Event delegation model has 3 components these are Event,Listener and Source..
A listener is an object that is notified when an event occurs. Listener has two major requirements. It must have been registered with one or more sources to receive notifications about specific types of events. It must implement methods to receive and process these notifications. The methods that receive and process events are defined in a set of interfaces found in java.awt.event. For example, the MouseMotionListener interface defines two methods to receive notifications when the mouse is dragged or moved. Any object may receive and process one or both of these events if it provides an implementation of this interface.