Is it possible that we declare new event?

Question

Can we declare new event?
If I want to create my own event for my porpose, is it possible?
For example, in C# using event keyword we can create new event mechanism.
Is it possible in Java?
If it's possible how can I do so?
If it's not possible, how can I solve problem If I encounter the situation that I need cusotum event mechanism?

Answer 1

Here is an example from Java sourcecode, a proper use of EventListenerList and actionlisteners:
JComponent:
protected EventListenerList listenerList = new EventListenerList();
JAbstractButton extends JComponent:
public void addActionListener(ActionListener l) {
listenerList.add(ActionListener.class, l);
public void removeActionListener(ActionListener l) {
     if ((l != null) && (getAction() == l)) {
     setAction(null);
     } else {
     listenerList.remove(ActionListener.class, l);
protected void fireActionPerformed(ActionEvent event) {
// Guaranteed to return a non-null array
Object[] listeners = listenerList.getListenerList();
ActionEvent e = null;
// Process the listeners last to first, notifying
// those that are interested in this event
for (int i = listeners.length-2; i>=0; i-=2) {
if (listeners==ActionListener.class) {
// Lazily create the event:
if (e == null) {
String actionCommand = event.getActionCommand();
if(actionCommand == null) {
actionCommand = getActionCommand();
e = new ActionEvent(AbstractButton.this,
ActionEvent.ACTION_PERFORMED,
actionCommand,
event.getWhen(),
event.getModifiers());
((ActionListener)listeners[i+1]).actionPerformed(e);
>>>>>>>>>>>>>>>>>>>>>>
And example from EventListenerList.java sourcecode:
* EventListenerList listenerList = new EventListenerList();
* FooEvent fooEvent = null;
* public void addFooListener(FooListener l) {
* listenerList.add(FooListener.class, l);
* public void removeFooListener(FooListener l) {
* listenerList.remove(FooListener.class, l);
* protected void fireFooXXX() {
* // Guaranteed to return a non-null array
* Object[] listeners = listenerList.getListenerList();
* // Process the listeners last to first, notifying
* // those that are interested in this event
* for (int i = listeners.length-2; i>=0; i-=2) {
* if (listeners[i]==FooListener.class) {
* // Lazily create the event:
* if (fooEvent == null) fooEvent = new FooEvent(this);
* ((FooListener)listeners[i+1]).fooXXX(fooEvent);