Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A Class that reads in an XML text document and

 *             write its contents to a database connection using SAX

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

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Matt Jones

 *

 *   '$Author: jones $'

 *     '$Date: 2000-06-26 21:31:07 -0700 (Mon, 26 Jun 2000) $'

 * '$Revision: 204 $'

 */

package edu.ucsb.nceas.metacat;

import java.io.*;

import java.sql.*;

import java.util.Stack;

import org.xml.sax.AttributeList;

import org.xml.sax.ContentHandler;

import org.xml.sax.DTDHandler;

import org.xml.sax.EntityResolver;

import org.xml.sax.ErrorHandler;

import org.xml.sax.InputSource;

import org.xml.sax.XMLReader;

import org.xml.sax.SAXException;

import org.xml.sax.SAXParseException;

import org.xml.sax.helpers.XMLReaderFactory;

/**

 * A Class that reads in an XML text document and

 * write its contents to a database connection using SAX

 */

public class DBWriter {

  private Connection	conn = null;

  private String parserName = null;

  /**

   * the main routine used to test the DBWriter utility.

   * <p>

   * Usage: java DBWriter <-f filename -a action -d docid>

   *

   * @param filename the filename to be loaded into the database

   */

  static public void main(String[] args) {

    try {

      String filename = null;

      String action   = null;

      String docid    = null;

      for ( int i=0 ; i < args.length; ++i ) {

        if ( args[i].equals( "-f" ) ) {

          filename =  args[++i];

        } else if ( args[i].equals( "-a" ) ) {

          action =  args[++i];

        } else if ( args[i].equals( "-d" ) ) {

          docid =  args[++i];

        } else {

          System.err.println

            ( "   args[" +i+ "] '" +args[i]+ "' ignored." );

        }

      }

      boolean argsAreValid = false;

      if (action != null) {

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

          if (filename != null) {

            argsAreValid = true;

          } 

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

          if ((filename != null) && (docid != null)) {

            argsAreValid = true;

          } 

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

          if (docid != null) {

            argsAreValid = true;

          } 

        } 

      } 

      if (!argsAreValid) {

        System.err.println("Wrong number of arguments!!!");

        System.err.println(

              "USAGE: java DBWriter <-f filename -a action -d docid>");

        return;

      }

      // Open a connection to the database

      MetaCatUtil   util = new MetaCatUtil();

      Connection dbconn = util.openDBConnection();

      DBWriter dbw = new DBWriter(dbconn, util.getOption("saxparser"));

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

        dbw.delete(docid);

        System.out.println("Document deleted: " + docid);

      } else {

        String newdocid = dbw.write(filename, action, docid);

        if ((docid != null) && (!docid.equals(newdocid))) {

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

            System.out.println("New document ID generated!!! ");

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

            System.out.println("ERROR: Couldn't update document!!! ");

          }

        } else if ((docid == null) && (action.equals("UPDATE"))) {

            System.out.println("ERROR: Couldn't update document!!! ");

        }

        System.out.println("Document processing finished for: " + filename

              + " (" + newdocid + ")");

      }

    } catch (AccessionNumberException ane) {

      System.out.println("ERROR: Couldn't delete document!!! ");

      System.out.println(ane.getMessage());

    } catch (Exception e) {

      System.err.println("EXCEPTION HANDLING REQUIRED");

      System.err.println(e.getMessage());

      e.printStackTrace(System.err);

    }

  }

  /**

   * construct a new instance of the class to write an XML file to the database

   *

   * @param conn the database connection to which to write the XML file

   * @param parserName the name of a SAX2 compliant parser class

   */

  public DBWriter(Connection conn, String parserName) {

    this.conn = conn;

    this.parserName = parserName;

  }

  /**

   * Insert XML stream to the database

   *

   * @param xml the xml stream to be loaded into the database

   */

  public String write( Reader xml, String action, String docid )

                throws Exception, IOException, SQLException, 

                       ClassNotFoundException, SAXException, SAXParseException {

    try {

        XMLReader parser = initializeParser(action, docid);

        conn.setAutoCommit(false);

        parser.parse(new InputSource(xml));

        conn.commit();

        conn.setAutoCommit(true);

        return docid;

      } catch (SAXParseException e) {

        conn.rollback();

        throw e;

      } catch (SAXException e) {

        // If its a problem with the accession number its ok, just the 

        // accession number was regenerated

        AccessionNumberGeneratedException ang = null;

        try {

          Exception embedded = e.getException();

          if ((embedded != null) && 

              (embedded instanceof AccessionNumberGeneratedException)) {

            ang = (AccessionNumberGeneratedException)e.getException();

          }

        } catch (ClassCastException cce) {

          // Do nothing and just fall through to the ang != null test

        }

        if (ang != null) {

          conn.commit();

          conn.setAutoCommit(true);

          return (ang.getMessage());

        } else {

          conn.rollback();

          throw e;

        }

      } catch (Exception e) {

        conn.rollback();

        throw e;

      }

  }

  /**

   * Insert an XML file to the database

   *

   * @param filename the filename to be loaded into the database

   */

  public String write( String filename, String action, String docid )

                throws Exception, IOException, SQLException, 

                       ClassNotFoundException, SAXException, SAXParseException {

     return write(new FileReader(new File(filename).toString()), action, docid);

  }

  private XMLReader initializeParser(String action, String docid) {

    XMLReader parser = null;

    //

    // Set up the SAX document handlers for parsing

    //

    try {

      ContentHandler chandler   = new DBSAXHandler(conn, action, docid);

      EntityResolver dbresolver = new DBEntityResolver(conn, 

                                      (DBSAXHandler)chandler);

      DTDHandler dtdhandler     = new DBDTDHandler(conn);

      // Get an instance of the parser

      parser = XMLReaderFactory.createXMLReader(parserName);

      // Turn off validation

      parser.setFeature("http://xml.org/sax/features/validation", false);

      // Set Handlers in the parser

      parser.setProperty("http://xml.org/sax/properties/declaration-handler",

                         chandler);

      parser.setProperty("http://xml.org/sax/properties/lexical-handler",

                         chandler);

      parser.setContentHandler(chandler);

      parser.setEntityResolver(dbresolver);

      parser.setDTDHandler(dtdhandler);

      parser.setErrorHandler((ErrorHandler)chandler);

    } catch (Exception e) {

       System.err.println(e.toString());

    }

    return parser;

  }

  /**

   * Delete an XML file from the database (actually, just make it a revision

   * in the xml_revisions table)

   *

   * @param docid the ID of the document to be deleted from the database

   */

  public void delete( String docid )

                  throws IOException, SQLException, 

                         ClassNotFoundException, AccessionNumberException {

    String newdocid = AccessionNumber.generate(docid, "DELETE");

    conn.setAutoCommit(false);

    // Copy the record to the xml_revisions table

    DBSAXDocument document = new DBSAXDocument(conn);

    document.saveDocument( docid );

    // Now delete it from the xml_documents table

    Statement stmt = conn.createStatement();

    stmt.execute("DELETE FROM xml_documents WHERE docid LIKE '" + docid + "'");

    stmt.close();

    conn.commit();

  }

}

/**

 * '$Log$

 * 'Revision 1.21  2000/06/26 10:35:05  jones

 * '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.

 * '

 * 'Revision 1.20.2.7  2000/06/26 10:18:06  jones

 * 'Partial fix for MetaCatServlet INSERT?UPDATE bug.  Only will work on

 * 'the first call to the servlet.  Subsequent calls fail.  Seems to be

 * 'related to exception handling.  Multiple successive DELETE actions

 * 'work fine.

 * '

 * 'Revision 1.20.2.6  2000/06/26 08:38:02  jones

 * 'Added DELETE feature to DBWriter.  Now takes an action "DELETE" and a

 * 'docid and will move the record from the xml_documents table to the

 * 'xml_revisions table.

 * 'Modified option parsing to support option symbols on command line.

 * '

 * 'Revision 1.20.2.5  2000/06/26 02:02:20  jones

 * 'Continued fixing problems with exception handling that deals

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

 * '

 * 'Revision 1.20.2.4  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 1.20.2.3  2000/06/25 23:38:16  jones

 * 'Added RCSfile keyword

 * '

 * 'Revision 1.20.2.2  2000/06/25 23:34:18  jones

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

 * ''

 */