JMenuScroller [1020525]

/**
 * A class that provides scrolling capabilities to a long menu dropdown or
 * popup menu.  A number of items can optionally be frozen at the top and/or
 * bottom of the menu.
 * <P>
 * <B>Implementation note:</B>  The default number of items to display
 * at a time is 15, and the default scrolling interval is 125 milliseconds.
 * <P>
 *
 * @version 1.5.0 04/05/12
 * @author Darryl
 * https://tips4java.wordpress.com/2009/02/01/menu-scroller/
 */
 
import javax.swing.Icon;

sclass JMenuScroller {

  VF1<JPopupMenu> fillMenu;
  private JPopupMenu menu;
  private Component[] menuItems;
  private MenuScrollItem upItem;
  private MenuScrollItem downItem;
  private final MenuScrollListener menuListener = new MenuScrollListener();
  private int scrollCount;
  private int interval;
  private int topFixedCount;
  private int bottomFixedCount;
  private int firstIndex = 0;
  private int keepVisibleIndex = -1;

  /**
   * Registers a menu to be scrolled with the default number of items to
   * display at a time and the default scrolling interval.
   * 
   * @param menu the menu
   * @return the JMenuScroller
   */
  public static JMenuScroller setScrollerFor(JMenu menu) {
    return new JMenuScroller(menu);
  }

  /**
   * Registers a popup menu to be scrolled with the default number of items to
   * display at a time and the default scrolling interval.
   * 
   * @param menu the popup menu
   * @return the JMenuScroller
   */
  public static JMenuScroller setScrollerFor(JPopupMenu menu) {
    return new JMenuScroller(menu);
  }

  /**
   * Registers a menu to be scrolled with the default number of items to
   * display at a time and the specified scrolling interval.
   * 
   * @param menu the menu
   * @param scrollCount the number of items to display at a time
   * @return the JMenuScroller
   * @throws IllegalArgumentException if scrollCount is 0 or negative
   */
  public static JMenuScroller setScrollerFor(JMenu menu, int scrollCount) {
    return new JMenuScroller(menu, scrollCount);
  }

  /**
   * Registers a popup menu to be scrolled with the default number of items to
   * display at a time and the specified scrolling interval.
   * 
   * @param menu the popup menu
   * @param scrollCount the number of items to display at a time
   * @return the JMenuScroller
   * @throws IllegalArgumentException if scrollCount is 0 or negative
   */
  public static JMenuScroller setScrollerFor(JPopupMenu menu, int scrollCount) {
    return new JMenuScroller(menu, scrollCount);
  }

  /**
   * Registers a menu to be scrolled, with the specified number of items to
   * display at a time and the specified scrolling interval.
   * 
   * @param menu the menu
   * @param scrollCount the number of items to be displayed at a time
   * @param interval the scroll interval, in milliseconds
   * @return the JMenuScroller
   * @throws IllegalArgumentException if scrollCount or interval is 0 or negative
   */
  public static JMenuScroller setScrollerFor(JMenu menu, int scrollCount, int interval) {
    return new JMenuScroller(menu, scrollCount, interval);
  }

  /**
   * Registers a popup menu to be scrolled, with the specified number of items to
   * display at a time and the specified scrolling interval.
   * 
   * @param menu the popup menu
   * @param scrollCount the number of items to be displayed at a time
   * @param interval the scroll interval, in milliseconds
   * @return the JMenuScroller
   * @throws IllegalArgumentException if scrollCount or interval is 0 or negative
   */
  public static JMenuScroller setScrollerFor(JPopupMenu menu, int scrollCount, int interval) {
    return new JMenuScroller(menu, scrollCount, interval);
  }

  /**
   * Registers a menu to be scrolled, with the specified number of items
   * to display in the scrolling region, the specified scrolling interval,
   * and the specified numbers of items fixed at the top and bottom of the
   * menu.
   * 
   * @param menu the menu
   * @param scrollCount the number of items to display in the scrolling portion
   * @param interval the scroll interval, in milliseconds
   * @param topFixedCount the number of items to fix at the top.  May be 0.
   * @param bottomFixedCount the number of items to fix at the bottom. May be 0
   * @throws IllegalArgumentException if scrollCount or interval is 0 or
   * negative or if topFixedCount or bottomFixedCount is negative
   * @return the JMenuScroller
   */
  public static JMenuScroller setScrollerFor(JMenu menu, int scrollCount, int interval,
          int topFixedCount, int bottomFixedCount) {
    return new JMenuScroller(menu, scrollCount, interval,
            topFixedCount, bottomFixedCount);
  }

  /**
   * Registers a popup menu to be scrolled, with the specified number of items
   * to display in the scrolling region, the specified scrolling interval,
   * and the specified numbers of items fixed at the top and bottom of the
   * popup menu.
   * 
   * @param menu the popup menu
   * @param scrollCount the number of items to display in the scrolling portion
   * @param interval the scroll interval, in milliseconds
   * @param topFixedCount the number of items to fix at the top.  May be 0
   * @param bottomFixedCount the number of items to fix at the bottom.  May be 0
   * @throws IllegalArgumentException if scrollCount or interval is 0 or
   * negative or if topFixedCount or bottomFixedCount is negative
   * @return the JMenuScroller
   */
  public static JMenuScroller setScrollerFor(JPopupMenu menu, int scrollCount, int interval,
          int topFixedCount, int bottomFixedCount) {
    return new JMenuScroller(menu, scrollCount, interval,
            topFixedCount, bottomFixedCount);
  }

  /**
   * Constructs a <code>JMenuScroller</code> that scrolls a menu with the
   * default number of items to display at a time, and default scrolling
   * interval.
   * 
   * @param menu the menu
   */
  public JMenuScroller(JMenu menu) {
    this(menu, 15);
  }

  /**
   * Constructs a <code>JMenuScroller</code> that scrolls a popup menu with the
   * default number of items to display at a time, and default scrolling
   * interval.
   * 
   * @param menu the popup menu
   */
  public JMenuScroller(JPopupMenu menu) {
    this(menu, 15);
  }

  /**
   * Constructs a <code>JMenuScroller</code> that scrolls a menu with the
   * specified number of items to display at a time, and default scrolling
   * interval.
   * 
   * @param menu the menu
   * @param scrollCount the number of items to display at a time
   * @throws IllegalArgumentException if scrollCount is 0 or negative
   */
  public JMenuScroller(JMenu menu, int scrollCount) {
    this(menu, scrollCount, 150);
  }

  /**
   * Constructs a <code>JMenuScroller</code> that scrolls a popup menu with the
   * specified number of items to display at a time, and default scrolling
   * interval.
   * 
   * @param menu the popup menu
   * @param scrollCount the number of items to display at a time
   * @throws IllegalArgumentException if scrollCount is 0 or negative
   */
  public JMenuScroller(JPopupMenu menu, int scrollCount) {
    this(menu, scrollCount, 150);
  }

  /**
   * Constructs a <code>JMenuScroller</code> that scrolls a menu with the
   * specified number of items to display at a time, and specified scrolling
   * interval.
   * 
   * @param menu the menu
   * @param scrollCount the number of items to display at a time
   * @param interval the scroll interval, in milliseconds
   * @throws IllegalArgumentException if scrollCount or interval is 0 or negative
   */
  public JMenuScroller(JMenu menu, int scrollCount, int interval) {
    this(menu, scrollCount, interval, 0, 0);
  }

  /**
   * Constructs a <code>JMenuScroller</code> that scrolls a popup menu with the
   * specified number of items to display at a time, and specified scrolling
   * interval.
   * 
   * @param menu the popup menu
   * @param scrollCount the number of items to display at a time
   * @param interval the scroll interval, in milliseconds
   * @throws IllegalArgumentException if scrollCount or interval is 0 or negative
   */
  public JMenuScroller(JPopupMenu menu, int scrollCount, int interval) {
    this(menu, scrollCount, interval, 0, 0);
  }

  /**
   * Constructs a <code>JMenuScroller</code> that scrolls a menu with the
   * specified number of items to display in the scrolling region, the
   * specified scrolling interval, and the specified numbers of items fixed at
   * the top and bottom of the menu.
   * 
   * @param menu the menu
   * @param scrollCount the number of items to display in the scrolling portion
   * @param interval the scroll interval, in milliseconds
   * @param topFixedCount the number of items to fix at the top.  May be 0
   * @param bottomFixedCount the number of items to fix at the bottom.  May be 0
   * @throws IllegalArgumentException if scrollCount or interval is 0 or
   * negative or if topFixedCount or bottomFixedCount is negative
   */
  public JMenuScroller(JMenu menu, int scrollCount, int interval,
          int topFixedCount, int bottomFixedCount) {
    this(menu.getPopupMenu(), scrollCount, interval, topFixedCount, bottomFixedCount);
  }

  /**
   * Constructs a <code>JMenuScroller</code> that scrolls a popup menu with the
   * specified number of items to display in the scrolling region, the
   * specified scrolling interval, and the specified numbers of items fixed at
   * the top and bottom of the popup menu.
   * 
   * @param menu the popup menu
   * @param scrollCount the number of items to display in the scrolling portion
   * @param interval the scroll interval, in milliseconds
   * @param topFixedCount the number of items to fix at the top.  May be 0
   * @param bottomFixedCount the number of items to fix at the bottom.  May be 0
   * @throws IllegalArgumentException if scrollCount or interval is 0 or
   * negative or if topFixedCount or bottomFixedCount is negative
   */
  public JMenuScroller(JPopupMenu menu, int scrollCount, int interval,
          int topFixedCount, int bottomFixedCount) {
    if (scrollCount <= 0 || interval <= 0) {
      throw new IllegalArgumentException("scrollCount and interval must be greater than 0");
    }
    if (topFixedCount < 0 || bottomFixedCount < 0) {
      throw new IllegalArgumentException("topFixedCount and bottomFixedCount cannot be negative");
    }

    upItem = new MenuScrollItem(UP, -1);
    downItem = new MenuScrollItem(DOWN, +1);
    setScrollCount(scrollCount);
    setInterval(interval);
    setTopFixedCount(topFixedCount);
    setBottomFixedCount(bottomFixedCount);

    this.menu = menu;
    menu.addPopupMenuListener(menuListener);
  }

  /**
   * Returns the scroll interval in milliseconds
   * 
   * @return the scroll interval in milliseconds
   */
  public int getInterval() {
    return interval;
  }

  /**
   * Sets the scroll interval in milliseconds
   * 
   * @param interval the scroll interval in milliseconds
   * @throws IllegalArgumentException if interval is 0 or negative
   */
  public void setInterval(int interval) {
    if (interval <= 0) {
      throw new IllegalArgumentException("interval must be greater than 0");
    }
    upItem.setInterval(interval);
    downItem.setInterval(interval);
    this.interval = interval;
  }

  /**
   * Returns the number of items in the scrolling portion of the menu.
   *
   * @return the number of items to display at a time
   */
  public int getscrollCount() {
    return scrollCount;
  }

  /**
   * Sets the number of items in the scrolling portion of the menu.
   * 
   * @param scrollCount the number of items to display at a time
   * @throws IllegalArgumentException if scrollCount is 0 or negative
   */
  public void setScrollCount(int scrollCount) {
    if (scrollCount <= 0) {
      throw new IllegalArgumentException("scrollCount must be greater than 0");
    }
    this.scrollCount = scrollCount;
    // XXX the following line closes all menus then this menu is made.
    // That doesn't seem right.
    // MenuSelectionManager.defaultManager().clearSelectedPath();
  }

  /**
   * Returns the number of items fixed at the top of the menu or popup menu.
   * 
   * @return the number of items
   */
  public int getTopFixedCount() {
    return topFixedCount;
  }

  /**
   * Sets the number of items to fix at the top of the menu or popup menu.
   * 
   * @param topFixedCount the number of items
   */
  public void setTopFixedCount(int topFixedCount) {
    if (firstIndex <= topFixedCount) {
      firstIndex = topFixedCount;
    } else {
      firstIndex += (topFixedCount - this.topFixedCount);
    }
    this.topFixedCount = topFixedCount;
  }

  /**
   * Returns the number of items fixed at the bottom of the menu or popup menu.
   * 
   * @return the number of items
   */
  public int getBottomFixedCount() {
    return bottomFixedCount;
  }

  /**
   * Sets the number of items to fix at the bottom of the menu or popup menu.
   * 
   * @param bottomFixedCount the number of items
   */
  public void setBottomFixedCount(int bottomFixedCount) {
    this.bottomFixedCount = bottomFixedCount;
  }

  /**
   * Scrolls the specified item into view each time the menu is opened.  Call this method with
   * <code>null</code> to restore the default behavior, which is to show the menu as it last
   * appeared.
   *
   * @param item the item to keep visible
   * @see #keepVisible(int)
   */
  public void keepVisible(JMenuItem item) {
    if (item == null) {
      keepVisibleIndex = -1;
    } else {
      int index = menu.getComponentIndex(item);
      keepVisibleIndex = index;
    }
  }

  /**
   * Scrolls the item at the specified index into view each time the menu is opened.  Call this
   * method with <code>-1</code> to restore the default behavior, which is to show the menu as
   * it last appeared.
   *
   * @param index the index of the item to keep visible
   * @see #keepVisible(javax.swing.JMenuItem)
   */
  public void keepVisible(int index) {
    keepVisibleIndex = index;
  }

  /**
   * Removes this JMenuScroller from the associated menu and restores the
   * default behavior of the menu.
   */
  public void dispose() {
    if (menu != null) {
      menu.removePopupMenuListener(menuListener);
      menu = null;
    }
  }

  /**
   * Ensures that the <code>dispose</code> method of this JMenuScroller is
   * called when there are no more refrences to it.
   * 
   * @exception  Throwable if an error occurs.
   * @see JMenuScroller#dispose()
   */
  @Override
  public void finalize() throws Throwable {
    dispose();
  }

  private void refreshMenu() {
    if (menuItems != null && menuItems.length > 0) {
      firstIndex = Math.max(topFixedCount, firstIndex);
      firstIndex = Math.min(menuItems.length - bottomFixedCount - scrollCount, firstIndex);

      upItem.setEnabled(firstIndex > topFixedCount);
      downItem.setEnabled(firstIndex + scrollCount < menuItems.length - bottomFixedCount);

      menu.removeAll();
      for (int i = 0; i < topFixedCount; i++) {
        menu.add(menuItems[i]);
      }
      if (topFixedCount > 0) {
        menu.addSeparator();
      }

      menu.add(upItem);
      for (int i = firstIndex; i < scrollCount + firstIndex; i++) {
        menu.add(menuItems[i]);
      }
      menu.add(downItem);

      if (bottomFixedCount > 0) {
        menu.addSeparator();
      }
      for (int i = menuItems.length - bottomFixedCount; i < menuItems.length; i++) {
        menu.add(menuItems[i]);
      }

      JComponent parent = (JComponent) upItem.getParent();
      parent.revalidate();
      parent.repaint();
    }
  }

  private class MenuScrollListener implements PopupMenuListener {

    @Override
    public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
      if (fillMenu != null) {
        clearPopupMenu(menu);
        callF(fillMenu, menu);
      }
      setMenuItems();
    }

    @Override
    public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
      if (fillMenu != null) clearPopupMenu(menu);
      else restoreMenuItems();
    }

    @Override
    public void popupMenuCanceled(PopupMenuEvent e) {
      if (fillMenu != null) clearPopupMenu(menu);
      else restoreMenuItems();
    }

    private void setMenuItems() {
      menuItems = menu.getComponents();
      if (keepVisibleIndex >= topFixedCount
              && keepVisibleIndex <= menuItems.length - bottomFixedCount
              && (keepVisibleIndex > firstIndex + scrollCount
              || keepVisibleIndex < firstIndex)) {
        firstIndex = Math.min(firstIndex, keepVisibleIndex);
        firstIndex = Math.max(firstIndex, keepVisibleIndex - scrollCount + 1);
      }
      if (menuItems.length > topFixedCount + scrollCount + bottomFixedCount) {
        refreshMenu();
      }
    }

    private void restoreMenuItems() {
      menu.removeAll();
      for (Component component : menuItems) {
        menu.add(component);
      }
    }
  }

  private class MenuScrollTimer extends javax.swing.Timer {

    public MenuScrollTimer(final int increment, int interval) {
      super(interval, new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {
          firstIndex += increment;
          refreshMenu();
        }
      });
    }
  }

  private class MenuScrollItem extends JMenuItem
          implements ChangeListener {

    private MenuScrollTimer timer;

    public MenuScrollItem(MenuIcon icon, int increment) {
      setIcon(icon);
      setDisabledIcon(icon);
      timer = new MenuScrollTimer(increment, interval);
      addChangeListener(this);
    }

    public void setInterval(int interval) {
      timer.setDelay(interval);
    }

    @Override
    public void stateChanged(ChangeEvent e) {
      if (isArmed() && !timer.isRunning()) {
        timer.start();
      }
      if (!isArmed() && timer.isRunning()) {
        timer.stop();
      }
    }
  }

  static MenuIcon UP = new MenuIcon(9, 1, 9);
  static MenuIcon DOWN = new MenuIcon(1, 9, 1);
    
  private sclass MenuIcon implements Icon {

    final int[] xPoints = {1, 5, 9};
    final int[] yPoints;

    MenuIcon(int... yPoints) {
      this.yPoints = yPoints;
    }

    @Override
    public void paintIcon(Component c, Graphics g, int x, int y) {
      Dimension size = c.getSize();
      Graphics g2 = g.create(size.width / 2 - 5, size.height / 2 - 5, 10, 10);
      g2.setColor(Color.GRAY);
      g2.drawPolygon(xPoints, yPoints, 3);
      if (c.isEnabled()) {
        g2.setColor(Color.BLACK);
        g2.fillPolygon(xPoints, yPoints, 3);
      }
      g2.dispose();
    }

    @Override
    public int getIconWidth() {
      return 0;
    }

    @Override
    public int getIconHeight() {
      return 10;
    }
  }
}

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Snippet ID:	#1020525
Snippet name:	JMenuScroller
Eternal ID of this version:	#1020525/9
Text MD5:	2ae482fbf35b849ee1f830d931eb7589
Transpilation MD5:	205532f784b2fce572766eba16759037
Author:	stefan
Category:	javax / gui
Type:	JavaX fragment (include)
Public (visible to everyone):	Yes
Archived (hidden from active list):	No
Created/modified:	2022-01-19 15:50:38
Source code size:	19267 bytes / 577 lines
Pitched / IR pitched:	No / No
Views / Downloads:	266 / 959
Version history:	8 change(s)
Referenced in:	[show references]

< > BotCompany Repo | #1020525 // JMenuScroller

JavaX fragment (include) [tags: use-pretranspiled]

1	/**
2	* A class that provides scrolling capabilities to a long menu dropdown or
3	* popup menu. A number of items can optionally be frozen at the top and/or
4	* bottom of the menu.
5	* <P>
6	* <B>Implementation note:</B> The default number of items to display
7	* at a time is 15, and the default scrolling interval is 125 milliseconds.
8	* <P>
9	*
10	* @version 1.5.0 04/05/12
11	* @author Darryl
12	* https://tips4java.wordpress.com/2009/02/01/menu-scroller/
13	*/
14
15	import javax.swing.Icon;
16
17	sclass JMenuScroller {
18
19	VF1<JPopupMenu> fillMenu;
20	private JPopupMenu menu;
21	private Component[] menuItems;
22	private MenuScrollItem upItem;
23	private MenuScrollItem downItem;
24	private final MenuScrollListener menuListener = new MenuScrollListener();
25	private int scrollCount;
26	private int interval;
27	private int topFixedCount;
28	private int bottomFixedCount;
29	private int firstIndex = 0;
30	private int keepVisibleIndex = -1;
31
32	/**
33	* Registers a menu to be scrolled with the default number of items to
34	* display at a time and the default scrolling interval.
35	*
36	* @param menu the menu
37	* @return the JMenuScroller
38	*/
39	public static JMenuScroller setScrollerFor(JMenu menu) {
40	return new JMenuScroller(menu);
41	}
42
43	/**
44	* Registers a popup menu to be scrolled with the default number of items to
45	* display at a time and the default scrolling interval.
46	*
47	* @param menu the popup menu
48	* @return the JMenuScroller
49	*/
50	public static JMenuScroller setScrollerFor(JPopupMenu menu) {
51	return new JMenuScroller(menu);
52	}
53
54	/**
55	* Registers a menu to be scrolled with the default number of items to
56	* display at a time and the specified scrolling interval.
57	*
58	* @param menu the menu
59	* @param scrollCount the number of items to display at a time
60	* @return the JMenuScroller
61	* @throws IllegalArgumentException if scrollCount is 0 or negative
62	*/
63	public static JMenuScroller setScrollerFor(JMenu menu, int scrollCount) {
64	return new JMenuScroller(menu, scrollCount);
65	}
66
67	/**
68	* Registers a popup menu to be scrolled with the default number of items to
69	* display at a time and the specified scrolling interval.
70	*
71	* @param menu the popup menu
72	* @param scrollCount the number of items to display at a time
73	* @return the JMenuScroller
74	* @throws IllegalArgumentException if scrollCount is 0 or negative
75	*/
76	public static JMenuScroller setScrollerFor(JPopupMenu menu, int scrollCount) {
77	return new JMenuScroller(menu, scrollCount);
78	}
79
80	/**
81	* Registers a menu to be scrolled, with the specified number of items to
82	* display at a time and the specified scrolling interval.
83	*
84	* @param menu the menu
85	* @param scrollCount the number of items to be displayed at a time
86	* @param interval the scroll interval, in milliseconds
87	* @return the JMenuScroller
88	* @throws IllegalArgumentException if scrollCount or interval is 0 or negative
89	*/
90	public static JMenuScroller setScrollerFor(JMenu menu, int scrollCount, int interval) {
91	return new JMenuScroller(menu, scrollCount, interval);
92	}
93
94	/**
95	* Registers a popup menu to be scrolled, with the specified number of items to
96	* display at a time and the specified scrolling interval.
97	*
98	* @param menu the popup menu
99	* @param scrollCount the number of items to be displayed at a time
100	* @param interval the scroll interval, in milliseconds
101	* @return the JMenuScroller
102	* @throws IllegalArgumentException if scrollCount or interval is 0 or negative
103	*/
104	public static JMenuScroller setScrollerFor(JPopupMenu menu, int scrollCount, int interval) {
105	return new JMenuScroller(menu, scrollCount, interval);
106	}
107
108	/**
109	* Registers a menu to be scrolled, with the specified number of items
110	* to display in the scrolling region, the specified scrolling interval,
111	* and the specified numbers of items fixed at the top and bottom of the
112	* menu.
113	*
114	* @param menu the menu
115	* @param scrollCount the number of items to display in the scrolling portion
116	* @param interval the scroll interval, in milliseconds
117	* @param topFixedCount the number of items to fix at the top. May be 0.
118	* @param bottomFixedCount the number of items to fix at the bottom. May be 0
119	* @throws IllegalArgumentException if scrollCount or interval is 0 or
120	* negative or if topFixedCount or bottomFixedCount is negative
121	* @return the JMenuScroller
122	*/
123	public static JMenuScroller setScrollerFor(JMenu menu, int scrollCount, int interval,
124	int topFixedCount, int bottomFixedCount) {
125	return new JMenuScroller(menu, scrollCount, interval,
126	topFixedCount, bottomFixedCount);
127	}
128
129	/**
130	* Registers a popup menu to be scrolled, with the specified number of items
131	* to display in the scrolling region, the specified scrolling interval,
132	* and the specified numbers of items fixed at the top and bottom of the
133	* popup menu.
134	*
135	* @param menu the popup menu
136	* @param scrollCount the number of items to display in the scrolling portion
137	* @param interval the scroll interval, in milliseconds
138	* @param topFixedCount the number of items to fix at the top. May be 0
139	* @param bottomFixedCount the number of items to fix at the bottom. May be 0
140	* @throws IllegalArgumentException if scrollCount or interval is 0 or
141	* negative or if topFixedCount or bottomFixedCount is negative
142	* @return the JMenuScroller
143	*/
144	public static JMenuScroller setScrollerFor(JPopupMenu menu, int scrollCount, int interval,
145	int topFixedCount, int bottomFixedCount) {
146	return new JMenuScroller(menu, scrollCount, interval,
147	topFixedCount, bottomFixedCount);
148	}
149
150	/**
151	* Constructs a <code>JMenuScroller</code> that scrolls a menu with the
152	* default number of items to display at a time, and default scrolling
153	* interval.
154	*
155	* @param menu the menu
156	*/
157	public JMenuScroller(JMenu menu) {
158	this(menu, 15);
159	}
160
161	/**
162	* Constructs a <code>JMenuScroller</code> that scrolls a popup menu with the
163	* default number of items to display at a time, and default scrolling
164	* interval.
165	*
166	* @param menu the popup menu
167	*/
168	public JMenuScroller(JPopupMenu menu) {
169	this(menu, 15);
170	}
171
172	/**
173	* Constructs a <code>JMenuScroller</code> that scrolls a menu with the
174	* specified number of items to display at a time, and default scrolling
175	* interval.
176	*
177	* @param menu the menu
178	* @param scrollCount the number of items to display at a time
179	* @throws IllegalArgumentException if scrollCount is 0 or negative
180	*/
181	public JMenuScroller(JMenu menu, int scrollCount) {
182	this(menu, scrollCount, 150);
183	}
184
185	/**
186	* Constructs a <code>JMenuScroller</code> that scrolls a popup menu with the
187	* specified number of items to display at a time, and default scrolling
188	* interval.
189	*
190	* @param menu the popup menu
191	* @param scrollCount the number of items to display at a time
192	* @throws IllegalArgumentException if scrollCount is 0 or negative
193	*/
194	public JMenuScroller(JPopupMenu menu, int scrollCount) {
195	this(menu, scrollCount, 150);
196	}
197
198	/**
199	* Constructs a <code>JMenuScroller</code> that scrolls a menu with the
200	* specified number of items to display at a time, and specified scrolling
201	* interval.
202	*
203	* @param menu the menu
204	* @param scrollCount the number of items to display at a time
205	* @param interval the scroll interval, in milliseconds
206	* @throws IllegalArgumentException if scrollCount or interval is 0 or negative
207	*/
208	public JMenuScroller(JMenu menu, int scrollCount, int interval) {
209	this(menu, scrollCount, interval, 0, 0);
210	}
211
212	/**
213	* Constructs a <code>JMenuScroller</code> that scrolls a popup menu with the
214	* specified number of items to display at a time, and specified scrolling
215	* interval.
216	*
217	* @param menu the popup menu
218	* @param scrollCount the number of items to display at a time
219	* @param interval the scroll interval, in milliseconds
220	* @throws IllegalArgumentException if scrollCount or interval is 0 or negative
221	*/
222	public JMenuScroller(JPopupMenu menu, int scrollCount, int interval) {
223	this(menu, scrollCount, interval, 0, 0);
224	}
225
226	/**
227	* Constructs a <code>JMenuScroller</code> that scrolls a menu with the
228	* specified number of items to display in the scrolling region, the
229	* specified scrolling interval, and the specified numbers of items fixed at
230	* the top and bottom of the menu.
231	*
232	* @param menu the menu
233	* @param scrollCount the number of items to display in the scrolling portion
234	* @param interval the scroll interval, in milliseconds
235	* @param topFixedCount the number of items to fix at the top. May be 0
236	* @param bottomFixedCount the number of items to fix at the bottom. May be 0
237	* @throws IllegalArgumentException if scrollCount or interval is 0 or
238	* negative or if topFixedCount or bottomFixedCount is negative
239	*/
240	public JMenuScroller(JMenu menu, int scrollCount, int interval,
241	int topFixedCount, int bottomFixedCount) {
242	this(menu.getPopupMenu(), scrollCount, interval, topFixedCount, bottomFixedCount);
243	}
244
245	/**
246	* Constructs a <code>JMenuScroller</code> that scrolls a popup menu with the
247	* specified number of items to display in the scrolling region, the
248	* specified scrolling interval, and the specified numbers of items fixed at
249	* the top and bottom of the popup menu.
250	*
251	* @param menu the popup menu
252	* @param scrollCount the number of items to display in the scrolling portion
253	* @param interval the scroll interval, in milliseconds
254	* @param topFixedCount the number of items to fix at the top. May be 0
255	* @param bottomFixedCount the number of items to fix at the bottom. May be 0
256	* @throws IllegalArgumentException if scrollCount or interval is 0 or
257	* negative or if topFixedCount or bottomFixedCount is negative
258	*/
259	public JMenuScroller(JPopupMenu menu, int scrollCount, int interval,
260	int topFixedCount, int bottomFixedCount) {
261	if (scrollCount <= 0 \|\| interval <= 0) {
262	throw new IllegalArgumentException("scrollCount and interval must be greater than 0");
263	}
264	if (topFixedCount < 0 \|\| bottomFixedCount < 0) {
265	throw new IllegalArgumentException("topFixedCount and bottomFixedCount cannot be negative");
266	}
267
268	upItem = new MenuScrollItem(UP, -1);
269	downItem = new MenuScrollItem(DOWN, +1);
270	setScrollCount(scrollCount);
271	setInterval(interval);
272	setTopFixedCount(topFixedCount);
273	setBottomFixedCount(bottomFixedCount);
274
275	this.menu = menu;
276	menu.addPopupMenuListener(menuListener);
277	}
278
279	/**
280	* Returns the scroll interval in milliseconds
281	*
282	* @return the scroll interval in milliseconds
283	*/
284	public int getInterval() {
285	return interval;
286	}
287
288	/**
289	* Sets the scroll interval in milliseconds
290	*
291	* @param interval the scroll interval in milliseconds
292	* @throws IllegalArgumentException if interval is 0 or negative
293	*/
294	public void setInterval(int interval) {
295	if (interval <= 0) {
296	throw new IllegalArgumentException("interval must be greater than 0");
297	}
298	upItem.setInterval(interval);
299	downItem.setInterval(interval);
300	this.interval = interval;
301	}
302
303	/**
304	* Returns the number of items in the scrolling portion of the menu.
305	*
306	* @return the number of items to display at a time
307	*/
308	public int getscrollCount() {
309	return scrollCount;
310	}
311
312	/**
313	* Sets the number of items in the scrolling portion of the menu.
314	*
315	* @param scrollCount the number of items to display at a time
316	* @throws IllegalArgumentException if scrollCount is 0 or negative
317	*/
318	public void setScrollCount(int scrollCount) {
319	if (scrollCount <= 0) {
320	throw new IllegalArgumentException("scrollCount must be greater than 0");
321	}
322	this.scrollCount = scrollCount;
323	// XXX the following line closes all menus then this menu is made.
324	// That doesn't seem right.
325	// MenuSelectionManager.defaultManager().clearSelectedPath();
326	}
327
328	/**
329	* Returns the number of items fixed at the top of the menu or popup menu.
330	*
331	* @return the number of items
332	*/
333	public int getTopFixedCount() {
334	return topFixedCount;
335	}
336
337	/**
338	* Sets the number of items to fix at the top of the menu or popup menu.
339	*
340	* @param topFixedCount the number of items
341	*/
342	public void setTopFixedCount(int topFixedCount) {
343	if (firstIndex <= topFixedCount) {
344	firstIndex = topFixedCount;
345	} else {
346	firstIndex += (topFixedCount - this.topFixedCount);
347	}
348	this.topFixedCount = topFixedCount;
349	}
350
351	/**
352	* Returns the number of items fixed at the bottom of the menu or popup menu.
353	*
354	* @return the number of items
355	*/
356	public int getBottomFixedCount() {
357	return bottomFixedCount;
358	}
359
360	/**
361	* Sets the number of items to fix at the bottom of the menu or popup menu.
362	*
363	* @param bottomFixedCount the number of items
364	*/
365	public void setBottomFixedCount(int bottomFixedCount) {
366	this.bottomFixedCount = bottomFixedCount;
367	}
368
369	/**
370	* Scrolls the specified item into view each time the menu is opened. Call this method with
371	* <code>null</code> to restore the default behavior, which is to show the menu as it last
372	* appeared.
373	*
374	* @param item the item to keep visible
375	* @see #keepVisible(int)
376	*/
377	public void keepVisible(JMenuItem item) {
378	if (item == null) {
379	keepVisibleIndex = -1;
380	} else {
381	int index = menu.getComponentIndex(item);
382	keepVisibleIndex = index;
383	}
384	}
385
386	/**
387	* Scrolls the item at the specified index into view each time the menu is opened. Call this
388	* method with <code>-1</code> to restore the default behavior, which is to show the menu as
389	* it last appeared.
390	*
391	* @param index the index of the item to keep visible
392	* @see #keepVisible(javax.swing.JMenuItem)
393	*/
394	public void keepVisible(int index) {
395	keepVisibleIndex = index;
396	}
397
398	/**
399	* Removes this JMenuScroller from the associated menu and restores the
400	* default behavior of the menu.
401	*/
402	public void dispose() {
403	if (menu != null) {
404	menu.removePopupMenuListener(menuListener);
405	menu = null;
406	}
407	}
408
409	/**
410	* Ensures that the <code>dispose</code> method of this JMenuScroller is
411	* called when there are no more refrences to it.
412	*
413	* @exception Throwable if an error occurs.
414	* @see JMenuScroller#dispose()
415	*/
416	@Override
417	public void finalize() throws Throwable {
418	dispose();
419	}
420
421	private void refreshMenu() {
422	if (menuItems != null && menuItems.length > 0) {
423	firstIndex = Math.max(topFixedCount, firstIndex);
424	firstIndex = Math.min(menuItems.length - bottomFixedCount - scrollCount, firstIndex);
425
426	upItem.setEnabled(firstIndex > topFixedCount);
427	downItem.setEnabled(firstIndex + scrollCount < menuItems.length - bottomFixedCount);
428
429	menu.removeAll();
430	for (int i = 0; i < topFixedCount; i++) {
431	menu.add(menuItems[i]);
432	}
433	if (topFixedCount > 0) {
434	menu.addSeparator();
435	}
436
437	menu.add(upItem);
438	for (int i = firstIndex; i < scrollCount + firstIndex; i++) {
439	menu.add(menuItems[i]);
440	}
441	menu.add(downItem);
442
443	if (bottomFixedCount > 0) {
444	menu.addSeparator();
445	}
446	for (int i = menuItems.length - bottomFixedCount; i < menuItems.length; i++) {
447	menu.add(menuItems[i]);
448	}
449
450	JComponent parent = (JComponent) upItem.getParent();
451	parent.revalidate();
452	parent.repaint();
453	}
454	}
455
456	private class MenuScrollListener implements PopupMenuListener {
457
458	@Override
459	public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
460	if (fillMenu != null) {
461	clearPopupMenu(menu);
462	callF(fillMenu, menu);
463	}
464	setMenuItems();
465	}
466
467	@Override
468	public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
469	if (fillMenu != null) clearPopupMenu(menu);
470	else restoreMenuItems();
471	}
472
473	@Override
474	public void popupMenuCanceled(PopupMenuEvent e) {
475	if (fillMenu != null) clearPopupMenu(menu);
476	else restoreMenuItems();
477	}
478
479	private void setMenuItems() {
480	menuItems = menu.getComponents();
481	if (keepVisibleIndex >= topFixedCount
482	&& keepVisibleIndex <= menuItems.length - bottomFixedCount
483	&& (keepVisibleIndex > firstIndex + scrollCount
484	\|\| keepVisibleIndex < firstIndex)) {
485	firstIndex = Math.min(firstIndex, keepVisibleIndex);
486	firstIndex = Math.max(firstIndex, keepVisibleIndex - scrollCount + 1);
487	}
488	if (menuItems.length > topFixedCount + scrollCount + bottomFixedCount) {
489	refreshMenu();
490	}
491	}
492
493	private void restoreMenuItems() {
494	menu.removeAll();
495	for (Component component : menuItems) {
496	menu.add(component);
497	}
498	}
499	}
500
501	private class MenuScrollTimer extends javax.swing.Timer {
502
503	public MenuScrollTimer(final int increment, int interval) {
504	super(interval, new ActionListener() {
505
506	@Override
507	public void actionPerformed(ActionEvent e) {
508	firstIndex += increment;
509	refreshMenu();
510	}
511	});
512	}
513	}
514
515	private class MenuScrollItem extends JMenuItem
516	implements ChangeListener {
517
518	private MenuScrollTimer timer;
519
520	public MenuScrollItem(MenuIcon icon, int increment) {
521	setIcon(icon);
522	setDisabledIcon(icon);
523	timer = new MenuScrollTimer(increment, interval);
524	addChangeListener(this);
525	}
526
527	public void setInterval(int interval) {
528	timer.setDelay(interval);
529	}
530
531	@Override
532	public void stateChanged(ChangeEvent e) {
533	if (isArmed() && !timer.isRunning()) {
534	timer.start();
535	}
536	if (!isArmed() && timer.isRunning()) {
537	timer.stop();
538	}
539	}
540	}
541
542	static MenuIcon UP = new MenuIcon(9, 1, 9);
543	static MenuIcon DOWN = new MenuIcon(1, 9, 1);
544
545	private sclass MenuIcon implements Icon {
546
547	final int[] xPoints = {1, 5, 9};
548	final int[] yPoints;
549
550	MenuIcon(int... yPoints) {
551	this.yPoints = yPoints;
552	}
553
554	@Override
555	public void paintIcon(Component c, Graphics g, int x, int y) {
556	Dimension size = c.getSize();
557	Graphics g2 = g.create(size.width / 2 - 5, size.height / 2 - 5, 10, 10);
558	g2.setColor(Color.GRAY);
559	g2.drawPolygon(xPoints, yPoints, 3);
560	if (c.isEnabled()) {
561	g2.setColor(Color.BLACK);
562	g2.fillPolygon(xPoints, yPoints, 3);
563	}
564	g2.dispose();
565	}
566
567	@Override
568	public int getIconWidth() {
569	return 0;
570	}
571
572	@Override
573	public int getIconHeight() {
574	return 10;
575	}
576	}
577	}