Core Java™ 2 Volume II - Advanced Features, Seventh Edition

An Example: Annotating Event Handlers

One of the more boring tasks in user interface programming is the wiring of listeners to event sources. Many listeners are of the form

myButton.addActionListener(new
   ActionListener()
   {
      public void actionPerformed(ActionEvent event)
      {
         doSomething();
      }
   });

In this section, we design an annotation to avoid this drudgery. The annotation has the form

@ActionListenerFor(source="myButton") void doSomething() { . . . }

The programmer no longer has to make calls to addActionListener. Instead, each method is simply tagged with an annotation. Example 13-1 shows the ButtonTest program from Volume 1, Chapter 8, reimplemented with these annotations.

We also need to define an annotation interface. The code is in Example ...