1 /* 2 * Copyright (c) 1997, 2013, 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 package javax.swing; 26 27 import java.awt.*; 28 import java.awt.event.*; 29 import java.beans.*; 30 31 /** 32 * The {@code Action} interface provides a useful extension to the 33 * {@code ActionListener} 34 * interface in cases where the same functionality may be accessed by 35 * several controls. 36 * <p> 37 * In addition to the {@code actionPerformed} method defined by the 38 * {@code ActionListener} interface, this interface allows the 39 * application to define, in a single place: 40 * <ul> 41 * <li>One or more text strings that describe the function. These strings 42 * can be used, for example, to display the flyover text for a button 43 * or to set the text in a menu item. 44 * <li>One or more icons that depict the function. These icons can be used 45 * for the images in a menu control, or for composite entries in a more 46 * sophisticated user interface. 47 * <li>The enabled/disabled state of the functionality. Instead of having 48 * to separately disable the menu item and the toolbar button, the 49 * application can disable the function that implements this interface. 50 * All components which are registered as listeners for the state change 51 * then know to disable event generation for that item and to modify the 52 * display accordingly. 53 * </ul> 54 * <p> 55 * This interface can be added to an existing class or used to create an 56 * adapter (typically, by subclassing {@code AbstractAction}). 57 * The {@code Action} object 58 * can then be added to multiple {@code Action}-aware containers 59 * and connected to {@code Action}-capable 60 * components. The GUI controls can then be activated or 61 * deactivated all at once by invoking the {@code Action} object's 62 * {@code setEnabled} method. 63 * <p> 64 * Note that {@code Action} implementations tend to be more expensive 65 * in terms of storage than a typical {@code ActionListener}, 66 * which does not offer the benefits of centralized control of 67 * functionality and broadcast of property changes. For this reason, 68 * you should take care to only use {@code Action}s where their benefits 69 * are desired, and use simple {@code ActionListener}s elsewhere. 70 * <br> 71 * 72 * <h3><a name="buttonActions"></a>Swing Components Supporting {@code Action}</h3> 73 * <p> 74 * Many of Swing's components have an {@code Action} property. When 75 * an {@code Action} is set on a component, the following things 76 * happen: 77 * <ul> 78 * <li>The {@code Action} is added as an {@code ActionListener} to 79 * the component. 80 * <li>The component configures some of its properties to match the 81 * {@code Action}. 82 * <li>The component installs a {@code PropertyChangeListener} on the 83 * {@code Action} so that the component can change its properties 84 * to reflect changes in the {@code Action}'s properties. 85 * </ul> 86 * <p> 87 * The following table describes the properties used by 88 * {@code Swing} components that support {@code Actions}. 89 * In the table, <em>button</em> refers to any 90 * {@code AbstractButton} subclass, which includes not only 91 * {@code JButton} but also classes such as 92 * {@code JMenuItem}. Unless otherwise stated, a 93 * {@code null} property value in an {@code Action} (or a 94 * {@code Action} that is {@code null}) results in the 95 * button's corresponding property being set to {@code null}. 96 * 97 * <table border="1" cellpadding="1" cellspacing="0" 98 * summary="Supported Action properties"> 99 * <tr valign="top" align="left"> 100 * <th style="background-color:#CCCCFF" align="left">Component Property 101 * <th style="background-color:#CCCCFF" align="left">Components 102 * <th style="background-color:#CCCCFF" align="left">Action Key 103 * <th style="background-color:#CCCCFF" align="left">Notes 104 * <tr valign="top" align="left"> 105 * <td><b>{@code enabled}</b> 106 * <td>All 107 * <td>The {@code isEnabled} method 108 * <td> 109 * <tr valign="top" align="left"> 110 * <td><b>{@code toolTipText}</b> 111 * <td>All 112 * <td>{@code SHORT_DESCRIPTION} 113 * <td> 114 * <tr valign="top" align="left"> 115 * <td><b>{@code actionCommand}</b> 116 * <td>All 117 * <td>{@code ACTION_COMMAND_KEY} 118 * <td> 119 * <tr valign="top" align="left"> 120 * <td><b>{@code mnemonic}</b> 121 * <td>All buttons 122 * <td>{@code MNEMONIC_KEY} 123 * <td>A {@code null} value or {@code Action} results in the 124 * button's {@code mnemonic} property being set to 125 * {@code '\0'}. 126 * <tr valign="top" align="left"> 127 * <td><b>{@code text}</b> 128 * <td>All buttons 129 * <td>{@code NAME} 130 * <td>If you do not want the text of the button to mirror that 131 * of the {@code Action}, set the property 132 * {@code hideActionText} to {@code true}. If 133 * {@code hideActionText} is {@code true}, setting the 134 * {@code Action} changes the text of the button to 135 * {@code null} and any changes to {@code NAME} 136 * are ignored. {@code hideActionText} is useful for 137 * tool bar buttons that typically only show an {@code Icon}. 138 * {@code JToolBar.add(Action)} sets the property to 139 * {@code true} if the {@code Action} has a 140 * non-{@code null} value for {@code LARGE_ICON_KEY} or 141 * {@code SMALL_ICON}. 142 * <tr valign="top" align="left"> 143 * <td><b>{@code displayedMnemonicIndex}</b> 144 * <td>All buttons 145 * <td>{@code DISPLAYED_MNEMONIC_INDEX_KEY} 146 * <td>If the value of {@code DISPLAYED_MNEMONIC_INDEX_KEY} is 147 * beyond the bounds of the text, it is ignored. When 148 * {@code setAction} is called, if the value from the 149 * {@code Action} is {@code null}, the displayed 150 * mnemonic index is not updated. In any subsequent changes to 151 * {@code DISPLAYED_MNEMONIC_INDEX_KEY}, {@code null} 152 * is treated as -1. 153 * <tr valign="top" align="left"> 154 * <td><b>{@code icon}</b> 155 * <td>All buttons except of {@code JCheckBox}, 156 * {@code JToggleButton} and {@code JRadioButton}. 157 * <td>either {@code LARGE_ICON_KEY} or 158 * {@code SMALL_ICON} 159 * <td>The {@code JMenuItem} subclasses only use 160 * {@code SMALL_ICON}. All other buttons will use 161 * {@code LARGE_ICON_KEY}; if the value is {@code null} they 162 * use {@code SMALL_ICON}. 163 * <tr valign="top" align="left"> 164 * <td><b>{@code accelerator}</b> 165 * <td>All {@code JMenuItem} subclasses, with the exception of 166 * {@code JMenu}. 167 * <td>{@code ACCELERATOR_KEY} 168 * <td> 169 * <tr valign="top" align="left"> 170 * <td><b>{@code selected}</b> 171 * <td>{@code JToggleButton}, {@code JCheckBox}, 172 * {@code JRadioButton}, {@code JCheckBoxMenuItem} and 173 * {@code JRadioButtonMenuItem} 174 * <td>{@code SELECTED_KEY} 175 * <td>Components that honor this property only use 176 * the value if it is {@code non-null}. For example, if 177 * you set an {@code Action} that has a {@code null} 178 * value for {@code SELECTED_KEY} on a {@code JToggleButton}, the 179 * {@code JToggleButton} will not update it's selected state in 180 * any way. Similarly, any time the {@code JToggleButton}'s 181 * selected state changes it will only set the value back on 182 * the {@code Action} if the {@code Action} has a {@code non-null} 183 * value for {@code SELECTED_KEY}. 184 * <br> 185 * Components that honor this property keep their selected state 186 * in sync with this property. When the same {@code Action} is used 187 * with multiple components, all the components keep their selected 188 * state in sync with this property. Mutually exclusive 189 * buttons, such as {@code JToggleButton}s in a {@code ButtonGroup}, 190 * force only one of the buttons to be selected. As such, do not 191 * use the same {@code Action} that defines a value for the 192 * {@code SELECTED_KEY} property with multiple mutually 193 * exclusive buttons. 194 * </table> 195 * <p> 196 * {@code JPopupMenu}, {@code JToolBar} and {@code JMenu} 197 * all provide convenience methods for creating a component and setting the 198 * {@code Action} on the corresponding component. Refer to each of 199 * these classes for more information. 200 * <p> 201 * {@code Action} uses {@code PropertyChangeListener} to 202 * inform listeners the {@code Action} has changed. The beans 203 * specification indicates that a {@code null} property name can 204 * be used to indicate multiple values have changed. By default Swing 205 * components that take an {@code Action} do not handle such a 206 * change. To indicate that Swing should treat {@code null} 207 * according to the beans specification set the system property 208 * {@code swing.actions.reconfigureOnNull} to the {@code String} 209 * value {@code true}. 210 * 211 * @author Georges Saab 212 * @see AbstractAction 213 * @since 1.2 214 */ 215 public interface Action extends ActionListener { 216 /** 217 * Useful constants that can be used as the storage-retrieval key 218 * when setting or getting one of this object's properties (text 219 * or icon). 220 */ 221 /** 222 * Not currently used. 223 */ 224 public static final String DEFAULT = "Default"; 225 /** 226 * The key used for storing the {@code String} name 227 * for the action, used for a menu or button. 228 */ 229 public static final String NAME = "Name"; 230 /** 231 * The key used for storing a short {@code String} 232 * description for the action, used for tooltip text. 233 */ 234 public static final String SHORT_DESCRIPTION = "ShortDescription"; 235 /** 236 * The key used for storing a longer {@code String} 237 * description for the action, could be used for context-sensitive help. 238 */ 239 public static final String LONG_DESCRIPTION = "LongDescription"; 240 /** 241 * The key used for storing a small {@code Icon}, such 242 * as {@code ImageIcon}. This is typically used with 243 * menus such as {@code JMenuItem}. 244 * <p> 245 * If the same {@code Action} is used with menus and buttons you'll 246 * typically specify both a {@code SMALL_ICON} and a 247 * {@code LARGE_ICON_KEY}. The menu will use the 248 * {@code SMALL_ICON} and the button will use the 249 * {@code LARGE_ICON_KEY}. 250 */ 251 public static final String SMALL_ICON = "SmallIcon"; 252 253 /** 254 * The key used to determine the command {@code String} for the 255 * {@code ActionEvent} that will be created when an 256 * {@code Action} is going to be notified as the result of 257 * residing in a {@code Keymap} associated with a 258 * {@code JComponent}. 259 */ 260 public static final String ACTION_COMMAND_KEY = "ActionCommandKey"; 261 262 /** 263 * The key used for storing a {@code KeyStroke} to be used as the 264 * accelerator for the action. 265 * 266 * @since 1.3 267 */ 268 public static final String ACCELERATOR_KEY="AcceleratorKey"; 269 270 /** 271 * The key used for storing an {@code Integer} that corresponds to 272 * one of the {@code KeyEvent} key codes. The value is 273 * commonly used to specify a mnemonic. For example: 274 * {@code myAction.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_A)} 275 * sets the mnemonic of {@code myAction} to 'a', while 276 * <code>myAction.putValue(Action.MNEMONIC_KEY, KeyEvent.getExtendedKeyCodeForChar('\u0444'))</code> 277 * sets the mnemonic of {@code myAction} to Cyrillic letter "Ef". 278 * 279 * @since 1.3 280 */ 281 public static final String MNEMONIC_KEY="MnemonicKey"; 282 283 /** 284 * The key used for storing a {@code Boolean} that corresponds 285 * to the selected state. This is typically used only for components 286 * that have a meaningful selection state. For example, 287 * {@code JRadioButton} and {@code JCheckBox} make use of 288 * this but instances of {@code JMenu} don't. 289 * <p> 290 * This property differs from the others in that it is both read 291 * by the component and set by the component. For example, 292 * if an {@code Action} is attached to a {@code JCheckBox} 293 * the selected state of the {@code JCheckBox} will be set from 294 * that of the {@code Action}. If the user clicks on the 295 * {@code JCheckBox} the selected state of the {@code JCheckBox} 296 * <b>and</b> the {@code Action} will <b>both</b> be updated. 297 * <p> 298 * Note: the value of this field is prefixed with 'Swing' to 299 * avoid possible collisions with existing {@code Actions}. 300 * 301 * @since 1.6 302 */ 303 public static final String SELECTED_KEY = "SwingSelectedKey"; 304 305 /** 306 * The key used for storing an {@code Integer} that corresponds 307 * to the index in the text (identified by the {@code NAME} 308 * property) that the decoration for a mnemonic should be rendered at. If 309 * the value of this property is greater than or equal to the length of 310 * the text, it will treated as -1. 311 * <p> 312 * Note: the value of this field is prefixed with 'Swing' to 313 * avoid possible collisions with existing {@code Actions}. 314 * 315 * @see AbstractButton#setDisplayedMnemonicIndex 316 * @since 1.6 317 */ 318 public static final String DISPLAYED_MNEMONIC_INDEX_KEY = 319 "SwingDisplayedMnemonicIndexKey"; 320 321 /** 322 * The key used for storing an {@code Icon}. This is typically 323 * used by buttons, such as {@code JButton} and 324 * {@code JToggleButton}. 325 * <p> 326 * If the same {@code Action} is used with menus and buttons you'll 327 * typically specify both a {@code SMALL_ICON} and a 328 * {@code LARGE_ICON_KEY}. The menu will use the 329 * {@code SMALL_ICON} and the button the {@code LARGE_ICON_KEY}. 330 * <p> 331 * Note: the value of this field is prefixed with 'Swing' to 332 * avoid possible collisions with existing {@code Actions}. 333 * 334 * @since 1.6 335 */ 336 public static final String LARGE_ICON_KEY = "SwingLargeIconKey"; 337 338 /** 339 * Gets one of this object's properties 340 * using the associated key. 341 * 342 * @param key a {@code String} containing the key 343 * @return the {@code Object} value 344 * @see #putValue 345 */ 346 public Object getValue(String key); 347 /** 348 * Sets one of this object's properties 349 * using the associated key. If the value has 350 * changed, a {@code PropertyChangeEvent} is sent 351 * to listeners. 352 * 353 * @param key a {@code String} containing the key 354 * @param value an {@code Object} value 355 */ 356 public void putValue(String key, Object value); 357 358 /** 359 * Sets the enabled state of the {@code Action}. When enabled, 360 * any component associated with this object is active and 361 * able to fire this object's {@code actionPerformed} method. 362 * If the value has changed, a {@code PropertyChangeEvent} is sent 363 * to listeners. 364 * 365 * @param b true to enable this {@code Action}, false to disable it 366 */ 367 public void setEnabled(boolean b); 368 /** 369 * Returns the enabled state of the {@code Action}. When enabled, 370 * any component associated with this object is active and 371 * able to fire this object's {@code actionPerformed} method. 372 * 373 * @return true if this {@code Action} is enabled 374 */ 375 public boolean isEnabled(); 376 377 /** 378 * Adds a {@code PropertyChange} listener. Containers and attached 379 * components use these methods to register interest in this 380 * {@code Action} object. When its enabled state or other property 381 * changes, the registered listeners are informed of the change. 382 * 383 * @param listener a {@code PropertyChangeListener} object 384 */ 385 public void addPropertyChangeListener(PropertyChangeListener listener); 386 /** 387 * Removes a {@code PropertyChange} listener. 388 * 389 * @param listener a {@code PropertyChangeListener} object 390 * @see #addPropertyChangeListener 391 */ 392 public void removePropertyChangeListener(PropertyChangeListener listener); 393 394 } --- EOF ---