awtkeystroke.java

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   * in {@link InputEvent}; the new style (*_DOWN_MASK) is preferred, but the
   * old style will work.
   *
   * @param keyCode the virtual key
   * @param modifiers the modifiers, or 0
   * @return the specified keystroke
   */
  public static AWTKeyStroke getAWTKeyStroke(int keyCode, int modifiers)
  {
    return getAWTKeyStroke(KeyEvent.CHAR_UNDEFINED, keyCode,
                           extend(modifiers), false);
  }

  /**
   * Returns a keystroke representing what caused the key event.
   *
   * @param event the key event to convert
   * @return the specified keystroke, or null if the event is invalid
   * @throws NullPointerException if event is null
   */
  public static AWTKeyStroke getAWTKeyStrokeForEvent(KeyEvent event)
  {
    switch (event.id)
      {
      case KeyEvent.KEY_TYPED:
        return getAWTKeyStroke(event.getKeyChar(), KeyEvent.VK_UNDEFINED,
                               extend(event.getModifiersEx()), false);
      case KeyEvent.KEY_PRESSED:
        return getAWTKeyStroke(KeyEvent.CHAR_UNDEFINED, event.getKeyCode(),
                               extend(event.getModifiersEx()), false);
      case KeyEvent.KEY_RELEASED:
        return getAWTKeyStroke(KeyEvent.CHAR_UNDEFINED, event.getKeyCode(),
                               extend(event.getModifiersEx()), true);
      default:
        return null;
      }
  }

  /**
   * Parses a string and returns the keystroke that it represents. The syntax
   * for keystrokes is listed below, with tokens separated by an arbitrary
   * number of spaces:
   * <pre>
   * keyStroke := &lt;modifiers&gt;* ( &lt;typedID&gt; | &lt;codeID&gt; )
   * modifiers := ( shift | control | ctrl | meta | alt
   *                | button1 | button2 | button3 )
   * typedID := typed &lt;single Unicode character&gt;
   * codeID := ( pressed | released )? &lt;name&gt;
   * name := &lt;the KeyEvent field name less the leading "VK_"&gt;
   * </pre>
   *
   * <p>Note that the grammar is rather weak, and not all valid keystrokes
   * can be generated in this manner (for example, a typed space, or anything
   * with the alt-graph modifier!). The output of AWTKeyStroke.toString()
   * will not meet the grammar. If pressed or released is not specified,
   * pressed is assumed. Examples:<br>
   * <code>
   * "INSERT" =&gt; getAWTKeyStroke(KeyEvent.VK_INSERT, 0);<br>
   * "control DELETE" =&gt;
   *    getAWTKeyStroke(KeyEvent.VK_DELETE, InputEvent.CTRL_MASK);<br>
   * "alt shift X" =&gt; getAWTKeyStroke(KeyEvent.VK_X,
   *    InputEvent.ALT_MASK | InputEvent.SHIFT_MASK);<br>
   * "alt shift released X" =&gt; getAWTKeyStroke(KeyEvent.VK_X,
   *    InputEvent.ALT_MASK | InputEvent.SHIFT_MASK, true);<br>
   * "typed a" =&gt; getAWTKeyStroke('a');
   * </code>      
   *
   * @param s the string to parse
   * @return the specified keystroke
   * @throws NullPointerException if s is null
   * @throws IllegalArgumentException if s cannot be parsed
   */
  public static AWTKeyStroke getAWTKeyStroke(String s)
  {
    StringTokenizer t = new StringTokenizer(s, " ");
    if (! t.hasMoreTokens())
      throw new IllegalArgumentException();
    int modifiers = 0;
    boolean released = false;
    String token = null;
    do
      {
        token = t.nextToken();
        if ("shift".equals(token))
          modifiers |= KeyEvent.SHIFT_MASK | KeyEvent.SHIFT_DOWN_MASK;
        else if ("ctrl".equals(token) || "control".equals(token))
          modifiers |= KeyEvent.CTRL_MASK | KeyEvent.CTRL_DOWN_MASK;
        else if ("meta".equals(token))
          modifiers |= KeyEvent.META_MASK | KeyEvent.META_DOWN_MASK;
        else if ("alt".equals(token))
          modifiers |= KeyEvent.ALT_MASK | KeyEvent.ALT_DOWN_MASK;
        else if ("button1".equals(token))
          modifiers |= KeyEvent.BUTTON1_DOWN_MASK;
        else if ("button2".equals(token))
          modifiers |= KeyEvent.BUTTON2_DOWN_MASK;
        else if ("button3".equals(token))
          modifiers |= KeyEvent.BUTTON3_DOWN_MASK;
        else if ("typed".equals(token))
          {
            if (t.hasMoreTokens())
              {
                token = t.nextToken();
                if (! t.hasMoreTokens() && token.length() == 1)
                  return getAWTKeyStroke(token.charAt(0),
                                         KeyEvent.VK_UNDEFINED, modifiers,
                                         false);
              }
            throw new IllegalArgumentException();
          }
        else if ("pressed".equals(token))
          {
            if (t.hasMoreTokens())
              token = t.nextToken();
            break;
          }
        else if ("released".equals(token))
          {
            released = true;
            if (t.hasMoreTokens())
              token = t.nextToken();
            break;
          }
        else
          break;
      }
    while (t.hasMoreTokens());
    // Now token contains the VK name we must parse.
    Integer code = (Integer) vktable.get(token);
    if (code == null || t.hasMoreTokens())
      throw new IllegalArgumentException();
    return getAWTKeyStroke(KeyEvent.CHAR_UNDEFINED, code.intValue(),
                           modifiers, released);
  }

  /**
   * Returns the character of this keystroke, if it was typed.
   *
   * @return the character value, or CHAR_UNDEFINED
   * @see #getAWTKeyStroke(char)
   */
  public final char getKeyChar()
  {
    return keyChar;
  }

  /**
   * Returns the virtual key code of this keystroke, if it was pressed or
   * released. This will be a VK_* constant from KeyEvent.
   *
   * @return the virtual key code value, or VK_UNDEFINED
   * @see #getAWTKeyStroke(int, int)
   */
  public final int getKeyCode()
  {
    return keyCode;
  }

  /**
   * Returns the modifiers for this keystroke. This will be a bitwise or of
   * constants from InputEvent; it includes the old style masks for shift,
   * control, alt, meta, and alt-graph (but not button1); as well as the new
   * style of extended modifiers for all modifiers.
   *
   * @return the modifiers
   * @see #getAWTKeyStroke(Character, int)
   * @see #getAWTKeyStroke(int, int)
   */
  public final int getModifiers()
  {
    return modifiers;
  }

  /**
   * Tests if this keystroke is a key release.
   *
   * @return true if this is a key release
   * @see #getAWTKeyStroke(int, int, boolean)
   */
  public final boolean isOnKeyRelease()
  {
    return onKeyRelease;
  }

  /**
   * Returns the AWT event type of this keystroke. This is one of
   * {@link KeyEvent#KEY_TYPED}, {@link KeyEvent#KEY_PRESSED}, or
   * {@link KeyEvent#KEY_RELEASED}.
   *
   * @return the key event type
   */
  public final int getKeyEventType()
  {
    return keyCode == KeyEvent.VK_UNDEFINED ? KeyEvent.KEY_TYPED
      : onKeyRelease ? KeyEvent.KEY_RELEASED : KeyEvent.KEY_PRESSED;
  }

  /**
   * Returns a hashcode for this key event. It is not documented, but appears
   * to be: <code>(getKeyChar() + 1) * (getKeyCode() + 1)
   * * (getModifiers() + 1) * 2 + (isOnKeyRelease() ? 1 : 2)</code>.
   *
   * @return the hashcode
   */
  public int hashCode()
  {
    return (keyChar + 1) * (keyCode + 1) * (modifiers + 1) * 2
      + (onKeyRelease ? 1 : 2);
  }

  /**
   * Tests two keystrokes for equality.
   *
   * @param o the object to test
   * @return true if it is equal
   */
  public final boolean equals(Object o)
  {
    if (! (o instanceof AWTKeyStroke))
      return false;
    AWTKeyStroke s = (AWTKeyStroke) o;
    return this == o || (keyChar == s.keyChar && keyCode == s.keyCode
                         && modifiers == s.modifiers
                         && onKeyRelease == s.onKeyRelease);
  }

  /**
   * Returns a string representation of this keystroke. For typed keystrokes,
   * this is <code>"keyChar " + KeyEvent.getKeyModifiersText(getModifiers())
   + getKeyChar()</code>; for pressed and released keystrokes, this is
   * <code>"keyCode " + KeyEvent.getKeyModifiersText(getModifiers())
   * + KeyEvent.getKeyText(getKeyCode())
   * + (isOnKeyRelease() ? "-R" : "-P")</code>.
   *
   * @return a string representation
   */
  public String toString()
  {
    if (keyCode == KeyEvent.VK_UNDEFINED)
      return "keyChar " + KeyEvent.getKeyModifiersText(modifiers) + keyChar;
    return "keyCode " + KeyEvent.getKeyModifiersText(modifiers)
      + KeyEvent.getKeyText(keyCode) + (onKeyRelease ? "-R" : "-P");
  }

  /**
   * Returns a cached version of the deserialized keystroke, if available.
   *
   * @return a cached replacement
   * @throws ObjectStreamException if something goes wrong
   */
  protected Object readResolve() throws ObjectStreamException
  {
    AWTKeyStroke s = (AWTKeyStroke) cache.get(this);
    if (s != null)
      return s;
    cache.put(this, this);
    return this;
  }

  /**
   * Gets the appropriate keystroke, creating one if necessary.
   *
   * @param keyChar the keyChar
   * @param keyCode the keyCode
   * @param modifiers the modifiers
   * @param release true for key release
   * @return the specified keystroke
   */
  private static AWTKeyStroke getAWTKeyStroke(char keyChar, int keyCode,
                                              int modifiers, boolean release)
  {
    // Check level 0 cache.
    AWTKeyStroke stroke = recent; // Avoid thread races.
    if (stroke != null && stroke.keyChar == keyChar
        && stroke.keyCode == keyCode && stroke.modifiers == modifiers
        && stroke.onKeyRelease == release)
      return stroke;
    // Create a new object, on the assumption that if it has a match in the
    // cache, the VM can easily garbage collect it as it is temporary.
    Constructor c = ctor; // Avoid thread races.
    if (c == null)
      stroke = new AWTKeyStroke(keyChar, keyCode, modifiers, release);
    else
      try
        {
          stroke = (AWTKeyStroke) c.newInstance(null);
          stroke.keyChar = keyChar;
          stroke.keyCode = keyCode;
          stroke.modifiers = modifiers;
          stroke.onKeyRelease = release;
        }
      catch (Exception e)
        {
          throw (Error) new InternalError().initCause(e);
        }
    // Check level 1 cache.
    AWTKeyStroke cached = (AWTKeyStroke) cache.get(stroke);
    if (cached == null)
      cache.put(stroke, stroke);
    else
      stroke = cached;
    return recent = stroke;
  }

  /**
   * Converts the modifiers to the appropriate format.
   *
   * @param mod the modifiers to convert
   * @return the adjusted modifiers
   */
  private static int extend(int mod)
  {
    if ((mod & (KeyEvent.SHIFT_MASK | KeyEvent.SHIFT_DOWN_MASK)) != 0)
      mod |= KeyEvent.SHIFT_MASK | KeyEvent.SHIFT_DOWN_MASK;
    if ((mod & (KeyEvent.CTRL_MASK | KeyEvent.CTRL_DOWN_MASK)) != 0)
      mod |= KeyEvent.CTRL_MASK | KeyEvent.CTRL_DOWN_MASK;
    if ((mod & (KeyEvent.META_MASK | KeyEvent.META_DOWN_MASK)) != 0)
      mod |= KeyEvent.META_MASK | KeyEvent.META_DOWN_MASK;
    if ((mod & (KeyEvent.ALT_MASK | KeyEvent.ALT_DOWN_MASK)) != 0)
      mod |= KeyEvent.ALT_MASK | KeyEvent.ALT_DOWN_MASK;
    if ((mod & (KeyEvent.ALT_GRAPH_MASK | KeyEvent.ALT_GRAPH_DOWN_MASK)) != 0)
      mod |= KeyEvent.ALT_GRAPH_MASK | KeyEvent.ALT_GRAPH_DOWN_MASK;
    if ((mod & KeyEvent.BUTTON1_MASK) != 0)
      mod |= KeyEvent.BUTTON1_DOWN_MASK;
    return mod & MODIFIERS_MASK;
  }
} // class AWTKeyStroke