1/*
2 * Copyright (c) 1998, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package javax.swing.plaf.basic;
27
28import javax.swing.*;
29import javax.swing.plaf.UIResource;
30
31import java.awt.Container;
32import java.awt.Dimension;
33
34/**
35 * The default layout manager for Popup menus and menubars.  This
36 * class is an extension of BoxLayout which adds the UIResource tag
37 * so that pluggable L&Fs can distinguish it from user-installed
38 * layout managers on menus.
39 *
40 * @author Georges Saab
41 */
42@SuppressWarnings("serial") // Superclass is not serializable across versions
43public class DefaultMenuLayout extends BoxLayout implements UIResource {
44
45    /**
46     * Constructs a new instance of {@code DefaultMenuLayout}.
47     *
48     * @param target the container that needs to be laid out
49     * @param axis the axis to lay out components along. Can be one of:
50     *              {@code BoxLayout.X_AXIS},
51     *              {@code BoxLayout.Y_AXIS},
52     *              {@code BoxLayout.LINE_AXIS} or
53     *              {@code BoxLayout.PAGE_AXIS}
54     */
55    public DefaultMenuLayout(Container target, int axis) {
56        super(target, axis);
57    }
58
59    public Dimension preferredLayoutSize(Container target) {
60        if (target instanceof JPopupMenu) {
61            JPopupMenu popupMenu = (JPopupMenu) target;
62            sun.swing.MenuItemLayoutHelper.clearUsedClientProperties(popupMenu);
63            if (popupMenu.getComponentCount() == 0) {
64                return new Dimension(0, 0);
65            }
66        }
67
68        // Make BoxLayout recalculate cached preferred sizes
69        super.invalidateLayout(target);
70
71        return super.preferredLayoutSize(target);
72    }
73}
74