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InputEvent.javaAPI DocJava SE 5 API11465Fri Aug 26 14:56:50 BST 2005java.awt.event

InputEvent

public abstract class InputEvent extends ComponentEvent
The root event class for all component-level input events. Input events are delivered to listeners before they are processed normally by the source where they originated. This allows listeners and component subclasses to "consume" the event so that the source will not process them in their default manner. For example, consuming mousePressed events on a Button component will prevent the Button from being activated.
author
Carl Quinn
version
1.34 06/02/04
see
KeyEvent
see
KeyAdapter
see
MouseEvent
see
MouseAdapter
see
MouseMotionAdapter
since
1.1

Fields Summary
public static final int
SHIFT_MASK
The Shift key modifier constant. It is recommended that SHIFT_DOWN_MASK be used instead.
public static final int
CTRL_MASK
The Control key modifier constant. It is recommended that CTRL_DOWN_MASK be used instead.
public static final int
META_MASK
The Meta key modifier constant. It is recommended that META_DOWN_MASK be used instead.
public static final int
ALT_MASK
The Alt key modifier constant. It is recommended that ALT_DOWN_MASK be used instead.
public static final int
ALT_GRAPH_MASK
The AltGraph key modifier constant.
public static final int
BUTTON1_MASK
The Mouse Button1 modifier constant. It is recommended that BUTTON1_DOWN_MASK be used instead.
public static final int
BUTTON2_MASK
The Mouse Button2 modifier constant. It is recommended that BUTTON2_DOWN_MASK be used instead. Note that BUTTON2_MASK has the same value as ALT_MASK.
public static final int
BUTTON3_MASK
The Mouse Button3 modifier constant. It is recommended that BUTTON3_DOWN_MASK be used instead. Note that BUTTON3_MASK has the same value as META_MASK.
public static final int
SHIFT_DOWN_MASK
The Shift key extended modifier constant.
public static final int
CTRL_DOWN_MASK
The Control key extended modifier constant.
public static final int
META_DOWN_MASK
The Meta key extended modifier constant.
public static final int
ALT_DOWN_MASK
The Alt key extended modifier constant.
public static final int
BUTTON1_DOWN_MASK
The Mouse Button1 extended modifier constant.
public static final int
BUTTON2_DOWN_MASK
The Mouse Button2 extended modifier constant.
public static final int
BUTTON3_DOWN_MASK
The Mouse Button3 extended modifier constant.
public static final int
ALT_GRAPH_DOWN_MASK
The AltGraph key extended modifier constant.
static final int
JDK_1_3_MODIFIERS
long
when
The input event's Time stamp in UTC format. The time stamp indicates when the input event was created.
int
modifiers
The state of the modifier mask at the time the input event was fired.
private transient boolean
canAccessSystemClipboard
static final long
serialVersionUID
Constructors Summary
InputEvent(Component source, int id, long when, int modifiers)
Constructs an InputEvent object with the specified source component, modifiers, and type.

Note that passing in an invalid id results in unspecified behavior. This method throws an IllegalArgumentException if source is null.

param
source the object where the event originated
param
id the event type
param
when the time the event occurred
param
modifiers represents the modifier keys and mouse buttons down while the event occurred
throws
IllegalArgumentException if source is null


     
        /* ensure that the necessary native libraries are loaded */
	NativeLibLoader.loadLibraries();
        if (!GraphicsEnvironment.isHeadless()) {
            initIDs();
        }
    
        super(source, id);
        this.when = when;
        this.modifiers = modifiers;
        canAccessSystemClipboard = canAccessSystemClipboard();
Methods Summary
private booleancanAccessSystemClipboard()

        boolean b = false;

        if (!GraphicsEnvironment.isHeadless()) {
            SecurityManager sm = System.getSecurityManager();
            if (sm != null) {
                try {
                    sm.checkSystemClipboardAccess();
                    b = true;
                } catch (SecurityException se) {
                }
            } else {
                b = true;
            }
        }

        return b;
public voidconsume()
Consumes this event so that it will not be processed in the default manner by the source which originated it.

        consumed = true;
public intgetModifiers()
Returns the modifier mask for this event.

        return modifiers & JDK_1_3_MODIFIERS;
public intgetModifiersEx()
Returns the extended modifier mask for this event. Extended modifiers represent the state of all modal keys, such as ALT, CTRL, META, and the mouse buttons just after the event occurred

For example, if the user presses button 1 followed by button 2, and then releases them in the same order, the following sequence of events is generated: 

MOUSE_PRESSED: BUTTON1_DOWN_MASK
MOUSE_PRESSED: BUTTON1_DOWN_MASK | BUTTON2_DOWN_MASK
MOUSE_RELEASED: BUTTON2_DOWN_MASK
MOUSE_CLICKED: BUTTON2_DOWN_MASK
MOUSE_RELEASED:
MOUSE_CLICKED:

It is not recommended to compare the return value of this method using == because new modifiers can be added in the future. For example, the appropriate way to check that SHIFT and BUTTON1 are down, but CTRL is up is demonstrated by the following code: 

int onmask = SHIFT_DOWN_MASK | BUTTON1_DOWN_MASK;
int offmask = CTRL_DOWN_MASK;
if (event.getModifiersEx() & (onmask | offmask) == onmask) {
...
}
The above code will work even if new modifiers are added.

since
1.4

        return modifiers & ~JDK_1_3_MODIFIERS;
public static java.lang.StringgetModifiersExText(int modifiers)
Returns a String describing the extended modifier keys and mouse buttons, such as "Shift", "Button1", or "Ctrl+Shift". These strings can be localized by changing the awt.properties file.

param
modifiers a modifier mask describing the extended modifier keys and mouse buttons for the event
return
a text description of the combination of extended modifier keys and mouse buttons that were held down during the event.
since
1.4


                                                                                                                  
         
        StringBuffer buf = new StringBuffer();
        if ((modifiers & InputEvent.META_DOWN_MASK) != 0) {
            buf.append(Toolkit.getProperty("AWT.meta", "Meta"));
            buf.append("+");
        }
        if ((modifiers & InputEvent.CTRL_DOWN_MASK) != 0) {
            buf.append(Toolkit.getProperty("AWT.control", "Ctrl"));
            buf.append("+");
        }
        if ((modifiers & InputEvent.ALT_DOWN_MASK) != 0) {
            buf.append(Toolkit.getProperty("AWT.alt", "Alt"));
            buf.append("+");
        }
        if ((modifiers & InputEvent.SHIFT_DOWN_MASK) != 0) {
            buf.append(Toolkit.getProperty("AWT.shift", "Shift"));
            buf.append("+");
        }
        if ((modifiers & InputEvent.ALT_GRAPH_DOWN_MASK) != 0) {
            buf.append(Toolkit.getProperty("AWT.altGraph", "Alt Graph"));
            buf.append("+");
        }
        if ((modifiers & InputEvent.BUTTON1_DOWN_MASK) != 0) {
            buf.append(Toolkit.getProperty("AWT.button1", "Button1"));
            buf.append("+");
        }
        if ((modifiers & InputEvent.BUTTON2_DOWN_MASK) != 0) {
            buf.append(Toolkit.getProperty("AWT.button2", "Button2"));
            buf.append("+");
        }
        if ((modifiers & InputEvent.BUTTON3_DOWN_MASK) != 0) {
            buf.append(Toolkit.getProperty("AWT.button3", "Button3"));
            buf.append("+");
        }
        if (buf.length() > 0) {
            buf.setLength(buf.length()-1); // remove trailing '+'
        }
        return buf.toString();
public longgetWhen()
Returns the timestamp of when this event occurred.

        return when;
private static native voidinitIDs()
Initialize JNI field and method IDs for fields that may be accessed from C.

public booleanisAltDown()
Returns whether or not the Alt modifier is down on this event.
        return (modifiers & ALT_MASK) != 0;
    
public booleanisAltGraphDown()
Returns whether or not the AltGraph modifier is down on this event.
        return (modifiers & ALT_GRAPH_MASK) != 0;
    
public booleanisConsumed()
Returns whether or not this event has been consumed.
see
#consume
        return consumed;
    
public booleanisControlDown()
Returns whether or not the Control modifier is down on this event.
        return (modifiers & CTRL_MASK) != 0;
    
public booleanisMetaDown()
Returns whether or not the Meta modifier is down on this event.
        return (modifiers & META_MASK) != 0;
    
public booleanisShiftDown()
Returns whether or not the Shift modifier is down on this event.
        return (modifiers & SHIFT_MASK) != 0;