Class KeyStroke

java.lang.Object

java.awt.AWTKeyStroke

javax.swing.KeyStroke

All Implemented Interfaces:: Serializable

public class KeyStroke extends AWTKeyStroke

A KeyStroke represents a key action on the keyboard, or equivalent input device. KeyStrokes can correspond to only a press or release of a particular key, just as KEY_PRESSED and KEY_RELEASED KeyEvents do; alternately, they can correspond to typing a specific Java character, just as KEY_TYPED KeyEvents do. In all cases, KeyStrokes can specify modifiers (alt, shift, control, meta, altGraph, or a combination thereof) which must be present during the action for an exact match.

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 JavaBeans has been added to the java.beans package. Please see XMLEncoder.

Since:

1.2

See Also:

Method Summary

Modifier and Type	Method	Description
`static KeyStroke`	`getKeyStroke(char keyChar)`	Returns a shared instance of a `KeyStroke` that represents a `KEY_TYPED` event for the specified character.
`static KeyStroke`	`getKeyStroke(char keyChar, boolean onKeyRelease)`	Deprecated. use getKeyStroke(char)
`static KeyStroke`	`getKeyStroke(int keyCode, int modifiers)`	Returns a shared instance of a KeyStroke, given a numeric key code and a set of modifiers.
`static KeyStroke`	`getKeyStroke(int keyCode, int modifiers, boolean onKeyRelease)`	Returns a shared instance of a KeyStroke, given a numeric key code and a set of modifiers, specifying whether the key is activated when it is pressed or released.
`static KeyStroke`	`getKeyStroke(Character keyChar, int modifiers)`	Returns a shared instance of a `KeyStroke` that represents a `KEY_TYPED` event for the specified Character object and a set of modifiers.
`static KeyStroke`	`getKeyStroke(String s)`	Parses a string and returns a `KeyStroke`.
`static KeyStroke`	`getKeyStrokeForEvent(KeyEvent anEvent)`	Returns a KeyStroke which represents the stroke which generated a given KeyEvent.

Methods declared in class AWTKeyStroke

equals, getAWTKeyStroke, getAWTKeyStroke, getAWTKeyStroke, getAWTKeyStroke, getAWTKeyStroke, getAWTKeyStrokeForEvent, getKeyChar, getKeyCode, getKeyEventType, getModifiers, hashCode, isOnKeyRelease, readResolve, registerSubclass, toString

Modifier and Type	Method	Description
`final boolean`	`equals(Object anObject)`	Returns true if this object is identical to the specified object.
`static AWTKeyStroke`	`getAWTKeyStroke(char keyChar)`	Returns a shared instance of an `AWTKeyStroke` that represents a `KEY_TYPED` event for the specified character.
`static AWTKeyStroke`	`getAWTKeyStroke(int keyCode, int modifiers)`	Returns a shared instance of an `AWTKeyStroke`, given a numeric key code and a set of modifiers.
`static AWTKeyStroke`	`getAWTKeyStroke(int keyCode, int modifiers, boolean onKeyRelease)`	Returns a shared instance of an `AWTKeyStroke`, given a numeric key code and a set of modifiers, specifying whether the key is activated when it is pressed or released.
`static AWTKeyStroke`	`getAWTKeyStroke(Character keyChar, int modifiers)`	Returns a shared instance of an `AWTKeyStroke` that represents a `KEY_TYPED` event for the specified Character object and a set of modifiers.
`static AWTKeyStroke`	`getAWTKeyStroke(String s)`	Parses a string and returns an `AWTKeyStroke`.
`static AWTKeyStroke`	`getAWTKeyStrokeForEvent(KeyEvent anEvent)`	Returns an `AWTKeyStroke` which represents the stroke which generated a given `KeyEvent`.
`final char`	`getKeyChar()`	Returns the character for this `AWTKeyStroke`.
`final int`	`getKeyCode()`	Returns the numeric key code for this `AWTKeyStroke`.
`final int`	`getKeyEventType()`	Returns the type of `KeyEvent` which corresponds to this `AWTKeyStroke`.
`final int`	`getModifiers()`	Returns the modifier keys for this `AWTKeyStroke`.
`int`	`hashCode()`	Returns a numeric value for this object that is likely to be unique, making it a good choice as the index value in a hash table.
`final boolean`	`isOnKeyRelease()`	Returns whether this `AWTKeyStroke` represents a key release.
`protected Object`	`readResolve()`	Returns a cached instance of `AWTKeyStroke` (or a subclass of `AWTKeyStroke`) which is equal to this instance.
`protected static void`	`registerSubclass(Class<?> subclass)`	Deprecated.
`String`	`toString()`	Returns a string that displays and identifies this object's properties.

Methods declared in class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Modifier and Type	Method	Description
`protected Object`	`clone()`	Creates and returns a copy of this object.
`protected void`	`finalize()`	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
`final Class<?>`	`getClass()`	Returns the runtime class of this `Object`.
`final void`	`notify()`	Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()`	Wakes up all threads that are waiting on this object's monitor.
`final void`	`wait()`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
`final void`	`wait(long timeoutMillis)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis, int nanos)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Method Details

getKeyStroke

public static KeyStroke getKeyStroke(char keyChar)

Returns a shared instance of a KeyStroke that represents a KEY_TYPED event for the specified character.

Parameters:: keyChar - the character value for a keyboard key
Returns:: a KeyStroke object for that key

getKeyStroke

@Deprecated public static KeyStroke getKeyStroke(char keyChar, boolean onKeyRelease)

Deprecated.

use getKeyStroke(char)

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.

Parameters:: keyChar - the character value for a keyboard key; onKeyRelease - true if this KeyStroke corresponds to a key release; false otherwise.
Returns:: a KeyStroke object for that key

getKeyStroke

public static KeyStroke getKeyStroke(Character keyChar, int modifiers)

Returns a shared instance of a KeyStroke that represents a 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:

java.awt.event.InputEvent.SHIFT_DOWN_MASK
java.awt.event.InputEvent.CTRL_DOWN_MASK
java.awt.event.InputEvent.META_DOWN_MASK
java.awt.event.InputEvent.ALT_DOWN_MASK
java.awt.event.InputEvent.ALT_GRAPH_DOWN_MASK

The old modifiers listed below also can be used, but they are mapped to _DOWN_ modifiers.

java.awt.event.InputEvent.SHIFT_MASK
java.awt.event.InputEvent.CTRL_MASK
java.awt.event.InputEvent.META_MASK
java.awt.event.InputEvent.ALT_MASK
java.awt.event.InputEvent.ALT_GRAPH_MASK

also can be used, but they are mapped to _DOWN_ modifiers. Since these numbers are all different powers of two, any combination of them is an integer in which each bit represents a different modifier key. Use 0 to specify no modifiers.

Parameters:

keyChar - the Character object for a keyboard character

modifiers - a bitwise-ored combination of any modifiers

Returns:

an KeyStroke object for that key

Throws:

IllegalArgumentException - if keyChar is null

Since:

1.3

See Also:

getKeyStroke

public static KeyStroke getKeyStroke(int keyCode, int modifiers, boolean onKeyRelease)

Returns a shared instance of a KeyStroke, given a numeric key code and a set of modifiers, specifying whether the key is activated when it is pressed or released.

The "virtual key" constants defined in java.awt.event.KeyEvent can be used to specify the key code. For example:

java.awt.event.KeyEvent.VK_ENTER
java.awt.event.KeyEvent.VK_TAB
java.awt.event.KeyEvent.VK_SPACE

Alternatively, the key code may be obtained by calling java.awt.event.KeyEvent.getExtendedKeyCodeForChar. The modifiers consist of any combination of:

java.awt.event.InputEvent.SHIFT_DOWN_MASK
java.awt.event.InputEvent.CTRL_DOWN_MASK
java.awt.event.InputEvent.META_DOWN_MASK
java.awt.event.InputEvent.ALT_DOWN_MASK
java.awt.event.InputEvent.ALT_GRAPH_DOWN_MASK

The old modifiers

java.awt.event.InputEvent.SHIFT_MASK
java.awt.event.InputEvent.CTRL_MASK
java.awt.event.InputEvent.META_MASK
java.awt.event.InputEvent.ALT_MASK
java.awt.event.InputEvent.ALT_GRAPH_MASK

Parameters:

keyCode - an int specifying the numeric code for a keyboard key

modifiers - a bitwise-ored combination of any modifiers

onKeyRelease - true if the KeyStroke should represent a key release; false otherwise.

Returns:

a KeyStroke object for that key

See Also:

getKeyStroke

public static KeyStroke getKeyStroke(int keyCode, int modifiers)

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.VK_ENTER
java.awt.event.KeyEvent.VK_TAB
java.awt.event.KeyEvent.VK_SPACE

Alternatively, the key code may be obtained by calling java.awt.event.KeyEvent.getExtendedKeyCodeForChar. The modifiers consist of any combination of:

java.awt.event.InputEvent.SHIFT_DOWN_MASK
java.awt.event.InputEvent.CTRL_DOWN_MASK
java.awt.event.InputEvent.META_DOWN_MASK
java.awt.event.InputEvent.ALT_DOWN_MASK
java.awt.event.InputEvent.ALT_GRAPH_DOWN_MASK

The old modifiers

java.awt.event.InputEvent.SHIFT_MASK
java.awt.event.InputEvent.CTRL_MASK
java.awt.event.InputEvent.META_MASK
java.awt.event.InputEvent.ALT_MASK
java.awt.event.InputEvent.ALT_GRAPH_MASK

Parameters:

keyCode - an int specifying the numeric code for a keyboard key

modifiers - a bitwise-ored combination of any modifiers

Returns:

a KeyStroke object for that key

See Also:

getKeyStrokeForEvent

public static KeyStroke getKeyStrokeForEvent(KeyEvent anEvent)

Returns a KeyStroke which represents the stroke which generated a given KeyEvent.

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.

Parameters:: anEvent - the KeyEvent from which to obtain the KeyStroke
Returns:: the KeyStroke that precipitated the event
Throws:: NullPointerException - if anEvent is null

getKeyStroke

public static KeyStroke getKeyStroke(String s)

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.

Parameters:

s - a String formatted as described above

Returns:

a KeyStroke object for that String, or null if the specified String is null, or is formatted incorrectly

See Also:

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