* KeyStrokes are used to define high-level (semantic) action events. Instead * of trapping every keystroke and throwing away the ones you are not * interested in, those keystrokes you care about automatically initiate * actions on the Components with which they are registered. *
* KeyStrokes are immutable, and are intended to be unique. Client code cannot
* create a KeyStroke; a variant of getKeyStroke must be used
* instead. These factory methods allow the KeyStroke implementation to cache
* and share instances efficiently.
*
* Warning:
* Serialized objects of this class will not be compatible with
* future Swing releases. The current serialization support is
* appropriate for short term storage or RMI between applications running
* the same version of Swing. As of 1.4, support for long term storage
* of all JavaBeansTM
* has been added to the java.beans package.
* Please see {@link java.beans.XMLEncoder}.
*
* @see javax.swing.text.Keymap
* @see #getKeyStroke
*
* @author Arnaud Weber
* @author David Mendenhall
*/
public class KeyStroke extends AWTKeyStroke {
/**
* Serial Version ID.
*/
private static final long serialVersionUID = -9060180771037902530L;
private KeyStroke() {
}
private KeyStroke(char keyChar, int keyCode, int modifiers,
boolean onKeyRelease) {
super(keyChar, keyCode, modifiers, onKeyRelease);
}
/**
* Returns a shared instance of a KeyStroke
* that represents a KEY_TYPED event for the
* specified character.
*
* @param keyChar the character value for a keyboard key
* @return a KeyStroke object for that key
*/
public static KeyStroke getKeyStroke(char keyChar) {
synchronized (AWTKeyStroke.class) {
registerSubclass(KeyStroke.class);
return (KeyStroke)getAWTKeyStroke(keyChar);
}
}
/**
* Returns an instance of a KeyStroke, specifying whether the key is
* considered to be activated when it is pressed or released. Unlike all
* other factory methods in this class, the instances returned by this
* method are not necessarily cached or shared.
*
* @param keyChar the character value for a keyboard key
* @param onKeyRelease true if this KeyStroke corresponds to a
* key release; false otherwise.
* @return a KeyStroke object for that key
* @deprecated use getKeyStroke(char)
*/
@Deprecated
public static KeyStroke getKeyStroke(char keyChar, boolean onKeyRelease) {
return new KeyStroke(keyChar, KeyEvent.VK_UNDEFINED, 0, onKeyRelease);
}
/**
* Returns a shared instance of a {@code KeyStroke}
* that represents a {@code KEY_TYPED} event for the
* specified Character object and a
* set of modifiers. Note that the first parameter is of type Character
* rather than char. This is to avoid inadvertent clashes with calls to
* getKeyStroke(int keyCode, int modifiers).
*
* The modifiers consist of any combination of following:
* The "virtual key" constants defined in java.awt.event.KeyEvent can be * used to specify the key code. For example:
java.awt.event.KeyEvent.getExtendedKeyCodeForChar.
*
* The modifiers consist of any combination of:true if the KeyStroke should represent
* a key release; false otherwise.
* @return a KeyStroke object for that key
*
* @see java.awt.event.KeyEvent
* @see java.awt.event.InputEvent
*/
public static KeyStroke getKeyStroke(int keyCode, int modifiers,
boolean onKeyRelease) {
synchronized (AWTKeyStroke.class) {
registerSubclass(KeyStroke.class);
return (KeyStroke)getAWTKeyStroke(keyCode, modifiers,
onKeyRelease);
}
}
/**
* Returns a shared instance of a KeyStroke, given a numeric key code and a
* set of modifiers. The returned KeyStroke will correspond to a key press.
* * The "virtual key" constants defined in java.awt.event.KeyEvent can be * used to specify the key code. For example:
java.awt.event.KeyEvent.getExtendedKeyCodeForChar.
*
* The modifiers consist of any combination of:
* This method obtains the keyChar from a KeyTyped event, and the keyCode
* from a KeyPressed or KeyReleased event. The KeyEvent modifiers are
* obtained for all three types of KeyEvent.
*
* @param anEvent the KeyEvent from which to obtain the KeyStroke
* @throws NullPointerException if anEvent is null
* @return the KeyStroke that precipitated the event
*/
public static KeyStroke getKeyStrokeForEvent(KeyEvent anEvent) {
synchronized (AWTKeyStroke.class) {
registerSubclass(KeyStroke.class);
return (KeyStroke)getAWTKeyStrokeForEvent(anEvent);
}
}
/**
* Parses a string and returns a KeyStroke.
* The string must have the following syntax:
*
* <modifiers>* (<typedID> | <pressedReleasedID>)
*
* modifiers := shift | control | ctrl | meta | alt | altGraph
* typedID := typed <typedKey>
* typedKey := string of length 1 giving Unicode character.
* pressedReleasedID := (pressed | released) key
* key := KeyEvent key code name, i.e. the name following "VK_".
*
* If typed, pressed or released is not specified, pressed is assumed. Here
* are some examples:
*
* "INSERT" => getKeyStroke(KeyEvent.VK_INSERT, 0);
* "control DELETE" => getKeyStroke(KeyEvent.VK_DELETE, InputEvent.CTRL_MASK);
* "alt shift X" => getKeyStroke(KeyEvent.VK_X, InputEvent.ALT_MASK | InputEvent.SHIFT_MASK);
* "alt shift released X" => getKeyStroke(KeyEvent.VK_X, InputEvent.ALT_MASK | InputEvent.SHIFT_MASK, true);
* "typed a" => getKeyStroke('a');
*
*
* In order to maintain backward-compatibility, specifying a null String,
* or a String which is formatted incorrectly, returns null.
*
* @param s a String formatted as described above
* @return a KeyStroke object for that String, or null if the specified
* String is null, or is formatted incorrectly
*
* @see java.awt.event.KeyEvent
*/
public static KeyStroke getKeyStroke(String s) {
if (s == null || s.length() == 0) {
return null;
}
synchronized (AWTKeyStroke.class) {
registerSubclass(KeyStroke.class);
try {
return (KeyStroke)getAWTKeyStroke(s);
} catch (IllegalArgumentException e) {
return null;
}
}
}
}