JTable - Please Help

[BeeGee]

Hello,

I am having problems with my code below. I do not get any compilation errors. However, when I run the code, I only see a Blank frame. Please help.

import java.awt.Container;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;

public class BooksDatabase extends JFrame {
	
	//JDBC driver name and database URL
	static final String JDBC_DRIVER = "sun.jdbc.odbc.JdbcOdbcDriver";
	static final String DATABASE_URL = "jdbc:odbc:DRIVER={Microsoft Access Driver (*.mdb)};DBQ=c:\\Books.mdb";
	private Connection con;
	private Statement statement;
	private JTable databaseTable;
	private Container container;
	private String [] AttributeNames;
	private Object[][] myArray=null;
	 
	int numberOfColumns, numberOfRows;
	 
	public BooksDatabase(){
		super("Books");
		//databaseTable.setVisible(false);
		container = getContentPane();
        container.setLayout(null);
		Query();
		
	}		
			
	private void init_Components() //initializes components that are going to be used.
	{
	        databaseTable = new JTable();
	        JScrollPane myPane = new JScrollPane(databaseTable,
					   JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
					  JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);   
	        
	        databaseTable.setModel(new DefaultTableModel(
	            new Object [][] { {null},{null}, {null}, {null}},new String [] {""} ) {
	              /**
					 * 
					 */
					private static final long serialVersionUID = 1L;
				@SuppressWarnings("unchecked")
				Class[] types = new Class [] { java.lang.Object.class};
	              boolean[]canEdit=new boolean[]{false};
	                   
	              @SuppressWarnings("unchecked")
				public Class getColumnClass(int columnIndex) {
	                    return types [columnIndex];
	              }
	           
	              public boolean isCellEditable(int rowIndex, int columnIndex) {
	                    return canEdit [columnIndex];
	              }
	        });

	        myPane.setViewportView(databaseTable);
	        myPane.setVisible(true);
	        add(myPane);
	       //jScrollPane1.setBounds(3, 120, 460, 150);
	      
	     
	        pack();
	}//end method init_Components
	
	

	private void Query() {
		try {
			

			//specify location of database on filesystem
			System.setProperty( "C:\\Books.mdb","null" );
			
			//load database driver class
			Class.forName(JDBC_DRIVER);
			
			//establish connection to database
			con = DriverManager.getConnection(DATABASE_URL);
	
			//create statement for querying database
			statement = con.createStatement();
			
			ResultSet resultSet = statement.executeQuery("SELECT authorid, firstName, lastName FROM Authors");
			ResultSetMetaData metaData = resultSet.getMetaData();
			numberOfColumns = metaData.getColumnCount();
			//int numberOfRows = 0;
            AttributeNames=new String[numberOfColumns];
            for(int i=0;i<numberOfColumns;i++)
                AttributeNames[i]=metaData.getColumnName(i+1);
            myArray=new Object[10000][numberOfColumns];
            int R=0;
            while(resultSet.next()) {
                for(int C=1; C<=numberOfColumns;C++)
                    myArray[R][C-1]=resultSet.getObject(C);
                R++;
            }
            resultSet.close();
            numberOfRows=R;
            Object[][] tempArray=myArray;
            myArray=new Object[numberOfRows][numberOfColumns];
            for(R=0;R<numberOfRows;R++)
                for(int C=0;C<numberOfColumns;C++)
                    myArray[R][C]=tempArray[R][C];
            databaseTable.setModel(new ResultSetTableModel());//sets this table to model ResultSetTableModel
            databaseTable.setVisible(true);//Makes the Table Visible
        }//end try
        catch(Exception e) {
            e.printStackTrace();
        }//end catch
        
     // ensures database connection is closed when user quits application
        addWindowListener(
        
           new WindowAdapter() 
           {
              // disconnects from database and exit when window has closed
              public void windowClosed( WindowEvent event )
              {
            	  //disconnectFromDatabase();
                 System.exit( 0 );
              } // end method windowClosed
           } // end WindowAdapter inner class
        ); // end call to addWindowListener
        
		
	}//end BooksDatabase Constructor
			
}//end BooksDatabase Class

//ResultSetTableModel.java

public class ResultSetTableModel extends AbstractTableModel {
	
	 private static final long serialVersionUID=317L;
	 private int numberOfRows, numberOfColumns;
	 String [] AttributeNames;
	 Object[][] myArray=null;
	 
     public int getColumnCount() {
         return (numberOfColumns);
     }
     public int getRowCount() {
         return(numberOfRows);
     }
     public String getColumnName(int i) {
         return (AttributeNames[i]);
     }
     public Object getValueAt(int row, int column) {
         return(myArray[row][column]);
     }
     public Class getColumnClass(int c) {
         return getValueAt(0, c).getClass();
     }
     public boolean isCellEditable(int row, int col) {
         //Note that the data/cell address is constant,
         //no matter where the cell appears onscreen.
         if (col < 3) {
             return false;
         } else {
             return true;
         }
     }
     public void setValueAt(Object value, int row, int col) {
         myArray[row][col] = value;
         fireTableCellUpdated(row, col);
     }       

}

import javax.swing.JFrame;


public class databaseTest {
	 public static void main( String args[] )
	   { 
	      BooksDatabase bd = new BooksDatabase(); 
	      bd.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
	     // bd.setSize( 325, 100 ); // set frame size
	      bd.setVisible( true ); // display frame
	   } // end main

}

Thank YOu

[Eranga]

Did you write this code, found somewhere ?

[r035198x]

You have a bit of reading to do:

Using Layout Managers (The Java™ Tutorials > Creating a GUI With JFC/Swing > Laying Out Components Within a Container)

Doing Swing right - Java insights

[BeeGee]

I got some of the code from a reference textbook but I wrote the rest myself. I am using the database set up by the authors Deitel Deitel.
Thanks.

[Eranga]

Fine. First of all just forget about the database part and look at the UI. Better to write a simple application first of all with a JTable and dummy values. r035198x send you a link about layouts. Read it completely. When you design a UI in Java you've follow some patterns to place controls.