J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1997-2006 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.tree; |
| 27 | // ISSUE: this class depends on nothing in AWT -- move to java.util? |
| 28 | |
| 29 | import java.io.*; |
| 30 | import java.util.*; |
| 31 | |
| 32 | |
| 33 | /** |
| 34 | * A <code>DefaultMutableTreeNode</code> is a general-purpose node in a tree data |
| 35 | * structure. |
| 36 | * For examples of using default mutable tree nodes, see |
| 37 | * <a |
| 38 | href="http://java.sun.com/docs/books/tutorial/uiswing/components/tree.html">How to Use Trees</a> |
| 39 | * in <em>The Java Tutorial.</em> |
| 40 | * |
| 41 | * <p> |
| 42 | * |
| 43 | * A tree node may have at most one parent and 0 or more children. |
| 44 | * <code>DefaultMutableTreeNode</code> provides operations for examining and modifying a |
| 45 | * node's parent and children and also operations for examining the tree that |
| 46 | * the node is a part of. A node's tree is the set of all nodes that can be |
| 47 | * reached by starting at the node and following all the possible links to |
| 48 | * parents and children. A node with no parent is the root of its tree; a |
| 49 | * node with no children is a leaf. A tree may consist of many subtrees, |
| 50 | * each node acting as the root for its own subtree. |
| 51 | * <p> |
| 52 | * This class provides enumerations for efficiently traversing a tree or |
| 53 | * subtree in various orders or for following the path between two nodes. |
| 54 | * A <code>DefaultMutableTreeNode</code> may also hold a reference to a user object, the |
| 55 | * use of which is left to the user. Asking a <code>DefaultMutableTreeNode</code> for its |
| 56 | * string representation with <code>toString()</code> returns the string |
| 57 | * representation of its user object. |
| 58 | * <p> |
| 59 | * <b>This is not a thread safe class.</b>If you intend to use |
| 60 | * a DefaultMutableTreeNode (or a tree of TreeNodes) in more than one thread, you |
| 61 | * need to do your own synchronizing. A good convention to adopt is |
| 62 | * synchronizing on the root node of a tree. |
| 63 | * <p> |
| 64 | * While DefaultMutableTreeNode implements the MutableTreeNode interface and |
| 65 | * will allow you to add in any implementation of MutableTreeNode not all |
| 66 | * of the methods in DefaultMutableTreeNode will be applicable to all |
| 67 | * MutableTreeNodes implementations. Especially with some of the enumerations |
| 68 | * that are provided, using some of these methods assumes the |
| 69 | * DefaultMutableTreeNode contains only DefaultMutableNode instances. All |
| 70 | * of the TreeNode/MutableTreeNode methods will behave as defined no |
| 71 | * matter what implementations are added. |
| 72 | * |
| 73 | * <p> |
| 74 | * <strong>Warning:</strong> |
| 75 | * Serialized objects of this class will not be compatible with |
| 76 | * future Swing releases. The current serialization support is |
| 77 | * appropriate for short term storage or RMI between applications running |
| 78 | * the same version of Swing. As of 1.4, support for long term storage |
| 79 | * of all JavaBeans<sup><font size="-2">TM</font></sup> |
| 80 | * has been added to the <code>java.beans</code> package. |
| 81 | * Please see {@link java.beans.XMLEncoder}. |
| 82 | * |
| 83 | * @see MutableTreeNode |
| 84 | * |
| 85 | * @author Rob Davis |
| 86 | */ |
| 87 | public class DefaultMutableTreeNode extends Object implements Cloneable, |
| 88 | MutableTreeNode, Serializable |
| 89 | { |
| 90 | private static final long serialVersionUID = -4298474751201349152L; |
| 91 | |
| 92 | /** |
| 93 | * An enumeration that is always empty. This is used when an enumeration |
| 94 | * of a leaf node's children is requested. |
| 95 | */ |
| 96 | static public final Enumeration<TreeNode> EMPTY_ENUMERATION |
| 97 | = Collections.emptyEnumeration(); |
| 98 | |
| 99 | /** this node's parent, or null if this node has no parent */ |
| 100 | protected MutableTreeNode parent; |
| 101 | |
| 102 | /** array of children, may be null if this node has no children */ |
| 103 | protected Vector children; |
| 104 | |
| 105 | /** optional user object */ |
| 106 | transient protected Object userObject; |
| 107 | |
| 108 | /** true if the node is able to have children */ |
| 109 | protected boolean allowsChildren; |
| 110 | |
| 111 | |
| 112 | /** |
| 113 | * Creates a tree node that has no parent and no children, but which |
| 114 | * allows children. |
| 115 | */ |
| 116 | public DefaultMutableTreeNode() { |
| 117 | this(null); |
| 118 | } |
| 119 | |
| 120 | /** |
| 121 | * Creates a tree node with no parent, no children, but which allows |
| 122 | * children, and initializes it with the specified user object. |
| 123 | * |
| 124 | * @param userObject an Object provided by the user that constitutes |
| 125 | * the node's data |
| 126 | */ |
| 127 | public DefaultMutableTreeNode(Object userObject) { |
| 128 | this(userObject, true); |
| 129 | } |
| 130 | |
| 131 | /** |
| 132 | * Creates a tree node with no parent, no children, initialized with |
| 133 | * the specified user object, and that allows children only if |
| 134 | * specified. |
| 135 | * |
| 136 | * @param userObject an Object provided by the user that constitutes |
| 137 | * the node's data |
| 138 | * @param allowsChildren if true, the node is allowed to have child |
| 139 | * nodes -- otherwise, it is always a leaf node |
| 140 | */ |
| 141 | public DefaultMutableTreeNode(Object userObject, boolean allowsChildren) { |
| 142 | super(); |
| 143 | parent = null; |
| 144 | this.allowsChildren = allowsChildren; |
| 145 | this.userObject = userObject; |
| 146 | } |
| 147 | |
| 148 | |
| 149 | // |
| 150 | // Primitives |
| 151 | // |
| 152 | |
| 153 | /** |
| 154 | * Removes <code>newChild</code> from its present parent (if it has a |
| 155 | * parent), sets the child's parent to this node, and then adds the child |
| 156 | * to this node's child array at index <code>childIndex</code>. |
| 157 | * <code>newChild</code> must not be null and must not be an ancestor of |
| 158 | * this node. |
| 159 | * |
| 160 | * @param newChild the MutableTreeNode to insert under this node |
| 161 | * @param childIndex the index in this node's child array |
| 162 | * where this node is to be inserted |
| 163 | * @exception ArrayIndexOutOfBoundsException if |
| 164 | * <code>childIndex</code> is out of bounds |
| 165 | * @exception IllegalArgumentException if |
| 166 | * <code>newChild</code> is null or is an |
| 167 | * ancestor of this node |
| 168 | * @exception IllegalStateException if this node does not allow |
| 169 | * children |
| 170 | * @see #isNodeDescendant |
| 171 | */ |
| 172 | public void insert(MutableTreeNode newChild, int childIndex) { |
| 173 | if (!allowsChildren) { |
| 174 | throw new IllegalStateException("node does not allow children"); |
| 175 | } else if (newChild == null) { |
| 176 | throw new IllegalArgumentException("new child is null"); |
| 177 | } else if (isNodeAncestor(newChild)) { |
| 178 | throw new IllegalArgumentException("new child is an ancestor"); |
| 179 | } |
| 180 | |
| 181 | MutableTreeNode oldParent = (MutableTreeNode)newChild.getParent(); |
| 182 | |
| 183 | if (oldParent != null) { |
| 184 | oldParent.remove(newChild); |
| 185 | } |
| 186 | newChild.setParent(this); |
| 187 | if (children == null) { |
| 188 | children = new Vector(); |
| 189 | } |
| 190 | children.insertElementAt(newChild, childIndex); |
| 191 | } |
| 192 | |
| 193 | /** |
| 194 | * Removes the child at the specified index from this node's children |
| 195 | * and sets that node's parent to null. The child node to remove |
| 196 | * must be a <code>MutableTreeNode</code>. |
| 197 | * |
| 198 | * @param childIndex the index in this node's child array |
| 199 | * of the child to remove |
| 200 | * @exception ArrayIndexOutOfBoundsException if |
| 201 | * <code>childIndex</code> is out of bounds |
| 202 | */ |
| 203 | public void remove(int childIndex) { |
| 204 | MutableTreeNode child = (MutableTreeNode)getChildAt(childIndex); |
| 205 | children.removeElementAt(childIndex); |
| 206 | child.setParent(null); |
| 207 | } |
| 208 | |
| 209 | /** |
| 210 | * Sets this node's parent to <code>newParent</code> but does not |
| 211 | * change the parent's child array. This method is called from |
| 212 | * <code>insert()</code> and <code>remove()</code> to |
| 213 | * reassign a child's parent, it should not be messaged from anywhere |
| 214 | * else. |
| 215 | * |
| 216 | * @param newParent this node's new parent |
| 217 | */ |
| 218 | public void setParent(MutableTreeNode newParent) { |
| 219 | parent = newParent; |
| 220 | } |
| 221 | |
| 222 | /** |
| 223 | * Returns this node's parent or null if this node has no parent. |
| 224 | * |
| 225 | * @return this node's parent TreeNode, or null if this node has no parent |
| 226 | */ |
| 227 | public TreeNode getParent() { |
| 228 | return parent; |
| 229 | } |
| 230 | |
| 231 | /** |
| 232 | * Returns the child at the specified index in this node's child array. |
| 233 | * |
| 234 | * @param index an index into this node's child array |
| 235 | * @exception ArrayIndexOutOfBoundsException if <code>index</code> |
| 236 | * is out of bounds |
| 237 | * @return the TreeNode in this node's child array at the specified index |
| 238 | */ |
| 239 | public TreeNode getChildAt(int index) { |
| 240 | if (children == null) { |
| 241 | throw new ArrayIndexOutOfBoundsException("node has no children"); |
| 242 | } |
| 243 | return (TreeNode)children.elementAt(index); |
| 244 | } |
| 245 | |
| 246 | /** |
| 247 | * Returns the number of children of this node. |
| 248 | * |
| 249 | * @return an int giving the number of children of this node |
| 250 | */ |
| 251 | public int getChildCount() { |
| 252 | if (children == null) { |
| 253 | return 0; |
| 254 | } else { |
| 255 | return children.size(); |
| 256 | } |
| 257 | } |
| 258 | |
| 259 | /** |
| 260 | * Returns the index of the specified child in this node's child array. |
| 261 | * If the specified node is not a child of this node, returns |
| 262 | * <code>-1</code>. This method performs a linear search and is O(n) |
| 263 | * where n is the number of children. |
| 264 | * |
| 265 | * @param aChild the TreeNode to search for among this node's children |
| 266 | * @exception IllegalArgumentException if <code>aChild</code> |
| 267 | * is null |
| 268 | * @return an int giving the index of the node in this node's child |
| 269 | * array, or <code>-1</code> if the specified node is a not |
| 270 | * a child of this node |
| 271 | */ |
| 272 | public int getIndex(TreeNode aChild) { |
| 273 | if (aChild == null) { |
| 274 | throw new IllegalArgumentException("argument is null"); |
| 275 | } |
| 276 | |
| 277 | if (!isNodeChild(aChild)) { |
| 278 | return -1; |
| 279 | } |
| 280 | return children.indexOf(aChild); // linear search |
| 281 | } |
| 282 | |
| 283 | /** |
| 284 | * Creates and returns a forward-order enumeration of this node's |
| 285 | * children. Modifying this node's child array invalidates any child |
| 286 | * enumerations created before the modification. |
| 287 | * |
| 288 | * @return an Enumeration of this node's children |
| 289 | */ |
| 290 | public Enumeration children() { |
| 291 | if (children == null) { |
| 292 | return EMPTY_ENUMERATION; |
| 293 | } else { |
| 294 | return children.elements(); |
| 295 | } |
| 296 | } |
| 297 | |
| 298 | /** |
| 299 | * Determines whether or not this node is allowed to have children. |
| 300 | * If <code>allows</code> is false, all of this node's children are |
| 301 | * removed. |
| 302 | * <p> |
| 303 | * Note: By default, a node allows children. |
| 304 | * |
| 305 | * @param allows true if this node is allowed to have children |
| 306 | */ |
| 307 | public void setAllowsChildren(boolean allows) { |
| 308 | if (allows != allowsChildren) { |
| 309 | allowsChildren = allows; |
| 310 | if (!allowsChildren) { |
| 311 | removeAllChildren(); |
| 312 | } |
| 313 | } |
| 314 | } |
| 315 | |
| 316 | /** |
| 317 | * Returns true if this node is allowed to have children. |
| 318 | * |
| 319 | * @return true if this node allows children, else false |
| 320 | */ |
| 321 | public boolean getAllowsChildren() { |
| 322 | return allowsChildren; |
| 323 | } |
| 324 | |
| 325 | /** |
| 326 | * Sets the user object for this node to <code>userObject</code>. |
| 327 | * |
| 328 | * @param userObject the Object that constitutes this node's |
| 329 | * user-specified data |
| 330 | * @see #getUserObject |
| 331 | * @see #toString |
| 332 | */ |
| 333 | public void setUserObject(Object userObject) { |
| 334 | this.userObject = userObject; |
| 335 | } |
| 336 | |
| 337 | /** |
| 338 | * Returns this node's user object. |
| 339 | * |
| 340 | * @return the Object stored at this node by the user |
| 341 | * @see #setUserObject |
| 342 | * @see #toString |
| 343 | */ |
| 344 | public Object getUserObject() { |
| 345 | return userObject; |
| 346 | } |
| 347 | |
| 348 | |
| 349 | // |
| 350 | // Derived methods |
| 351 | // |
| 352 | |
| 353 | /** |
| 354 | * Removes the subtree rooted at this node from the tree, giving this |
| 355 | * node a null parent. Does nothing if this node is the root of its |
| 356 | * tree. |
| 357 | */ |
| 358 | public void removeFromParent() { |
| 359 | MutableTreeNode parent = (MutableTreeNode)getParent(); |
| 360 | if (parent != null) { |
| 361 | parent.remove(this); |
| 362 | } |
| 363 | } |
| 364 | |
| 365 | /** |
| 366 | * Removes <code>aChild</code> from this node's child array, giving it a |
| 367 | * null parent. |
| 368 | * |
| 369 | * @param aChild a child of this node to remove |
| 370 | * @exception IllegalArgumentException if <code>aChild</code> |
| 371 | * is null or is not a child of this node |
| 372 | */ |
| 373 | public void remove(MutableTreeNode aChild) { |
| 374 | if (aChild == null) { |
| 375 | throw new IllegalArgumentException("argument is null"); |
| 376 | } |
| 377 | |
| 378 | if (!isNodeChild(aChild)) { |
| 379 | throw new IllegalArgumentException("argument is not a child"); |
| 380 | } |
| 381 | remove(getIndex(aChild)); // linear search |
| 382 | } |
| 383 | |
| 384 | /** |
| 385 | * Removes all of this node's children, setting their parents to null. |
| 386 | * If this node has no children, this method does nothing. |
| 387 | */ |
| 388 | public void removeAllChildren() { |
| 389 | for (int i = getChildCount()-1; i >= 0; i--) { |
| 390 | remove(i); |
| 391 | } |
| 392 | } |
| 393 | |
| 394 | /** |
| 395 | * Removes <code>newChild</code> from its parent and makes it a child of |
| 396 | * this node by adding it to the end of this node's child array. |
| 397 | * |
| 398 | * @see #insert |
| 399 | * @param newChild node to add as a child of this node |
| 400 | * @exception IllegalArgumentException if <code>newChild</code> |
| 401 | * is null |
| 402 | * @exception IllegalStateException if this node does not allow |
| 403 | * children |
| 404 | */ |
| 405 | public void add(MutableTreeNode newChild) { |
| 406 | if(newChild != null && newChild.getParent() == this) |
| 407 | insert(newChild, getChildCount() - 1); |
| 408 | else |
| 409 | insert(newChild, getChildCount()); |
| 410 | } |
| 411 | |
| 412 | |
| 413 | |
| 414 | // |
| 415 | // Tree Queries |
| 416 | // |
| 417 | |
| 418 | /** |
| 419 | * Returns true if <code>anotherNode</code> is an ancestor of this node |
| 420 | * -- if it is this node, this node's parent, or an ancestor of this |
| 421 | * node's parent. (Note that a node is considered an ancestor of itself.) |
| 422 | * If <code>anotherNode</code> is null, this method returns false. This |
| 423 | * operation is at worst O(h) where h is the distance from the root to |
| 424 | * this node. |
| 425 | * |
| 426 | * @see #isNodeDescendant |
| 427 | * @see #getSharedAncestor |
| 428 | * @param anotherNode node to test as an ancestor of this node |
| 429 | * @return true if this node is a descendant of <code>anotherNode</code> |
| 430 | */ |
| 431 | public boolean isNodeAncestor(TreeNode anotherNode) { |
| 432 | if (anotherNode == null) { |
| 433 | return false; |
| 434 | } |
| 435 | |
| 436 | TreeNode ancestor = this; |
| 437 | |
| 438 | do { |
| 439 | if (ancestor == anotherNode) { |
| 440 | return true; |
| 441 | } |
| 442 | } while((ancestor = ancestor.getParent()) != null); |
| 443 | |
| 444 | return false; |
| 445 | } |
| 446 | |
| 447 | /** |
| 448 | * Returns true if <code>anotherNode</code> is a descendant of this node |
| 449 | * -- if it is this node, one of this node's children, or a descendant of |
| 450 | * one of this node's children. Note that a node is considered a |
| 451 | * descendant of itself. If <code>anotherNode</code> is null, returns |
| 452 | * false. This operation is at worst O(h) where h is the distance from the |
| 453 | * root to <code>anotherNode</code>. |
| 454 | * |
| 455 | * @see #isNodeAncestor |
| 456 | * @see #getSharedAncestor |
| 457 | * @param anotherNode node to test as descendant of this node |
| 458 | * @return true if this node is an ancestor of <code>anotherNode</code> |
| 459 | */ |
| 460 | public boolean isNodeDescendant(DefaultMutableTreeNode anotherNode) { |
| 461 | if (anotherNode == null) |
| 462 | return false; |
| 463 | |
| 464 | return anotherNode.isNodeAncestor(this); |
| 465 | } |
| 466 | |
| 467 | /** |
| 468 | * Returns the nearest common ancestor to this node and <code>aNode</code>. |
| 469 | * Returns null, if no such ancestor exists -- if this node and |
| 470 | * <code>aNode</code> are in different trees or if <code>aNode</code> is |
| 471 | * null. A node is considered an ancestor of itself. |
| 472 | * |
| 473 | * @see #isNodeAncestor |
| 474 | * @see #isNodeDescendant |
| 475 | * @param aNode node to find common ancestor with |
| 476 | * @return nearest ancestor common to this node and <code>aNode</code>, |
| 477 | * or null if none |
| 478 | */ |
| 479 | public TreeNode getSharedAncestor(DefaultMutableTreeNode aNode) { |
| 480 | if (aNode == this) { |
| 481 | return this; |
| 482 | } else if (aNode == null) { |
| 483 | return null; |
| 484 | } |
| 485 | |
| 486 | int level1, level2, diff; |
| 487 | TreeNode node1, node2; |
| 488 | |
| 489 | level1 = getLevel(); |
| 490 | level2 = aNode.getLevel(); |
| 491 | |
| 492 | if (level2 > level1) { |
| 493 | diff = level2 - level1; |
| 494 | node1 = aNode; |
| 495 | node2 = this; |
| 496 | } else { |
| 497 | diff = level1 - level2; |
| 498 | node1 = this; |
| 499 | node2 = aNode; |
| 500 | } |
| 501 | |
| 502 | // Go up the tree until the nodes are at the same level |
| 503 | while (diff > 0) { |
| 504 | node1 = node1.getParent(); |
| 505 | diff--; |
| 506 | } |
| 507 | |
| 508 | // Move up the tree until we find a common ancestor. Since we know |
| 509 | // that both nodes are at the same level, we won't cross paths |
| 510 | // unknowingly (if there is a common ancestor, both nodes hit it in |
| 511 | // the same iteration). |
| 512 | |
| 513 | do { |
| 514 | if (node1 == node2) { |
| 515 | return node1; |
| 516 | } |
| 517 | node1 = node1.getParent(); |
| 518 | node2 = node2.getParent(); |
| 519 | } while (node1 != null);// only need to check one -- they're at the |
| 520 | // same level so if one is null, the other is |
| 521 | |
| 522 | if (node1 != null || node2 != null) { |
| 523 | throw new Error ("nodes should be null"); |
| 524 | } |
| 525 | |
| 526 | return null; |
| 527 | } |
| 528 | |
| 529 | |
| 530 | /** |
| 531 | * Returns true if and only if <code>aNode</code> is in the same tree |
| 532 | * as this node. Returns false if <code>aNode</code> is null. |
| 533 | * |
| 534 | * @see #getSharedAncestor |
| 535 | * @see #getRoot |
| 536 | * @return true if <code>aNode</code> is in the same tree as this node; |
| 537 | * false if <code>aNode</code> is null |
| 538 | */ |
| 539 | public boolean isNodeRelated(DefaultMutableTreeNode aNode) { |
| 540 | return (aNode != null) && (getRoot() == aNode.getRoot()); |
| 541 | } |
| 542 | |
| 543 | |
| 544 | /** |
| 545 | * Returns the depth of the tree rooted at this node -- the longest |
| 546 | * distance from this node to a leaf. If this node has no children, |
| 547 | * returns 0. This operation is much more expensive than |
| 548 | * <code>getLevel()</code> because it must effectively traverse the entire |
| 549 | * tree rooted at this node. |
| 550 | * |
| 551 | * @see #getLevel |
| 552 | * @return the depth of the tree whose root is this node |
| 553 | */ |
| 554 | public int getDepth() { |
| 555 | Object last = null; |
| 556 | Enumeration enum_ = breadthFirstEnumeration(); |
| 557 | |
| 558 | while (enum_.hasMoreElements()) { |
| 559 | last = enum_.nextElement(); |
| 560 | } |
| 561 | |
| 562 | if (last == null) { |
| 563 | throw new Error ("nodes should be null"); |
| 564 | } |
| 565 | |
| 566 | return ((DefaultMutableTreeNode)last).getLevel() - getLevel(); |
| 567 | } |
| 568 | |
| 569 | |
| 570 | |
| 571 | /** |
| 572 | * Returns the number of levels above this node -- the distance from |
| 573 | * the root to this node. If this node is the root, returns 0. |
| 574 | * |
| 575 | * @see #getDepth |
| 576 | * @return the number of levels above this node |
| 577 | */ |
| 578 | public int getLevel() { |
| 579 | TreeNode ancestor; |
| 580 | int levels = 0; |
| 581 | |
| 582 | ancestor = this; |
| 583 | while((ancestor = ancestor.getParent()) != null){ |
| 584 | levels++; |
| 585 | } |
| 586 | |
| 587 | return levels; |
| 588 | } |
| 589 | |
| 590 | |
| 591 | /** |
| 592 | * Returns the path from the root, to get to this node. The last |
| 593 | * element in the path is this node. |
| 594 | * |
| 595 | * @return an array of TreeNode objects giving the path, where the |
| 596 | * first element in the path is the root and the last |
| 597 | * element is this node. |
| 598 | */ |
| 599 | public TreeNode[] getPath() { |
| 600 | return getPathToRoot(this, 0); |
| 601 | } |
| 602 | |
| 603 | /** |
| 604 | * Builds the parents of node up to and including the root node, |
| 605 | * where the original node is the last element in the returned array. |
| 606 | * The length of the returned array gives the node's depth in the |
| 607 | * tree. |
| 608 | * |
| 609 | * @param aNode the TreeNode to get the path for |
| 610 | * @param depth an int giving the number of steps already taken towards |
| 611 | * the root (on recursive calls), used to size the returned array |
| 612 | * @return an array of TreeNodes giving the path from the root to the |
| 613 | * specified node |
| 614 | */ |
| 615 | protected TreeNode[] getPathToRoot(TreeNode aNode, int depth) { |
| 616 | TreeNode[] retNodes; |
| 617 | |
| 618 | /* Check for null, in case someone passed in a null node, or |
| 619 | they passed in an element that isn't rooted at root. */ |
| 620 | if(aNode == null) { |
| 621 | if(depth == 0) |
| 622 | return null; |
| 623 | else |
| 624 | retNodes = new TreeNode[depth]; |
| 625 | } |
| 626 | else { |
| 627 | depth++; |
| 628 | retNodes = getPathToRoot(aNode.getParent(), depth); |
| 629 | retNodes[retNodes.length - depth] = aNode; |
| 630 | } |
| 631 | return retNodes; |
| 632 | } |
| 633 | |
| 634 | /** |
| 635 | * Returns the user object path, from the root, to get to this node. |
| 636 | * If some of the TreeNodes in the path have null user objects, the |
| 637 | * returned path will contain nulls. |
| 638 | */ |
| 639 | public Object[] getUserObjectPath() { |
| 640 | TreeNode[] realPath = getPath(); |
| 641 | Object[] retPath = new Object[realPath.length]; |
| 642 | |
| 643 | for(int counter = 0; counter < realPath.length; counter++) |
| 644 | retPath[counter] = ((DefaultMutableTreeNode)realPath[counter]) |
| 645 | .getUserObject(); |
| 646 | return retPath; |
| 647 | } |
| 648 | |
| 649 | /** |
| 650 | * Returns the root of the tree that contains this node. The root is |
| 651 | * the ancestor with a null parent. |
| 652 | * |
| 653 | * @see #isNodeAncestor |
| 654 | * @return the root of the tree that contains this node |
| 655 | */ |
| 656 | public TreeNode getRoot() { |
| 657 | TreeNode ancestor = this; |
| 658 | TreeNode previous; |
| 659 | |
| 660 | do { |
| 661 | previous = ancestor; |
| 662 | ancestor = ancestor.getParent(); |
| 663 | } while (ancestor != null); |
| 664 | |
| 665 | return previous; |
| 666 | } |
| 667 | |
| 668 | |
| 669 | /** |
| 670 | * Returns true if this node is the root of the tree. The root is |
| 671 | * the only node in the tree with a null parent; every tree has exactly |
| 672 | * one root. |
| 673 | * |
| 674 | * @return true if this node is the root of its tree |
| 675 | */ |
| 676 | public boolean isRoot() { |
| 677 | return getParent() == null; |
| 678 | } |
| 679 | |
| 680 | |
| 681 | /** |
| 682 | * Returns the node that follows this node in a preorder traversal of this |
| 683 | * node's tree. Returns null if this node is the last node of the |
| 684 | * traversal. This is an inefficient way to traverse the entire tree; use |
| 685 | * an enumeration, instead. |
| 686 | * |
| 687 | * @see #preorderEnumeration |
| 688 | * @return the node that follows this node in a preorder traversal, or |
| 689 | * null if this node is last |
| 690 | */ |
| 691 | public DefaultMutableTreeNode getNextNode() { |
| 692 | if (getChildCount() == 0) { |
| 693 | // No children, so look for nextSibling |
| 694 | DefaultMutableTreeNode nextSibling = getNextSibling(); |
| 695 | |
| 696 | if (nextSibling == null) { |
| 697 | DefaultMutableTreeNode aNode = (DefaultMutableTreeNode)getParent(); |
| 698 | |
| 699 | do { |
| 700 | if (aNode == null) { |
| 701 | return null; |
| 702 | } |
| 703 | |
| 704 | nextSibling = aNode.getNextSibling(); |
| 705 | if (nextSibling != null) { |
| 706 | return nextSibling; |
| 707 | } |
| 708 | |
| 709 | aNode = (DefaultMutableTreeNode)aNode.getParent(); |
| 710 | } while(true); |
| 711 | } else { |
| 712 | return nextSibling; |
| 713 | } |
| 714 | } else { |
| 715 | return (DefaultMutableTreeNode)getChildAt(0); |
| 716 | } |
| 717 | } |
| 718 | |
| 719 | |
| 720 | /** |
| 721 | * Returns the node that precedes this node in a preorder traversal of |
| 722 | * this node's tree. Returns <code>null</code> if this node is the |
| 723 | * first node of the traversal -- the root of the tree. |
| 724 | * This is an inefficient way to |
| 725 | * traverse the entire tree; use an enumeration, instead. |
| 726 | * |
| 727 | * @see #preorderEnumeration |
| 728 | * @return the node that precedes this node in a preorder traversal, or |
| 729 | * null if this node is the first |
| 730 | */ |
| 731 | public DefaultMutableTreeNode getPreviousNode() { |
| 732 | DefaultMutableTreeNode previousSibling; |
| 733 | DefaultMutableTreeNode myParent = (DefaultMutableTreeNode)getParent(); |
| 734 | |
| 735 | if (myParent == null) { |
| 736 | return null; |
| 737 | } |
| 738 | |
| 739 | previousSibling = getPreviousSibling(); |
| 740 | |
| 741 | if (previousSibling != null) { |
| 742 | if (previousSibling.getChildCount() == 0) |
| 743 | return previousSibling; |
| 744 | else |
| 745 | return previousSibling.getLastLeaf(); |
| 746 | } else { |
| 747 | return myParent; |
| 748 | } |
| 749 | } |
| 750 | |
| 751 | /** |
| 752 | * Creates and returns an enumeration that traverses the subtree rooted at |
| 753 | * this node in preorder. The first node returned by the enumeration's |
| 754 | * <code>nextElement()</code> method is this node.<P> |
| 755 | * |
| 756 | * Modifying the tree by inserting, removing, or moving a node invalidates |
| 757 | * any enumerations created before the modification. |
| 758 | * |
| 759 | * @see #postorderEnumeration |
| 760 | * @return an enumeration for traversing the tree in preorder |
| 761 | */ |
| 762 | public Enumeration preorderEnumeration() { |
| 763 | return new PreorderEnumeration(this); |
| 764 | } |
| 765 | |
| 766 | /** |
| 767 | * Creates and returns an enumeration that traverses the subtree rooted at |
| 768 | * this node in postorder. The first node returned by the enumeration's |
| 769 | * <code>nextElement()</code> method is the leftmost leaf. This is the |
| 770 | * same as a depth-first traversal.<P> |
| 771 | * |
| 772 | * Modifying the tree by inserting, removing, or moving a node invalidates |
| 773 | * any enumerations created before the modification. |
| 774 | * |
| 775 | * @see #depthFirstEnumeration |
| 776 | * @see #preorderEnumeration |
| 777 | * @return an enumeration for traversing the tree in postorder |
| 778 | */ |
| 779 | public Enumeration postorderEnumeration() { |
| 780 | return new PostorderEnumeration(this); |
| 781 | } |
| 782 | |
| 783 | /** |
| 784 | * Creates and returns an enumeration that traverses the subtree rooted at |
| 785 | * this node in breadth-first order. The first node returned by the |
| 786 | * enumeration's <code>nextElement()</code> method is this node.<P> |
| 787 | * |
| 788 | * Modifying the tree by inserting, removing, or moving a node invalidates |
| 789 | * any enumerations created before the modification. |
| 790 | * |
| 791 | * @see #depthFirstEnumeration |
| 792 | * @return an enumeration for traversing the tree in breadth-first order |
| 793 | */ |
| 794 | public Enumeration breadthFirstEnumeration() { |
| 795 | return new BreadthFirstEnumeration(this); |
| 796 | } |
| 797 | |
| 798 | /** |
| 799 | * Creates and returns an enumeration that traverses the subtree rooted at |
| 800 | * this node in depth-first order. The first node returned by the |
| 801 | * enumeration's <code>nextElement()</code> method is the leftmost leaf. |
| 802 | * This is the same as a postorder traversal.<P> |
| 803 | * |
| 804 | * Modifying the tree by inserting, removing, or moving a node invalidates |
| 805 | * any enumerations created before the modification. |
| 806 | * |
| 807 | * @see #breadthFirstEnumeration |
| 808 | * @see #postorderEnumeration |
| 809 | * @return an enumeration for traversing the tree in depth-first order |
| 810 | */ |
| 811 | public Enumeration depthFirstEnumeration() { |
| 812 | return postorderEnumeration(); |
| 813 | } |
| 814 | |
| 815 | /** |
| 816 | * Creates and returns an enumeration that follows the path from |
| 817 | * <code>ancestor</code> to this node. The enumeration's |
| 818 | * <code>nextElement()</code> method first returns <code>ancestor</code>, |
| 819 | * then the child of <code>ancestor</code> that is an ancestor of this |
| 820 | * node, and so on, and finally returns this node. Creation of the |
| 821 | * enumeration is O(m) where m is the number of nodes between this node |
| 822 | * and <code>ancestor</code>, inclusive. Each <code>nextElement()</code> |
| 823 | * message is O(1).<P> |
| 824 | * |
| 825 | * Modifying the tree by inserting, removing, or moving a node invalidates |
| 826 | * any enumerations created before the modification. |
| 827 | * |
| 828 | * @see #isNodeAncestor |
| 829 | * @see #isNodeDescendant |
| 830 | * @exception IllegalArgumentException if <code>ancestor</code> is |
| 831 | * not an ancestor of this node |
| 832 | * @return an enumeration for following the path from an ancestor of |
| 833 | * this node to this one |
| 834 | */ |
| 835 | public Enumeration pathFromAncestorEnumeration(TreeNode ancestor) { |
| 836 | return new PathBetweenNodesEnumeration(ancestor, this); |
| 837 | } |
| 838 | |
| 839 | |
| 840 | // |
| 841 | // Child Queries |
| 842 | // |
| 843 | |
| 844 | /** |
| 845 | * Returns true if <code>aNode</code> is a child of this node. If |
| 846 | * <code>aNode</code> is null, this method returns false. |
| 847 | * |
| 848 | * @return true if <code>aNode</code> is a child of this node; false if |
| 849 | * <code>aNode</code> is null |
| 850 | */ |
| 851 | public boolean isNodeChild(TreeNode aNode) { |
| 852 | boolean retval; |
| 853 | |
| 854 | if (aNode == null) { |
| 855 | retval = false; |
| 856 | } else { |
| 857 | if (getChildCount() == 0) { |
| 858 | retval = false; |
| 859 | } else { |
| 860 | retval = (aNode.getParent() == this); |
| 861 | } |
| 862 | } |
| 863 | |
| 864 | return retval; |
| 865 | } |
| 866 | |
| 867 | |
| 868 | /** |
| 869 | * Returns this node's first child. If this node has no children, |
| 870 | * throws NoSuchElementException. |
| 871 | * |
| 872 | * @return the first child of this node |
| 873 | * @exception NoSuchElementException if this node has no children |
| 874 | */ |
| 875 | public TreeNode getFirstChild() { |
| 876 | if (getChildCount() == 0) { |
| 877 | throw new NoSuchElementException("node has no children"); |
| 878 | } |
| 879 | return getChildAt(0); |
| 880 | } |
| 881 | |
| 882 | |
| 883 | /** |
| 884 | * Returns this node's last child. If this node has no children, |
| 885 | * throws NoSuchElementException. |
| 886 | * |
| 887 | * @return the last child of this node |
| 888 | * @exception NoSuchElementException if this node has no children |
| 889 | */ |
| 890 | public TreeNode getLastChild() { |
| 891 | if (getChildCount() == 0) { |
| 892 | throw new NoSuchElementException("node has no children"); |
| 893 | } |
| 894 | return getChildAt(getChildCount()-1); |
| 895 | } |
| 896 | |
| 897 | |
| 898 | /** |
| 899 | * Returns the child in this node's child array that immediately |
| 900 | * follows <code>aChild</code>, which must be a child of this node. If |
| 901 | * <code>aChild</code> is the last child, returns null. This method |
| 902 | * performs a linear search of this node's children for |
| 903 | * <code>aChild</code> and is O(n) where n is the number of children; to |
| 904 | * traverse the entire array of children, use an enumeration instead. |
| 905 | * |
| 906 | * @see #children |
| 907 | * @exception IllegalArgumentException if <code>aChild</code> is |
| 908 | * null or is not a child of this node |
| 909 | * @return the child of this node that immediately follows |
| 910 | * <code>aChild</code> |
| 911 | */ |
| 912 | public TreeNode getChildAfter(TreeNode aChild) { |
| 913 | if (aChild == null) { |
| 914 | throw new IllegalArgumentException("argument is null"); |
| 915 | } |
| 916 | |
| 917 | int index = getIndex(aChild); // linear search |
| 918 | |
| 919 | if (index == -1) { |
| 920 | throw new IllegalArgumentException("node is not a child"); |
| 921 | } |
| 922 | |
| 923 | if (index < getChildCount() - 1) { |
| 924 | return getChildAt(index + 1); |
| 925 | } else { |
| 926 | return null; |
| 927 | } |
| 928 | } |
| 929 | |
| 930 | |
| 931 | /** |
| 932 | * Returns the child in this node's child array that immediately |
| 933 | * precedes <code>aChild</code>, which must be a child of this node. If |
| 934 | * <code>aChild</code> is the first child, returns null. This method |
| 935 | * performs a linear search of this node's children for <code>aChild</code> |
| 936 | * and is O(n) where n is the number of children. |
| 937 | * |
| 938 | * @exception IllegalArgumentException if <code>aChild</code> is null |
| 939 | * or is not a child of this node |
| 940 | * @return the child of this node that immediately precedes |
| 941 | * <code>aChild</code> |
| 942 | */ |
| 943 | public TreeNode getChildBefore(TreeNode aChild) { |
| 944 | if (aChild == null) { |
| 945 | throw new IllegalArgumentException("argument is null"); |
| 946 | } |
| 947 | |
| 948 | int index = getIndex(aChild); // linear search |
| 949 | |
| 950 | if (index == -1) { |
| 951 | throw new IllegalArgumentException("argument is not a child"); |
| 952 | } |
| 953 | |
| 954 | if (index > 0) { |
| 955 | return getChildAt(index - 1); |
| 956 | } else { |
| 957 | return null; |
| 958 | } |
| 959 | } |
| 960 | |
| 961 | |
| 962 | // |
| 963 | // Sibling Queries |
| 964 | // |
| 965 | |
| 966 | |
| 967 | /** |
| 968 | * Returns true if <code>anotherNode</code> is a sibling of (has the |
| 969 | * same parent as) this node. A node is its own sibling. If |
| 970 | * <code>anotherNode</code> is null, returns false. |
| 971 | * |
| 972 | * @param anotherNode node to test as sibling of this node |
| 973 | * @return true if <code>anotherNode</code> is a sibling of this node |
| 974 | */ |
| 975 | public boolean isNodeSibling(TreeNode anotherNode) { |
| 976 | boolean retval; |
| 977 | |
| 978 | if (anotherNode == null) { |
| 979 | retval = false; |
| 980 | } else if (anotherNode == this) { |
| 981 | retval = true; |
| 982 | } else { |
| 983 | TreeNode myParent = getParent(); |
| 984 | retval = (myParent != null && myParent == anotherNode.getParent()); |
| 985 | |
| 986 | if (retval && !((DefaultMutableTreeNode)getParent()) |
| 987 | .isNodeChild(anotherNode)) { |
| 988 | throw new Error("sibling has different parent"); |
| 989 | } |
| 990 | } |
| 991 | |
| 992 | return retval; |
| 993 | } |
| 994 | |
| 995 | |
| 996 | /** |
| 997 | * Returns the number of siblings of this node. A node is its own sibling |
| 998 | * (if it has no parent or no siblings, this method returns |
| 999 | * <code>1</code>). |
| 1000 | * |
| 1001 | * @return the number of siblings of this node |
| 1002 | */ |
| 1003 | public int getSiblingCount() { |
| 1004 | TreeNode myParent = getParent(); |
| 1005 | |
| 1006 | if (myParent == null) { |
| 1007 | return 1; |
| 1008 | } else { |
| 1009 | return myParent.getChildCount(); |
| 1010 | } |
| 1011 | } |
| 1012 | |
| 1013 | |
| 1014 | /** |
| 1015 | * Returns the next sibling of this node in the parent's children array. |
| 1016 | * Returns null if this node has no parent or is the parent's last child. |
| 1017 | * This method performs a linear search that is O(n) where n is the number |
| 1018 | * of children; to traverse the entire array, use the parent's child |
| 1019 | * enumeration instead. |
| 1020 | * |
| 1021 | * @see #children |
| 1022 | * @return the sibling of this node that immediately follows this node |
| 1023 | */ |
| 1024 | public DefaultMutableTreeNode getNextSibling() { |
| 1025 | DefaultMutableTreeNode retval; |
| 1026 | |
| 1027 | DefaultMutableTreeNode myParent = (DefaultMutableTreeNode)getParent(); |
| 1028 | |
| 1029 | if (myParent == null) { |
| 1030 | retval = null; |
| 1031 | } else { |
| 1032 | retval = (DefaultMutableTreeNode)myParent.getChildAfter(this); // linear search |
| 1033 | } |
| 1034 | |
| 1035 | if (retval != null && !isNodeSibling(retval)) { |
| 1036 | throw new Error("child of parent is not a sibling"); |
| 1037 | } |
| 1038 | |
| 1039 | return retval; |
| 1040 | } |
| 1041 | |
| 1042 | |
| 1043 | /** |
| 1044 | * Returns the previous sibling of this node in the parent's children |
| 1045 | * array. Returns null if this node has no parent or is the parent's |
| 1046 | * first child. This method performs a linear search that is O(n) where n |
| 1047 | * is the number of children. |
| 1048 | * |
| 1049 | * @return the sibling of this node that immediately precedes this node |
| 1050 | */ |
| 1051 | public DefaultMutableTreeNode getPreviousSibling() { |
| 1052 | DefaultMutableTreeNode retval; |
| 1053 | |
| 1054 | DefaultMutableTreeNode myParent = (DefaultMutableTreeNode)getParent(); |
| 1055 | |
| 1056 | if (myParent == null) { |
| 1057 | retval = null; |
| 1058 | } else { |
| 1059 | retval = (DefaultMutableTreeNode)myParent.getChildBefore(this); // linear search |
| 1060 | } |
| 1061 | |
| 1062 | if (retval != null && !isNodeSibling(retval)) { |
| 1063 | throw new Error("child of parent is not a sibling"); |
| 1064 | } |
| 1065 | |
| 1066 | return retval; |
| 1067 | } |
| 1068 | |
| 1069 | |
| 1070 | |
| 1071 | // |
| 1072 | // Leaf Queries |
| 1073 | // |
| 1074 | |
| 1075 | /** |
| 1076 | * Returns true if this node has no children. To distinguish between |
| 1077 | * nodes that have no children and nodes that <i>cannot</i> have |
| 1078 | * children (e.g. to distinguish files from empty directories), use this |
| 1079 | * method in conjunction with <code>getAllowsChildren</code> |
| 1080 | * |
| 1081 | * @see #getAllowsChildren |
| 1082 | * @return true if this node has no children |
| 1083 | */ |
| 1084 | public boolean isLeaf() { |
| 1085 | return (getChildCount() == 0); |
| 1086 | } |
| 1087 | |
| 1088 | |
| 1089 | /** |
| 1090 | * Finds and returns the first leaf that is a descendant of this node -- |
| 1091 | * either this node or its first child's first leaf. |
| 1092 | * Returns this node if it is a leaf. |
| 1093 | * |
| 1094 | * @see #isLeaf |
| 1095 | * @see #isNodeDescendant |
| 1096 | * @return the first leaf in the subtree rooted at this node |
| 1097 | */ |
| 1098 | public DefaultMutableTreeNode getFirstLeaf() { |
| 1099 | DefaultMutableTreeNode node = this; |
| 1100 | |
| 1101 | while (!node.isLeaf()) { |
| 1102 | node = (DefaultMutableTreeNode)node.getFirstChild(); |
| 1103 | } |
| 1104 | |
| 1105 | return node; |
| 1106 | } |
| 1107 | |
| 1108 | |
| 1109 | /** |
| 1110 | * Finds and returns the last leaf that is a descendant of this node -- |
| 1111 | * either this node or its last child's last leaf. |
| 1112 | * Returns this node if it is a leaf. |
| 1113 | * |
| 1114 | * @see #isLeaf |
| 1115 | * @see #isNodeDescendant |
| 1116 | * @return the last leaf in the subtree rooted at this node |
| 1117 | */ |
| 1118 | public DefaultMutableTreeNode getLastLeaf() { |
| 1119 | DefaultMutableTreeNode node = this; |
| 1120 | |
| 1121 | while (!node.isLeaf()) { |
| 1122 | node = (DefaultMutableTreeNode)node.getLastChild(); |
| 1123 | } |
| 1124 | |
| 1125 | return node; |
| 1126 | } |
| 1127 | |
| 1128 | |
| 1129 | /** |
| 1130 | * Returns the leaf after this node or null if this node is the |
| 1131 | * last leaf in the tree. |
| 1132 | * <p> |
| 1133 | * In this implementation of the <code>MutableNode</code> interface, |
| 1134 | * this operation is very inefficient. In order to determine the |
| 1135 | * next node, this method first performs a linear search in the |
| 1136 | * parent's child-list in order to find the current node. |
| 1137 | * <p> |
| 1138 | * That implementation makes the operation suitable for short |
| 1139 | * traversals from a known position. But to traverse all of the |
| 1140 | * leaves in the tree, you should use <code>depthFirstEnumeration</code> |
| 1141 | * to enumerate the nodes in the tree and use <code>isLeaf</code> |
| 1142 | * on each node to determine which are leaves. |
| 1143 | * |
| 1144 | * @see #depthFirstEnumeration |
| 1145 | * @see #isLeaf |
| 1146 | * @return returns the next leaf past this node |
| 1147 | */ |
| 1148 | public DefaultMutableTreeNode getNextLeaf() { |
| 1149 | DefaultMutableTreeNode nextSibling; |
| 1150 | DefaultMutableTreeNode myParent = (DefaultMutableTreeNode)getParent(); |
| 1151 | |
| 1152 | if (myParent == null) |
| 1153 | return null; |
| 1154 | |
| 1155 | nextSibling = getNextSibling(); // linear search |
| 1156 | |
| 1157 | if (nextSibling != null) |
| 1158 | return nextSibling.getFirstLeaf(); |
| 1159 | |
| 1160 | return myParent.getNextLeaf(); // tail recursion |
| 1161 | } |
| 1162 | |
| 1163 | |
| 1164 | /** |
| 1165 | * Returns the leaf before this node or null if this node is the |
| 1166 | * first leaf in the tree. |
| 1167 | * <p> |
| 1168 | * In this implementation of the <code>MutableNode</code> interface, |
| 1169 | * this operation is very inefficient. In order to determine the |
| 1170 | * previous node, this method first performs a linear search in the |
| 1171 | * parent's child-list in order to find the current node. |
| 1172 | * <p> |
| 1173 | * That implementation makes the operation suitable for short |
| 1174 | * traversals from a known position. But to traverse all of the |
| 1175 | * leaves in the tree, you should use <code>depthFirstEnumeration</code> |
| 1176 | * to enumerate the nodes in the tree and use <code>isLeaf</code> |
| 1177 | * on each node to determine which are leaves. |
| 1178 | * |
| 1179 | * @see #depthFirstEnumeration |
| 1180 | * @see #isLeaf |
| 1181 | * @return returns the leaf before this node |
| 1182 | */ |
| 1183 | public DefaultMutableTreeNode getPreviousLeaf() { |
| 1184 | DefaultMutableTreeNode previousSibling; |
| 1185 | DefaultMutableTreeNode myParent = (DefaultMutableTreeNode)getParent(); |
| 1186 | |
| 1187 | if (myParent == null) |
| 1188 | return null; |
| 1189 | |
| 1190 | previousSibling = getPreviousSibling(); // linear search |
| 1191 | |
| 1192 | if (previousSibling != null) |
| 1193 | return previousSibling.getLastLeaf(); |
| 1194 | |
| 1195 | return myParent.getPreviousLeaf(); // tail recursion |
| 1196 | } |
| 1197 | |
| 1198 | |
| 1199 | /** |
| 1200 | * Returns the total number of leaves that are descendants of this node. |
| 1201 | * If this node is a leaf, returns <code>1</code>. This method is O(n) |
| 1202 | * where n is the number of descendants of this node. |
| 1203 | * |
| 1204 | * @see #isNodeAncestor |
| 1205 | * @return the number of leaves beneath this node |
| 1206 | */ |
| 1207 | public int getLeafCount() { |
| 1208 | int count = 0; |
| 1209 | |
| 1210 | TreeNode node; |
| 1211 | Enumeration enum_ = breadthFirstEnumeration(); // order matters not |
| 1212 | |
| 1213 | while (enum_.hasMoreElements()) { |
| 1214 | node = (TreeNode)enum_.nextElement(); |
| 1215 | if (node.isLeaf()) { |
| 1216 | count++; |
| 1217 | } |
| 1218 | } |
| 1219 | |
| 1220 | if (count < 1) { |
| 1221 | throw new Error("tree has zero leaves"); |
| 1222 | } |
| 1223 | |
| 1224 | return count; |
| 1225 | } |
| 1226 | |
| 1227 | |
| 1228 | // |
| 1229 | // Overrides |
| 1230 | // |
| 1231 | |
| 1232 | /** |
| 1233 | * Returns the result of sending <code>toString()</code> to this node's |
| 1234 | * user object, or the empty string if the node has no user object. |
| 1235 | * |
| 1236 | * @see #getUserObject |
| 1237 | */ |
| 1238 | public String toString() { |
| 1239 | if (userObject == null) { |
| 1240 | return ""; |
| 1241 | } else { |
| 1242 | return userObject.toString(); |
| 1243 | } |
| 1244 | } |
| 1245 | |
| 1246 | /** |
| 1247 | * Overridden to make clone public. Returns a shallow copy of this node; |
| 1248 | * the new node has no parent or children and has a reference to the same |
| 1249 | * user object, if any. |
| 1250 | * |
| 1251 | * @return a copy of this node |
| 1252 | */ |
| 1253 | public Object clone() { |
| 1254 | DefaultMutableTreeNode newNode = null; |
| 1255 | |
| 1256 | try { |
| 1257 | newNode = (DefaultMutableTreeNode)super.clone(); |
| 1258 | |
| 1259 | // shallow copy -- the new node has no parent or children |
| 1260 | newNode.children = null; |
| 1261 | newNode.parent = null; |
| 1262 | |
| 1263 | } catch (CloneNotSupportedException e) { |
| 1264 | // Won't happen because we implement Cloneable |
| 1265 | throw new Error(e.toString()); |
| 1266 | } |
| 1267 | |
| 1268 | return newNode; |
| 1269 | } |
| 1270 | |
| 1271 | |
| 1272 | // Serialization support. |
| 1273 | private void writeObject(ObjectOutputStream s) throws IOException { |
| 1274 | Object[] tValues; |
| 1275 | |
| 1276 | s.defaultWriteObject(); |
| 1277 | // Save the userObject, if its Serializable. |
| 1278 | if(userObject != null && userObject instanceof Serializable) { |
| 1279 | tValues = new Object[2]; |
| 1280 | tValues[0] = "userObject"; |
| 1281 | tValues[1] = userObject; |
| 1282 | } |
| 1283 | else |
| 1284 | tValues = new Object[0]; |
| 1285 | s.writeObject(tValues); |
| 1286 | } |
| 1287 | |
| 1288 | private void readObject(ObjectInputStream s) |
| 1289 | throws IOException, ClassNotFoundException { |
| 1290 | Object[] tValues; |
| 1291 | |
| 1292 | s.defaultReadObject(); |
| 1293 | |
| 1294 | tValues = (Object[])s.readObject(); |
| 1295 | |
| 1296 | if(tValues.length > 0 && tValues[0].equals("userObject")) |
| 1297 | userObject = tValues[1]; |
| 1298 | } |
| 1299 | |
| 1300 | final class PreorderEnumeration implements Enumeration<TreeNode> { |
| 1301 | protected Stack stack; |
| 1302 | |
| 1303 | public PreorderEnumeration(TreeNode rootNode) { |
| 1304 | super(); |
| 1305 | Vector v = new Vector(1); |
| 1306 | v.addElement(rootNode); // PENDING: don't really need a vector |
| 1307 | stack = new Stack(); |
| 1308 | stack.push(v.elements()); |
| 1309 | } |
| 1310 | |
| 1311 | public boolean hasMoreElements() { |
| 1312 | return (!stack.empty() && |
| 1313 | ((Enumeration)stack.peek()).hasMoreElements()); |
| 1314 | } |
| 1315 | |
| 1316 | public TreeNode nextElement() { |
| 1317 | Enumeration enumer = (Enumeration)stack.peek(); |
| 1318 | TreeNode node = (TreeNode)enumer.nextElement(); |
| 1319 | Enumeration children = node.children(); |
| 1320 | |
| 1321 | if (!enumer.hasMoreElements()) { |
| 1322 | stack.pop(); |
| 1323 | } |
| 1324 | if (children.hasMoreElements()) { |
| 1325 | stack.push(children); |
| 1326 | } |
| 1327 | return node; |
| 1328 | } |
| 1329 | |
| 1330 | } // End of class PreorderEnumeration |
| 1331 | |
| 1332 | |
| 1333 | |
| 1334 | final class PostorderEnumeration implements Enumeration<TreeNode> { |
| 1335 | protected TreeNode root; |
| 1336 | protected Enumeration<TreeNode> children; |
| 1337 | protected Enumeration<TreeNode> subtree; |
| 1338 | |
| 1339 | public PostorderEnumeration(TreeNode rootNode) { |
| 1340 | super(); |
| 1341 | root = rootNode; |
| 1342 | children = root.children(); |
| 1343 | subtree = EMPTY_ENUMERATION; |
| 1344 | } |
| 1345 | |
| 1346 | public boolean hasMoreElements() { |
| 1347 | return root != null; |
| 1348 | } |
| 1349 | |
| 1350 | public TreeNode nextElement() { |
| 1351 | TreeNode retval; |
| 1352 | |
| 1353 | if (subtree.hasMoreElements()) { |
| 1354 | retval = subtree.nextElement(); |
| 1355 | } else if (children.hasMoreElements()) { |
| 1356 | subtree = new PostorderEnumeration( |
| 1357 | (TreeNode)children.nextElement()); |
| 1358 | retval = subtree.nextElement(); |
| 1359 | } else { |
| 1360 | retval = root; |
| 1361 | root = null; |
| 1362 | } |
| 1363 | |
| 1364 | return retval; |
| 1365 | } |
| 1366 | |
| 1367 | } // End of class PostorderEnumeration |
| 1368 | |
| 1369 | |
| 1370 | |
| 1371 | final class BreadthFirstEnumeration implements Enumeration<TreeNode> { |
| 1372 | protected Queue queue; |
| 1373 | |
| 1374 | public BreadthFirstEnumeration(TreeNode rootNode) { |
| 1375 | super(); |
| 1376 | Vector v = new Vector(1); |
| 1377 | v.addElement(rootNode); // PENDING: don't really need a vector |
| 1378 | queue = new Queue(); |
| 1379 | queue.enqueue(v.elements()); |
| 1380 | } |
| 1381 | |
| 1382 | public boolean hasMoreElements() { |
| 1383 | return (!queue.isEmpty() && |
| 1384 | ((Enumeration)queue.firstObject()).hasMoreElements()); |
| 1385 | } |
| 1386 | |
| 1387 | public TreeNode nextElement() { |
| 1388 | Enumeration enumer = (Enumeration)queue.firstObject(); |
| 1389 | TreeNode node = (TreeNode)enumer.nextElement(); |
| 1390 | Enumeration children = node.children(); |
| 1391 | |
| 1392 | if (!enumer.hasMoreElements()) { |
| 1393 | queue.dequeue(); |
| 1394 | } |
| 1395 | if (children.hasMoreElements()) { |
| 1396 | queue.enqueue(children); |
| 1397 | } |
| 1398 | return node; |
| 1399 | } |
| 1400 | |
| 1401 | |
| 1402 | // A simple queue with a linked list data structure. |
| 1403 | final class Queue { |
| 1404 | QNode head; // null if empty |
| 1405 | QNode tail; |
| 1406 | |
| 1407 | final class QNode { |
| 1408 | public Object object; |
| 1409 | public QNode next; // null if end |
| 1410 | public QNode(Object object, QNode next) { |
| 1411 | this.object = object; |
| 1412 | this.next = next; |
| 1413 | } |
| 1414 | } |
| 1415 | |
| 1416 | public void enqueue(Object anObject) { |
| 1417 | if (head == null) { |
| 1418 | head = tail = new QNode(anObject, null); |
| 1419 | } else { |
| 1420 | tail.next = new QNode(anObject, null); |
| 1421 | tail = tail.next; |
| 1422 | } |
| 1423 | } |
| 1424 | |
| 1425 | public Object dequeue() { |
| 1426 | if (head == null) { |
| 1427 | throw new NoSuchElementException("No more elements"); |
| 1428 | } |
| 1429 | |
| 1430 | Object retval = head.object; |
| 1431 | QNode oldHead = head; |
| 1432 | head = head.next; |
| 1433 | if (head == null) { |
| 1434 | tail = null; |
| 1435 | } else { |
| 1436 | oldHead.next = null; |
| 1437 | } |
| 1438 | return retval; |
| 1439 | } |
| 1440 | |
| 1441 | public Object firstObject() { |
| 1442 | if (head == null) { |
| 1443 | throw new NoSuchElementException("No more elements"); |
| 1444 | } |
| 1445 | |
| 1446 | return head.object; |
| 1447 | } |
| 1448 | |
| 1449 | public boolean isEmpty() { |
| 1450 | return head == null; |
| 1451 | } |
| 1452 | |
| 1453 | } // End of class Queue |
| 1454 | |
| 1455 | } // End of class BreadthFirstEnumeration |
| 1456 | |
| 1457 | |
| 1458 | |
| 1459 | final class PathBetweenNodesEnumeration implements Enumeration<TreeNode> { |
| 1460 | protected Stack<TreeNode> stack; |
| 1461 | |
| 1462 | public PathBetweenNodesEnumeration(TreeNode ancestor, |
| 1463 | TreeNode descendant) |
| 1464 | { |
| 1465 | super(); |
| 1466 | |
| 1467 | if (ancestor == null || descendant == null) { |
| 1468 | throw new IllegalArgumentException("argument is null"); |
| 1469 | } |
| 1470 | |
| 1471 | TreeNode current; |
| 1472 | |
| 1473 | stack = new Stack<TreeNode>(); |
| 1474 | stack.push(descendant); |
| 1475 | |
| 1476 | current = descendant; |
| 1477 | while (current != ancestor) { |
| 1478 | current = current.getParent(); |
| 1479 | if (current == null && descendant != ancestor) { |
| 1480 | throw new IllegalArgumentException("node " + ancestor + |
| 1481 | " is not an ancestor of " + descendant); |
| 1482 | } |
| 1483 | stack.push(current); |
| 1484 | } |
| 1485 | } |
| 1486 | |
| 1487 | public boolean hasMoreElements() { |
| 1488 | return stack.size() > 0; |
| 1489 | } |
| 1490 | |
| 1491 | public TreeNode nextElement() { |
| 1492 | try { |
| 1493 | return stack.pop(); |
| 1494 | } catch (EmptyStackException e) { |
| 1495 | throw new NoSuchElementException("No more elements"); |
| 1496 | } |
| 1497 | } |
| 1498 | |
| 1499 | } // End of class PathBetweenNodesEnumeration |
| 1500 | |
| 1501 | |
| 1502 | |
| 1503 | } // End of class DefaultMutableTreeNode |