Java Swing, 2nd Edition

The JTable Class

Before we get ahead of ourselves, let’s look at the JTable class and its supporting cast members.

Table Columns

With Swing tables, the basic unit is not an individual cell but a column. Most columns in real-world tables represent a certain type of information that is consistent for all records. For example, a record containing a person’s name is a String and might be the first column of the table. For every other record (row), the first cell is always a String. The columns do not need to all have the same data type. The same record could hold not only a person’s name, but whether or not they owned a computer. That column would hold Boolean values, not String values. The models supporting JTable reflect this view of the world. There is a TableModel that handles the contents of each cell in the table. You will also find a TableColumnModel that tracks the state of the columns in the table (how many columns, the total width, whether or not you can select columns, etc.).

The ability to store different types of data also affects how the table draws the data. The table column that maps to the “owns a computer” field could use a JCheckBox object for the cells of this column while using regular JLabel objects for the cells of other columns. But again, each column has one data type and one class responsible for drawing it.

Now, as the JTable class evolves, you may find alternate ways to think about tables without relying so heavily on columns. You’ll want to keep an eye on ...