Metacat

/**

 *        Name: DBSAXDocument.java

 *     Purpose: A Class that writes an XML document main data

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

 *              National Center for Ecological Analysis and Synthesis

 *     Authors: Jivka Bojilova

 *

 *     Version: '$Id: DBSAXDocument.java 152 2000-06-13 21:23:35Z bojilova $'

 */

package edu.ucsb.nceas.metacat;

import java.sql.*;

import java.io.IOException;

import java.util.Hashtable;

import java.util.Enumeration;

/** 

 * A Class that writes an XML document main data to a database connection

 */

public class DBSAXDocument {

    private Connection      conn;

    private long            rootnodeid;

    private String          docname;

    private String          doctype;

    private String          doctitle;

    private long            docid;

    /** 

     * Construct a new document instance

     *

     * @param conn the JDBC Connection to which all information is written

     * @param rootnodeid - sequence id of the root node in the document

     * @param docname - the name of DTD, i.e. the name immediately following 

     *        the DOCTYPE keyword ( should be the root element name ) or

     *        the root element name if no DOCTYPE declaration provided

     *        (Oracle's and IBM parsers are not aware if it is not the 

     *        root element name)

     * @param doctype - Public ID of the DTD, i.e. the name immediately 

     *                  following the PUBLIC keyword in DOCTYPE declaration or

     *                  the docname if no Public ID provided or

     *                  null if no DOCTYPE declaration provided

     *

     */

    public DBSAXDocument (Connection conn, long rootnodeid, String docname, 

                          String doctype)

    {

      this.conn = conn;

      this.rootnodeid = rootnodeid;

      this.docname = docname;

      this.doctype = doctype;

      writeDocumentToDB();

    }

    /** creates SQL code and inserts new document into DB connection */

    private void writeDocumentToDB() {

        try {

          PreparedStatement pstmt;

          pstmt = conn.prepareStatement(

                "INSERT INTO xml_documents " +

                "(docid, rootnodeid, docname, doctype) " +

                "VALUES (null, ?, ?, ?)");

          // Bind the values to the query

          pstmt.setLong(1, rootnodeid);

          pstmt.setString(2, docname);

          pstmt.setString(3, doctype);

          // Do the insertion

          pstmt.execute();

          pstmt.close();

          long assigned_id=0;

          Statement stmt;

          stmt = conn.createStatement();

          stmt.execute("SELECT xml_documents_id_seq.currval FROM dual");

          ResultSet rs = stmt.getResultSet();

          boolean tableHasRows = rs.next();

          if (tableHasRows) {

            assigned_id = rs.getLong(1);

            this.docid = assigned_id;

          }

          stmt.close();

        } catch (SQLException e) {

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

        }

    }

    /** Get doc id */

    public long getDocID() {

      return docid;

    }

    /**

     * Get the document title

     */

    public String getTitle() {

      return doctitle;

    }

    /**

     * Set the document title

     *

     * @param title the new title for the document

     */

    public void setTitle( String title ) {

      this.doctitle = title;

      try {

        PreparedStatement pstmt;

        pstmt = conn.prepareStatement(

              "UPDATE xml_documents " +

              " SET doctitle = ? " +

              "WHERE docid = ?");

        // Bind the values to the query

        pstmt.setString(1, doctitle);

        pstmt.setLong(2, docid);

        // Do the insertion

        pstmt.execute();

        pstmt.close();

      } catch (SQLException e) {

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

      }

    }

    /**

     * Look up the title of the first child element named "title"

     * and record it as the document title

     */

    public void setTitleFromChildElement() {

        String title = null;

        long assigned_id=0;

        PreparedStatement pstmt;

        try {

          pstmt = conn.prepareStatement(

                  "SELECT nodedata FROM xml_nodes " +

                  "WHERE nodetype = 'TEXT' " +

                  "AND rootnodeid = ? " +

                  "AND parentnodeid IN " +

                  "  (SELECT nodeid FROM xml_nodes " +

                  "  WHERE nodename = 'title' " +

                  "  AND nodetype =  'ELEMENT' " +

                  "  AND rootnodeid = ? ) " +

                  "ORDER BY nodeid");

          // The above query might be slow, and probably will be because

          // it gets ALL of the title elements while searching for one

          // title in a small subtree but it avoids the problem of using

          // Oracle's Hierarchical Query syntax which is not portable --

          // the commented out SQL that follows shows an equivalent query

          // using Oracle-specific hierarchical query

/*

          pstmt = conn.prepareStatement(

                  "SELECT nodedata FROM xml_nodes " +

                  "WHERE nodetype = 'TEXT' " +

                  "AND parentnodeid IN " +

                  "(SELECT nodeid FROM xml_nodes " +

                  "WHERE nodename = 'title' " +

                  "START WITH nodeid = ? " +

                  "CONNECT BY PRIOR nodeid = parentnodeid)");

*/

          // Bind the values to the query

          pstmt.setLong(1, rootnodeid);

          pstmt.setLong(2, rootnodeid);

          pstmt.execute();

          ResultSet rs = pstmt.getResultSet();

          boolean tableHasRows = rs.next();

          if (tableHasRows) {

            title = rs.getString(1);

          }

          pstmt.close();

        } catch (SQLException e) {

          System.out.println("Error getting id: " + e.getMessage());

        }

        // assign the new title

        this.setTitle(title);

    }

}