Class 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:
getAWTKeyStroke(char), Serialized Form

Constructor Summary

Constructors
Modifier Constructor Description
protected AWTKeyStroke()

Constructs an AWTKeyStroke with default values.
protected AWTKeyStroke​(char keyChar, int keyCode, int modifiers, boolean onKeyRelease)

Constructs an AWTKeyStroke with the specified values.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type Method Description
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.
char getKeyChar()

Returns the character for this AWTKeyStroke.
int getKeyCode()

Returns the numeric key code for this AWTKeyStroke.
int getKeyEventType()

Returns the type of KeyEvent which corresponds to this AWTKeyStroke.
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.
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 java.lang.Object

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

Constructor Detail

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:
getAWTKeyStroke(char)

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:
getAWTKeyStroke(char)

Method Detail

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:
InputEvent

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
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:
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:
KeyEvent, InputEvent

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
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:
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:
KeyEvent, InputEvent

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:
getAWTKeyStroke(char), KeyEvent.getKeyChar()

getKeyCode

public final int getKeyCode()

Returns the numeric key code for this AWTKeyStroke.

Returns:
an int containing the key code value
See Also:
getAWTKeyStroke(int,int), KeyEvent.getKeyCode()

getModifiers

public final int getModifiers()

Returns the modifier keys for this AWTKeyStroke.

Returns:
an int containing the modifiers
See Also:
getAWTKeyStroke(int,int)

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:
getAWTKeyStroke(int,int,boolean)

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:
KeyEvent

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:
Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

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:
Object.hashCode(), HashMap

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:
getAWTKeyStroke(String)

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