredata = true;

     // This loop deals with the case where there are more characters

     // than can fit in a single database text field (limit is

     // MAXDATACHARS).  If the text to be inserted exceeds MAXDATACHARS,

     // write a series of nodes that are MAXDATACHARS long, and then the

     // final node contains the remainder

     while (moredata) {

       if (leftover > MAXDATACHARS) {

         data = new String(cbuf, offset, MAXDATACHARS);

         leftover -= MAXDATACHARS;

         offset += MAXDATACHARS;

       } else {

         data = new String(cbuf, offset, leftover);

         moredata = false;

       }

     // write the title of document if there are tag <title>

     if ( currentNode.getTagName().equals("title") ) {

       if ( leftover > MAXTITLELEN )

         currentDocument.setTitle(new String(cbuf, start, MAXTITLELEN));

       else

         currentDocument.setTitle(new String(cbuf, start, leftover));

    * SAX Handler that is called for each XML text node that is Ignorable

    * white space

    */

    * SAX Handler called once for each processing instruction found:

    * node that PI may occur before or after the root element.

    */

   public void processingInstruction(String target, String data)

          throws SAXException {

                          String qName) throws SAXException {

     DBSAXNode currentNode = (DBSAXNode)nodeStack.pop();

   // the next section implements the LexicalHandler interface

   //

   /** SAX Handler that receives notification of DOCTYPE. Sets the DTD */

   public void startDTD(String name, String publicId, String systemId)

               throws SAXException {

     docname = name;

     doctype = publicId;

     systemid = systemId;

     MetaCatUtil.debugMessage("DOCTYPE: " + doctype);

     MetaCatUtil.debugMessage("  SYSID: " + systemid);

   /**

    * SAX Handler that receives notification of end of DTD

    */

   public void endDTD() throws SAXException {

   /**

    * SAX Handler that receives notification of comments in the DTD

    */

   public void comment(char[] ch, int start, int length) throws SAXException {

   /**

    * SAX Handler that receives notification of the start of CDATA sections

    */

   public void startCDATA() throws SAXException {

   /**

    * SAX Handler that receives notification of the end of CDATA sections

    */

   public void endCDATA() throws SAXException {

   /**

    * SAX Handler that receives notification of the start of entities

    */

   public void startEntity(String name) throws SAXException {

     if (name.equals("[dtd]")) {

       processingDTD = true;

     }

   /**

    * SAX Handler that receives notification of the end of entities

    */

   public void endEntity(String name) throws SAXException {

     if (name.equals("[dtd]")) {

       processingDTD = false;

     }

   /**

    * SAX Handler that receives notification of element declarations

    */

   public void elementDecl(String name, String model)

                        throws org.xml.sax.SAXException {

   /**

    * SAX Handler that receives notification of attribute declarations

    */

   public void attributeDecl(String eName, String aName,

                        String type, String valueDefault, String value)

                        throws org.xml.sax.SAXException {

                        + aName + " " + type + " " + valueDefault + " "

                        + value);

   /**

    * SAX Handler that receives notification of internal entity declarations

    */

   public void internalEntityDecl(String name, String value)

                        throws org.xml.sax.SAXException {

   /**

    * SAX Handler that receives notification of external entity declarations

    */

   public void externalEntityDecl(String name, String publicId,

                        String systemId)

                        throws org.xml.sax.SAXException {

                              + " " + systemId);

   // the next section implements the ErrorHandler interface

   //

    * SAX Handler that receives notification of fatal parsing errors

    */

   public void fatalError(SAXParseException exception) throws SAXException {

     MetaCatUtil.debugMessage("FATALERROR");

     throw (new SAXException("Fatal processing error.", exception));

   }

   /**

    * SAX Handler that receives notification of recoverable parsing errors

    */

   public void error(SAXParseException exception) throws SAXException {

     MetaCatUtil.debugMessage("ERROR");

   }

   /**

    * SAX Handler that receives notification of warnings

    */

   public void warning(SAXParseException exception) throws SAXException {

     MetaCatUtil.debugMessage("FATALERROR");

   }

   //

   // Helper, getter and setter methods

   //

   /**

    * get the document name

    */

   public String getDocname() {

     return docname;

   }

   /**

    * get the document processing state

    */

     return processingDTD;