Tables - The Definitive Guide to Java Swing - page 690

Table 18-7. TableModelEvent Properties

Property Name Data Type Access

column int Read-only

firstRow int Read-only

lastRow int Read-only

type int Read-only

The event type can be one of three type constants of TableModelEvent : INSERT , UPDATE ,
or DELETE .
If the column property setting for the TableModelEvent is ALL_COLUMNS , then all the columns
in the data model are affected. If the firstRow property is HEADER_ROW , it means the table header
changed.

Sorting JTable Elements
The JTable component doesn't come with built-in support for sorting. Nevertheless, this
feature is frequently requested. Sorting doesn't require changing the data model, but it does
require changing the view of the data model that the JTable has. This type of change is described
by the Decorator pattern, in which you maintain the same API to the data but add sorting capa-
bilities to the view. The participants of the Decorator design pattern are as follows:

• Component : The component defines the service interface that will be decorated.

• ConcreteComponent : The concrete component is the object to be decorated.

• Decorator : The decorator is an abstract wrapper to a concrete component; it maintains
the service interface.

• ConcreteDecorator (s) [ A , B , C , . . .]: The concrete decorator objects extend the decorator
by adding decorating responsibilities while maintaining the same programming interface.
They redirect service requests to the concrete component referred to by their abstract
superclass.

■ Note The streams of the java.io package are examples of the Decorator pattern. The various filter
streams add capabilities to the basic stream classes and maintain the same API for access.

In the particular case for table sorting, only the Component , ConcreteComponent , and
Decorator are required, because there is only one concrete decorator. The Component is the
TableModel interface, the ConcreteComponent is the actual model, and the Decorator is the
sorted model.