Simulating one column using two columns in a JTable

Question

What I need to do is "join" the two first columns of a JTable...
What do I mean by saying "join" ?
I want to make dissapear the right border of the first column, and the same thing for the left border of the second column, also do both things for the column headers of that two columns.
All that to simulate having one column when there's actually two differents columns.
How can i do that ? Thanks !

Answer 1

Make a TableModel that filters your original table model.
See JTable.setModel.
public class MergedColumnsTableModel extends javax.swing.table.AbstractTableModel
     javax.swing.TableModel model;
     int[] columnSpans;
      * Assume for simplicity that model does not change (no columns inserted/deleted).
     public MergedColumnsTableModel(javax.swing.TableModel model) {
          this.model = model;
          columnSpans = new int[model.getColumnCount()];
          for (int columnIndex = 0; columnIndex < columnSpans.length; ++columnIndex) {
               columnSpans[columnIndex] = 1;
     public void merge2(int columnIndex) {
          int leftSpan = columnSpans[columnIndex];
          int rightSpan = columnSpans[columnIndex + leftSpan];
          columnSpans[columnIndex + leftSpan] = 0;
          columnSpans[columnIndex] += rightSpan;
     public int getRowCount() {
          return model.getRowCount();
     public int getColumnCount() {
          int n = 0;
          for (int i = 0; i < columnSpans.length; ++i) {
               if (columnSpans[i] != 0) {
                    ++n;
          return n;
     public Object getValueAt(int row, int column) {
          int n = 0;
          for (int i = 0; i < columnSpans.length; ++i) {
               if (columnSpans[i] != 0) {
                    if (n == column) { // We are at the column
                         return model.getValueAt(row, i);
                    ++n;
}