java.awt
Class Event

java.lang.Object
  |
  +--java.awt.Event

public class Event

extends Object

implements Serializable

Event is a platform-independent class that encapsulates events from the platform's Graphical User Interface in the Java 1.0 event model. In Java 1.1 and later versions, the Event class is maintained only for backwards compatibilty. The information in this class description is provided to assist programmers in converting Java 1.0 programs to the new event model.

In the Java 1.0 event model, an event contains an id field that indicates what type of event it is and which other Event variables are relevant for the event.

For keyboard events, key contains a value indicating which key was activated, and modifiers contains the modifiers for that event. For the KEY_PRESS and KEY_RELEASE event ids, the value of key is the unicode character code for the key. For KEY_ACTION and KEY_ACTION_RELEASE, the value of key is one of the defined action-key identifiers in the Event class (PGUP, PGDN, F1, F2, etc).

Since:

JDK1.0

See Also:

Serialized Form

Field Summary

static int	ACTION_EVENT This event indicates that the user wants some action to occur.
static int	ALT_MASK This flag indicates that the Alt key was down when the event occurred.
Object	arg An arbitrary argument of the event.
static int	BACK_SPACE The BackSpace key.
static int	CAPS_LOCK The Caps Lock key, a non-ASCII action key.
int	clickCount For MOUSE_DOWN events, this field indicates the number of consecutive clicks.
static int	CTRL_MASK This flag indicates that the Control key was down when the event occurred.
static int	DELETE The Delete key.
static int	DOWN The Down Arrow key, a non-ASCII action key.
static int	END The End key, a non-ASCII action key.
static int	ENTER The Enter key.
static int	ESCAPE The Escape key.
Event	evt The next event.
static int	F1 The F1 function key, a non-ASCII action key.
static int	F10 The F10 function key, a non-ASCII action key.
static int	F11 The F11 function key, a non-ASCII action key.
static int	F12 The F12 function key, a non-ASCII action key.
static int	F2 The F2 function key, a non-ASCII action key.
static int	F3 The F3 function key, a non-ASCII action key.
static int	F4 The F4 function key, a non-ASCII action key.
static int	F5 The F5 function key, a non-ASCII action key.
static int	F6 The F6 function key, a non-ASCII action key.
static int	F7 The F7 function key, a non-ASCII action key.
static int	F8 The F8 function key, a non-ASCII action key.
static int	F9 The F9 function key, a non-ASCII action key.
static int	GOT_FOCUS A component gained the focus.
static int	HOME The Home key, a non-ASCII action key.
int	id Indicates which type of event the event is, and which other Event variables are relevant for the event.
static int	INSERT The Insert key, a non-ASCII action key.
int	key The key code of the key that was pressed in a keyboard event.
static int	KEY_ACTION The user has pressed a non-ASCII action key.
static int	KEY_ACTION_RELEASE The user has released a non-ASCII action key.
static int	KEY_PRESS The user has pressed a normal key.
static int	KEY_RELEASE The user has released a normal key.
static int	LEFT The Left Arrow key, a non-ASCII action key.
static int	LIST_DESELECT An item in a list has been deselected.
static int	LIST_SELECT An item in a list has been selected.
static int	LOAD_FILE A file loading event.
static int	LOST_FOCUS A component lost the focus.
static int	META_MASK This flag indicates that the Meta key was down when the event occurred.
int	modifiers The state of the modifier keys.
static int	MOUSE_DOWN The user has pressed the mouse button.
static int	MOUSE_DRAG The user has moved the mouse with a button pressed.
static int	MOUSE_ENTER The mouse has entered a component.
static int	MOUSE_EXIT The mouse has exited a component.
static int	MOUSE_MOVE The mouse has moved with no button pressed.
static int	MOUSE_UP The user has released the mouse button.
static int	NUM_LOCK The Num Lock key, a non-ASCII action key.
static int	PAUSE The Pause key, a non-ASCII action key.
static int	PGDN The Page Down key, a non-ASCII action key.
static int	PGUP The Page Up key, a non-ASCII action key.
static int	PRINT_SCREEN The Print Screen key, a non-ASCII action key.
static int	RIGHT The Right Arrow key, a non-ASCII action key.
static int	SAVE_FILE A file saving event.
static int	SCROLL_ABSOLUTE The user has moved the bubble (thumb) in a scroll bar, moving to an "absolute" position, rather than to an offset from the last postion.
static int	SCROLL_BEGIN The scroll begin event.
static int	SCROLL_END The scroll end event.
static int	SCROLL_LINE_DOWN The user has activated the line down area of a scroll bar.
static int	SCROLL_LINE_UP The user has activated the line up area of a scroll bar.
static int	SCROLL_LOCK The Scroll Lock key, a non-ASCII action key.
static int	SCROLL_PAGE_DOWN The user has activated the page down area of a scroll bar.
static int	SCROLL_PAGE_UP The user has activated the page up area of a scroll bar.
static int	SHIFT_MASK This flag indicates that the Shift key was down when the event occurred.
static int	TAB The Tab key.
Object	target The target component.
static int	UP The Up Arrow key, a non-ASCII action key.
long	when The time stamp.
static int	WINDOW_DEICONIFY The user has asked the window manager to de-iconify the window.
static int	WINDOW_DESTROY The user has asked the window manager to kill the window.
static int	WINDOW_EXPOSE The user has asked the window manager to expose the window.
static int	WINDOW_ICONIFY The user has asked the window manager to iconify the window.
static int	WINDOW_MOVED The user has asked the window manager to move the window.
int	x The x coordinate of the event.
int	y The y coordinate of the event.

Constructor Summary

Event(Object target, int id, Object arg)
Creates an instance of Event with the specified target component, event type, and argument.

Event(Object target, long when, int id, int x, int y, int key, int modifiers)
Creates an instance of Event, with the specified target component, time stamp, event type, x and y coordinates, keyboard key, state of the modifier keys, and an argument set to null.

Event(Object target, long when, int id, int x, int y, int key, int modifiers, Object arg)
Creates an instance of Event with the specified target component, time stamp, event type, x and y coordinates, keyboard key, state of the modifier keys, and argument.

Method Summary

boolean	controlDown() Checks if the Control key is down.
boolean	metaDown() Checks if the Meta key is down.
protected String	paramString() Returns the parameter string representing this event.
boolean	shiftDown() Checks if the Shift key is down.
String	toString() Returns a representation of this event's values as a string.
void	translate(int x, int y) Translates this event so that its x and y coordinates are increased by dx and dy, respectively.

Methods inherited from class java.lang.Object

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

Field Detail

SHIFT_MASK

public static final int SHIFT_MASK

This flag indicates that the Shift key was down when the event occurred.

CTRL_MASK

public static final int CTRL_MASK

This flag indicates that the Control key was down when the event occurred.

META_MASK

public static final int META_MASK

This flag indicates that the Meta key was down when the event occurred. For mouse events, this flag indicates that the right button was pressed or released.

ALT_MASK

public static final int ALT_MASK

This flag indicates that the Alt key was down when the event occurred. For mouse events, this flag indicates that the middle mouse button was pressed or released.

HOME

public static final int HOME

The Home key, a non-ASCII action key.

END

public static final int END

The End key, a non-ASCII action key.

PGUP

public static final int PGUP

The Page Up key, a non-ASCII action key.

PGDN

public static final int PGDN

The Page Down key, a non-ASCII action key.

UP

public static final int UP

The Up Arrow key, a non-ASCII action key.

DOWN

public static final int DOWN

The Down Arrow key, a non-ASCII action key.

LEFT

public static final int LEFT

The Left Arrow key, a non-ASCII action key.

RIGHT

public static final int RIGHT

The Right Arrow key, a non-ASCII action key.

F1

public static final int F1

The F1 function key, a non-ASCII action key.

F2

public static final int F2

The F2 function key, a non-ASCII action key.

F3

public static final int F3

The F3 function key, a non-ASCII action key.

F4

public static final int F4

The F4 function key, a non-ASCII action key.

F5

public static final int F5

The F5 function key, a non-ASCII action key.

F6

public static final int F6

The F6 function key, a non-ASCII action key.

F7

public static final int F7

The F7 function key, a non-ASCII action key.

F8

public static final int F8

The F8 function key, a non-ASCII action key.

F9

public static final int F9

The F9 function key, a non-ASCII action key.

F10

public static final int F10

The F10 function key, a non-ASCII action key.

F11

public static final int F11

The F11 function key, a non-ASCII action key.

F12

public static final int F12

The F12 function key, a non-ASCII action key.

PRINT_SCREEN

public static final int PRINT_SCREEN

The Print Screen key, a non-ASCII action key.

SCROLL_LOCK

public static final int SCROLL_LOCK

The Scroll Lock key, a non-ASCII action key.

CAPS_LOCK

public static final int CAPS_LOCK

The Caps Lock key, a non-ASCII action key.

NUM_LOCK

public static final int NUM_LOCK

The Num Lock key, a non-ASCII action key.

PAUSE

public static final int PAUSE

The Pause key, a non-ASCII action key.

INSERT

public static final int INSERT

The Insert key, a non-ASCII action key.

ENTER

public static final int ENTER

The Enter key.

BACK_SPACE

public static final int BACK_SPACE

The BackSpace key.

TAB

public static final int TAB

The Tab key.

ESCAPE

public static final int ESCAPE

The Escape key.

DELETE

public static final int DELETE

The Delete key.

WINDOW_DESTROY

public static final int WINDOW_DESTROY

The user has asked the window manager to kill the window.

WINDOW_EXPOSE

public static final int WINDOW_EXPOSE

The user has asked the window manager to expose the window.

WINDOW_ICONIFY

public static final int WINDOW_ICONIFY

The user has asked the window manager to iconify the window.

WINDOW_DEICONIFY

public static final int WINDOW_DEICONIFY

The user has asked the window manager to de-iconify the window.

WINDOW_MOVED

public static final int WINDOW_MOVED

The user has asked the window manager to move the window.

KEY_PRESS

public static final int KEY_PRESS

The user has pressed a normal key.

KEY_RELEASE

public static final int KEY_RELEASE

The user has released a normal key.

KEY_ACTION

public static final int KEY_ACTION

The user has pressed a non-ASCII action key. The key field contains a value that indicates that the event occurred on one of the action keys, which comprise the 12 function keys, the arrow (cursor) keys, Page Up, Page Down, Home, End, Print Screen, Scroll Lock, Caps Lock, Num Lock, Pause, and Insert.

KEY_ACTION_RELEASE

public static final int KEY_ACTION_RELEASE

The user has released a non-ASCII action key. The key field contains a value that indicates that the event occurred on one of the action keys, which comprise the 12 function keys, the arrow (cursor) keys, Page Up, Page Down, Home, End, Print Screen, Scroll Lock, Caps Lock, Num Lock, Pause, and Insert.

MOUSE_DOWN

public static final int MOUSE_DOWN

The user has pressed the mouse button. The ALT_MASK flag indicates that the middle button has been pressed. The META_MASKflag indicates that the right button has been pressed.

See Also:

ALT_MASK, META_MASK

MOUSE_UP

public static final int MOUSE_UP

The user has released the mouse button. The ALT_MASK flag indicates that the middle button has been released. The META_MASKflag indicates that the right button has been released.

See Also:

ALT_MASK, META_MASK

MOUSE_MOVE

public static final int MOUSE_MOVE

The mouse has moved with no button pressed.

MOUSE_ENTER

public static final int MOUSE_ENTER

The mouse has entered a component.

MOUSE_EXIT

public static final int MOUSE_EXIT

The mouse has exited a component.

MOUSE_DRAG

public static final int MOUSE_DRAG

The user has moved the mouse with a button pressed. The ALT_MASK flag indicates that the middle button is being pressed. The META_MASK flag indicates that the right button is being pressed.

See Also:

ALT_MASK, META_MASK

SCROLL_LINE_UP

public static final int SCROLL_LINE_UP

The user has activated the line up area of a scroll bar.

SCROLL_LINE_DOWN

public static final int SCROLL_LINE_DOWN

The user has activated the line down area of a scroll bar.

SCROLL_PAGE_UP

public static final int SCROLL_PAGE_UP

The user has activated the page up area of a scroll bar.

SCROLL_PAGE_DOWN

public static final int SCROLL_PAGE_DOWN

The user has activated the page down area of a scroll bar.

SCROLL_ABSOLUTE

public static final int SCROLL_ABSOLUTE

The user has moved the bubble (thumb) in a scroll bar, moving to an "absolute" position, rather than to an offset from the last postion.

SCROLL_BEGIN

public static final int SCROLL_BEGIN

The scroll begin event.

SCROLL_END

public static final int SCROLL_END

The scroll end event.

LIST_SELECT

public static final int LIST_SELECT

An item in a list has been selected.

LIST_DESELECT

public static final int LIST_DESELECT

An item in a list has been deselected.

ACTION_EVENT

public static final int ACTION_EVENT

This event indicates that the user wants some action to occur.

LOAD_FILE

public static final int LOAD_FILE

A file loading event.

SAVE_FILE

public static final int SAVE_FILE

A file saving event.

GOT_FOCUS

public static final int GOT_FOCUS

A component gained the focus.

LOST_FOCUS

public static final int LOST_FOCUS

A component lost the focus.

target

public Object target

The target component. This indicates the component over which the event occurred or with which the event is associated. This object has been replaced by AWTEvent.getSource()

See Also:

EventObject.getSource()

when

public long when

The time stamp. Replaced by InputEvent.getWhen().

See Also:

java.awt.InputEvent#getWhen()

id

public int id

Indicates which type of event the event is, and which other Event variables are relevant for the event. This has been replaced by AWTEvent.getID()

See Also:

java.awt.AWTEvent.getID()

x

public int x

The x coordinate of the event. Replaced by MouseEvent.getX()

See Also:

java.awt.MouseEvent#getX()

y

public int y

The y coordinate of the event. Replaced by MouseEvent.getY()

See Also:

java.awt.MouseEvent#getY()

key

public int key

The key code of the key that was pressed in a keyboard event. This has been replaced by KeyEvent.getKeyCode()

See Also:

java.awt.KeyEvent#getKeyCode()

modifiers

public int modifiers

The state of the modifier keys. This is replaced with InputEvent.getModifiers() In java 1.1 MouseEvent and KeyEvent are subclasses of InputEvent.

See Also:

java.awt.InputEvent#getModifiers()

clickCount

public int clickCount

For MOUSE_DOWN events, this field indicates the number of consecutive clicks. For other events, its value is 0. This field has been replaced by MouseEvent.getClickCount().

See Also:

java.awt.MouseEvent.getClickCount().

arg

public Object arg

An arbitrary argument of the event. The value of this field depends on the type of event. arg has been replaced b event specific property.

evt

public Event evt

The next event. This field is set when putting events into a linked list. This has been replaced by EventQueue.

See Also:

EventQueue

Constructor Detail

Event

public Event(Object target,
             long when,
             int id,
             int x,
             int y,
             int key,
             int modifiers,
             Object arg)

Creates an instance of Event with the specified target component, time stamp, event type, x and y coordinates, keyboard key, state of the modifier keys, and argument.

Parameters:

target - the target component.

when - the time stamp.

id - the event type.

x - the x coordinate.

y - the y coordinate.

key - the key pressed in a keyboard event.

modifiers - the state of the modifier keys.

arg - the specified argument.

Event

public Event(Object target,
             long when,
             int id,
             int x,
             int y,
             int key,
             int modifiers)

Creates an instance of Event, with the specified target component, time stamp, event type, x and y coordinates, keyboard key, state of the modifier keys, and an argument set to null.

Parameters:

target - the target component.

when - the time stamp.

id - the event type.

x - the x coordinate.

y - the y coordinate.

key - the key pressed in a keyboard event.

modifiers - the state of the modifier keys.

Event

public Event(Object target,
             int id,
             Object arg)

Creates an instance of Event with the specified target component, event type, and argument.

Parameters:

target - the target component.

id - the event type.

arg - the specified argument.

Method Detail

translate

public void translate(int x,
                      int y)

Translates this event so that its x and y coordinates are increased by dx and dy, respectively.

This method translates an event relative to the given component. This involves, at a minimum, translating the coordinates into the local coordinate system of the given component. It may also involve translating a region in the case of an expose event.

Parameters:

dx - the distance to translate the x coordinate.

dy - the distance to translate the y coordinate.

shiftDown

public boolean shiftDown()

Checks if the Shift key is down.

Returns:

true if the key is down; false otherwise.

See Also:

modifiers, controlDown(), metaDown()

controlDown

public boolean controlDown()

Checks if the Control key is down.

Returns:

true if the key is down; false otherwise.

See Also:

modifiers, shiftDown(), metaDown()

metaDown

public boolean metaDown()

Checks if the Meta key is down.

Returns:

true if the key is down; false otherwise.

See Also:

modifiers, shiftDown(), controlDown()

paramString

protected String paramString()

Returns the parameter string representing this event. This string is useful for debugging.

Returns:

the parameter string of this event.

toString

public String toString()

Returns a representation of this event's values as a string.

Returns:

a string that represents the event and the values of its member fields.

Overrides:

toString in class Object

Since:

JDK1.1

See Also:

paramString()