array Index out of Bounds exception== 0

[Allgorythm]

Hi I cant figure why does the program telling me an ArrayIndexOutOfBounds when adding a row in a Table?

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
public class DataBaseSample {

     private JTable mainTable;
     private JScrollPane sp ;
     private JViewport jv;
     private JTable rowHeaderTableColumn;
     private JPanel panel;
     private JButton rowRemover;
     private JFrame frame;
     private TableModel tableModel;
     private DefaultTableModel mainTableModel;
     private Integer[] rowHeaderData;

     public DataBaseSample() {

         frame = new JFrame();
         rowRemover = new JButton("Add Row");
         panel = new JPanel();
         tableModel = new AbstractTableModel() {

             String[] header = {"Rows"};

             public int getColumnCount() {

                 return 1;
             }

             public int getRowCount() {

                 return mainTable.getRowCount();
             }

            @Override
             public String getColumnName(int col) {

                 // this will set the row headers column name
                 return header[0];
             }

             public Object getValueAt(int row, int col) {

                 // this will set the row headers row data
                 return rowHeaderData[col] + row;
             }
         };

         TableColumnModel rowHeaderModel = new DefaultTableColumnModel() {

             boolean first = true;

            @Override
             public void addColumn(TableColumn tableColumn) {

                 if (first) {

                     tableColumn.setMaxWidth(tableColumn.getPreferredWidth());

                     super.addColumn(tableColumn);
                     tableColumn.setMaxWidth(100);
                     first = false;
                 }
             }
         };

         Object[][] rows = new Object[0][3];
         String[] cols = {"Column 1", "Column 2", "Column 3"};
         

         mainTableModel = new DefaultTableModel(rows, cols);
         mainTable = new JTable(mainTableModel);
         rowHeaderTableColumn = new JTable(tableModel, rowHeaderModel);
         rowHeaderTableColumn.createDefaultColumnsFromModel();
         rowHeaderTableColumn.setBackground(Color.lightGray);
         rowHeaderTableColumn.setColumnSelectionAllowed(false);
         rowHeaderTableColumn.setCellSelectionEnabled(false);

         jv = new JViewport();
         jv.setView(rowHeaderTableColumn);
         jv.setPreferredSize(rowHeaderTableColumn.getMaximumSize());

         mainTable.setSelectionModel(rowHeaderTableColumn.getSelectionModel());
         mainTable.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
         panel.setLayout(new BorderLayout());

         rowHeaderData = new Integer[mainTable.getRowCount()];
         for (int count = 0; count <= mainTable.getRowCount() - 1; count++) {

             rowHeaderData[count] = count + 1;
         }

         sp = new JScrollPane(mainTable);
         sp.setRowHeader(jv);
         sp.setCorner(ScrollPaneConstants.UPPER_LEFT_CORNER, rowHeaderTableColumn.getTableHeader());

         rowRemover.addActionListener(new RowRemoverButtonActionListener());

         panel.add(rowRemover, BorderLayout.NORTH);
         panel.add(sp, BorderLayout.SOUTH);

         frame.getContentPane().add(panel);

         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setSize(500, 500);
         frame.setLocationRelativeTo(null);
         frame.setVisible(true);
     }

     private class RowRemoverButtonActionListener implements ActionListener {

         public void actionPerformed(ActionEvent e) {

             // set to zero to avoid array index out of bounds -1
             mainTableModel.addRow(new Object[] {null,null,null});

             sp.setRowHeader(jv);
         }
     }

     public static void main(String args[]) {
         
         new DataBaseSample();
 
     }
}

[m00nchile]

I just rushed through the code, so I'm not a 100% on this, but I'm pretty sure this is the problem:

Object[][] rows = new Object[0][3];

Why are you trying to create a table with 0 elements? int[] array = new int[1]; will have only one element at index 0, is this perhaps what you wanted? Since multidimensional arrays are formed like this (this is what java does in the background, I'm not saying you should do this):

int[][] array = new int[1][3];
//the equivalent
int[] array2 = new int[1];
array2[0] = new int[3];

[jassi]

The declaration of your rows is wrong. You are declaring it with 0 rows.

Object[][] rows = new Object[0][3];

Solution:

Declare your object as

Object[][] rows = new Object[1][3];

[Allgorythm]

Why are you trying to create a table with 0 elements?

i was just trying to put my program or table in a situation like this. what if the default number of rows is zero? just in case and for
the compiler is pointing on this part >

  public Object getValueAt(int row, int col) {

                 // this will set the row headers row data
                 return rowHeaderData[col] + row;
             }

i tried to make an if-else statement that if rowHeaderData.length == 0, do something, or col == 0 then do something and row == 0 , then do something..

i tried to make them 1 if their values are 0, but still the compier throws me an ArrayOutOfBounds

[jassi]

Then you check it first that it is zero.

If it is zero then add a row from your side only.

[Fubarable]

Perhaps you want your rowHeaderData to not be an array but instead an ArrayList, and then when you add a row, add to this list as well.

edit: Ignore the above. I've not used row headers before, but perhaps something as simple as changing the row header's table model's getValueAt(..) to

         public Object getValueAt(int row, int col) {
            return "Row " + row;
         }
      };

but again, this is "shooting from the hip". Let's see what the experts say...

[Allgorythm]

:eek:

edit: Ignore the above. I've not used row headers before, but perhaps something as simple as changing the row header's table model's getValueAt(..) to
Code:
public Object getValueAt(int row, int col) {
return "Row " + row;
}
};
but again, this is "shooting from the hip". Let's see what the experts say...

are you not sure of this? but it helped me! it SOLVED the problem!
i never thought of that, instead of

return rowHeaderData[col] + row;

-relying to the data counts of the main table ,your code can generate my rowheadertable its own data counts.. wow thanks!

i just did this one. >

        
     public Object getValueAt(int row, int col) {

                 
                 return 1 + row;
             }

i just only need a number that will represents the count for each row, i hope i wont encounter any future problems. thanks
!