Question

When we implement Listener, Renderer or Editor, inside methods how Java its calling automatically?

Code:

Class A implements ActionListener{
   A(){
    //bla bla
    //bla bla 
    this.addActionListener(btn);

   }
   public void actionPerformed(ActionEvent e){**// How actionPerformed method called        //automatically if we register button**

   }
}

How its calling actionPerformed method automatically after registering button object? We are just passing the btn object into addActionListener(btn). How inside its calling that method?

I checked through netbeans inside addActionListener method*. There is no calling method of actionPerformed method. Also if we register it keeps on working. Is it calling by thread anywhere inside? But i checked source code. nothing is there. How?

Answer 1

Events are dispatched from an EventListenerList, owned by the parent JComponent, using a convention outlined in the API and discussed here. Editors and Renderers are evoked by the owning view component.

Addendum: Can we create interface same as it is? How?

Yes, JFreeChart is a fairly accessible example. Although a chart is not itself a JComponent, it uses the same model for its own events.