To respond to an event a component receives you register an event
listener for the event type with the component. Event
listeners are objects which implement a
java.util.EventListener
interface. The AWT defines eleven
sub-interfaces of java.util.EventListener
, one for
each type of event:
java.awt.event.ComponentListener
java.awt.event.ContainerListener
java.awt.event.FocusListener
java.awt.event.KeyListener
java.awt.event.MouseListener
java.awt.event.MouseMotionListener
java.awt.event.WindowListener
java.awt.event.ActionListener
java.awt.event.AdjustmentListener
java.awt.event.ItemListener
java.awt.event.TextListener
Each of these interfaces defines the events an event listener of
that type must be prepared to respond to. For example,
MouseListener
declares these five methods,
public void mouseClicked(MouseEvent evt)
public void mousePressed(MouseEvent evt)
public void mouseReleased(MouseEvent evt)
public void mouseEntered(MouseEvent evt)
public void mouseExited(MouseEvent evt)
When a component receives a mouse event, its
processMouseEvent()
method checks the ID of the mouse event
to determine whether this is a mouse pressed, mouse released, mouse
entered, or mouse exited event. Then it calls the corresponding
method in each registered MouseListener
object.