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