libjava/classpath/javax/swing/LookAndFeel.java

   1 /* LookAndFeel.java --
   2    Copyright (C) 2002, 2004, 2005, 2006,  Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package javax.swing;
  40
  41 import java.awt.Color;
  42 import java.awt.Component;
  43 import java.awt.Font;
  44 import java.awt.Toolkit;
  45 import java.net.URL;
  46
  47 import javax.swing.border.Border;
  48 import javax.swing.plaf.ComponentInputMapUIResource;
  49 import javax.swing.plaf.IconUIResource;
  50 import javax.swing.plaf.InputMapUIResource;
  51 import javax.swing.plaf.UIResource;
  52 import javax.swing.plaf.metal.MetalLookAndFeel;
  53 import javax.swing.text.JTextComponent;
  54
  55 /**
  56  * A <i>look-and-feel</i> controls most aspects of the appearance and
  57  * operation of user interface components in <code>javax.swing</code>.  A
  58  * cross-platform look-and-feel (the {@link MetalLookAndFeel}) is provided.
  59  *
  60  * @see UIManager#getInstalledLookAndFeels()
  61  * @see UIManager#setLookAndFeel(LookAndFeel)
  62  */
  63 public abstract class LookAndFeel
  64 {
  65   /**
  66    * Creates and returns a look-and-feel specific defaults table.  This method
  67    * is called once by {@link UIManager#setLookAndFeel(LookAndFeel)} and
  68    * shouldn't be called again (as it creates a large table of defaults).
  69    *
  70    * @return The UI defaults.
  71    */
  72   public UIDefaults getDefaults()
  73   {
  74     return null;
  75   }
  76
  77   /**
  78    * Returns a description of the look and feel.
  79    *
  80    * @return A description of the look and feel.
  81    */
  82   public abstract String getDescription();
  83
  84   /**
  85    * Returns the value of <code>Toolkit.getDefaultToolkit()
  86    * .getDesktopProperty(systemPropertyName)</code>, or
  87    * <code>fallbackValue</code> if no such property is defined.
  88    *
  89    * @param systemPropertyName  the system property name.
  90    * @param fallbackValue  the fallback value.
  91    *
  92    * @return The property value or <code>fallbackValue</code>.
  93    */
  94   public static Object getDesktopPropertyValue(String systemPropertyName,
  95       Object fallbackValue)
  96   {
  97     Object value = Toolkit.getDefaultToolkit().getDesktopProperty(
  98         systemPropertyName);
  99     return value != null ? value : fallbackValue;
 100   }
 101
 102   /**
 103    * Returns an identifier for the look and feel.
 104    *
 105    * @return An identifier for the look and feel.
 106    */
 107   public abstract String getID();
 108
 109   /**
 110    * Returns the name for the look and feel.
 111    *
 112    * @return The name for the look and feel.
 113    */
 114   public abstract String getName();
 115
 116   /**
 117    * Returns <code>true</code> when the look-and-feel supports window
 118    * decorations, and <code>false</code> otherwise. This default implementation
 119    * always returns <code>false</code> and needs to be overridden when the
 120    * derived look-and-feel supports this.
 121    *
 122    * @return <code>false</code>.
 123    *
 124    * @since 1.4
 125    */
 126   public boolean getSupportsWindowDecorations()
 127   {
 128     return false;
 129   }
 130
 131   /**
 132    * Initializes the look-and-feel.  The
 133    * {@link UIManager#setLookAndFeel(LookAndFeel)} method calls this method
 134    * before the first call (and typically the only call) to
 135    * {@link #getDefaults()}.  This default implementation does nothing, but
 136    * subclasses can override this behaviour.
 137    */
 138   public void initialize()
 139   {
 140     // We do nothing here. This method is meant to be overridden by
 141     // LookAndFeel implementations.
 142   }
 143
 144   /**
 145    * Convenience method for installing a component's default {@link Border}
 146    * object on the specified component if either the border is currently
 147    * <code>null</code> or already an instance of {@link UIResource}.
 148    *
 149    * @param c  the component (<code>null</code> not permitted).
 150    * @param defaultBorderName  the border name (for lookup in the UIDefaults
 151    *     table).
 152    */
 153   public static void installBorder(JComponent c, String defaultBorderName)
 154   {
 155     Border b = c.getBorder();
 156     if (b == null || b instanceof UIResource)
 157       c.setBorder(UIManager.getBorder(defaultBorderName));
 158   }
 159
 160   /**
 161    * Convenience method for initializing a component's foreground and
 162    * background color properties with values from the current defaults table.
 163    *
 164    * @param c  the component (<code>null</code> not permitted).
 165    * @param defaultBgName  the key for the background color in the UIDefaults
 166    *     table.
 167    * @param defaultFgName  the key for the foreground color in the UIDefaults
 168    *     table.
 169    */
 170   public static void installColors(JComponent c, String defaultBgName,
 171                                    String defaultFgName)
 172   {
 173     // Install background.
 174     Color bg = c.getBackground();
 175     if (bg == null || bg instanceof UIResource)
 176       c.setBackground(UIManager.getColor(defaultBgName));
 177
 178     // Install foreground.
 179     Color fg = c.getForeground();
 180     if (fg == null || fg instanceof UIResource)
 181       c.setForeground(UIManager.getColor(defaultFgName));
 182   }
 183
 184   /**
 185    * Convenience method for initializing a component's foreground, background
 186    * and font properties with values from the current defaults table.
 187    *
 188    * @param component  the component (<code>null</code> not permitted).
 189    * @param defaultBgName  the key for the background color in the UIDefaults
 190    *     table.
 191    * @param defaultFgName  the key for the foreground color in the UIDefaults
 192    *     table.
 193    * @param defaultFontName  the key for the font in the UIDefaults table.
 194    */
 195   public static void installColorsAndFont(JComponent component,
 196                                           String defaultBgName,
 197                                           String defaultFgName,
 198                                           String defaultFontName)
 199   {
 200     // Install colors.
 201     installColors(component, defaultBgName, defaultFgName);
 202     // Install font.
 203     Font f = component.getFont();
 204     if (f == null || f instanceof UIResource)
 205       component.setFont(UIManager.getFont(defaultFontName));
 206   }
 207
 208   /**
 209    * Returns <code>true</code> if the look-and-feel is the "native"
 210    * look-and-feel for the current platform, and <code>false</code> otherwise.
 211    * A native look-and-feel emulates the appearance and behaviour of the
 212    * default windowing system on the host operating system.
 213    *
 214    * @return A flag indicating whether or not this is the native look and feel
 215    *         for the current platform.
 216    */
 217   public abstract boolean isNativeLookAndFeel();
 218
 219   /**
 220    * Returns <code>true</code> if the look-and-feel is supported on the
 221    * current operating system, and <code>false</code> otherwise.  This
 222    * mechanism is provided so that it is possible to prevent a look-and-feel
 223    * from being used on some operating systems (usually for legal, not
 224    * technical, reasons).
 225    *
 226    * @return A flag indicating whether or not the look-and-feel is supported
 227    *         on the current platform.
 228    */
 229   public abstract boolean isSupportedLookAndFeel();
 230
 231   /**
 232    * Loads the bindings in keys into retMap. Does not remove existing entries
 233    * from retMap.  <code>keys</code> describes the InputMap, every even indexed
 234    * item is either a KeyStroke or a String representing a KeyStroke and every
 235    * odd indexed item is the Object associated with that KeyStroke in an
 236    * ActionMap.
 237    *
 238    * @param retMap the InputMap into which we load bindings
 239    * @param keys the Object array describing the InputMap as above
 240    */
 241   public static void loadKeyBindings(InputMap retMap, Object[] keys)
 242   {
 243     if (keys == null)
 244       return;
 245     for (int i = 0; i < keys.length - 1; i+= 2)
 246       {
 247         Object key = keys[i];
 248         KeyStroke keyStroke;
 249         if (key instanceof KeyStroke)
 250           keyStroke = (KeyStroke)key;
 251         else
 252           keyStroke = KeyStroke.getKeyStroke((String)key);
 253         retMap.put(keyStroke, keys[i+1]);
 254       }
 255   }
 256
 257   /**
 258    * Creates a ComponentInputMap from keys.
 259    * <code>keys</code> describes the InputMap, every even indexed
 260    * item is either a KeyStroke or a String representing a KeyStroke and every
 261    * odd indexed item is the Object associated with that KeyStroke in an
 262    * ActionMap.
 263    *
 264    * @param c the JComponent associated with the ComponentInputMap
 265    * @param keys the Object array describing the InputMap as above
 266    *
 267    * @return A new input map.
 268    */
 269   public static ComponentInputMap makeComponentInputMap(JComponent c,
 270                                                         Object[] keys)
 271   {
 272     ComponentInputMap retMap = new ComponentInputMapUIResource(c);
 273     loadKeyBindings(retMap, keys);
 274     return retMap;
 275   }
 276
 277   /**
 278    * Utility method that creates a UIDefaults.LazyValue that creates an
 279    * ImageIcon UIResource for the specified gifFile filename.
 280    *
 281    * @param baseClass  the base class for accessing the icon resource.
 282    * @param gifFile  the file name.
 283    *
 284    * @return A {@link UIDefaults.LazyValue} that serves up an
 285    *     {@link IconUIResource}.
 286    */
 287   public static Object makeIcon(Class baseClass, String gifFile)
 288   {
 289     final URL file = baseClass.getResource(gifFile);
 290     return new UIDefaults.LazyValue()
 291       {
 292         public Object createValue(UIDefaults table)
 293         {
 294           return new IconUIResource(new ImageIcon(file));
 295         }
 296       };
 297   }
 298
 299   /**
 300    * Creates a InputMap from keys.
 301    * <code>keys</code> describes the InputMap, every even indexed
 302    * item is either a KeyStroke or a String representing a KeyStroke and every
 303    * odd indexed item is the Object associated with that KeyStroke in an
 304    * ActionMap.
 305    *
 306    * @param keys the Object array describing the InputMap as above
 307    *
 308    * @return A new input map.
 309    */
 310   public static InputMap makeInputMap(Object[] keys)
 311   {
 312     InputMap retMap = new InputMapUIResource();
 313     loadKeyBindings(retMap, keys);
 314     return retMap;
 315   }
 316
 317   /**
 318    * Convenience method for building lists of KeyBindings.
 319    * <code>keyBindingList</code> is an array of KeyStroke-Action pairs where
 320    * even indexed elements are KeyStrokes or Strings representing KeyStrokes
 321    * and odd indexed elements are the associated Actions.
 322    *
 323    * @param keyBindingList the array of KeyStroke-Action pairs
 324    * @return a JTextComponent.KeyBinding array
 325    */
 326   public static JTextComponent.KeyBinding[] makeKeyBindings(
 327       Object[] keyBindingList)
 328   {
 329     JTextComponent.KeyBinding[] retBindings =
 330       new JTextComponent.KeyBinding[keyBindingList.length / 2];
 331     for (int i = 0; i < keyBindingList.length - 1; i+= 2)
 332       {
 333         KeyStroke stroke;
 334         if (keyBindingList[i] instanceof KeyStroke)
 335           stroke = (KeyStroke)keyBindingList[i];
 336         else
 337           stroke = KeyStroke.getKeyStroke((String)keyBindingList[i]);
 338         retBindings[i/2] = new JTextComponent.KeyBinding(stroke,
 339             (String) keyBindingList[i+1]);
 340       }
 341     return retBindings;
 342   }
 343
 344   /**
 345    * Invoked when the user attempts an invalid operation. The default
 346    * implementation just beeps. Subclasses that wish to change this need to
 347    * override this method.
 348    *
 349    * @param component the component the error occured in
 350    */
 351   public void provideErrorFeedback(Component component)
 352   {
 353     Toolkit.getDefaultToolkit().beep();
 354   }
 355
 356   /**
 357    * Returns a string that displays and identifies this object's properties.
 358    *
 359    * @return string containing the description and class name.
 360    */
 361   public String toString()
 362   {
 363     return getDescription() + " " + getClass().getName();
 364   }
 365
 366   /**
 367    * UIManager.setLookAndFeel calls this method just before we're replaced by
 368    * a new default look and feel.
 369    */
 370   public void uninitialize()
 371   {
 372     // We do nothing here. This method is meant to be overridden by
 373     // LookAndFeel implementations.
 374   }
 375
 376   /**
 377    * Convenience method for un-installing a component's default border on the
 378    * specified component if the border is currently an instance of UIResource.
 379    *
 380    * @param c  the component (<code>null</code> not permitted).
 381    */
 382   public static void uninstallBorder(JComponent c)
 383   {
 384     if (c.getBorder() instanceof UIResource)
 385       c.setBorder(null);
 386   }
 387
 388   /**
 389    * This methods installs a UI property if it hasn't already been set by an
 390    * application. This method is used by UI delegates that install a default
 391    * value for a property with a primitive type but do not want to override
 392    * a value that has been set by an application.
 393    *
 394    * The supported properties depend on the actual type of the component and
 395    * are listed in the table below. The supported properties are of course
 396    * inherited to subclasses.
 397    *
 398    * <table>
 399    * <tr><th>Type</th><th>Supported properties</th></tr>
 400    * <tr><td><code>JComponent</code></td>
 401    *     <td><code>opaque, autoscrolls</code></td></tr>
 402    * <tr><td><code>AbstractButton</code></td>
 403    *     <td><code>borderPainted, rolloverEnabled, iconTextGap,
 404    *      contentAreaFilled</code></td></tr>
 405    * <tr><td><code>JDesktopPane</code></td>
 406    *     <td><code>dragMode</code></td></tr>
 407    * <tr><td><code>JSplitPane</code></td>
 408    *     <td><code>dividerSize, oneTouchExpandable</code></td></tr>
 409    * <tr><td><code>JTable</code></td>
 410    *     <td><code>rowHeight</code></td></tr>
 411    * <tr><td><code>JTree</code></td>
 412    *     <td><code>rowHeight, scrollsOnExpand, showsRootHandles</code></td></tr>
 413    * </table>
 414    *
 415    * @param c the component to install the property to
 416    * @param propertyName the name of the property
 417    * @param value the value of the property
 418    *
 419    * @throws IllegalArgumentException if the specified property cannot be set
 420    *         by this method
 421    * @throws ClassCastException if the property value does not match the
 422    *         property type
 423    * @throws NullPointerException if <code>c</code> or
 424    *         <code>propertyValue</code> is <code>null</code>
 425    *
 426    * @since 1.5
 427    */
 428   public static void installProperty(JComponent c, String propertyName,
 429                                      Object value)
 430   {
 431     c.setUIProperty(propertyName, value);
 432   }
 433 }