Merging cells in JTable...help

Question

Can someone give me some direction into how I can handle this....

Answer 1

After hours of poking around, I figured out all i needed was an extended BasicTableUI class. With the help of tames MergedCell example, I havepulled out what I need out of his class and stripped it down alot to what I needed. hopefully this will help others also...
package foo;
import java.lang.*;
import java.util.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.plaf.basic.*;
/*This class extends BasicTableUI class which is responsible for drawing the cells in a JTable
Functionality has been added to this class to allow a column cell to be spanned, or merged across
the entire length of the table.*/
See the paintRow() method to define when and how to span the cells.
public class LogicTableUI extends BasicTableUI
     public void paint(Graphics g, JComponent c)
          //get the rectangle bounds of the current graphic to be drawn
          Rectangle oldClipBounds = g.getClipBounds();
          //makes a new rectangle the same size as the current rectangle
          Rectangle clipBounds = new Rectangle(oldClipBounds);
          //gets the width of all combined columns and assigns to tableWidth
          int tableWidth = table.getColumnModel().getTotalColumnWidth();
          //sets the width of the new rectangle to equal the either the current rect size of the table width
          clipBounds.width = Math.min(clipBounds.width, tableWidth);
          //Sets the current clip to the rectangle specified by the given coordinates
          g.setClip(clipBounds);
          //define the first and last rows that are visible
          int firstIndex = table.rowAtPoint(new Point(0, clipBounds.y));
          int lastIndex = table.getRowCount()-1;
          //define a rowRect. This is a rectangle spanning the entire visible part of the table
          Rectangle rowRect = new Rectangle(0,0,tableWidth, table.getRowHeight() + table.getRowMargin());
          rowRect.y = firstIndex*rowRect.height;
          //for every row that is visible, paint it
          for (int index = firstIndex; index <= lastIndex; index++)
               //is the clipBounds of the current object to be drawn in this row?
               if (rowRect.intersects(clipBounds))
                    paintRow(g, index);
               //move to next row
               rowRect.y += rowRect.height;
          g.setClip(oldClipBounds);
     private void paintRow(Graphics g, int row)
          //define rect as the current graphic objects bounds
          Rectangle rect = g.getClipBounds();
          //the graphic has not been drawn yet
          boolean drawn = false;
          //define how many columns we have to draw for this row
          int numColumns = table.getColumnCount();
          //for every column in the row, paint it
          for (int column = 0; column < numColumns; column++)
               //define cellRect
               Rectangle cellRect = table.getCellRect(row,column,true);
               int cellRow;
               int cellColumn;
               cellRow = row;
               cellColumn = column;
               if (cellRect.intersects(rect))
                    drawn = true;
                    DefinitionTableModel tblmod = (DefinitionTableModel) table.getModel();
                    try
                         LogicGroup grp = tblmod.getLogicGroupByRow(cellRow);
                         //is this a statement row? If so, apply special treatment to the cell,
                         //otherwise paint the cell normally
                         if (grp.getEnd()==cellRow)
                              //We are on a row we want to span. If its the 1st column, increase
                              //the width of the rectangle to span the entire table width and
                              //call paintCell. Otherwise, do not even paint the cell.
                              if (cellColumn==0)
                                   cellRect.width=table.getColumnModel().getTotalColumnWidth();
                                   paintCell(g, cellRect, cellRow, cellColumn);
                         else
                              paintCell(g, cellRect, cellRow, cellColumn);
                    catch(Exception e)
                         e.printStackTrace();
               else
                    if (drawn)
                         break;
     private void paintCell(Graphics g, Rectangle cellRect, int row, int column)
          int spacingHeight = table.getRowMargin();
          int spacingWidth = table.getColumnModel().getColumnMargin();
          Color c = g.getColor();
          g.setColor(table.getGridColor());
          g.drawRect(cellRect.x,cellRect.y,cellRect.width-1,cellRect.height-1);
          g.setColor(c);
          cellRect.setBounds(cellRect.x + spacingWidth/2, cellRect.y + spacingHeight/2,
          cellRect.width - spacingWidth, cellRect.height - spacingHeight);
          if (table.isEditing() && table.getEditingRow()==row &&
               table.getEditingColumn()==column)
               Component component = table.getEditorComponent();
               component.setBounds(cellRect);
               component.validate();
          else
               TableCellRenderer renderer = table.getCellRenderer(row, column);
               Component component = table.prepareRenderer(renderer, row, column);
               if (component.getParent() == null)
                    rendererPane.add(component);
               rendererPane.paintComponent(g, component, table, cellRect.x, cellRect.y,
                    cellRect.width, cellRect.height, true);
//end of class