J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1997-2005 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 | |
| 26 | package javax.swing.plaf; |
| 27 | |
| 28 | import javax.swing.JComponent; |
| 29 | import javax.swing.SwingUtilities; |
| 30 | import javax.accessibility.Accessible; |
| 31 | |
| 32 | import java.awt.Component; |
| 33 | import java.awt.Container; |
| 34 | import java.awt.Dimension; |
| 35 | import java.awt.Graphics; |
| 36 | import java.awt.Insets; |
| 37 | |
| 38 | |
| 39 | /** |
| 40 | * The base class for all UI delegate objects in the Swing pluggable |
| 41 | * look and feel architecture. The UI delegate object for a Swing |
| 42 | * component is responsible for implementing the aspects of the |
| 43 | * component that depend on the look and feel. |
| 44 | * The <code>JComponent</code> class |
| 45 | * invokes methods from this class in order to delegate operations |
| 46 | * (painting, layout calculations, etc.) that may vary depending on the |
| 47 | * look and feel installed. <b>Client programs should not invoke methods |
| 48 | * on this class directly.</b> |
| 49 | * |
| 50 | * @see javax.swing.JComponent |
| 51 | * @see javax.swing.UIManager |
| 52 | * |
| 53 | */ |
| 54 | public abstract class ComponentUI { |
| 55 | /** |
| 56 | * Sole constructor. (For invocation by subclass constructors, |
| 57 | * typically implicit.) |
| 58 | */ |
| 59 | public ComponentUI() { |
| 60 | } |
| 61 | |
| 62 | /** |
| 63 | * Configures the specified component appropriate for the look and feel. |
| 64 | * This method is invoked when the <code>ComponentUI</code> instance is being installed |
| 65 | * as the UI delegate on the specified component. This method should |
| 66 | * completely configure the component for the look and feel, |
| 67 | * including the following: |
| 68 | * <ol> |
| 69 | * <li>Install any default property values for color, fonts, borders, |
| 70 | * icons, opacity, etc. on the component. Whenever possible, |
| 71 | * property values initialized by the client program should <i>not</i> |
| 72 | * be overridden. |
| 73 | * <li>Install a <code>LayoutManager</code> on the component if necessary. |
| 74 | * <li>Create/add any required sub-components to the component. |
| 75 | * <li>Create/install event listeners on the component. |
| 76 | * <li>Create/install a <code>PropertyChangeListener</code> on the component in order |
| 77 | * to detect and respond to component property changes appropriately. |
| 78 | * <li>Install keyboard UI (mnemonics, traversal, etc.) on the component. |
| 79 | * <li>Initialize any appropriate instance data. |
| 80 | * </ol> |
| 81 | * @param c the component where this UI delegate is being installed |
| 82 | * |
| 83 | * @see #uninstallUI |
| 84 | * @see javax.swing.JComponent#setUI |
| 85 | * @see javax.swing.JComponent#updateUI |
| 86 | */ |
| 87 | public void installUI(JComponent c) { |
| 88 | } |
| 89 | |
| 90 | /** |
| 91 | * Reverses configuration which was done on the specified component during |
| 92 | * <code>installUI</code>. This method is invoked when this |
| 93 | * <code>UIComponent</code> instance is being removed as the UI delegate |
| 94 | * for the specified component. This method should undo the |
| 95 | * configuration performed in <code>installUI</code>, being careful to |
| 96 | * leave the <code>JComponent</code> instance in a clean state (no |
| 97 | * extraneous listeners, look-and-feel-specific property objects, etc.). |
| 98 | * This should include the following: |
| 99 | * <ol> |
| 100 | * <li>Remove any UI-set borders from the component. |
| 101 | * <li>Remove any UI-set layout managers on the component. |
| 102 | * <li>Remove any UI-added sub-components from the component. |
| 103 | * <li>Remove any UI-added event/property listeners from the component. |
| 104 | * <li>Remove any UI-installed keyboard UI from the component. |
| 105 | * <li>Nullify any allocated instance data objects to allow for GC. |
| 106 | * </ol> |
| 107 | * @param c the component from which this UI delegate is being removed; |
| 108 | * this argument is often ignored, |
| 109 | * but might be used if the UI object is stateless |
| 110 | * and shared by multiple components |
| 111 | * |
| 112 | * @see #installUI |
| 113 | * @see javax.swing.JComponent#updateUI |
| 114 | */ |
| 115 | public void uninstallUI(JComponent c) { |
| 116 | } |
| 117 | |
| 118 | /** |
| 119 | * Paints the specified component appropriate for the look and feel. |
| 120 | * This method is invoked from the <code>ComponentUI.update</code> method when |
| 121 | * the specified component is being painted. Subclasses should override |
| 122 | * this method and use the specified <code>Graphics</code> object to |
| 123 | * render the content of the component. |
| 124 | * |
| 125 | * @param g the <code>Graphics</code> context in which to paint |
| 126 | * @param c the component being painted; |
| 127 | * this argument is often ignored, |
| 128 | * but might be used if the UI object is stateless |
| 129 | * and shared by multiple components |
| 130 | * |
| 131 | * @see #update |
| 132 | */ |
| 133 | public void paint(Graphics g, JComponent c) { |
| 134 | } |
| 135 | |
| 136 | /** |
| 137 | * Notifies this UI delegate that it's time to paint the specified |
| 138 | * component. This method is invoked by <code>JComponent</code> |
| 139 | * when the specified component is being painted. |
| 140 | * By default this method will fill the specified component with |
| 141 | * its background color (if its <code>opaque</code> property is |
| 142 | * <code>true</code>) and then immediately call <code>paint</code>. |
| 143 | * In general this method need not be overridden by subclasses; |
| 144 | * all look-and-feel rendering code should reside in the <code>paint</code> |
| 145 | * method. |
| 146 | * |
| 147 | * @param g the <code>Graphics</code> context in which to paint |
| 148 | * @param c the component being painted; |
| 149 | * this argument is often ignored, |
| 150 | * but might be used if the UI object is stateless |
| 151 | * and shared by multiple components |
| 152 | * |
| 153 | * @see #paint |
| 154 | * @see javax.swing.JComponent#paintComponent |
| 155 | */ |
| 156 | public void update(Graphics g, JComponent c) { |
| 157 | if (c.isOpaque()) { |
| 158 | g.setColor(c.getBackground()); |
| 159 | g.fillRect(0, 0, c.getWidth(),c.getHeight()); |
| 160 | } |
| 161 | paint(g, c); |
| 162 | } |
| 163 | |
| 164 | /** |
| 165 | * Returns the specified component's preferred size appropriate for |
| 166 | * the look and feel. If <code>null</code> is returned, the preferred |
| 167 | * size will be calculated by the component's layout manager instead |
| 168 | * (this is the preferred approach for any component with a specific |
| 169 | * layout manager installed). The default implementation of this |
| 170 | * method returns <code>null</code>. |
| 171 | * |
| 172 | * @param c the component whose preferred size is being queried; |
| 173 | * this argument is often ignored, |
| 174 | * but might be used if the UI object is stateless |
| 175 | * and shared by multiple components |
| 176 | * |
| 177 | * @see javax.swing.JComponent#getPreferredSize |
| 178 | * @see java.awt.LayoutManager#preferredLayoutSize |
| 179 | */ |
| 180 | public Dimension getPreferredSize(JComponent c) { |
| 181 | return null; |
| 182 | } |
| 183 | |
| 184 | /** |
| 185 | * Returns the specified component's minimum size appropriate for |
| 186 | * the look and feel. If <code>null</code> is returned, the minimum |
| 187 | * size will be calculated by the component's layout manager instead |
| 188 | * (this is the preferred approach for any component with a specific |
| 189 | * layout manager installed). The default implementation of this |
| 190 | * method invokes <code>getPreferredSize</code> and returns that value. |
| 191 | * |
| 192 | * @param c the component whose minimum size is being queried; |
| 193 | * this argument is often ignored, |
| 194 | * but might be used if the UI object is stateless |
| 195 | * and shared by multiple components |
| 196 | * |
| 197 | * @return a <code>Dimension</code> object or <code>null</code> |
| 198 | * |
| 199 | * @see javax.swing.JComponent#getMinimumSize |
| 200 | * @see java.awt.LayoutManager#minimumLayoutSize |
| 201 | * @see #getPreferredSize |
| 202 | */ |
| 203 | public Dimension getMinimumSize(JComponent c) { |
| 204 | return getPreferredSize(c); |
| 205 | } |
| 206 | |
| 207 | /** |
| 208 | * Returns the specified component's maximum size appropriate for |
| 209 | * the look and feel. If <code>null</code> is returned, the maximum |
| 210 | * size will be calculated by the component's layout manager instead |
| 211 | * (this is the preferred approach for any component with a specific |
| 212 | * layout manager installed). The default implementation of this |
| 213 | * method invokes <code>getPreferredSize</code> and returns that value. |
| 214 | * |
| 215 | * @param c the component whose maximum size is being queried; |
| 216 | * this argument is often ignored, |
| 217 | * but might be used if the UI object is stateless |
| 218 | * and shared by multiple components |
| 219 | * @return a <code>Dimension</code> object or <code>null</code> |
| 220 | * |
| 221 | * @see javax.swing.JComponent#getMaximumSize |
| 222 | * @see java.awt.LayoutManager2#maximumLayoutSize |
| 223 | */ |
| 224 | public Dimension getMaximumSize(JComponent c) { |
| 225 | return getPreferredSize(c); |
| 226 | } |
| 227 | |
| 228 | /** |
| 229 | * Returns <code>true</code> if the specified <i>x,y</i> location is |
| 230 | * contained within the look and feel's defined shape of the specified |
| 231 | * component. <code>x</code> and <code>y</code> are defined to be relative |
| 232 | * to the coordinate system of the specified component. Although |
| 233 | * a component's <code>bounds</code> is constrained to a rectangle, |
| 234 | * this method provides the means for defining a non-rectangular |
| 235 | * shape within those bounds for the purpose of hit detection. |
| 236 | * |
| 237 | * @param c the component where the <i>x,y</i> location is being queried; |
| 238 | * this argument is often ignored, |
| 239 | * but might be used if the UI object is stateless |
| 240 | * and shared by multiple components |
| 241 | * @param x the <i>x</i> coordinate of the point |
| 242 | * @param y the <i>y</i> coordinate of the point |
| 243 | * |
| 244 | * @see javax.swing.JComponent#contains |
| 245 | * @see java.awt.Component#contains |
| 246 | */ |
| 247 | public boolean contains(JComponent c, int x, int y) { |
| 248 | return c.inside(x, y); |
| 249 | } |
| 250 | |
| 251 | /** |
| 252 | * Returns an instance of the UI delegate for the specified component. |
| 253 | * Each subclass must provide its own static <code>createUI</code> |
| 254 | * method that returns an instance of that UI delegate subclass. |
| 255 | * If the UI delegate subclass is stateless, it may return an instance |
| 256 | * that is shared by multiple components. If the UI delegate is |
| 257 | * stateful, then it should return a new instance per component. |
| 258 | * The default implementation of this method throws an error, as it |
| 259 | * should never be invoked. |
| 260 | */ |
| 261 | public static ComponentUI createUI(JComponent c) { |
| 262 | throw new Error("ComponentUI.createUI not implemented."); |
| 263 | } |
| 264 | |
| 265 | /** |
| 266 | * Returns the baseline. The baseline is measured from the top of |
| 267 | * the component. This method is primarily meant for |
| 268 | * <code>LayoutManager</code>s to align components along their |
| 269 | * baseline. A return value less than 0 indicates this component |
| 270 | * does not have a reasonable baseline and that |
| 271 | * <code>LayoutManager</code>s should not align this component on |
| 272 | * its baseline. |
| 273 | * <p> |
| 274 | * This method returns -1. Subclasses that have a meaningful baseline |
| 275 | * should override appropriately. |
| 276 | * |
| 277 | * @param c <code>JComponent</code> baseline is being requested for |
| 278 | * @param width the width to get the baseline for |
| 279 | * @param height the height to get the baseline for |
| 280 | * @throws NullPointerException if <code>c</code> is <code>null</code> |
| 281 | * @throws IllegalArgumentException if width or height is < 0 |
| 282 | * @return baseline or a value < 0 indicating there is no reasonable |
| 283 | * baseline |
| 284 | * @see javax.swing.JComponent#getBaseline(int,int) |
| 285 | * @since 1.6 |
| 286 | */ |
| 287 | public int getBaseline(JComponent c, int width, int height) { |
| 288 | if (c == null) { |
| 289 | throw new NullPointerException("Component must be non-null"); |
| 290 | } |
| 291 | if (width < 0 || height < 0) { |
| 292 | throw new IllegalArgumentException( |
| 293 | "Width and height must be >= 0"); |
| 294 | } |
| 295 | return -1; |
| 296 | } |
| 297 | |
| 298 | /** |
| 299 | * Returns an enum indicating how the baseline of he component |
| 300 | * changes as the size changes. This method is primarily meant for |
| 301 | * layout managers and GUI builders. |
| 302 | * <p> |
| 303 | * This method returns <code>BaselineResizeBehavior.OTHER</code>. |
| 304 | * Subclasses that support a baseline should override appropriately. |
| 305 | * |
| 306 | * @param c <code>JComponent</code> to return baseline resize behavior for |
| 307 | * @return an enum indicating how the baseline changes as the component |
| 308 | * size changes |
| 309 | * @throws NullPointerException if <code>c</code> is <code>null</code> |
| 310 | * @see javax.swing.JComponent#getBaseline(int, int) |
| 311 | * @since 1.6 |
| 312 | */ |
| 313 | public Component.BaselineResizeBehavior getBaselineResizeBehavior( |
| 314 | JComponent c) { |
| 315 | if (c == null) { |
| 316 | throw new NullPointerException("Component must be non-null"); |
| 317 | } |
| 318 | return Component.BaselineResizeBehavior.OTHER; |
| 319 | } |
| 320 | |
| 321 | /** |
| 322 | * Returns the number of accessible children in the object. If all |
| 323 | * of the children of this object implement <code>Accessible</code>, |
| 324 | * this |
| 325 | * method should return the number of children of this object. |
| 326 | * UIs might wish to override this if they present areas on the |
| 327 | * screen that can be viewed as components, but actual components |
| 328 | * are not used for presenting those areas. |
| 329 | * |
| 330 | * Note: As of v1.3, it is recommended that developers call |
| 331 | * <code>Component.AccessibleAWTComponent.getAccessibleChildrenCount()</code> instead |
| 332 | * of this method. |
| 333 | * |
| 334 | * @see #getAccessibleChild |
| 335 | * @return the number of accessible children in the object |
| 336 | */ |
| 337 | public int getAccessibleChildrenCount(JComponent c) { |
| 338 | return SwingUtilities.getAccessibleChildrenCount(c); |
| 339 | } |
| 340 | |
| 341 | /** |
| 342 | * Returns the <code>i</code>th <code>Accessible</code> child of the object. |
| 343 | * UIs might need to override this if they present areas on the |
| 344 | * screen that can be viewed as components, but actual components |
| 345 | * are not used for presenting those areas. |
| 346 | * |
| 347 | * <p> |
| 348 | * |
| 349 | * Note: As of v1.3, it is recommended that developers call |
| 350 | * <code>Component.AccessibleAWTComponent.getAccessibleChild()</code> instead of |
| 351 | * this method. |
| 352 | * |
| 353 | * @see #getAccessibleChildrenCount |
| 354 | * @param i zero-based index of child |
| 355 | * @return the <code>i</code>th <code>Accessible</code> child of the object |
| 356 | */ |
| 357 | public Accessible getAccessibleChild(JComponent c, int i) { |
| 358 | return SwingUtilities.getAccessibleChild(c, i); |
| 359 | } |
| 360 | } |