java.awt.event

Class ComponentEvent

java.lang.Object

java.util.EventObject

java.awt.AWTEvent

java.awt.event.ComponentEvent

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

ContainerEvent, FocusEvent, InputEvent, PaintEvent, WindowEvent

public class ComponentEvent
extends AWTEvent

A low-level event which indicates that a component moved, changed size, or changed visibility (also, the root class for the other component-level events).

Component events are provided for notification purposes ONLY; The AWT will automatically handle component moves and resizes internally so that GUI layout works properly regardless of whether a program is receiving these events or not.

In addition to serving as the base class for other component-related events (InputEvent, FocusEvent, WindowEvent, ContainerEvent), this class defines the events that indicate changes in a component's size, position, or visibility.

This low-level event is generated by a component object (such as a List) when the component is moved, resized, rendered invisible, or made visible again. The event is passed to every ComponentListener or ComponentAdapter object which registered to receive such events using the component's addComponentListener method. (ComponentAdapter objects implement the ComponentListener interface.) Each such listener object gets this ComponentEvent when the event occurs.

An unspecified behavior will be caused if the id parameter of any particular ComponentEvent instance is not in the range from COMPONENT_FIRST to COMPONENT_LAST.

Since:

1.1

See Also:

ComponentAdapter, ComponentListener, Tutorial: Writing a Component Listener, Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static int	COMPONENT_FIRST The first number in the range of ids used for component events.
static int	COMPONENT_HIDDEN This event indicates that the component was rendered invisible.
static int	COMPONENT_LAST The last number in the range of ids used for component events.
static int	COMPONENT_MOVED This event indicates that the component's position changed.
static int	COMPONENT_RESIZED This event indicates that the component's size changed.
static int	COMPONENT_SHOWN This event indicates that the component was made visible.

Fields inherited from class java.awt.AWTEvent

ACTION_EVENT_MASK, ADJUSTMENT_EVENT_MASK, COMPONENT_EVENT_MASK, consumed, CONTAINER_EVENT_MASK, FOCUS_EVENT_MASK, HIERARCHY_BOUNDS_EVENT_MASK, HIERARCHY_EVENT_MASK, id, INPUT_METHOD_EVENT_MASK, INVOCATION_EVENT_MASK, ITEM_EVENT_MASK, KEY_EVENT_MASK, MOUSE_EVENT_MASK, MOUSE_MOTION_EVENT_MASK, MOUSE_WHEEL_EVENT_MASK, PAINT_EVENT_MASK, RESERVED_ID_MAX, TEXT_EVENT_MASK, WINDOW_EVENT_MASK, WINDOW_FOCUS_EVENT_MASK, WINDOW_STATE_EVENT_MASK

Fields inherited from class java.util.EventObject

source

Constructor Summary

Constructors

Constructor and Description
ComponentEvent(Component source, int id) Constructs a ComponentEvent object.

Method Summary

Methods

Modifier and Type	Method and Description
Component	getComponent() Returns the originator of the event.
String	paramString() Returns a parameter string identifying this event.

Methods inherited from class java.awt.AWTEvent

consume, getID, isConsumed, setSource, toString

Methods inherited from class java.util.EventObject

getSource

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

COMPONENT_FIRST

public static final int COMPONENT_FIRST

The first number in the range of ids used for component events.

See Also:

Constant Field Values

COMPONENT_LAST

public static final int COMPONENT_LAST

The last number in the range of ids used for component events.

See Also:

Constant Field Values

COMPONENT_MOVED

public static final int COMPONENT_MOVED

This event indicates that the component's position changed.

See Also:

Constant Field Values

COMPONENT_RESIZED

public static final int COMPONENT_RESIZED

This event indicates that the component's size changed.

See Also:

Constant Field Values

COMPONENT_SHOWN

public static final int COMPONENT_SHOWN

This event indicates that the component was made visible.

See Also:

Constant Field Values

COMPONENT_HIDDEN

public static final int COMPONENT_HIDDEN

This event indicates that the component was rendered invisible.

See Also:

Constant Field Values

Constructor Detail

ComponentEvent

public ComponentEvent(Component source,
              int id)

Constructs a ComponentEvent object.

This method throws an IllegalArgumentException if source is null.

Parameters:

source - The Component that originated the event

id - An integer indicating the type of event. For information on allowable values, see the class description for ComponentEvent

Throws:

IllegalArgumentException - if source is null

See Also:

getComponent(), AWTEvent.getID()

Method Detail

getComponent

public Component getComponent()

Returns the originator of the event.

Returns:

the Component object that originated the event, or null if the object is not a Component.

paramString

public String paramString()

Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.

Overrides:

paramString in class AWTEvent

Returns:

a string identifying the event and its attributes