Row Number Table

Sometimes you may have a requirement for your table to look like a spreadsheet. That is you want column headings on the top and row numbers along the side. Well, a JTable has a default API to show a column header. It does this by adding the JTableHeader component to the column header area of a JScrollPane. Although there is no component in the API to display row numbers, the scroll pane also supports a row header area for a row header component. So all we need to do is create a row header component and the problem is solved.

The RowNumberTable is such a component. It is a simple extension of JTable that shares properties of the main table along with the TableModel and SelectionModel of the main table. Although it shares the TableModel it does not actually use any of the data in the model, it just needs to be notified when rows are added or removed so it can paint itself correctly.

You can use the RowNumberTable in your program with code like the following…

JTable mainTable = new JTable(...);
JScrollPane scrollPane = new JScrollPane(mainTable);
JTable rowTable = new RowNumberTable(mainTable);
scrollPane.setRowHeaderView(rowTable);
scrollPane.setCorner(JScrollPane.UPPER_LEFT_CORNER,
    rowTable.getTableHeader());

which will generate a table looking something like…

Get The Code

RowNumberTable.java

Related Reading

Using a Scroll Pane: Providing Custom Decorations