ActionCommand and getSource() are not enough

Question

Hi,
I have a question about the basic concept of event-handling in Java. I'll illustrate my problem by example.
Suppose my program contains two classes, i.e Main and GUI, whereas MainClass implements ActionListener. The action takes place on a JPanel in GUI with a JButton (for invokation of a JColorChooser) and a JComboBox (listing the index of an object which color can be changed) on it. What I want to do is the following: Click on the ColorButton, choose a color and apply it to the object with index specified by the JComboBox. This should be done in MainClass. Normally the ColorButton has an ActionCommand, i.e. "Color changed", but this information is not enough, I have to know which object is meant. So what is the right way to handle events if additional information is needed like in this case the object index? Maybe one has to pass some data through the ActionEvent.
I hope anybody can help me.
Thanks in advance.
Manticore

Answer 1

Here are two alternative approaches. There are several more.
1.
A JComboBox will fire ActionEvents when its selection changes. Since your MainClass is already implementing the ActionListener interface, you can let it listen to these changes just as it listens to events from the button. If the source of the ActionEvent is the JComboBox you get its selected item and store it, so that when the event from the button comes you know which item is selected.
2.
Have a method in your GUI class that retrieves the currently selected item from the combobox. The MainClass then needs a reference to the GUI class, and it can call that method when the ActionEvent from the button occurs.