public class

AWTKeyStroke

extends Object
implements Serializable
java.lang.Object
   ↳ java.awt.AWTKeyStroke
Known Direct Subclasses

Class Overview

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.

See Also

Summary

Protected Constructors
AWTKeyStroke()
Constructs an AWTKeyStroke with default values.
AWTKeyStroke(char keyChar, int keyCode, int modifiers, boolean onKeyRelease)
Constructs an AWTKeyStroke with the specified values.
Public Methods
final boolean equals(Object anObject)
Returns true if this object is identical to the specified object.
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(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(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.
String toString()
Returns a string that displays and identifies this object's properties.
Protected Methods
Object readResolve()
Returns a cached instance of AWTKeyStroke (or a subclass of AWTKeyStroke) which is equal to this instance.
static void registerSubclass(Class<?> subclass)
Registers a new class which the factory methods in AWTKeyStroke will use when generating new instances of AWTKeyStrokes.
[Expand]
Inherited Methods
From class java.lang.Object

Protected Constructors

protected AWTKeyStroke ()

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

PropertyDefault 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

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

Public Methods

public final boolean equals (Object anObject)

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

Parameters
anObject the Object to compare this object to
Returns
  • true if the objects are identical

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
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

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

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

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

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

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

public final char getKeyChar ()

Returns the character for this AWTKeyStroke.

Returns
  • a char value
See Also

public final int getKeyCode ()

Returns the numeric key code for this AWTKeyStroke.

Returns
  • an int containing the key code value
See Also

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

public final int getModifiers ()

Returns the modifier keys for this AWTKeyStroke.

Returns
  • an int containing the modifiers
See Also

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.

Returns
  • an int that represents this object

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

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.

Returns
  • a String representation of this object
See Also

Protected Methods

protected Object readResolve ()

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

protected static void registerSubclass (Class<?> subclass)

Registers a new class which the factory methods in AWTKeyStroke will use when generating new instances of AWTKeyStrokes. After invoking this method, the factory methods will return instances of the specified Class. The specified Class must be either AWTKeyStroke or derived from AWTKeyStroke, and it must have a no-arg constructor. The constructor can be of any accessibility, including private. This operation flushes the current AWTKeyStroke cache.

Parameters
subclass the new Class of which the factory methods should create instances
Throws
IllegalArgumentException if subclass is null, or if subclass does not have a no-arg constructor
ClassCastException if subclass is not AWTKeyStroke, or a class derived from AWTKeyStroke