J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000-2003 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 java.awt; |
| 26 | |
| 27 | import java.util.logging.*; |
| 28 | import java.util.List; |
| 29 | import java.util.ArrayList; |
| 30 | |
| 31 | /** |
| 32 | * A FocusTraversalPolicy that determines traversal order based on the order |
| 33 | * of child Components in a Container. From a particular focus cycle root, the |
| 34 | * policy makes a pre-order traversal of the Component hierarchy, and traverses |
| 35 | * a Container's children according to the ordering of the array returned by |
| 36 | * <code>Container.getComponents()</code>. Portions of the hierarchy that are |
| 37 | * not visible and displayable will not be searched. |
| 38 | * <p> |
| 39 | * By default, ContainerOrderFocusTraversalPolicy implicitly transfers focus |
| 40 | * down-cycle. That is, during normal forward focus traversal, the Component |
| 41 | * traversed after a focus cycle root will be the focus-cycle-root's default |
| 42 | * Component to focus. This behavior can be disabled using the |
| 43 | * <code>setImplicitDownCycleTraversal</code> method. |
| 44 | * <p> |
| 45 | * By default, methods of this class with return a Component only if it is |
| 46 | * visible, displayable, enabled, and focusable. Subclasses can modify this |
| 47 | * behavior by overriding the <code>accept</code> method. |
| 48 | * <p> |
| 49 | * This policy takes into account <a |
| 50 | * href="doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus traversal |
| 51 | * policy providers</a>. When searching for first/last/next/previous Component, |
| 52 | * if a focus traversal policy provider is encountered, its focus traversal |
| 53 | * policy is used to perform the search operation. |
| 54 | * |
| 55 | * @author David Mendenhall |
| 56 | * |
| 57 | * @see Container#getComponents |
| 58 | * @since 1.4 |
| 59 | */ |
| 60 | public class ContainerOrderFocusTraversalPolicy extends FocusTraversalPolicy |
| 61 | implements java.io.Serializable |
| 62 | { |
| 63 | private static final Logger log = Logger.getLogger("java.awt.ContainerOrderFocusTraversalPolicy"); |
| 64 | |
| 65 | final private int FORWARD_TRAVERSAL = 0; |
| 66 | final private int BACKWARD_TRAVERSAL = 1; |
| 67 | |
| 68 | /* |
| 69 | * JDK 1.4 serialVersionUID |
| 70 | */ |
| 71 | private static final long serialVersionUID = 486933713763926351L; |
| 72 | |
| 73 | private boolean implicitDownCycleTraversal = true; |
| 74 | |
| 75 | /** |
| 76 | * Used by getComponentAfter and getComponentBefore for efficiency. In |
| 77 | * order to maintain compliance with the specification of |
| 78 | * FocusTraversalPolicy, if traversal wraps, we should invoke |
| 79 | * getFirstComponent or getLastComponent. These methods may be overriden in |
| 80 | * subclasses to behave in a non-generic way. However, in the generic case, |
| 81 | * these methods will simply return the first or last Components of the |
| 82 | * sorted list, respectively. Since getComponentAfter and |
| 83 | * getComponentBefore have already built the list before determining |
| 84 | * that they need to invoke getFirstComponent or getLastComponent, the |
| 85 | * list should be reused if possible. |
| 86 | */ |
| 87 | transient private Container cachedRoot; |
| 88 | transient private List cachedCycle; |
| 89 | |
| 90 | /* |
| 91 | * We suppose to use getFocusTraversalCycle & getComponentIndex methods in order |
| 92 | * to divide the policy into two parts: |
| 93 | * 1) Making the focus traversal cycle. |
| 94 | * 2) Traversing the cycle. |
| 95 | * The 1st point assumes producing a list of components representing the focus |
| 96 | * traversal cycle. The two methods mentioned above should implement this logic. |
| 97 | * The 2nd point assumes implementing the common concepts of operating on the |
| 98 | * cycle: traversing back and forth, retrieving the initial/default/first/last |
| 99 | * component. These concepts are described in the AWT Focus Spec and they are |
| 100 | * applied to the FocusTraversalPolicy in general. |
| 101 | * Thus, a descendant of this policy may wish to not reimplement the logic of |
| 102 | * the 2nd point but just override the implementation of the 1st one. |
| 103 | * A striking example of such a descendant is the javax.swing.SortingFocusTraversalPolicy. |
| 104 | */ |
| 105 | /*protected*/ private List<Component> getFocusTraversalCycle(Container aContainer) { |
| 106 | List<Component> cycle = new ArrayList<Component>(); |
| 107 | enumerateCycle(aContainer, cycle); |
| 108 | return cycle; |
| 109 | } |
| 110 | /*protected*/ private int getComponentIndex(List<Component> cycle, Component aComponent) { |
| 111 | return cycle.indexOf(aComponent); |
| 112 | } |
| 113 | |
| 114 | private void enumerateCycle(Container container, List cycle) { |
| 115 | if (!(container.isVisible() && container.isDisplayable())) { |
| 116 | return; |
| 117 | } |
| 118 | |
| 119 | cycle.add(container); |
| 120 | |
| 121 | Component[] components = container.getComponents(); |
| 122 | for (int i = 0; i < components.length; i++) { |
| 123 | Component comp = components[i]; |
| 124 | if (comp instanceof Container) { |
| 125 | Container cont = (Container)comp; |
| 126 | |
| 127 | if (!cont.isFocusCycleRoot() && !cont.isFocusTraversalPolicyProvider()) { |
| 128 | enumerateCycle(cont, cycle); |
| 129 | continue; |
| 130 | } |
| 131 | } |
| 132 | cycle.add(comp); |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | private Container getTopmostProvider(Container focusCycleRoot, Component aComponent) { |
| 137 | Container aCont = aComponent.getParent(); |
| 138 | Container ftp = null; |
| 139 | while (aCont != focusCycleRoot && aCont != null) { |
| 140 | if (aCont.isFocusTraversalPolicyProvider()) { |
| 141 | ftp = aCont; |
| 142 | } |
| 143 | aCont = aCont.getParent(); |
| 144 | } |
| 145 | if (aCont == null) { |
| 146 | return null; |
| 147 | } |
| 148 | return ftp; |
| 149 | } |
| 150 | |
| 151 | /* |
| 152 | * Checks if a new focus cycle takes place and returns a Component to traverse focus to. |
| 153 | * @param comp a possible focus cycle root or policy provider |
| 154 | * @param traversalDirection the direction of the traversal |
| 155 | * @return a Component to traverse focus to if {@code comp} is a root or provider |
| 156 | * and implicit down-cycle is set, otherwise {@code null} |
| 157 | */ |
| 158 | private Component getComponentDownCycle(Component comp, int traversalDirection) { |
| 159 | Component retComp = null; |
| 160 | |
| 161 | if (comp instanceof Container) { |
| 162 | Container cont = (Container)comp; |
| 163 | |
| 164 | if (cont.isFocusCycleRoot()) { |
| 165 | if (getImplicitDownCycleTraversal()) { |
| 166 | retComp = cont.getFocusTraversalPolicy().getDefaultComponent(cont); |
| 167 | |
| 168 | if (retComp != null && log.isLoggable(Level.FINE)) { |
| 169 | log.fine("### Transfered focus down-cycle to " + retComp + |
| 170 | " in the focus cycle root " + cont); |
| 171 | } |
| 172 | } else { |
| 173 | return null; |
| 174 | } |
| 175 | } else if (cont.isFocusTraversalPolicyProvider()) { |
| 176 | retComp = (traversalDirection == FORWARD_TRAVERSAL ? |
| 177 | cont.getFocusTraversalPolicy().getDefaultComponent(cont) : |
| 178 | cont.getFocusTraversalPolicy().getLastComponent(cont)); |
| 179 | |
| 180 | if (retComp != null && log.isLoggable(Level.FINE)) { |
| 181 | log.fine("### Transfered focus to " + retComp + " in the FTP provider " + cont); |
| 182 | } |
| 183 | } |
| 184 | } |
| 185 | return retComp; |
| 186 | } |
| 187 | |
| 188 | /** |
| 189 | * Returns the Component that should receive the focus after aComponent. |
| 190 | * aContainer must be a focus cycle root of aComponent or a focus traversal policy provider. |
| 191 | * <p> |
| 192 | * By default, ContainerOrderFocusTraversalPolicy implicitly transfers |
| 193 | * focus down-cycle. That is, during normal forward focus traversal, the |
| 194 | * Component traversed after a focus cycle root will be the focus-cycle- |
| 195 | * root's default Component to focus. This behavior can be disabled using |
| 196 | * the <code>setImplicitDownCycleTraversal</code> method. |
| 197 | * <p> |
| 198 | * If aContainer is <a href="doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus |
| 199 | * traversal policy provider</a>, the focus is always transferred down-cycle. |
| 200 | * |
| 201 | * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider |
| 202 | * @param aComponent a (possibly indirect) child of aContainer, or |
| 203 | * aContainer itself |
| 204 | * @return the Component that should receive the focus after aComponent, or |
| 205 | * null if no suitable Component can be found |
| 206 | * @throws IllegalArgumentException if aContainer is not a focus cycle |
| 207 | * root of aComponent or focus traversal policy provider, or if either aContainer or |
| 208 | * aComponent is null |
| 209 | */ |
| 210 | public Component getComponentAfter(Container aContainer, Component aComponent) { |
| 211 | if (log.isLoggable(Level.FINE)) log.fine("### Searching in " + aContainer + " for component after " + aComponent); |
| 212 | |
| 213 | if (aContainer == null || aComponent == null) { |
| 214 | throw new IllegalArgumentException("aContainer and aComponent cannot be null"); |
| 215 | } |
| 216 | if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) { |
| 217 | throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider"); |
| 218 | |
| 219 | } else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) { |
| 220 | throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent"); |
| 221 | } |
| 222 | |
| 223 | synchronized(aContainer.getTreeLock()) { |
| 224 | |
| 225 | if (!(aContainer.isVisible() && aContainer.isDisplayable())) { |
| 226 | return null; |
| 227 | } |
| 228 | |
| 229 | // Before all the ckecks below we first see if it's an FTP provider or a focus cycle root. |
| 230 | // If it's the case just go down cycle (if it's set to "implicit"). |
| 231 | Component comp = getComponentDownCycle(aComponent, FORWARD_TRAVERSAL); |
| 232 | if (comp != null) { |
| 233 | return comp; |
| 234 | } |
| 235 | |
| 236 | // See if the component is inside of policy provider. |
| 237 | Container provider = getTopmostProvider(aContainer, aComponent); |
| 238 | if (provider != null) { |
| 239 | if (log.isLoggable(Level.FINE)) { |
| 240 | log.fine("### Asking FTP " + provider + " for component after " + aComponent); |
| 241 | } |
| 242 | |
| 243 | // FTP knows how to find component after the given. We don't. |
| 244 | FocusTraversalPolicy policy = provider.getFocusTraversalPolicy(); |
| 245 | Component afterComp = policy.getComponentAfter(provider, aComponent); |
| 246 | |
| 247 | // Null result means that we overstepped the limit of the FTP's cycle. |
| 248 | // In that case we must quit the cycle, otherwise return the component found. |
| 249 | if (afterComp != null) { |
| 250 | if (log.isLoggable(Level.FINE)) log.fine("### FTP returned " + afterComp); |
| 251 | return afterComp; |
| 252 | } |
| 253 | aComponent = provider; |
| 254 | } |
| 255 | |
| 256 | List<Component> cycle = getFocusTraversalCycle(aContainer); |
| 257 | |
| 258 | if (log.isLoggable(Level.FINE)) log.fine("### Cycle is " + cycle + ", component is " + aComponent); |
| 259 | |
| 260 | int index = getComponentIndex(cycle, aComponent); |
| 261 | |
| 262 | if (index < 0) { |
| 263 | if (log.isLoggable(Level.FINE)) { |
| 264 | log.fine("### Didn't find component " + aComponent + " in a cycle " + aContainer); |
| 265 | } |
| 266 | return getFirstComponent(aContainer); |
| 267 | } |
| 268 | |
| 269 | for (index++; index < cycle.size(); index++) { |
| 270 | comp = cycle.get(index); |
| 271 | if (accept(comp)) { |
| 272 | return comp; |
| 273 | } else if ((comp = getComponentDownCycle(comp, FORWARD_TRAVERSAL)) != null) { |
| 274 | return comp; |
| 275 | } |
| 276 | } |
| 277 | |
| 278 | if (aContainer.isFocusCycleRoot()) { |
| 279 | this.cachedRoot = aContainer; |
| 280 | this.cachedCycle = cycle; |
| 281 | |
| 282 | comp = getFirstComponent(aContainer); |
| 283 | |
| 284 | this.cachedRoot = null; |
| 285 | this.cachedCycle = null; |
| 286 | |
| 287 | return comp; |
| 288 | } |
| 289 | } |
| 290 | return null; |
| 291 | } |
| 292 | |
| 293 | /** |
| 294 | * Returns the Component that should receive the focus before aComponent. |
| 295 | * aContainer must be a focus cycle root of aComponent or a <a |
| 296 | * href="doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus traversal policy |
| 297 | * provider</a>. |
| 298 | * |
| 299 | * @param aContainer a focus cycle root of aComponent or focus traversal policy provider |
| 300 | * @param aComponent a (possibly indirect) child of aContainer, or |
| 301 | * aContainer itself |
| 302 | * @return the Component that should receive the focus before aComponent, |
| 303 | * or null if no suitable Component can be found |
| 304 | * @throws IllegalArgumentException if aContainer is not a focus cycle |
| 305 | * root of aComponent or focus traversal policy provider, or if either aContainer or |
| 306 | * aComponent is null |
| 307 | */ |
| 308 | public Component getComponentBefore(Container aContainer, Component aComponent) { |
| 309 | if (aContainer == null || aComponent == null) { |
| 310 | throw new IllegalArgumentException("aContainer and aComponent cannot be null"); |
| 311 | } |
| 312 | if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) { |
| 313 | throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider"); |
| 314 | |
| 315 | } else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) { |
| 316 | throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent"); |
| 317 | } |
| 318 | |
| 319 | synchronized(aContainer.getTreeLock()) { |
| 320 | |
| 321 | if (!(aContainer.isVisible() && aContainer.isDisplayable())) { |
| 322 | return null; |
| 323 | } |
| 324 | |
| 325 | // See if the component is inside of policy provider. |
| 326 | Container provider = getTopmostProvider(aContainer, aComponent); |
| 327 | if (provider != null) { |
| 328 | if (log.isLoggable(Level.FINE)) { |
| 329 | log.fine("### Asking FTP " + provider + " for component after " + aComponent); |
| 330 | } |
| 331 | |
| 332 | // FTP knows how to find component after the given. We don't. |
| 333 | FocusTraversalPolicy policy = provider.getFocusTraversalPolicy(); |
| 334 | Component beforeComp = policy.getComponentBefore(provider, aComponent); |
| 335 | |
| 336 | // Null result means that we overstepped the limit of the FTP's cycle. |
| 337 | // In that case we must quit the cycle, otherwise return the component found. |
| 338 | if (beforeComp != null) { |
| 339 | if (log.isLoggable(Level.FINE)) log.fine("### FTP returned " + beforeComp); |
| 340 | return beforeComp; |
| 341 | } |
| 342 | aComponent = provider; |
| 343 | |
| 344 | // If the provider is traversable it's returned. |
| 345 | if (accept(aComponent)) { |
| 346 | return aComponent; |
| 347 | } |
| 348 | } |
| 349 | |
| 350 | List<Component> cycle = getFocusTraversalCycle(aContainer); |
| 351 | |
| 352 | if (log.isLoggable(Level.FINE)) log.fine("### Cycle is " + cycle + ", component is " + aComponent); |
| 353 | |
| 354 | int index = getComponentIndex(cycle, aComponent); |
| 355 | |
| 356 | if (index < 0) { |
| 357 | if (log.isLoggable(Level.FINE)) { |
| 358 | log.fine("### Didn't find component " + aComponent + " in a cycle " + aContainer); |
| 359 | } |
| 360 | return getLastComponent(aContainer); |
| 361 | } |
| 362 | |
| 363 | Component comp = null; |
| 364 | Component tryComp = null; |
| 365 | |
| 366 | for (index--; index>=0; index--) { |
| 367 | comp = cycle.get(index); |
| 368 | if (comp != aContainer && (tryComp = getComponentDownCycle(comp, BACKWARD_TRAVERSAL)) != null) { |
| 369 | return tryComp; |
| 370 | } else if (accept(comp)) { |
| 371 | return comp; |
| 372 | } |
| 373 | } |
| 374 | |
| 375 | if (aContainer.isFocusCycleRoot()) { |
| 376 | this.cachedRoot = aContainer; |
| 377 | this.cachedCycle = cycle; |
| 378 | |
| 379 | comp = getLastComponent(aContainer); |
| 380 | |
| 381 | this.cachedRoot = null; |
| 382 | this.cachedCycle = null; |
| 383 | |
| 384 | return comp; |
| 385 | } |
| 386 | } |
| 387 | return null; |
| 388 | } |
| 389 | |
| 390 | /** |
| 391 | * Returns the first Component in the traversal cycle. This method is used |
| 392 | * to determine the next Component to focus when traversal wraps in the |
| 393 | * forward direction. |
| 394 | * |
| 395 | * @param aContainer the focus cycle root or focus traversal policy provider whose first |
| 396 | * Component is to be returned |
| 397 | * @return the first Component in the traversal cycle of aContainer, |
| 398 | * or null if no suitable Component can be found |
| 399 | * @throws IllegalArgumentException if aContainer is null |
| 400 | */ |
| 401 | public Component getFirstComponent(Container aContainer) { |
| 402 | List<Component> cycle; |
| 403 | |
| 404 | if (log.isLoggable(Level.FINE)) log.fine("### Getting first component in " + aContainer); |
| 405 | if (aContainer == null) { |
| 406 | throw new IllegalArgumentException("aContainer cannot be null"); |
| 407 | |
| 408 | } |
| 409 | |
| 410 | synchronized(aContainer.getTreeLock()) { |
| 411 | |
| 412 | if (!(aContainer.isVisible() && aContainer.isDisplayable())) { |
| 413 | return null; |
| 414 | } |
| 415 | |
| 416 | if (this.cachedRoot == aContainer) { |
| 417 | cycle = this.cachedCycle; |
| 418 | } else { |
| 419 | cycle = getFocusTraversalCycle(aContainer); |
| 420 | } |
| 421 | |
| 422 | if (cycle.size() == 0) { |
| 423 | if (log.isLoggable(Level.FINE)) log.fine("### Cycle is empty"); |
| 424 | return null; |
| 425 | } |
| 426 | if (log.isLoggable(Level.FINE)) log.fine("### Cycle is " + cycle); |
| 427 | |
| 428 | for (int i = 0; i < cycle.size(); i++) { |
| 429 | Component comp = cycle.get(i); |
| 430 | if (accept(comp)) { |
| 431 | return comp; |
| 432 | } else if (comp instanceof Container && comp != aContainer) { |
| 433 | Container cont = (Container)comp; |
| 434 | if (cont.isFocusTraversalPolicyProvider()) { |
| 435 | return cont.getFocusTraversalPolicy().getDefaultComponent(cont); |
| 436 | } |
| 437 | } |
| 438 | } |
| 439 | } |
| 440 | return null; |
| 441 | } |
| 442 | |
| 443 | /** |
| 444 | * Returns the last Component in the traversal cycle. This method is used |
| 445 | * to determine the next Component to focus when traversal wraps in the |
| 446 | * reverse direction. |
| 447 | * |
| 448 | * @param aContainer the focus cycle root or focus traversal policy provider whose last |
| 449 | * Component is to be returned |
| 450 | * @return the last Component in the traversal cycle of aContainer, |
| 451 | * or null if no suitable Component can be found |
| 452 | * @throws IllegalArgumentException if aContainer is null |
| 453 | */ |
| 454 | public Component getLastComponent(Container aContainer) { |
| 455 | List<Component> cycle; |
| 456 | if (log.isLoggable(Level.FINE)) log.fine("### Getting last component in " + aContainer); |
| 457 | |
| 458 | if (aContainer == null) { |
| 459 | throw new IllegalArgumentException("aContainer cannot be null"); |
| 460 | } |
| 461 | |
| 462 | synchronized(aContainer.getTreeLock()) { |
| 463 | |
| 464 | if (!(aContainer.isVisible() && aContainer.isDisplayable())) { |
| 465 | return null; |
| 466 | } |
| 467 | |
| 468 | if (this.cachedRoot == aContainer) { |
| 469 | cycle = this.cachedCycle; |
| 470 | } else { |
| 471 | cycle = getFocusTraversalCycle(aContainer); |
| 472 | } |
| 473 | |
| 474 | if (cycle.size() == 0) { |
| 475 | if (log.isLoggable(Level.FINE)) log.fine("### Cycle is empty"); |
| 476 | return null; |
| 477 | } |
| 478 | if (log.isLoggable(Level.FINE)) log.fine("### Cycle is " + cycle); |
| 479 | |
| 480 | for (int i= cycle.size() - 1; i >= 0; i--) { |
| 481 | Component comp = cycle.get(i); |
| 482 | if (accept(comp)) { |
| 483 | return comp; |
| 484 | } else if (comp instanceof Container && comp != aContainer) { |
| 485 | Container cont = (Container)comp; |
| 486 | if (cont.isFocusTraversalPolicyProvider()) { |
| 487 | return cont.getFocusTraversalPolicy().getLastComponent(cont); |
| 488 | } |
| 489 | } |
| 490 | } |
| 491 | } |
| 492 | return null; |
| 493 | } |
| 494 | |
| 495 | /** |
| 496 | * Returns the default Component to focus. This Component will be the first |
| 497 | * to receive focus when traversing down into a new focus traversal cycle |
| 498 | * rooted at aContainer. The default implementation of this method |
| 499 | * returns the same Component as <code>getFirstComponent</code>. |
| 500 | * |
| 501 | * @param aContainer the focus cycle root or focus traversal policy provider whose default |
| 502 | * Component is to be returned |
| 503 | * @return the default Component in the traversal cycle of aContainer, |
| 504 | * or null if no suitable Component can be found |
| 505 | * @see #getFirstComponent |
| 506 | * @throws IllegalArgumentException if aContainer is null |
| 507 | */ |
| 508 | public Component getDefaultComponent(Container aContainer) { |
| 509 | return getFirstComponent(aContainer); |
| 510 | } |
| 511 | |
| 512 | /** |
| 513 | * Sets whether this ContainerOrderFocusTraversalPolicy transfers focus |
| 514 | * down-cycle implicitly. If <code>true</code>, during normal forward focus |
| 515 | * traversal, the Component traversed after a focus cycle root will be the |
| 516 | * focus-cycle-root's default Component to focus. If <code>false</code>, |
| 517 | * the next Component in the focus traversal cycle rooted at the specified |
| 518 | * focus cycle root will be traversed instead. The default value for this |
| 519 | * property is <code>true</code>. |
| 520 | * |
| 521 | * @param implicitDownCycleTraversal whether this |
| 522 | * ContainerOrderFocusTraversalPolicy transfers focus down-cycle |
| 523 | * implicitly |
| 524 | * @see #getImplicitDownCycleTraversal |
| 525 | * @see #getFirstComponent |
| 526 | */ |
| 527 | public void setImplicitDownCycleTraversal(boolean implicitDownCycleTraversal) { |
| 528 | this.implicitDownCycleTraversal = implicitDownCycleTraversal; |
| 529 | } |
| 530 | |
| 531 | /** |
| 532 | * Returns whether this ContainerOrderFocusTraversalPolicy transfers focus |
| 533 | * down-cycle implicitly. If <code>true</code>, during normal forward focus |
| 534 | * traversal, the Component traversed after a focus cycle root will be the |
| 535 | * focus-cycle-root's default Component to focus. If <code>false</code>, |
| 536 | * the next Component in the focus traversal cycle rooted at the specified |
| 537 | * focus cycle root will be traversed instead. |
| 538 | * |
| 539 | * @return whether this ContainerOrderFocusTraversalPolicy transfers focus |
| 540 | * down-cycle implicitly |
| 541 | * @see #setImplicitDownCycleTraversal |
| 542 | * @see #getFirstComponent |
| 543 | */ |
| 544 | public boolean getImplicitDownCycleTraversal() { |
| 545 | return implicitDownCycleTraversal; |
| 546 | } |
| 547 | |
| 548 | /** |
| 549 | * Determines whether a Component is an acceptable choice as the new |
| 550 | * focus owner. By default, this method will accept a Component if and |
| 551 | * only if it is visible, displayable, enabled, and focusable. |
| 552 | * |
| 553 | * @param aComponent the Component whose fitness as a focus owner is to |
| 554 | * be tested |
| 555 | * @return <code>true</code> if aComponent is visible, displayable, |
| 556 | * enabled, and focusable; <code>false</code> otherwise |
| 557 | */ |
| 558 | protected boolean accept(Component aComponent) { |
| 559 | if (!(aComponent.isVisible() && aComponent.isDisplayable() && |
| 560 | aComponent.isFocusable() && aComponent.isEnabled())) { |
| 561 | return false; |
| 562 | } |
| 563 | |
| 564 | // Verify that the Component is recursively enabled. Disabling a |
| 565 | // heavyweight Container disables its children, whereas disabling |
| 566 | // a lightweight Container does not. |
| 567 | if (!(aComponent instanceof Window)) { |
| 568 | for (Container enableTest = aComponent.getParent(); |
| 569 | enableTest != null; |
| 570 | enableTest = enableTest.getParent()) |
| 571 | { |
| 572 | if (!(enableTest.isEnabled() || enableTest.isLightweight())) { |
| 573 | return false; |
| 574 | } |
| 575 | if (enableTest instanceof Window) { |
| 576 | break; |
| 577 | } |
| 578 | } |
| 579 | } |
| 580 | |
| 581 | return true; |
| 582 | } |
| 583 | } |