swingutilities.java

gcc的组建

  public static boolean isMiddleMouseButton(MouseEvent event)
  {
    return ((event.getModifiersEx() & InputEvent.BUTTON2_DOWN_MASK)
	     == InputEvent.BUTTON2_DOWN_MASK);
  }

  /**
   * Checks if right mouse button was clicked.
   *
   * @param event the event to check
   *
   * @return true if right mouse was clicked, false otherwise.
   */
  public static boolean isRightMouseButton(MouseEvent event)
  {
    return ((event.getModifiersEx() & InputEvent.BUTTON3_DOWN_MASK)
	     == InputEvent.BUTTON3_DOWN_MASK);
  }
  
  /**
   * This frame should be used when constructing a Window/JDialog without
   * a parent. In this case, we are forced to use this frame as a window's
   * parent, because we simply cannot pass null instead of parent to Window
   * constructor, since doing it will result in NullPointerException.
   */
  private static class OwnerFrame extends Frame
  {
    public void setVisible(boolean b)
    {
      // Do nothing here. 
    }
    
    public boolean isShowing()
    {
      return true;
    }
  }

  public static boolean notifyAction(Action action,
                                     KeyStroke ks,
                                     KeyEvent event,
                                     Object sender,
                                     int modifiers)
  {
    if (action != null && action.isEnabled())
      {
        String name = (String) action.getValue(Action.ACTION_COMMAND_KEY);
        if (name == null
            && event.getKeyChar() != KeyEvent.CHAR_UNDEFINED)
          name = new String(new char[] {event.getKeyChar()});
        action.actionPerformed(new ActionEvent(sender,
                                               ActionEvent.ACTION_PERFORMED,
                                               name, modifiers));
        return true;
      }
    return false;
  }

  /**
   * <p>Change the shared, UI-managed {@link ActionMap} for a given
   * component. ActionMaps are arranged in a hierarchy, in order to
   * encourage sharing of common actions between components. The hierarchy
   * unfortunately places UI-managed ActionMaps at the <em>end</em> of the
   * parent-pointer chain, as illustrated:</p>
   *
   * <pre>
   *  [{@link javax.swing.JComponent#getActionMap()}] 
   *          --&gt; [{@link javax.swing.ActionMap}] 
   *     parent --&gt; [{@link javax.swing.text.JTextComponent.KeymapActionMap}] 
   *       parent --&gt; [{@link javax.swing.plaf.ActionMapUIResource}]
   * </pre>
   *
   * <p>Our goal with this method is to replace the first ActionMap along
   * this chain which is an instance of {@link ActionMapUIResource}, since
   * these are the ActionMaps which are supposed to be shared between
   * components.</p>
   *
   * <p>If the provided ActionMap is <code>null</code>, we interpret the
   * call as a request to remove the UI-managed ActionMap from the
   * component's ActionMap parent chain.</p>
   */
  public static void replaceUIActionMap(JComponent component, 
                                        ActionMap uiActionMap)
  {
    ActionMap child = component.getActionMap();
    if (child == null)
      component.setActionMap(uiActionMap);
    else
      {
        ActionMap parent = child.getParent();
        while (parent != null && !(parent instanceof ActionMapUIResource))
          {
            child = parent;
            parent = child.getParent();
          }
        child.setParent(uiActionMap);
      }
  }

  /**
   * <p>Change the shared, UI-managed {@link InputMap} for a given
   * component. InputMaps are arranged in a hierarchy, in order to
   * encourage sharing of common input mappings between components. The
   * hierarchy unfortunately places UI-managed InputMaps at the
   * <em>end</em> of the parent-pointer chain, as illustrated:</p>
   *
   * <pre>
   *  [{@link javax.swing.JComponent#getInputMap()}] 
   *          --&gt; [{@link javax.swing.InputMap}] 
   *     parent --&gt; [{@link javax.swing.text.JTextComponent.KeymapWrapper}] 
   *       parent --&gt; [{@link javax.swing.plaf.InputMapUIResource}]
   * </pre>
   *
   * <p>Our goal with this method is to replace the first InputMap along
   * this chain which is an instance of {@link InputMapUIResource}, since
   * these are the InputMaps which are supposed to be shared between
   * components.</p>
   *
   * <p>If the provided InputMap is <code>null</code>, we interpret the
   * call as a request to remove the UI-managed InputMap from the
   * component's InputMap parent chain.</p>
   */
  public static void replaceUIInputMap(JComponent component, 
                                       int condition, 
                                       InputMap uiInputMap)
  {
    InputMap child = component.getInputMap(condition);
    if (child == null)
      component.setInputMap(condition, uiInputMap);
    else
      {
        InputMap parent = child.getParent();
        while (parent != null && !(parent instanceof InputMapUIResource))
          {
            child = parent;
            parent = parent.getParent();
          }
        child.setParent(uiInputMap);
      }
  }

  /**
   * Subtracts a rectangle from another and return the area as an array
   * of rectangles.
   * Returns the areas of rectA which are not covered by rectB.
   * If the rectangles do not overlap, or if either parameter is
   * <code>null</code>, a zero-size array is returned.
   * @param rectA The first rectangle
   * @param rectB The rectangle to subtract from the first
   * @return An array of rectangles representing the area in rectA
   * not overlapped by rectB
   */
  public static Rectangle[] computeDifference(Rectangle rectA, Rectangle rectB)
  {
    if (rectA == null || rectB == null)
      return new Rectangle[0];

    Rectangle[] r = new Rectangle[4];
    int x1 = rectA.x;
    int y1 = rectA.y;
    int w1 = rectA.width;
    int h1 = rectA.height;
    int x2 = rectB.x;
    int y2 = rectB.y;
    int w2 = rectB.width;
    int h2 = rectB.height;

    // (outer box = rectA)
    // ------------- 
    // |_____0_____|
    // |  |rectB|  |
    // |_1|_____|_2|
    // |     3     |
    // -------------
    int H0 = (y2 > y1) ? y2 - y1 : 0; // height of box 0
    int H3 = (y2 + h2 < y1 + h1) ? y1 + h1 - y2 - h2 : 0; // height box 3
    int W1 = (x2 > x1) ? x2 - x1 : 0; // width box 1
    int W2 = (x1 + w1 > x2 + w2) ? x1 + w1 - x2 - w2 : 0; // w. box 2
    int H12 = (H0 + H3 < h1) ? h1 - H0 - H3 : 0; // height box 1 & 2

    if (H0 > 0)
      r[0] = new Rectangle(x1, y1, w1, H0);
    else
      r[0] = null;

    if (W1 > 0 && H12 > 0)
      r[1] = new Rectangle(x1, y1 + H0, W1, H12);
    else
      r[1] = null;

    if (W2 > 0 && H12 > 0)
      r[2] = new Rectangle(x2 + w2, y1 + H0, W2, H12);
    else
      r[2] = null;

    if (H3 > 0)
      r[3] = new Rectangle(x1, y1 + H0 + H12, w1, H3);
    else
      r[3] = null;

    // sort out null objects
    int n = 0;
    for (int i = 0; i < 4; i++)
      if (r[i] != null)
	n++;
    Rectangle[] out = new Rectangle[n];
    for (int i = 3; i >= 0; i--)
      if (r[i] != null)
	out[--n] = r[i];

    return out;
  }

  /**
   * Calculates the intersection of two rectangles.
   *
   * @param x upper-left x coodinate of first rectangle
   * @param y upper-left y coodinate of first rectangle
   * @param w width of first rectangle
   * @param h height of first rectangle
   * @param rect a Rectangle object of the second rectangle
   * @throws NullPointerException if rect is null.
   *
   * @return a rectangle corresponding to the intersection of the
   * two rectangles. A zero rectangle is returned if the rectangles
   * do not overlap.
   */
  public static Rectangle computeIntersection(int x, int y, int w, int h,
                                              Rectangle rect)
  {
    int x2 = (int) rect.getX();
    int y2 = (int) rect.getY();
    int w2 = (int) rect.getWidth();
    int h2 = (int) rect.getHeight();

    int dx = (x > x2) ? x : x2;
    int dy = (y > y2) ? y : y2;
    int dw = (x + w < x2 + w2) ? (x + w - dx) : (x2 + w2 - dx);
    int dh = (y + h < y2 + h2) ? (y + h - dy) : (y2 + h2 - dy);

    if (dw >= 0 && dh >= 0)
      return new Rectangle(dx, dy, dw, dh);

    return new Rectangle(0, 0, 0, 0);
  }
  
  /**
   * Calculates the width of a given string.
   *
   * @param fm the <code>FontMetrics</code> object to use
   * @param str the string
   * 
   * @return the width of the the string.
   */
  public static int computeStringWidth(FontMetrics fm, String str)
  {
    return fm.stringWidth(str);
  }

  /**
   * Calculates the union of two rectangles.
   *
   * @param x upper-left x coodinate of first rectangle
   * @param y upper-left y coodinate of first rectangle
   * @param w width of first rectangle
   * @param h height of first rectangle
   * @param rect a Rectangle object of the second rectangle
   * @throws NullPointerException if rect is null.
   *
   * @return a rectangle corresponding to the union of the
   * two rectangles. A rectangle encompassing both is returned if the
   * rectangles do not overlap.
   */
  public static Rectangle computeUnion(int x, int y, int w, int h,
                                       Rectangle rect)
  {
    int x2 = (int) rect.getX();
    int y2 = (int) rect.getY();
    int w2 = (int) rect.getWidth();
    int h2 = (int) rect.getHeight();

    int dx = (x < x2) ? x : x2;
    int dy = (y < y2) ? y : y2;
    int dw = (x + w > x2 + w2) ? (x + w - dx) : (x2 + w2 - dx);
    int dh = (y + h > y2 + h2) ? (y + h - dy) : (y2 + h2 - dy);

    if (dw >= 0 && dh >= 0)
      return new Rectangle(dx, dy, dw, dh);

    return new Rectangle(0, 0, 0, 0);
  }

  /**
   * Tests if a rectangle contains another.
   * @param a first rectangle
   * @param b second rectangle
   * @return true if a contains b, false otherwise
   * @throws NullPointerException
   */
  public static boolean isRectangleContainingRectangle(Rectangle a, Rectangle b)
  {
    // Note: zero-size rects inclusive, differs from Rectangle.contains()
    return b.width >= 0 && b.height >= 0 && b.width >= 0 && b.height >= 0
           && b.x >= a.x && b.x + b.width <= a.x + a.width && b.y >= a.y
           && b.y + b.height <= a.y + a.height;
  }

  /**
   * Returns the InputMap that is provided by the ComponentUI of
   * <code>component</code> for the specified condition.
   *
   * @param component the component for which the InputMap is returned
   * @param cond the condition that specifies which of the three input
   *     maps should be returned, may be
   *     {@link JComponent#WHEN_IN_FOCUSED_WINDOW},
   *     {@link JComponent#WHEN_FOCUSED} or
   *     {@link JComponent#WHEN_ANCESTOR_OF_FOCUSED_COMPONENT}
   *
   * @return The input map.
   */
  public static InputMap getUIInputMap(JComponent component, int cond)
  {
    if (UIManager.getUI(component) != null)
      // we assume here that the UI class sets the parent of the component's
      // InputMap, which is the correct behaviour. If it's not, then
      // this can be considered a bug
      return component.getInputMap(cond).getParent();
    else
      return null;
  }

  /**
   * Returns the ActionMap that is provided by the ComponentUI of
   * <code>component</code>.
   *
   * @param component the component for which the ActionMap is returned
   */
  public static ActionMap getUIActionMap(JComponent component)
  {
    if (UIManager.getUI(component) != null)
      // we assume here that the UI class sets the parent of the component's
      // ActionMap, which is the correct behaviour. If it's not, then
      // this can be considered a bug
      return component.getActionMap().getParent();
    else
      return null;
  }
}