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Wednesday 17 September 2014

Java Awt Event Classes

The Event classes represent the event. Java provides us various Event classes but we will discuss those which are more frequently used.

EventObject class

It is the root class from which all event state objects shall be derived. All Events are constructed with a reference to the object, the source, that is logically deemed to be the object upon which the Event in question initially occurred upon. This class is defined in java.util package.

Class declaration

Following is the declaration for java.util.EventObject class:
public class EventObject
   extends Object
      implements Serializable

Field

Following are the fields for java.util.EventObject class:
  • protected Object source -- The object on which the Event initially occurred.

Class constructors

S.N.Constructor & Description
1EventObject(Object source)
Constructs a prototypical Event.

Class methods

S.N.Method & Description
1Object getSource()
The object on which the Event initially occurred.
2String toString()
Returns a String representation of this EventObject.

Methods inherited

This class inherits methods from the following classes:
  • java.lang.Object

AWT Event Classes:

Following is the list of commonly used event classes.
Sr. No.Control & Description
1AWTEvent
It is the root event class for all AWT events. This class and its subclasses supercede the original java.awt.Event class.
2ActionEvent
The ActionEvent is generated when button is clicked or the item of a list is double clicked.
3InputEvent
The InputEvent class is root event class for all component-level input events.
4KeyEvent
On entering the character the Key event is generated.
5MouseEvent
This event indicates a mouse action occurred in a component.
6TextEvent
The object of this class represents the text events.
7WindowEvent
The object of this class represents the change in state of a window.
8AdjustmentEvent
The object of this class represents the adjustment event emitted by Adjustable objects.
9ComponentEvent
The object of this class represents the change in state of a window.
10ContainerEvent
The object of this class represents the change in state of a window.
11MouseMotionEvent
The object of this class represents the change in state of a window.
12PaintEvent
The object of this class represents the change in state of a window.

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