Metacat

/**

 *        Name: DBElement.java

 *     Purpose: A Class that represents an XML element and can

 *		write its contents to a database connection

 * Institution: National Center for Ecological Analysis and Synthesis

 *   Copyright: 1998

 *     Authors: Matt Jones

 *

 *     Version: '$Id: DBElement.java 13 1999-09-19 23:01:18Z jones $'

 */

//package project;

import com.sun.xml.tree.ElementNode;

import org.w3c.dom.DOMException;

import org.w3c.dom.Element;

import org.w3c.dom.Attr;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;

import org.w3c.dom.NamedNodeMap;

import org.w3c.dom.ProcessingInstruction;

import org.w3c.dom.Text;

import java.sql.*;

import java.io.IOException;

public class DBElement extends ElementNode {

    public DBElement () {

      super();

    };

    /**

     * Writes this element and all of its children out to the 

     * given database connection 

     */

    public void writeXmlToDB(Connection conn, int parentID) 

		throws IOException {

        int maxid=0;

        int newid=0;

        Statement stmt;

        try {

          stmt = conn.createStatement();

          stmt.execute("SELECT MAX(nodeid) FROM xml_elements");

          try {

            ResultSet rs = stmt.getResultSet();

            try {

              boolean tableHasRows = rs.next();

              if (tableHasRows) {

                try {

                  maxid = rs.getInt(1);

                } catch (SQLException e) {

                  System.out.println("Error with getInt: " + e.getMessage());

                }

              }

            } catch (SQLException e) {

              System.out.println("Error with next: " + e.getMessage());

            }

          } catch (SQLException e) {

            System.out.println("Error with getrset: " + e.getMessage());

          }

          stmt.close();

        } catch (SQLException e) {

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

        }

        // assign a new ID number

        newid = maxid + 1;

        try {

          PreparedStatement pstmt;

          if (parentID != 0) {

            pstmt = conn.prepareStatement(

                "INSERT INTO xml_elements(nodeid, nodename, parentnodeid) " + 

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

          } else {

            pstmt = conn.prepareStatement(

                "INSERT INTO xml_elements(nodeid, nodename) " + 

		"VALUES (?, ?)");

          }

          // Bind the values to the query

          pstmt.setInt(1, newid); // The first ? is for NODEID

          pstmt.setString(2, getTagName());// The second ? is for NODENAME

          if (parentID != 0) {

            pstmt.setInt(3, parentID);

          }

          // Do the insertion

          pstmt.execute();

          pstmt.close();

        } catch (SQLException e) {

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

        }

        System.out.println("ID: " + newid + "\tTag: " + getTagName());

        // Now save this node's attributes

	writeAttributesToDB(conn, newid);

        // Now save this node's children

	if (hasChildNodes()) {

            try {

	      writeChildrenXmlToDB(conn, newid);

            } catch (SQLException e) {

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

            }

        }

    }

    public void writeChildrenXmlToDB(Connection conn, int parentID) 

		throws IOException, SQLException {

      NodeList children = getChildNodes();

      if (children != null) {

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

          if (children.item(i) instanceof ElementNode) {

            ((DBElement)children.item(i)).writeXmlToDB(conn, parentID);

          } else if (children.item(i) instanceof Text) {

             // Write the text to the now created parent node

             PreparedStatement pstmt = conn.prepareStatement(

                "UPDATE xml_elements SET nodedata = ? " + 

		"WHERE nodeid = ?");

             pstmt.setString(1, ((Text)children.item(i)).getNodeValue()); 

             pstmt.setInt(2, parentID); 

             pstmt.execute();

             pstmt.close();

          } else {

            System.out.println("    Other Node Type skipped.");

          }

        }

      }

    }

    /**

     * Writes this element's attributes out to the 

     * given database connection 

     */

    public void writeAttributesToDB(Connection conn, int nodeid) 

		throws IOException {

        NamedNodeMap attributes = getAttributes();

        if (attributes != null) {

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

               String name = ((Attr)attributes.item(i)).getName();

               String value = ((Attr)attributes.item(i)).getValue();

               System.out.println("    Saving attribute: " + name + "=" + value);

               int maxid=0;

               int newid=0;

               Statement stmt;

               try {

                 stmt = conn.createStatement();

                 stmt.execute("SELECT MAX(attributeid) FROM xml_attributes");

                 try {

                   ResultSet rs = stmt.getResultSet();

                   try {

                     boolean tableHasRows = rs.next();

                     if (tableHasRows) {

                       try {

                         maxid = rs.getInt(1);

                       } catch (SQLException e) {

                         System.out.println("Error with getInt: " + e.getMessage());

                       }

              }

                   } catch (SQLException e) {

                     System.out.println("Error with next: " + e.getMessage());

                   }

                 } catch (SQLException e) {

                   System.out.println("Error with getrset: " + e.getMessage());

                 }

                 stmt.close();

               } catch (SQLException e) {

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

               }

               // assign a new ID number

               newid = maxid + 1;

               try {

                 PreparedStatement pstmt;

                 pstmt = conn.prepareStatement(

                  "INSERT INTO xml_attributes(attributeid, nodeid, " +

                  "attributenumber, attributename, attributevalue) " +

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

                 // Bind the values to the query

                 pstmt.setInt(1, newid); 		// ATTRIBUTEID

                 pstmt.setInt(2, nodeid);		// NODEID

                 pstmt.setInt(3, i+1); 			// ATTRIBUTENUMBER

                 pstmt.setString(4, name);		// ATTRIBUTENAME

                 pstmt.setString(5, value);		// ATTRIBUTEVALUE

                 // Do the insertion

                 pstmt.execute();

                 pstmt.close();

               } catch (SQLException e) {

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

               }

            }

        }

    }

    // used by JTree to display this node

    public String toString ()

    {

	StringBuffer	value = new StringBuffer ();

	value.append ('<');

	value.append (getTagName ());

	value.append (getAttributes ().toString ());

	value.append ('>');

	return value.toString ();

    }

}