J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2005 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | package javax.swing; |
| 26 | |
| 27 | import java.awt.Container; |
| 28 | import javax.swing.plaf.ComponentUI; |
| 29 | import sun.awt.AppContext; |
| 30 | |
| 31 | /** |
| 32 | * <code>LayoutStyle</code> provides information about how to position |
| 33 | * components. This class is primarily useful for visual tools and |
| 34 | * layout managers. Most developers will not need to use this class. |
| 35 | * <p> |
| 36 | * You typically don't set or create a |
| 37 | * <code>LayoutStyle</code>. Instead use the static method |
| 38 | * <code>getInstance</code> to obtain the current instance. |
| 39 | * |
| 40 | * @since 1.6 |
| 41 | */ |
| 42 | public abstract class LayoutStyle { |
| 43 | /** |
| 44 | * Sets the shared instance of <code>LayoutStyle</code>. Specifying |
| 45 | * <code>null</code> results in using the <code>LayoutStyle</code> from |
| 46 | * the current <code>LookAndFeel</code>. |
| 47 | * |
| 48 | * @param style the <code>LayoutStyle</code>, or <code>null</code> |
| 49 | * @see #getInstance |
| 50 | */ |
| 51 | public static void setInstance(LayoutStyle style) { |
| 52 | synchronized(LayoutStyle.class) { |
| 53 | if (style == null) { |
| 54 | AppContext.getAppContext().remove(LayoutStyle.class); |
| 55 | } |
| 56 | else { |
| 57 | AppContext.getAppContext().put(LayoutStyle.class, style); |
| 58 | } |
| 59 | } |
| 60 | } |
| 61 | |
| 62 | /** |
| 63 | * Returns the shared instance of <code>LayoutStyle</code>. If an instance |
| 64 | * has not been specified in <code>setInstance</code>, this will return |
| 65 | * the <code>LayoutStyle</code> from the current <code>LookAndFeel</code>. |
| 66 | * |
| 67 | * @see LookAndFeel#getLayoutStyle |
| 68 | * @return the shared instance of <code>LayoutStyle</code> |
| 69 | */ |
| 70 | public static LayoutStyle getInstance() { |
| 71 | LayoutStyle style; |
| 72 | synchronized(LayoutStyle.class) { |
| 73 | style = (LayoutStyle)AppContext.getAppContext(). |
| 74 | get(LayoutStyle.class); |
| 75 | } |
| 76 | if (style == null) { |
| 77 | return UIManager.getLookAndFeel().getLayoutStyle(); |
| 78 | } |
| 79 | return style; |
| 80 | } |
| 81 | |
| 82 | |
| 83 | /** |
| 84 | * <code>ComponentPlacement</code> is an enumeration of the |
| 85 | * possible ways two components can be placed relative to each |
| 86 | * other. <code>ComponentPlacement</code> is used by the |
| 87 | * <code>LayoutStyle</code> method <code>getPreferredGap</code>. Refer to |
| 88 | * <code>LayoutStyle</code> for more information. |
| 89 | * |
| 90 | * @see LayoutStyle#getPreferredGap(JComponent,JComponent, |
| 91 | * ComponentPlacement,int,Container) |
| 92 | * @since 1.6 |
| 93 | */ |
| 94 | public enum ComponentPlacement { |
| 95 | /** |
| 96 | * Enumeration value indicating the two components are |
| 97 | * visually related and will be placed in the same parent. |
| 98 | * For example, a <code>JLabel</code> providing a label for a |
| 99 | * <code>JTextField</code> is typically visually associated |
| 100 | * with the <code>JTextField</code>; the constant <code>RELATED</code> |
| 101 | * is used for this. |
| 102 | */ |
| 103 | RELATED, |
| 104 | |
| 105 | /** |
| 106 | * Enumeration value indicating the two components are |
| 107 | * visually unrelated and will be placed in the same parent. |
| 108 | * For example, groupings of components are usually visually |
| 109 | * separated; the constant <code>UNRELATED</code> is used for this. |
| 110 | */ |
| 111 | UNRELATED, |
| 112 | |
| 113 | /** |
| 114 | * Enumeration value indicating the distance to indent a component |
| 115 | * is being requested. For example, often times the children of |
| 116 | * a label will be horizontally indented from the label. To determine |
| 117 | * the preferred distance for such a gap use the |
| 118 | * <code>INDENT</code> type. |
| 119 | * <p> |
| 120 | * This value is typically only useful with a direction of |
| 121 | * <code>EAST</code> or <code>WEST</code>. |
| 122 | */ |
| 123 | INDENT; |
| 124 | } |
| 125 | |
| 126 | |
| 127 | /** |
| 128 | * Creates a new <code>LayoutStyle</code>. You generally don't |
| 129 | * create a <code>LayoutStyle</code>. Instead use the method |
| 130 | * <code>getInstance</code> to obtain the current |
| 131 | * <code>LayoutStyle</code>. |
| 132 | */ |
| 133 | public LayoutStyle() { |
| 134 | } |
| 135 | |
| 136 | /** |
| 137 | * Returns the amount of space to use between two components. |
| 138 | * The return value indicates the distance to place |
| 139 | * <code>component2</code> relative to <code>component1</code>. |
| 140 | * For example, the following returns the amount of space to place |
| 141 | * between <code>component2</code> and <code>component1</code> |
| 142 | * when <code>component2</code> is placed vertically above |
| 143 | * <code>component1</code>: |
| 144 | * <pre> |
| 145 | * int gap = getPreferredGap(component1, component2, |
| 146 | * ComponentPlacement.RELATED, |
| 147 | * SwingConstants.NORTH, parent); |
| 148 | * </pre> |
| 149 | * The <code>type</code> parameter indicates the relation between |
| 150 | * the two components. If the two components will be contained in |
| 151 | * the same parent and are showing similar logically related |
| 152 | * items, use <code>RELATED</code>. If the two components will be |
| 153 | * contained in the same parent but show logically unrelated items |
| 154 | * use <code>UNRELATED</code>. Some look and feels may not |
| 155 | * distinguish between the <code>RELATED</code> and |
| 156 | * <code>UNRELATED</code> types. |
| 157 | * <p> |
| 158 | * The return value is not intended to take into account the |
| 159 | * current size and position of <code>component2</code> or |
| 160 | * <code>component1</code>. The return value may take into |
| 161 | * consideration various properties of the components. For |
| 162 | * example, the space may vary based on font size, or the preferred |
| 163 | * size of the component. |
| 164 | * |
| 165 | * @param component1 the <code>JComponent</code> |
| 166 | * <code>component2</code> is being placed relative to |
| 167 | * @param component2 the <code>JComponent</code> being placed |
| 168 | * @param position the position <code>component2</code> is being placed |
| 169 | * relative to <code>component1</code>; one of |
| 170 | * <code>SwingConstants.NORTH</code>, |
| 171 | * <code>SwingConstants.SOUTH</code>, |
| 172 | * <code>SwingConstants.EAST</code> or |
| 173 | * <code>SwingConstants.WEST</code> |
| 174 | * @param type how the two components are being placed |
| 175 | * @param parent the parent of <code>component2</code>; this may differ |
| 176 | * from the actual parent and it may be <code>null</code> |
| 177 | * @return the amount of space to place between the two components |
| 178 | * @throws NullPointerException if <code>component1</code>, |
| 179 | * <code>component2</code> or <code>type</code> is |
| 180 | * <code>null</code> |
| 181 | * @throws IllegalArgumentException if <code>position</code> is not |
| 182 | * one of <code>SwingConstants.NORTH</code>, |
| 183 | * <code>SwingConstants.SOUTH</code>, |
| 184 | * <code>SwingConstants.EAST</code> or |
| 185 | * <code>SwingConstants.WEST</code> |
| 186 | * @see LookAndFeel#getLayoutStyle |
| 187 | * @since 1.6 |
| 188 | */ |
| 189 | public abstract int getPreferredGap(JComponent component1, |
| 190 | JComponent component2, |
| 191 | ComponentPlacement type, int position, |
| 192 | Container parent); |
| 193 | |
| 194 | /** |
| 195 | * Returns the amount of space to place between the component and specified |
| 196 | * edge of its parent. |
| 197 | * |
| 198 | * @param component the <code>JComponent</code> being positioned |
| 199 | * @param position the position <code>component</code> is being placed |
| 200 | * relative to its parent; one of |
| 201 | * <code>SwingConstants.NORTH</code>, |
| 202 | * <code>SwingConstants.SOUTH</code>, |
| 203 | * <code>SwingConstants.EAST</code> or |
| 204 | * <code>SwingConstants.WEST</code> |
| 205 | * @param parent the parent of <code>component</code>; this may differ |
| 206 | * from the actual parent and may be <code>null</code> |
| 207 | * @return the amount of space to place between the component and specified |
| 208 | * edge |
| 209 | * @throws IllegalArgumentException if <code>position</code> is not |
| 210 | * one of <code>SwingConstants.NORTH</code>, |
| 211 | * <code>SwingConstants.SOUTH</code>, |
| 212 | * <code>SwingConstants.EAST</code> or |
| 213 | * <code>SwingConstants.WEST</code> |
| 214 | */ |
| 215 | public abstract int getContainerGap(JComponent component, int position, |
| 216 | Container parent); |
| 217 | } |