public InvoiceTableModel() 
{
    
    invoices = new ArrayList();
}

 public  void addInvoice(Invoice invoice) 
{
    invoices.add (invoice);
    invalidateCaches();
    fireTableDataChanged();
}

 public Class getColumnClass(int columnIndex) 
{
    return COLUMN_TYPES[columnIndex];
}

Returns Object.class regardless of columnIndex.

 public int getColumnCount() 
{
    return COLUMN_NAMES.length;
}

Returns the number of columns in the model. A JTable uses this method to determine how many columns it should create and display by default.

 public String getColumnName(int column) 
{
    return COLUMN_NAMES[column];
}

Returns a default name for the column using spreadsheet conventions: A, B, C, ... Z, AA, AB, etc. If column cannot be found, returns an empty string.

 public Invoice getInvoice(int invoice) 
{
    return (Invoice) invoices.get (invoice);
}

 public int getRowCount() 
{
    return totalSize;
}

Returns the number of rows in the model. A JTable uses this method to determine how many rows it should display. This method should be quick, as it is called frequently during rendering.

 public Object getValueAt(int rowIndex,
    int columnIndex) 
{
    // just make sure we can access the invoices by the array
    fillCache();
    final Invoice inv = invoicePerRow[rowIndex];
    final Article art = articlesPerRow[rowIndex];
    switch (columnIndex)
    {
      case 0: return inv;
      case 1: return inv.getCustomer().getFirstName();
      case 2: return inv.getCustomer().getLastName();
      case 3: return inv.getCustomer().getStreet();
      case 4: return inv.getCustomer().getTown();
      case 5: return inv.getCustomer().getPostalCode();
      case 6: return inv.getCustomer().getCountry();
      case 7: return inv.getCustomer().getSalutation();
      case 8: return inv.getDate();
      case 9: return inv.getInvoiceNumber();
      case 10: return art.getName();
      case 11: return art.getArticleNumber();
      case 12: return art.getArticleDetails();
      case 13: return new Float(art.getPrice());
      case 14: return new Integer(inv.getArticleCount());
    }
    throw new IndexOutOfBoundsException("ColumnIndex");
}

Returns the value for the cell at columnIndex and rowIndex.

 public  void invalidateCaches() 
{
    int size = 0;
    for (int i = 0; i <  invoices.size(); i++)
    {
      final Invoice inv = getInvoice(i);
      size += inv.getArticleCount();
    }
    this.totalSize = size;
    this.invoicePerRow = null;
    this.articlesPerRow = null;
}

 public  void removeInvoice(Invoice invoice) 
{
    invoices.remove (invoice);
    invalidateCaches();
    fireTableDataChanged();
}