Class AWTKeyStroke

java.lang.Object

java.awt.AWTKeyStroke

All Implemented Interfaces:: Serializable

Direct Known Subclasses:: KeyStroke

public class AWTKeyStroke extends Object implements Serializable

An AWTKeyStroke represents a key action on the keyboard, or equivalent input device. AWTKeyStrokes 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, AWTKeyStrokes can specify modifiers (alt, shift, control, meta, altGraph, or a combination thereof) which must be present during the action for an exact match.

AWTKeyStrokes are immutable, and are intended to be unique. Client code should never create an AWTKeyStroke on its own, but should instead use a variant of getAWTKeyStroke. Client use of these factory methods allows the AWTKeyStroke implementation to cache and share instances efficiently.

Since:

1.4

See Also:

Constructor Summary

AWTKeyStroke()

AWTKeyStroke(char keyChar,
 int keyCode,
 int modifiers,
 boolean onKeyRelease)

Modifier	Constructor	Description
`protected`	Constructs an `AWTKeyStroke` with default values.
`protected`	Constructs an `AWTKeyStroke` with the specified values.

Method Summary

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.

Constructor Details

AWTKeyStroke

protected AWTKeyStroke()

Constructs an AWTKeyStroke with default values. The default values used are:

AWTKeyStroke default values
Property	Default Value
Key Char	`KeyEvent.CHAR_UNDEFINED`
Key Code	`KeyEvent.VK_UNDEFINED`
Modifiers	none
On key release?	`false`

AWTKeyStrokes should not be constructed by client code. Use a variant of getAWTKeyStroke instead.

See Also:

AWTKeyStroke

protected AWTKeyStroke(char keyChar, int keyCode, int modifiers, boolean onKeyRelease)

Constructs an AWTKeyStroke with the specified values. AWTKeyStrokes should not be constructed by client code. Use a variant of getAWTKeyStroke instead.

Parameters:

keyChar - the character value for a keyboard key

keyCode - the key code for this AWTKeyStroke

modifiers - a bitwise-ored combination of any modifiers

onKeyRelease - true if this AWTKeyStroke corresponds to a key release; false otherwise

See Also:

Method Details

registerSubclass

@Deprecated protected static void registerSubclass(Class<?> subclass)

Deprecated.

The method has no effect and is only left present to avoid introducing a binary incompatibility.

Parameters:: subclass - the new Class of which the factory methods should create instances

getAWTKeyStroke

public static AWTKeyStroke getAWTKeyStroke(char keyChar)

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

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

getAWTKeyStroke

public 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. Note that the first parameter is of type Character rather than char. This is to avoid inadvertent clashes with calls to getAWTKeyStroke(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 AWTKeyStroke object for that key

Throws:

IllegalArgumentException - if keyChar is null

See Also:

getAWTKeyStroke

public 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.

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 AWTKeyStroke should represent a key release; false otherwise

Returns:

an AWTKeyStroke object for that key

See Also:

getAWTKeyStroke

public static AWTKeyStroke getAWTKeyStroke(int keyCode, int modifiers)

Returns a shared instance of an AWTKeyStroke, given a numeric key code and a set of modifiers. The returned AWTKeyStroke 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

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:

an AWTKeyStroke object for that key

See Also:

getAWTKeyStrokeForEvent

public static AWTKeyStroke getAWTKeyStrokeForEvent(KeyEvent anEvent)

Returns an AWTKeyStroke 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 AWTKeyStroke
Returns:: the AWTKeyStroke that precipitated the event
Throws:: NullPointerException - if anEvent is null

getAWTKeyStroke

public static AWTKeyStroke getAWTKeyStroke(String s)

Parses a string and returns an AWTKeyStroke. 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" => getAWTKeyStroke(KeyEvent.VK_INSERT, 0);
    "control DELETE" => getAWTKeyStroke(KeyEvent.VK_DELETE, InputEvent.CTRL_MASK);
    "alt shift X" => getAWTKeyStroke(KeyEvent.VK_X, InputEvent.ALT_MASK | InputEvent.SHIFT_MASK);
    "alt shift released X" => getAWTKeyStroke(KeyEvent.VK_X, InputEvent.ALT_MASK | InputEvent.SHIFT_MASK, true);
    "typed a" => getAWTKeyStroke('a');

Parameters:: s - a String formatted as described above
Returns:: an AWTKeyStroke object for that String
Throws:: IllegalArgumentException - if s is null, or is formatted incorrectly

getKeyChar

public final char getKeyChar()

Returns the character for this AWTKeyStroke.

Returns:

a char value

See Also:

getKeyCode

public final int getKeyCode()

Returns the numeric key code for this AWTKeyStroke.

Returns:

an int containing the key code value

See Also:

getModifiers

public final int getModifiers()

Returns the modifier keys for this AWTKeyStroke.

Returns:

an int containing the modifiers

See Also:

isOnKeyRelease

public final boolean isOnKeyRelease()

Returns whether this AWTKeyStroke represents a key release.

Returns:

true if this AWTKeyStroke represents a key release; false otherwise

See Also:

getKeyEventType

public final int getKeyEventType()

Returns the type of KeyEvent which corresponds to this AWTKeyStroke.

Returns:

KeyEvent.KEY_PRESSED, KeyEvent.KEY_TYPED, or KeyEvent.KEY_RELEASED

See Also:

hashCode

public 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.

Overrides:

hashCode in class Object

Returns:

an int that represents this object

See Also:

equals

public final boolean equals(Object anObject)

Returns true if this object is identical to the specified object.

Overrides:

equals in class Object

Parameters:

anObject - the Object to compare this object to

Returns:

true if the objects are identical

See Also:

toString

public String toString()

Returns a string that displays and identifies this object's properties. The String returned by this method can be passed as a parameter to getAWTKeyStroke(String) to produce a key stroke equal to this key stroke.

Overrides:

toString in class Object

Returns:

a String representation of this object

See Also:

readResolve

protected Object readResolve() throws ObjectStreamException

Returns a cached instance of AWTKeyStroke (or a subclass of AWTKeyStroke) which is equal to this instance.

Returns:: a cached instance which is equal to this instance
Throws:: ObjectStreamException - if a serialization problem occurs

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