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 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

 */

                          implements LexicalHandler, DeclHandler {

   private String 	systemid;

   private String       docid = null;

    *

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

    */

     // if it doesn't already exist

     if (!stackCreated) {

       nodeStack = new Stack();

       stackCreated = true;

     }

    *

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

    */

   public DBSAXHandler(Connection conn, String action, String docid) {

     this(conn);

     this.action = action;

     this.docid = docid;

   }

     rootNode = new DBSAXNode(conn, docname);

                               rootNode.getTagName());

     // added as it is encountered

     nodeStack.push(rootNode);

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

     if ((docid != null) && (!docid.equals(currentDocument.getDocID()))) {

       throw (new SAXException("New document ID generated:",

       throw (new SAXException("New document ID generated:",

   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);

         //doctype = DBEntityResolver.doctype;

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

       rootNode.writeNodename(docname);

       rootNode.writeRootNodeID(rootNode.getNodeID());

       try {

         currentDocument = new DBSAXDocument(conn, rootNode.getNodeID(),

                                           docname, doctype, docid, action);

         } catch (AccessionNumberException ane) {

       rootNode.writeDocID(currentDocument.getDocID());

     }

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

       currentNode.setAttribute(atts.getLocalName(i), atts.getValue(i));

     }

     // added as it is encountered

     nodeStack.push(currentNode);

  }

     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;

       }

       currentNode.writeChildNodeToDB("TEXT", null, data);

     }

    * 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 {

     currentNode.writeChildNodeToDB("PI", target, data);

                          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 {

     currentNode.writeChildNodeToDB("COMMENT", null, new String(ch));

   /**

    * 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;

/**

 * '$Log$

 * 'Call to DBSAXNode constructor simplified

 * '

 * 'Fixed bug in DBEntityResolver so that it now properly delegates to

 * 'the system id found inthe database.

 * 'Changed DBValidate to use DBEntityResolver, rather than the OASIS

 * 'catalog, and to return validation results in XML format.

 * '

 * 'Fixed bug where TEXT nodes couldn't be longer than 4000 characters, which

 * 'is the maximum length of a VARCHAR2 field in Oracle.  Now, if text

 * 'exceeds the field length, I break the text up into a series of TEXT

 * 'nodes each of the max field length, and the remainder in the last

 * 'TEXT node. The only problem with this is that our current search

 * 'algorithms only will find phrases within a single TEXT nodes, so if

 * 'the search term spans the node boundary, the search algorithm will not

 * 'return a hit. I expect this is extremely rare, basically inconsequential.

 * '

 * 'Fixed bugs associated with the new UPDATE and DELETE functions of

 * 'DBWriter.  There were problematic interactions between some static

 * 'variables used in DBEntityResolver and the way in which the

 * 'Servlet objects are re-used across multiple client invocations.

 * '

 * 'Generally cleaned up error reporting.  Now all errors and success

 * 'results are reported as XML documents from MetaCatServlet.  Need

 * 'to make the command line tools do the same.

 * '

 * 'Merged in substantial changes to DBWriter and associated classes and to

 * 'the MetaCatServlet in order to accomodate the new UPDATE and DELETE

 * 'functions.  The command line tools and the parameters for the

 * 'servlet have changed substantially.

 * '

 * 'Continued fixing problems with exception handling that deals

 * 'with INSERT and UPDATE actions and the docid passed to DBWriter

 * '

 * 'Revision 1.27.2.5  2000/06/26 00:51:06  jones

 * 'If docid passed to DBWriter.write() is not unique, classes now generate

 * 'an AccessionNumberException containing the new docid generated as a

 * 'replacement.  The docid is then extracted from the exception and

 * 'returned to the calling application for user feedback or client processing.

 * '

 * 'Revision 1.27.2.4  2000/06/25 23:38:16  jones

 * 'Added RCSfile keyword

 * '

 * 'Revision 1.27.2.3  2000/06/25 23:34:17  jones

 * 'Changed documentation formatting, added log entries at bottom of source files

 * ''

 */