1 /*
2 * Copyright (c) 1997, 2008, 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
26 package java.util;
27
28 /**
29 * A Red-Black tree based {@link NavigableMap} implementation.
30 * The map is sorted according to the {@linkplain Comparable natural
31 * ordering} of its keys, or by a {@link Comparator} provided at map
32 * creation time, depending on which constructor is used.
33 *
34 * <p>This implementation provides guaranteed log(n) time cost for the
35 * <tt>containsKey</tt>, <tt>get</tt>, <tt>put</tt> and <tt>remove</tt>
36 * operations. Algorithms are adaptations of those in Cormen, Leiserson, and
37 * Rivest's <I>Introduction to Algorithms</I>.
38 *
39 * <p>Note that the ordering maintained by a tree map, like any sorted map, and
40 * whether or not an explicit comparator is provided, must be <em>consistent
41 * with {@code equals}</em> if this sorted map is to correctly implement the
42 * {@code Map} interface. (See {@code Comparable} or {@code Comparator} for a
43 * precise definition of <i>consistent with equals</i>.) This is so because
44 * the <tt>Map</tt> interface is defined in terms of the {@code equals}
45 * operation, but a sorted map performs all key comparisons using its {@code
46 * compareTo} (or {@code compare}) method, so two keys that are deemed equal by
47 * this method are, from the standpoint of the sorted map, equal. The behavior
48 * of a sorted map <em>is</em> well-defined even if its ordering is
49 * inconsistent with {@code equals}; it just fails to obey the general contract
50 * of the {@code Map} interface.
51 *
52 * <p><strong>Note that this implementation is not synchronized.</strong>
53 * If multiple threads access a map concurrently, and at least one of the
54 * threads modifies the map structurally, it <i>must</i> be synchronized
55 * externally. (A structural modification is any operation that adds or
56 * deletes one or more mappings; merely changing the value associated
57 * with an existing key is not a structural modification.) This is
58 * typically accomplished by synchronizing on some object that naturally
59 * encapsulates the map.
60 * If no such object exists, the map should be "wrapped" using the
61 * {@link Collections#synchronizedSortedMap Collections.synchronizedSortedMap}
62 * method. This is best done at creation time, to prevent accidental
63 * unsynchronized access to the map: <pre>
64 * SortedMap m = Collections.synchronizedSortedMap(new TreeMap(...));</pre>
65 *
66 * <p>The iterators returned by the <tt>iterator</tt> method of the collections
67 * returned by all of this class's "collection view methods" are
68 * <i>fail-fast</i>: if the map is structurally modified at any time after the
69 * iterator is created, in any way except through the iterator's own
70 * <tt>remove</tt> method, the iterator will throw a {@link
71 * ConcurrentModificationException}. Thus, in the face of concurrent
72 * modification, the iterator fails quickly and cleanly, rather than risking
73 * arbitrary, non-deterministic behavior at an undetermined time in the future.
74 *
75 * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
76 * as it is, generally speaking, impossible to make any hard guarantees in the
77 * presence of unsynchronized concurrent modification. Fail-fast iterators
78 * throw <tt>ConcurrentModificationException</tt> on a best-effort basis.
79 * Therefore, it would be wrong to write a program that depended on this
80 * exception for its correctness: <i>the fail-fast behavior of iterators
81 * should be used only to detect bugs.</i>
82 *
83 * <p>All <tt>Map.Entry</tt> pairs returned by methods in this class
84 * and its views represent snapshots of mappings at the time they were
85 * produced. They do <em>not</em> support the <tt>Entry.setValue</tt>
86 * method. (Note however that it is possible to change mappings in the
87 * associated map using <tt>put</tt>.)
88 *
89 * <p>This class is a member of the
90 * <a href="{@docRoot}/../technotes/guides/collections/index.html">
91 * Java Collections Framework</a>.
92 *
93 * @param <K> the type of keys maintained by this map
94 * @param <V> the type of mapped values
95 *
96 * @author Josh Bloch and Doug Lea
97 * @see Map
98 * @see HashMap
99 * @see Hashtable
100 * @see Comparable
101 * @see Comparator
102 * @see Collection
103 * @since 1.2
104 */
105
106 public class TreeMap<K,V>
107 extends AbstractMap<K,V>
108 implements NavigableMap<K,V>, Cloneable, java.io.Serializable
109 {
110 /**
111 * The comparator used to maintain order in this tree map, or
112 * null if it uses the natural ordering of its keys.
113 *
114 * @serial
115 */
116 private final Comparator<? super K> comparator;
117
118 private transient Entry<K,V> root = null;
119
120 /**
121 * The number of entries in the tree
122 */
123 private transient int size = 0;
124
125 /**
126 * The number of structural modifications to the tree.
127 */
128 private transient int modCount = 0;
129
130 /**
131 * Constructs a new, empty tree map, using the natural ordering of its
132 * keys. All keys inserted into the map must implement the {@link
133 * Comparable} interface. Furthermore, all such keys must be
134 * <i>mutually comparable</i>: <tt>k1.compareTo(k2)</tt> must not throw
135 * a <tt>ClassCastException</tt> for any keys <tt>k1</tt> and
136 * <tt>k2</tt> in the map. If the user attempts to put a key into the
137 * map that violates this constraint (for example, the user attempts to
138 * put a string key into a map whose keys are integers), the
139 * <tt>put(Object key, Object value)</tt> call will throw a
140 * <tt>ClassCastException</tt>.
141 */
142 public TreeMap() {
143 comparator = null;
144 }
145
146 /**
147 * Constructs a new, empty tree map, ordered according to the given
148 * comparator. All keys inserted into the map must be <i>mutually
149 * comparable</i> by the given comparator: <tt>comparator.compare(k1,
150 * k2)</tt> must not throw a <tt>ClassCastException</tt> for any keys
151 * <tt>k1</tt> and <tt>k2</tt> in the map. If the user attempts to put
152 * a key into the map that violates this constraint, the <tt>put(Object
153 * key, Object value)</tt> call will throw a
154 * <tt>ClassCastException</tt>.
155 *
156 * @param comparator the comparator that will be used to order this map.
157 * If <tt>null</tt>, the {@linkplain Comparable natural
158 * ordering} of the keys will be used.
159 */
160 public TreeMap(Comparator<? super K> comparator) {
161 this.comparator = comparator;
162 }
163
164 /**
165 * Constructs a new tree map containing the same mappings as the given
166 * map, ordered according to the <i>natural ordering</i> of its keys.
167 * All keys inserted into the new map must implement the {@link
168 * Comparable} interface. Furthermore, all such keys must be
169 * <i>mutually comparable</i>: <tt>k1.compareTo(k2)</tt> must not throw
170 * a <tt>ClassCastException</tt> for any keys <tt>k1</tt> and
171 * <tt>k2</tt> in the map. This method runs in n*log(n) time.
172 *
173 * @param m the map whose mappings are to be placed in this map
174 * @throws ClassCastException if the keys in m are not {@link Comparable},
175 * or are not mutually comparable
176 * @throws NullPointerException if the specified map is null
177 */
178 public TreeMap(Map<? extends K, ? extends V> m) {
179 comparator = null;
180 putAll(m);
181 }
182
183 /**
184 * Constructs a new tree map containing the same mappings and
185 * using the same ordering as the specified sorted map. This
186 * method runs in linear time.
187 *
188 * @param m the sorted map whose mappings are to be placed in this map,
189 * and whose comparator is to be used to sort this map
190 * @throws NullPointerException if the specified map is null
191 */
192 public TreeMap(SortedMap<K, ? extends V> m) {
193 comparator = m.comparator();
194 try {
195 buildFromSorted(m.size(), m.entrySet().iterator(), null, null);
196 } catch (java.io.IOException cannotHappen) {
197 } catch (ClassNotFoundException cannotHappen) {
198 }
199 }
200
201
202 // Query Operations
203
204 /**
205 * Returns the number of key-value mappings in this map.
206 *
207 * @return the number of key-value mappings in this map
208 */
209 public int size() {
210 return size;
211 }
212
213 /**
214 * Returns <tt>true</tt> if this map contains a mapping for the specified
215 * key.
216 *
217 * @param key key whose presence in this map is to be tested
218 * @return <tt>true</tt> if this map contains a mapping for the
219 * specified key
220 * @throws ClassCastException if the specified key cannot be compared
221 * with the keys currently in the map
222 * @throws NullPointerException if the specified key is null
223 * and this map uses natural ordering, or its comparator
224 * does not permit null keys
225 */
226 public boolean containsKey(Object key) {
227 return getEntry(key) != null;
228 }
229
230 /**
231 * Returns <tt>true</tt> if this map maps one or more keys to the
232 * specified value. More formally, returns <tt>true</tt> if and only if
233 * this map contains at least one mapping to a value <tt>v</tt> such
234 * that <tt>(value==null ? v==null : value.equals(v))</tt>. This
235 * operation will probably require time linear in the map size for
236 * most implementations.
237 *
238 * @param value value whose presence in this map is to be tested
239 * @return <tt>true</tt> if a mapping to <tt>value</tt> exists;
240 * <tt>false</tt> otherwise
241 * @since 1.2
242 */
243 public boolean containsValue(Object value) {
244 for (Entry<K,V> e = getFirstEntry(); e != null; e = successor(e))
245 if (valEquals(value, e.value))
246 return true;
247 return false;
248 }
249
250 /**
251 * Returns the value to which the specified key is mapped,
252 * or {@code null} if this map contains no mapping for the key.
253 *
254 * <p>More formally, if this map contains a mapping from a key
255 * {@code k} to a value {@code v} such that {@code key} compares
256 * equal to {@code k} according to the map's ordering, then this
257 * method returns {@code v}; otherwise it returns {@code null}.
258 * (There can be at most one such mapping.)
259 *
260 * <p>A return value of {@code null} does not <i>necessarily</i>
261 * indicate that the map contains no mapping for the key; it's also
262 * possible that the map explicitly maps the key to {@code null}.
263 * The {@link #containsKey containsKey} operation may be used to
264 * distinguish these two cases.
265 *
266 * @throws ClassCastException if the specified key cannot be compared
267 * with the keys currently in the map
268 * @throws NullPointerException if the specified key is null
269 * and this map uses natural ordering, or its comparator
270 * does not permit null keys
271 */
272 public V get(Object key) {
273 Entry<K,V> p = getEntry(key);
274 return (p==null ? null : p.value);
275 }
276
277 public Comparator<? super K> comparator() {
278 return comparator;
279 }
280
281 /**
282 * @throws NoSuchElementException {@inheritDoc}
283 */
284 public K firstKey() {
285 return key(getFirstEntry());
286 }
287
288 /**
289 * @throws NoSuchElementException {@inheritDoc}
290 */
291 public K lastKey() {
292 return key(getLastEntry());
293 }
294
295 /**
296 * Copies all of the mappings from the specified map to this map.
297 * These mappings replace any mappings that this map had for any
298 * of the keys currently in the specified map.
299 *
300 * @param map mappings to be stored in this map
301 * @throws ClassCastException if the class of a key or value in
302 * the specified map prevents it from being stored in this map
303 * @throws NullPointerException if the specified map is null or
304 * the specified map contains a null key and this map does not
305 * permit null keys
306 */
307 public void putAll(Map<? extends K, ? extends V> map) {
308 int mapSize = map.size();
309 if (size==0 && mapSize!=0 && map instanceof SortedMap) {
310 Comparator c = ((SortedMap)map).comparator();
311 if (c == comparator || (c != null && c.equals(comparator))) {
312 ++modCount;
313 try {
314 buildFromSorted(mapSize, map.entrySet().iterator(),
315 null, null);
316 } catch (java.io.IOException cannotHappen) {
317 } catch (ClassNotFoundException cannotHappen) {
318 }
319 return;
320 }
321 }
322 super.putAll(map);
323 }
324
325 /**
326 * Returns this map's entry for the given key, or <tt>null</tt> if the map
327 * does not contain an entry for the key.
328 *
329 * @return this map's entry for the given key, or <tt>null</tt> if the map
330 * does not contain an entry for the key
331 * @throws ClassCastException if the specified key cannot be compared
332 * with the keys currently in the map
333 * @throws NullPointerException if the specified key is null
334 * and this map uses natural ordering, or its comparator
335 * does not permit null keys
336 */
337 final Entry<K,V> getEntry(Object key) {
338 // Offload comparator-based version for sake of performance
339 if (comparator != null)
340 return getEntryUsingComparator(key);
341 if (key == null)
342 throw new NullPointerException();
343 Comparable<? super K> k = (Comparable<? super K>) key;
344 Entry<K,V> p = root;
345 while (p != null) {
346 int cmp = k.compareTo(p.key);
347 if (cmp < 0)
348 p = p.left;
349 else if (cmp > 0)
350 p = p.right;
351 else
352 return p;
353 }
354 return null;
355 }
356
357 /**
358 * Version of getEntry using comparator. Split off from getEntry
359 * for performance. (This is not worth doing for most methods,
360 * that are less dependent on comparator performance, but is
361 * worthwhile here.)
362 */
363 final Entry<K,V> getEntryUsingComparator(Object key) {
364 K k = (K) key;
365 Comparator<? super K> cpr = comparator;
366 if (cpr != null) {
367 Entry<K,V> p = root;
368 while (p != null) {
369 int cmp = cpr.compare(k, p.key);
370 if (cmp < 0)
371 p = p.left;
372 else if (cmp > 0)
373 p = p.right;
374 else
375 return p;
376 }
377 }
378 return null;
379 }
380
381 /**
382 * Gets the entry corresponding to the specified key; if no such entry
383 * exists, returns the entry for the least key greater than the specified
384 * key; if no such entry exists (i.e., the greatest key in the Tree is less
385 * than the specified key), returns <tt>null</tt>.
386 */
387 final Entry<K,V> getCeilingEntry(K key) {
388 Entry<K,V> p = root;
389 while (p != null) {
390 int cmp = compare(key, p.key);
391 if (cmp < 0) {
392 if (p.left != null)
393 p = p.left;
394 else
395 return p;
396 } else if (cmp > 0) {
397 if (p.right != null) {
398 p = p.right;
399 } else {
400 Entry<K,V> parent = p.parent;
401 Entry<K,V> ch = p;
402 while (parent != null && ch == parent.right) {
403 ch = parent;
404 parent = parent.parent;
405 }
406 return parent;
407 }
408 } else
409 return p;
410 }
411 return null;
412 }
413
414 /**
415 * Gets the entry corresponding to the specified key; if no such entry
416 * exists, returns the entry for the greatest key less than the specified
417 * key; if no such entry exists, returns <tt>null</tt>.
418 */
419 final Entry<K,V> getFloorEntry(K key) {
420 Entry<K,V> p = root;
421 while (p != null) {
422 int cmp = compare(key, p.key);
423 if (cmp > 0) {
424 if (p.right != null)
425 p = p.right;
426 else
427 return p;
428 } else if (cmp < 0) {
429 if (p.left != null) {
430 p = p.left;
431 } else {
432 Entry<K,V> parent = p.parent;
433 Entry<K,V> ch = p;
434 while (parent != null && ch == parent.left) {
435 ch = parent;
436 parent = parent.parent;
437 }
438 return parent;
439 }
440 } else
441 return p;
442
443 }
444 return null;
445 }
446
447 /**
448 * Gets the entry for the least key greater than the specified
449 * key; if no such entry exists, returns the entry for the least
450 * key greater than the specified key; if no such entry exists
451 * returns <tt>null</tt>.
452 */
453 final Entry<K,V> getHigherEntry(K key) {
454 Entry<K,V> p = root;
455 while (p != null) {
456 int cmp = compare(key, p.key);
457 if (cmp < 0) {
458 if (p.left != null)
459 p = p.left;
460 else
461 return p;
462 } else {
463 if (p.right != null) {
464 p = p.right;
465 } else {
466 Entry<K,V> parent = p.parent;
467 Entry<K,V> ch = p;
468 while (parent != null && ch == parent.right) {
469 ch = parent;
470 parent = parent.parent;
471 }
472 return parent;
473 }
474 }
475 }
476 return null;
477 }
478
479 /**
480 * Returns the entry for the greatest key less than the specified key; if
481 * no such entry exists (i.e., the least key in the Tree is greater than
482 * the specified key), returns <tt>null</tt>.
483 */
484 final Entry<K,V> getLowerEntry(K key) {
485 Entry<K,V> p = root;
486 while (p != null) {
487 int cmp = compare(key, p.key);
488 if (cmp > 0) {
489 if (p.right != null)
490 p = p.right;
491 else
492 return p;
493 } else {
494 if (p.left != null) {
495 p = p.left;
496 } else {
497 Entry<K,V> parent = p.parent;
498 Entry<K,V> ch = p;
499 while (parent != null && ch == parent.left) {
500 ch = parent;
501 parent = parent.parent;
502 }
503 return parent;
504 }
505 }
506 }
507 return null;
508 }
509
510 /**
511 * Associates the specified value with the specified key in this map.
512 * If the map previously contained a mapping for the key, the old
513 * value is replaced.
514 *
515 * @param key key with which the specified value is to be associated
516 * @param value value to be associated with the specified key
517 *
518 * @return the previous value associated with <tt>key</tt>, or
519 * <tt>null</tt> if there was no mapping for <tt>key</tt>.
520 * (A <tt>null</tt> return can also indicate that the map
521 * previously associated <tt>null</tt> with <tt>key</tt>.)
522 * @throws ClassCastException if the specified key cannot be compared
523 * with the keys currently in the map
524 * @throws NullPointerException if the specified key is null
525 * and this map uses natural ordering, or its comparator
526 * does not permit null keys
527 */
528 public V put(K key, V value) {
529 Entry<K,V> t = root;
530 if (t == null) {
531 // TBD:
532 // 5045147: (coll) Adding null to an empty TreeSet should
533 // throw NullPointerException
534 //
535 // compare(key, key); // type check
536 root = new Entry<K,V>(key, value, null);
537 size = 1;
538 modCount++;
539 return null;
540 }
541 int cmp;
542 Entry<K,V> parent;
543 // split comparator and comparable paths
544 Comparator<? super K> cpr = comparator;
545 if (cpr != null) {
546 do {
547 parent = t;
548 cmp = cpr.compare(key, t.key);
549 if (cmp < 0)
550 t = t.left;
551 else if (cmp > 0)
552 t = t.right;
553 else
554 return t.setValue(value);
555 } while (t != null);
556 }
557 else {
558 if (key == null)
559 throw new NullPointerException();
560 Comparable<? super K> k = (Comparable<? super K>) key;
561 do {
562 parent = t;
563 cmp = k.compareTo(t.key);
564 if (cmp < 0)
565 t = t.left;
566 else if (cmp > 0)
567 t = t.right;
568 else
569 return t.setValue(value);
570 } while (t != null);
571 }
572 Entry<K,V> e = new Entry<K,V>(key, value, parent);
573 if (cmp < 0)
574 parent.left = e;
575 else
576 parent.right = e;
577 fixAfterInsertion(e);
578 size++;
579 modCount++;
580 return null;
581 }
582
583 /**
584 * Removes the mapping for this key from this TreeMap if present.
585 *
586 * @param key key for which mapping should be removed
587 * @return the previous value associated with <tt>key</tt>, or
588 * <tt>null</tt> if there was no mapping for <tt>key</tt>.
589 * (A <tt>null</tt> return can also indicate that the map
590 * previously associated <tt>null</tt> with <tt>key</tt>.)
591 * @throws ClassCastException if the specified key cannot be compared
592 * with the keys currently in the map
593 * @throws NullPointerException if the specified key is null
594 * and this map uses natural ordering, or its comparator
595 * does not permit null keys
596 */
597 public V remove(Object key) {
598 Entry<K,V> p = getEntry(key);
599 if (p == null)
600 return null;
601
602 V oldValue = p.value;
603 deleteEntry(p);
604 return oldValue;
605 }
606
607 /**
608 * Removes all of the mappings from this map.
609 * The map will be empty after this call returns.
610 */
611 public void clear() {
612 modCount++;
613 size = 0;
614 root = null;
615 }
616
617 /**
618 * Returns a shallow copy of this <tt>TreeMap</tt> instance. (The keys and
619 * values themselves are not cloned.)
620 *
621 * @return a shallow copy of this map
622 */
623 public Object clone() {
624 TreeMap<K,V> clone = null;
625 try {
626 clone = (TreeMap<K,V>) super.clone();
627 } catch (CloneNotSupportedException e) {
628 throw new InternalError();
629 }
630
631 // Put clone into "virgin" state (except for comparator)
632 clone.root = null;
633 clone.size = 0;
634 clone.modCount = 0;
635 clone.entrySet = null;
636 clone.navigableKeySet = null;
637 clone.descendingMap = null;
638
639 // Initialize clone with our mappings
640 try {
641 clone.buildFromSorted(size, entrySet().iterator(), null, null);
642 } catch (java.io.IOException cannotHappen) {
643 } catch (ClassNotFoundException cannotHappen) {
644 }
645
646 return clone;
647 }
648
649 // NavigableMap API methods
650
651 /**
652 * @since 1.6
653 */
654 public Map.Entry<K,V> firstEntry() {
655 return exportEntry(getFirstEntry());
656 }
657
658 /**
659 * @since 1.6
660 */
661 public Map.Entry<K,V> lastEntry() {
662 return exportEntry(getLastEntry());
663 }
664
665 /**
666 * @since 1.6
667 */
668 public Map.Entry<K,V> pollFirstEntry() {
669 Entry<K,V> p = getFirstEntry();
670 Map.Entry<K,V> result = exportEntry(p);
671 if (p != null)
672 deleteEntry(p);
673 return result;
674 }
675
676 /**
677 * @since 1.6
678 */
679 public Map.Entry<K,V> pollLastEntry() {
680 Entry<K,V> p = getLastEntry();
681 Map.Entry<K,V> result = exportEntry(p);
682 if (p != null)
683 deleteEntry(p);
684 return result;
685 }
686
687 /**
688 * @throws ClassCastException {@inheritDoc}
689 * @throws NullPointerException if the specified key is null
690 * and this map uses natural ordering, or its comparator
691 * does not permit null keys
692 * @since 1.6
693 */
694 public Map.Entry<K,V> lowerEntry(K key) {
695 return exportEntry(getLowerEntry(key));
696 }
697
698 /**
699 * @throws ClassCastException {@inheritDoc}
700 * @throws NullPointerException if the specified key is null
701 * and this map uses natural ordering, or its comparator
702 * does not permit null keys
703 * @since 1.6
704 */
705 public K lowerKey(K key) {
706 return keyOrNull(getLowerEntry(key));
707 }
708
709 /**
710 * @throws ClassCastException {@inheritDoc}
711 * @throws NullPointerException if the specified key is null
712 * and this map uses natural ordering, or its comparator
713 * does not permit null keys
714 * @since 1.6
715 */
716 public Map.Entry<K,V> floorEntry(K key) {
717 return exportEntry(getFloorEntry(key));
718 }
719
720 /**
721 * @throws ClassCastException {@inheritDoc}
722 * @throws NullPointerException if the specified key is null
723 * and this map uses natural ordering, or its comparator
724 * does not permit null keys
725 * @since 1.6
726 */
727 public K floorKey(K key) {
728 return keyOrNull(getFloorEntry(key));
729 }
730
731 /**
732 * @throws ClassCastException {@inheritDoc}
733 * @throws NullPointerException if the specified key is null
734 * and this map uses natural ordering, or its comparator
735 * does not permit null keys
736 * @since 1.6
737 */
738 public Map.Entry<K,V> ceilingEntry(K key) {
739 return exportEntry(getCeilingEntry(key));
740 }
741
742 /**
743 * @throws ClassCastException {@inheritDoc}
744 * @throws NullPointerException if the specified key is null
745 * and this map uses natural ordering, or its comparator
746 * does not permit null keys
747 * @since 1.6
748 */
749 public K ceilingKey(K key) {
750 return keyOrNull(getCeilingEntry(key));
751 }
752
753 /**
754 * @throws ClassCastException {@inheritDoc}
755 * @throws NullPointerException if the specified key is null
756 * and this map uses natural ordering, or its comparator
757 * does not permit null keys
758 * @since 1.6
759 */
760 public Map.Entry<K,V> higherEntry(K key) {
761 return exportEntry(getHigherEntry(key));
762 }
763
764 /**
765 * @throws ClassCastException {@inheritDoc}
766 * @throws NullPointerException if the specified key is null
767 * and this map uses natural ordering, or its comparator
768 * does not permit null keys
769 * @since 1.6
770 */
771 public K higherKey(K key) {
772 return keyOrNull(getHigherEntry(key));
773 }
774
775 // Views
776
777 /**
778 * Fields initialized to contain an instance of the entry set view
779 * the first time this view is requested. Views are stateless, so
780 * there's no reason to create more than one.
781 */
782 private transient EntrySet entrySet = null;
783 private transient KeySet<K> navigableKeySet = null;
784 private transient NavigableMap<K,V> descendingMap = null;
785
786 /**
787 * Returns a {@link Set} view of the keys contained in this map.
788 * The set's iterator returns the keys in ascending order.
789 * The set is backed by the map, so changes to the map are
790 * reflected in the set, and vice-versa. If the map is modified
791 * while an iteration over the set is in progress (except through
792 * the iterator's own <tt>remove</tt> operation), the results of
793 * the iteration are undefined. The set supports element removal,
794 * which removes the corresponding mapping from the map, via the
795 * <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
796 * <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
797 * operations. It does not support the <tt>add</tt> or <tt>addAll</tt>
798 * operations.
799 */
800 public Set<K> keySet() {
801 return navigableKeySet();
802 }
803
804 /**
805 * @since 1.6
806 */
807 public NavigableSet<K> navigableKeySet() {
808 KeySet<K> nks = navigableKeySet;
809 return (nks != null) ? nks : (navigableKeySet = new KeySet(this));
810 }
811
812 /**
813 * @since 1.6
814 */
815 public NavigableSet<K> descendingKeySet() {
816 return descendingMap().navigableKeySet();
817 }
818
819 /**
820 * Returns a {@link Collection} view of the values contained in this map.
821 * The collection's iterator returns the values in ascending order
822 * of the corresponding keys.
823 * The collection is backed by the map, so changes to the map are
824 * reflected in the collection, and vice-versa. If the map is
825 * modified while an iteration over the collection is in progress
826 * (except through the iterator's own <tt>remove</tt> operation),
827 * the results of the iteration are undefined. The collection
828 * supports element removal, which removes the corresponding
829 * mapping from the map, via the <tt>Iterator.remove</tt>,
830 * <tt>Collection.remove</tt>, <tt>removeAll</tt>,
831 * <tt>retainAll</tt> and <tt>clear</tt> operations. It does not
832 * support the <tt>add</tt> or <tt>addAll</tt> operations.
833 */
834 public Collection<V> values() {
835 Collection<V> vs = values;
836 return (vs != null) ? vs : (values = new Values());
837 }
838
839 /**
840 * Returns a {@link Set} view of the mappings contained in this map.
841 * The set's iterator returns the entries in ascending key order.
842 * The set is backed by the map, so changes to the map are
843 * reflected in the set, and vice-versa. If the map is modified
844 * while an iteration over the set is in progress (except through
845 * the iterator's own <tt>remove</tt> operation, or through the
846 * <tt>setValue</tt> operation on a map entry returned by the
847 * iterator) the results of the iteration are undefined. The set
848 * supports element removal, which removes the corresponding
849 * mapping from the map, via the <tt>Iterator.remove</tt>,
850 * <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt> and
851 * <tt>clear</tt> operations. It does not support the
852 * <tt>add</tt> or <tt>addAll</tt> operations.
853 */
854 public Set<Map.Entry<K,V>> entrySet() {
855 EntrySet es = entrySet;
856 return (es != null) ? es : (entrySet = new EntrySet());
857 }
858
859 /**
860 * @since 1.6
861 */
862 public NavigableMap<K, V> descendingMap() {
863 NavigableMap<K, V> km = descendingMap;
864 return (km != null) ? km :
865 (descendingMap = new DescendingSubMap(this,
866 true, null, true,
867 true, null, true));
868 }
869
870 /**
871 * @throws ClassCastException {@inheritDoc}
872 * @throws NullPointerException if <tt>fromKey</tt> or <tt>toKey</tt> is
873 * null and this map uses natural ordering, or its comparator
874 * does not permit null keys
875 * @throws IllegalArgumentException {@inheritDoc}
876 * @since 1.6
877 */
878 public NavigableMap<K,V> subMap(K fromKey, boolean fromInclusive,
879 K toKey, boolean toInclusive) {
880 return new AscendingSubMap(this,
881 false, fromKey, fromInclusive,
882 false, toKey, toInclusive);
883 }
884
885 /**
886 * @throws ClassCastException {@inheritDoc}
887 * @throws NullPointerException if <tt>toKey</tt> is null
888 * and this map uses natural ordering, or its comparator
889 * does not permit null keys
890 * @throws IllegalArgumentException {@inheritDoc}
891 * @since 1.6
892 */
893 public NavigableMap<K,V> headMap(K toKey, boolean inclusive) {
894 return new AscendingSubMap(this,
895 true, null, true,
896 false, toKey, inclusive);
897 }
898
899 /**
900 * @throws ClassCastException {@inheritDoc}
901 * @throws NullPointerException if <tt>fromKey</tt> is null
902 * and this map uses natural ordering, or its comparator
903 * does not permit null keys
904 * @throws IllegalArgumentException {@inheritDoc}
905 * @since 1.6
906 */
907 public NavigableMap<K,V> tailMap(K fromKey, boolean inclusive) {
908 return new AscendingSubMap(this,
909 false, fromKey, inclusive,
910 true, null, true);
911 }
912
913 /**
914 * @throws ClassCastException {@inheritDoc}
915 * @throws NullPointerException if <tt>fromKey</tt> or <tt>toKey</tt> is
916 * null and this map uses natural ordering, or its comparator
917 * does not permit null keys
918 * @throws IllegalArgumentException {@inheritDoc}
919 */
920 public SortedMap<K,V> subMap(K fromKey, K toKey) {
921 return subMap(fromKey, true, toKey, false);
922 }
923
924 /**
925 * @throws ClassCastException {@inheritDoc}
926 * @throws NullPointerException if <tt>toKey</tt> is null
927 * and this map uses natural ordering, or its comparator
928 * does not permit null keys
929 * @throws IllegalArgumentException {@inheritDoc}
930 */
931 public SortedMap<K,V> headMap(K toKey) {
932 return headMap(toKey, false);
933 }
934
935 /**
936 * @throws ClassCastException {@inheritDoc}
937 * @throws NullPointerException if <tt>fromKey</tt> is null
938 * and this map uses natural ordering, or its comparator
939 * does not permit null keys
940 * @throws IllegalArgumentException {@inheritDoc}
941 */
942 public SortedMap<K,V> tailMap(K fromKey) {
943 return tailMap(fromKey, true);
944 }
945
946 // View class support
947
948 class Values extends AbstractCollection<V> {
949 public Iterator<V> iterator() {
950 return new ValueIterator(getFirstEntry());
951 }
952
953 public int size() {
954 return TreeMap.this.size();
955 }
956
957 public boolean contains(Object o) {
958 return TreeMap.this.containsValue(o);
959 }
960
961 public boolean remove(Object o) {
962 for (Entry<K,V> e = getFirstEntry(); e != null; e = successor(e)) {
963 if (valEquals(e.getValue(), o)) {
964 deleteEntry(e);
965 return true;
966 }
967 }
968 return false;
969 }
970
971 public void clear() {
972 TreeMap.this.clear();
973 }
974 }
975
976 class EntrySet extends AbstractSet<Map.Entry<K,V>> {
977 public Iterator<Map.Entry<K,V>> iterator() {
978 return new EntryIterator(getFirstEntry());
979 }
980
981 public boolean contains(Object o) {
982 if (!(o instanceof Map.Entry))
983 return false;
984 Map.Entry<K,V> entry = (Map.Entry<K,V>) o;
985 V value = entry.getValue();
986 Entry<K,V> p = getEntry(entry.getKey());
987 return p != null && valEquals(p.getValue(), value);
988 }
989
990 public boolean remove(Object o) {
991 if (!(o instanceof Map.Entry))
992 return false;
993 Map.Entry<K,V> entry = (Map.Entry<K,V>) o;
994 V value = entry.getValue();
995 Entry<K,V> p = getEntry(entry.getKey());
996 if (p != null && valEquals(p.getValue(), value)) {
997 deleteEntry(p);
998 return true;
999 }
1000 return false;
1001 }
1002
1003 public int size() {
1004 return TreeMap.this.size();
1005 }
1006
1007 public void clear() {
1008 TreeMap.this.clear();
1009 }
1010 }
1011
1012 /*
1013 * Unlike Values and EntrySet, the KeySet class is static,
1014 * delegating to a NavigableMap to allow use by SubMaps, which
1015 * outweighs the ugliness of needing type-tests for the following
1016 * Iterator methods that are defined appropriately in main versus
1017 * submap classes.
1018 */
1019
1020 Iterator<K> keyIterator() {
1021 return new KeyIterator(getFirstEntry());
1022 }
1023
1024 Iterator<K> descendingKeyIterator() {
1025 return new DescendingKeyIterator(getLastEntry());
1026 }
1027
1028 static final class KeySet<E> extends AbstractSet<E> implements NavigableSet<E> {
1029 private final NavigableMap<E, Object> m;
1030 KeySet(NavigableMap<E,Object> map) { m = map; }
1031
1032 public Iterator<E> iterator() {
1033 if (m instanceof TreeMap)
1034 return ((TreeMap<E,Object>)m).keyIterator();
1035 else
1036 return (Iterator<E>)(((TreeMap.NavigableSubMap)m).keyIterator());
1037 }
1038
1039 public Iterator<E> descendingIterator() {
1040 if (m instanceof TreeMap)
1041 return ((TreeMap<E,Object>)m).descendingKeyIterator();
1042 else
1043 return (Iterator<E>)(((TreeMap.NavigableSubMap)m).descendingKeyIterator());
1044 }
1045
1046 public int size() { return m.size(); }
1047 public boolean isEmpty() { return m.isEmpty(); }
1048 public boolean contains(Object o) { return m.containsKey(o); }
1049 public void clear() { m.clear(); }
1050 public E lower(E e) { return m.lowerKey(e); }
1051 public E floor(E e) { return m.floorKey(e); }
1052 public E ceiling(E e) { return m.ceilingKey(e); }
1053 public E higher(E e) { return m.higherKey(e); }
1054 public E first() { return m.firstKey(); }
1055 public E last() { return m.lastKey(); }
1056 public Comparator<? super E> comparator() { return m.comparator(); }
1057 public E pollFirst() {
1058 Map.Entry<E,Object> e = m.pollFirstEntry();
1059 return e == null? null : e.getKey();
1060 }
1061 public E pollLast() {
1062 Map.Entry<E,Object> e = m.pollLastEntry();
1063 return e == null? null : e.getKey();
1064 }
1065 public boolean remove(Object o) {
1066 int oldSize = size();
1067 m.remove(o);
1068 return size() != oldSize;
1069 }
1070 public NavigableSet<E> subSet(E fromElement, boolean fromInclusive,
1071 E toElement, boolean toInclusive) {
1072 return new KeySet<E>(m.subMap(fromElement, fromInclusive,
1073 toElement, toInclusive));
1074 }
1075 public NavigableSet<E> headSet(E toElement, boolean inclusive) {
1076 return new KeySet<E>(m.headMap(toElement, inclusive));
1077 }
1078 public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
1079 return new KeySet<E>(m.tailMap(fromElement, inclusive));
1080 }
1081 public SortedSet<E> subSet(E fromElement, E toElement) {
1082 return subSet(fromElement, true, toElement, false);
1083 }
1084 public SortedSet<E> headSet(E toElement) {
1085 return headSet(toElement, false);
1086 }
1087 public SortedSet<E> tailSet(E fromElement) {
1088 return tailSet(fromElement, true);
1089 }
1090 public NavigableSet<E> descendingSet() {
1091 return new KeySet(m.descendingMap());
1092 }
1093 }
1094
1095 /**
1096 * Base class for TreeMap Iterators
1097 */
1098 abstract class PrivateEntryIterator<T> implements Iterator<T> {
1099 Entry<K,V> next;
1100 Entry<K,V> lastReturned;
1101 int expectedModCount;
1102
1103 PrivateEntryIterator(Entry<K,V> first) {
1104 expectedModCount = modCount;
1105 lastReturned = null;
1106 next = first;
1107 }
1108
1109 public final boolean hasNext() {
1110 return next != null;
1111 }
1112
1113 final Entry<K,V> nextEntry() {
1114 Entry<K,V> e = next;
1115 if (e == null)
1116 throw new NoSuchElementException();
1117 if (modCount != expectedModCount)
1118 throw new ConcurrentModificationException();
1119 next = successor(e);
1120 lastReturned = e;
1121 return e;
1122 }
1123
1124 final Entry<K,V> prevEntry() {
1125 Entry<K,V> e = next;
1126 if (e == null)
1127 throw new NoSuchElementException();
1128 if (modCount != expectedModCount)
1129 throw new ConcurrentModificationException();
1130 next = predecessor(e);
1131 lastReturned = e;
1132 return e;
1133 }
1134
1135 public void remove() {
1136 if (lastReturned == null)
1137 throw new IllegalStateException();
1138 if (modCount != expectedModCount)
1139 throw new ConcurrentModificationException();
1140 // deleted entries are replaced by their successors
1141 if (lastReturned.left != null && lastReturned.right != null)
1142 next = lastReturned;
1143 deleteEntry(lastReturned);
1144 expectedModCount = modCount;
1145 lastReturned = null;
1146 }
1147 }
1148
1149 final class EntryIterator extends PrivateEntryIterator<Map.Entry<K,V>> {
1150 EntryIterator(Entry<K,V> first) {
1151 super(first);
1152 }
1153 public Map.Entry<K,V> next() {
1154 return nextEntry();
1155 }
1156 }
1157
1158 final class ValueIterator extends PrivateEntryIterator<V> {
1159 ValueIterator(Entry<K,V> first) {
1160 super(first);
1161 }
1162 public V next() {
1163 return nextEntry().value;
1164 }
1165 }
1166
1167 final class KeyIterator extends PrivateEntryIterator<K> {
1168 KeyIterator(Entry<K,V> first) {
1169 super(first);
1170 }
1171 public K next() {
1172 return nextEntry().key;
1173 }
1174 }
1175
1176 final class DescendingKeyIterator extends PrivateEntryIterator<K> {
1177 DescendingKeyIterator(Entry<K,V> first) {
1178 super(first);
1179 }
1180 public K next() {
1181 return prevEntry().key;
1182 }
1183 }
1184
1185 // Little utilities
1186
1187 /**
1188 * Compares two keys using the correct comparison method for this TreeMap.
1189 */
1190 final int compare(Object k1, Object k2) {
1191 return comparator==null ? ((Comparable<? super K>)k1).compareTo((K)k2)
1192 : comparator.compare((K)k1, (K)k2);
1193 }
1194
1195 /**
1196 * Test two values for equality. Differs from o1.equals(o2) only in
1197 * that it copes with <tt>null</tt> o1 properly.
1198 */
1199 final static boolean valEquals(Object o1, Object o2) {
1200 return (o1==null ? o2==null : o1.equals(o2));
1201 }
1202
1203 /**
1204 * Return SimpleImmutableEntry for entry, or null if null
1205 */
1206 static <K,V> Map.Entry<K,V> exportEntry(TreeMap.Entry<K,V> e) {
1207 return e == null? null :
1208 new AbstractMap.SimpleImmutableEntry<K,V>(e);
1209 }
1210
1211 /**
1212 * Return key for entry, or null if null
1213 */
1214 static <K,V> K keyOrNull(TreeMap.Entry<K,V> e) {
1215 return e == null? null : e.key;
1216 }
1217
1218 /**
1219 * Returns the key corresponding to the specified Entry.
1220 * @throws NoSuchElementException if the Entry is null
1221 */
1222 static <K> K key(Entry<K,?> e) {
1223 if (e==null)
1224 throw new NoSuchElementException();
1225 return e.key;
1226 }
1227
1228
1229 // SubMaps
1230
1231 /**
1232 * Dummy value serving as unmatchable fence key for unbounded
1233 * SubMapIterators
1234 */
1235 private static final Object UNBOUNDED = new Object();
1236
1237 /**
1238 * @serial include
1239 */
1240 static abstract class NavigableSubMap<K,V> extends AbstractMap<K,V>
1241 implements NavigableMap<K,V>, java.io.Serializable {
1242 /**
1243 * The backing map.
1244 */
1245 final TreeMap<K,V> m;
1246
1247 /**
1248 * Endpoints are represented as triples (fromStart, lo,
1249 * loInclusive) and (toEnd, hi, hiInclusive). If fromStart is
1250 * true, then the low (absolute) bound is the start of the
1251 * backing map, and the other values are ignored. Otherwise,
1252 * if loInclusive is true, lo is the inclusive bound, else lo
1253 * is the exclusive bound. Similarly for the upper bound.
1254 */
1255 final K lo, hi;
1256 final boolean fromStart, toEnd;
1257 final boolean loInclusive, hiInclusive;
1258
1259 NavigableSubMap(TreeMap<K,V> m,
1260 boolean fromStart, K lo, boolean loInclusive,
1261 boolean toEnd, K hi, boolean hiInclusive) {
1262 if (!fromStart && !toEnd) {
1263 if (m.compare(lo, hi) > 0)
1264 throw new IllegalArgumentException("fromKey > toKey");
1265 } else {
1266 if (!fromStart) // type check
1267 m.compare(lo, lo);
1268 if (!toEnd)
1269 m.compare(hi, hi);
1270 }
1271
1272 this.m = m;
1273 this.fromStart = fromStart;
1274 this.lo = lo;
1275 this.loInclusive = loInclusive;
1276 this.toEnd = toEnd;
1277 this.hi = hi;
1278 this.hiInclusive = hiInclusive;
1279 }
1280
1281 // internal utilities
1282
1283 final boolean tooLow(Object key) {
1284 if (!fromStart) {
1285 int c = m.compare(key, lo);
1286 if (c < 0 || (c == 0 && !loInclusive))
1287 return true;
1288 }
1289 return false;
1290 }
1291
1292 final boolean tooHigh(Object key) {
1293 if (!toEnd) {
1294 int c = m.compare(key, hi);
1295 if (c > 0 || (c == 0 && !hiInclusive))
1296 return true;
1297 }
1298 return false;
1299 }
1300
1301 final boolean inRange(Object key) {
1302 return !tooLow(key) && !tooHigh(key);
1303 }
1304
1305 final boolean inClosedRange(Object key) {
1306 return (fromStart || m.compare(key, lo) >= 0)
1307 && (toEnd || m.compare(hi, key) >= 0);
1308 }
1309
1310 final boolean inRange(Object key, boolean inclusive) {
1311 return inclusive ? inRange(key) : inClosedRange(key);
1312 }
1313
1314 /*
1315 * Absolute versions of relation operations.
1316 * Subclasses map to these using like-named "sub"
1317 * versions that invert senses for descending maps
1318 */
1319
1320 final TreeMap.Entry<K,V> absLowest() {
1321 TreeMap.Entry<K,V> e =
1322 (fromStart ? m.getFirstEntry() :
1323 (loInclusive ? m.getCeilingEntry(lo) :
1324 m.getHigherEntry(lo)));
1325 return (e == null || tooHigh(e.key)) ? null : e;
1326 }
1327
1328 final TreeMap.Entry<K,V> absHighest() {
1329 TreeMap.Entry<K,V> e =
1330 (toEnd ? m.getLastEntry() :
1331 (hiInclusive ? m.getFloorEntry(hi) :
1332 m.getLowerEntry(hi)));
1333 return (e == null || tooLow(e.key)) ? null : e;
1334 }
1335
1336 final TreeMap.Entry<K,V> absCeiling(K key) {
1337 if (tooLow(key))
1338 return absLowest();
1339 TreeMap.Entry<K,V> e = m.getCeilingEntry(key);
1340 return (e == null || tooHigh(e.key)) ? null : e;
1341 }
1342
1343 final TreeMap.Entry<K,V> absHigher(K key) {
1344 if (tooLow(key))
1345 return absLowest();
1346 TreeMap.Entry<K,V> e = m.getHigherEntry(key);
1347 return (e == null || tooHigh(e.key)) ? null : e;
1348 }
1349
1350 final TreeMap.Entry<K,V> absFloor(K key) {
1351 if (tooHigh(key))
1352 return absHighest();
1353 TreeMap.Entry<K,V> e = m.getFloorEntry(key);
1354 return (e == null || tooLow(e.key)) ? null : e;
1355 }
1356
1357 final TreeMap.Entry<K,V> absLower(K key) {
1358 if (tooHigh(key))
1359 return absHighest();
1360 TreeMap.Entry<K,V> e = m.getLowerEntry(key);
1361 return (e == null || tooLow(e.key)) ? null : e;
1362 }
1363
1364 /** Returns the absolute high fence for ascending traversal */
1365 final TreeMap.Entry<K,V> absHighFence() {
1366 return (toEnd ? null : (hiInclusive ?
1367 m.getHigherEntry(hi) :
1368 m.getCeilingEntry(hi)));
1369 }
1370
1371 /** Return the absolute low fence for descending traversal */
1372 final TreeMap.Entry<K,V> absLowFence() {
1373 return (fromStart ? null : (loInclusive ?
1374 m.getLowerEntry(lo) :
1375 m.getFloorEntry(lo)));
1376 }
1377
1378 // Abstract methods defined in ascending vs descending classes
1379 // These relay to the appropriate absolute versions
1380
1381 abstract TreeMap.Entry<K,V> subLowest();
1382 abstract TreeMap.Entry<K,V> subHighest();
1383 abstract TreeMap.Entry<K,V> subCeiling(K key);
1384 abstract TreeMap.Entry<K,V> subHigher(K key);
1385 abstract TreeMap.Entry<K,V> subFloor(K key);
1386 abstract TreeMap.Entry<K,V> subLower(K key);
1387
1388 /** Returns ascending iterator from the perspective of this submap */
1389 abstract Iterator<K> keyIterator();
1390
1391 /** Returns descending iterator from the perspective of this submap */
1392 abstract Iterator<K> descendingKeyIterator();
1393
1394 // public methods
1395
1396 public boolean isEmpty() {
1397 return (fromStart && toEnd) ? m.isEmpty() : entrySet().isEmpty();
1398 }
1399
1400 public int size() {
1401 return (fromStart && toEnd) ? m.size() : entrySet().size();
1402 }
1403
1404 public final boolean containsKey(Object key) {
1405 return inRange(key) && m.containsKey(key);
1406 }
1407
1408 public final V put(K key, V value) {
1409 if (!inRange(key))
1410 throw new IllegalArgumentException("key out of range");
1411 return m.put(key, value);
1412 }
1413
1414 public final V get(Object key) {
1415 return !inRange(key)? null : m.get(key);
1416 }
1417
1418 public final V remove(Object key) {
1419 return !inRange(key)? null : m.remove(key);
1420 }
1421
1422 public final Map.Entry<K,V> ceilingEntry(K key) {
1423 return exportEntry(subCeiling(key));
1424 }
1425
1426 public final K ceilingKey(K key) {
1427 return keyOrNull(subCeiling(key));
1428 }
1429
1430 public final Map.Entry<K,V> higherEntry(K key) {
1431 return exportEntry(subHigher(key));
1432 }
1433
1434 public final K higherKey(K key) {
1435 return keyOrNull(subHigher(key));
1436 }
1437
1438 public final Map.Entry<K,V> floorEntry(K key) {
1439 return exportEntry(subFloor(key));
1440 }
1441
1442 public final K floorKey(K key) {
1443 return keyOrNull(subFloor(key));
1444 }
1445
1446 public final Map.Entry<K,V> lowerEntry(K key) {
1447 return exportEntry(subLower(key));
1448 }
1449
1450 public final K lowerKey(K key) {
1451 return keyOrNull(subLower(key));
1452 }
1453
1454 public final K firstKey() {
1455 return key(subLowest());
1456 }
1457
1458 public final K lastKey() {
1459 return key(subHighest());
1460 }
1461
1462 public final Map.Entry<K,V> firstEntry() {
1463 return exportEntry(subLowest());
1464 }
1465
1466 public final Map.Entry<K,V> lastEntry() {
1467 return exportEntry(subHighest());
1468 }
1469
1470 public final Map.Entry<K,V> pollFirstEntry() {
1471 TreeMap.Entry<K,V> e = subLowest();
1472 Map.Entry<K,V> result = exportEntry(e);
1473 if (e != null)
1474 m.deleteEntry(e);
1475 return result;
1476 }
1477
1478 public final Map.Entry<K,V> pollLastEntry() {
1479 TreeMap.Entry<K,V> e = subHighest();
1480 Map.Entry<K,V> result = exportEntry(e);
1481 if (e != null)
1482 m.deleteEntry(e);
1483 return result;
1484 }
1485
1486 // Views
1487 transient NavigableMap<K,V> descendingMapView = null;
1488 transient EntrySetView entrySetView = null;
1489 transient KeySet<K> navigableKeySetView = null;
1490
1491 public final NavigableSet<K> navigableKeySet() {
1492 KeySet<K> nksv = navigableKeySetView;
1493 return (nksv != null) ? nksv :
1494 (navigableKeySetView = new TreeMap.KeySet(this));
1495 }
1496
1497 public final Set<K> keySet() {
1498 return navigableKeySet();
1499 }
1500
1501 public NavigableSet<K> descendingKeySet() {
1502 return descendingMap().navigableKeySet();
1503 }
1504
1505 public final SortedMap<K,V> subMap(K fromKey, K toKey) {
1506 return subMap(fromKey, true, toKey, false);
1507 }
1508
1509 public final SortedMap<K,V> headMap(K toKey) {
1510 return headMap(toKey, false);
1511 }
1512
1513 public final SortedMap<K,V> tailMap(K fromKey) {
1514 return tailMap(fromKey, true);
1515 }
1516
1517 // View classes
1518
1519 abstract class EntrySetView extends AbstractSet<Map.Entry<K,V>> {
1520 private transient int size = -1, sizeModCount;
1521
1522 public int size() {
1523 if (fromStart && toEnd)
1524 return m.size();
1525 if (size == -1 || sizeModCount != m.modCount) {
1526 sizeModCount = m.modCount;
1527 size = 0;
1528 Iterator i = iterator();
1529 while (i.hasNext()) {
1530 size++;
1531 i.next();
1532 }
1533 }
1534 return size;
1535 }
1536
1537 public boolean isEmpty() {
1538 TreeMap.Entry<K,V> n = absLowest();
1539 return n == null || tooHigh(n.key);
1540 }
1541
1542 public boolean contains(Object o) {
1543 if (!(o instanceof Map.Entry))
1544 return false;
1545 Map.Entry<K,V> entry = (Map.Entry<K,V>) o;
1546 K key = entry.getKey();
1547 if (!inRange(key))
1548 return false;
1549 TreeMap.Entry node = m.getEntry(key);
1550 return node != null &&
1551 valEquals(node.getValue(), entry.getValue());
1552 }
1553
1554 public boolean remove(Object o) {
1555 if (!(o instanceof Map.Entry))
1556 return false;
1557 Map.Entry<K,V> entry = (Map.Entry<K,V>) o;
1558 K key = entry.getKey();
1559 if (!inRange(key))
1560 return false;
1561 TreeMap.Entry<K,V> node = m.getEntry(key);
1562 if (node!=null && valEquals(node.getValue(),entry.getValue())){
1563 m.deleteEntry(node);
1564 return true;
1565 }
1566 return false;
1567 }
1568 }
1569
1570 /**
1571 * Iterators for SubMaps
1572 */
1573 abstract class SubMapIterator<T> implements Iterator<T> {
1574 TreeMap.Entry<K,V> lastReturned;
1575 TreeMap.Entry<K,V> next;
1576 final Object fenceKey;
1577 int expectedModCount;
1578
1579 SubMapIterator(TreeMap.Entry<K,V> first,
1580 TreeMap.Entry<K,V> fence) {
1581 expectedModCount = m.modCount;
1582 lastReturned = null;
1583 next = first;
1584 fenceKey = fence == null ? UNBOUNDED : fence.key;
1585 }
1586
1587 public final boolean hasNext() {
1588 return next != null && next.key != fenceKey;
1589 }
1590
1591 final TreeMap.Entry<K,V> nextEntry() {
1592 TreeMap.Entry<K,V> e = next;
1593 if (e == null || e.key == fenceKey)
1594 throw new NoSuchElementException();
1595 if (m.modCount != expectedModCount)
1596 throw new ConcurrentModificationException();
1597 next = successor(e);
1598 lastReturned = e;
1599 return e;
1600 }
1601
1602 final TreeMap.Entry<K,V> prevEntry() {
1603 TreeMap.Entry<K,V> e = next;
1604 if (e == null || e.key == fenceKey)
1605 throw new NoSuchElementException();
1606 if (m.modCount != expectedModCount)
1607 throw new ConcurrentModificationException();
1608 next = predecessor(e);
1609 lastReturned = e;
1610 return e;
1611 }
1612
1613 final void removeAscending() {
1614 if (lastReturned == null)
1615 throw new IllegalStateException();
1616 if (m.modCount != expectedModCount)
1617 throw new ConcurrentModificationException();
1618 // deleted entries are replaced by their successors
1619 if (lastReturned.left != null && lastReturned.right != null)
1620 next = lastReturned;
1621 m.deleteEntry(lastReturned);
1622 lastReturned = null;
1623 expectedModCount = m.modCount;
1624 }
1625
1626 final void removeDescending() {
1627 if (lastReturned == null)
1628 throw new IllegalStateException();
1629 if (m.modCount != expectedModCount)
1630 throw new ConcurrentModificationException();
1631 m.deleteEntry(lastReturned);
1632 lastReturned = null;
1633 expectedModCount = m.modCount;
1634 }
1635
1636 }
1637
1638 final class SubMapEntryIterator extends SubMapIterator<Map.Entry<K,V>> {
1639 SubMapEntryIterator(TreeMap.Entry<K,V> first,
1640 TreeMap.Entry<K,V> fence) {
1641 super(first, fence);
1642 }
1643 public Map.Entry<K,V> next() {
1644 return nextEntry();
1645 }
1646 public void remove() {
1647 removeAscending();
1648 }
1649 }
1650
1651 final class SubMapKeyIterator extends SubMapIterator<K> {
1652 SubMapKeyIterator(TreeMap.Entry<K,V> first,
1653 TreeMap.Entry<K,V> fence) {
1654 super(first, fence);
1655 }
1656 public K next() {
1657 return nextEntry().key;
1658 }
1659 public void remove() {
1660 removeAscending();
1661 }
1662 }
1663
1664 final class DescendingSubMapEntryIterator extends SubMapIterator<Map.Entry<K,V>> {
1665 DescendingSubMapEntryIterator(TreeMap.Entry<K,V> last,
1666 TreeMap.Entry<K,V> fence) {
1667 super(last, fence);
1668 }
1669
1670 public Map.Entry<K,V> next() {
1671 return prevEntry();
1672 }
1673 public void remove() {
1674 removeDescending();
1675 }
1676 }
1677
1678 final class DescendingSubMapKeyIterator extends SubMapIterator<K> {
1679 DescendingSubMapKeyIterator(TreeMap.Entry<K,V> last,
1680 TreeMap.Entry<K,V> fence) {
1681 super(last, fence);
1682 }
1683 public K next() {
1684 return prevEntry().key;
1685 }
1686 public void remove() {
1687 removeDescending();
1688 }
1689 }
1690 }
1691
1692 /**
1693 * @serial include
1694 */
1695 static final class AscendingSubMap<K,V> extends NavigableSubMap<K,V> {
1696 private static final long serialVersionUID = 912986545866124060L;
1697
1698 AscendingSubMap(TreeMap<K,V> m,
1699 boolean fromStart, K lo, boolean loInclusive,
1700 boolean toEnd, K hi, boolean hiInclusive) {
1701 super(m, fromStart, lo, loInclusive, toEnd, hi, hiInclusive);
1702 }
1703
1704 public Comparator<? super K> comparator() {
1705 return m.comparator();
1706 }
1707
1708 public NavigableMap<K,V> subMap(K fromKey, boolean fromInclusive,
1709 K toKey, boolean toInclusive) {
1710 if (!inRange(fromKey, fromInclusive))
1711 throw new IllegalArgumentException("fromKey out of range");
1712 if (!inRange(toKey, toInclusive))
1713 throw new IllegalArgumentException("toKey out of range");
1714 return new AscendingSubMap(m,
1715 false, fromKey, fromInclusive,
1716 false, toKey, toInclusive);
1717 }
1718
1719 public NavigableMap<K,V> headMap(K toKey, boolean inclusive) {
1720 if (!inRange(toKey, inclusive))
1721 throw new IllegalArgumentException("toKey out of range");
1722 return new AscendingSubMap(m,
1723 fromStart, lo, loInclusive,
1724 false, toKey, inclusive);
1725 }
1726
1727 public NavigableMap<K,V> tailMap(K fromKey, boolean inclusive){
1728 if (!inRange(fromKey, inclusive))
1729 throw new IllegalArgumentException("fromKey out of range");
1730 return new AscendingSubMap(m,
1731 false, fromKey, inclusive,
1732 toEnd, hi, hiInclusive);
1733 }
1734
1735 public NavigableMap<K,V> descendingMap() {
1736 NavigableMap<K,V> mv = descendingMapView;
1737 return (mv != null) ? mv :
1738 (descendingMapView =
1739 new DescendingSubMap(m,
1740 fromStart, lo, loInclusive,
1741 toEnd, hi, hiInclusive));
1742 }
1743
1744 Iterator<K> keyIterator() {
1745 return new SubMapKeyIterator(absLowest(), absHighFence());
1746 }
1747
1748 Iterator<K> descendingKeyIterator() {
1749 return new DescendingSubMapKeyIterator(absHighest(), absLowFence());
1750 }
1751
1752 final class AscendingEntrySetView extends EntrySetView {
1753 public Iterator<Map.Entry<K,V>> iterator() {
1754 return new SubMapEntryIterator(absLowest(), absHighFence());
1755 }
1756 }
1757
1758 public Set<Map.Entry<K,V>> entrySet() {
1759 EntrySetView es = entrySetView;
1760 return (es != null) ? es : new AscendingEntrySetView();
1761 }
1762
1763 TreeMap.Entry<K,V> subLowest() { return absLowest(); }
1764 TreeMap.Entry<K,V> subHighest() { return absHighest(); }
1765 TreeMap.Entry<K,V> subCeiling(K key) { return absCeiling(key); }
1766 TreeMap.Entry<K,V> subHigher(K key) { return absHigher(key); }
1767 TreeMap.Entry<K,V> subFloor(K key) { return absFloor(key); }
1768 TreeMap.Entry<K,V> subLower(K key) { return absLower(key); }
1769 }
1770
1771 /**
1772 * @serial include
1773 */
1774 static final class DescendingSubMap<K,V> extends NavigableSubMap<K,V> {
1775 private static final long serialVersionUID = 912986545866120460L;
1776 DescendingSubMap(TreeMap<K,V> m,
1777 boolean fromStart, K lo, boolean loInclusive,
1778 boolean toEnd, K hi, boolean hiInclusive) {
1779 super(m, fromStart, lo, loInclusive, toEnd, hi, hiInclusive);
1780 }
1781
1782 private final Comparator<? super K> reverseComparator =
1783 Collections.reverseOrder(m.comparator);
1784
1785 public Comparator<? super K> comparator() {
1786 return reverseComparator;
1787 }
1788
1789 public NavigableMap<K,V> subMap(K fromKey, boolean fromInclusive,
1790 K toKey, boolean toInclusive) {
1791 if (!inRange(fromKey, fromInclusive))
1792 throw new IllegalArgumentException("fromKey out of range");
1793 if (!inRange(toKey, toInclusive))
1794 throw new IllegalArgumentException("toKey out of range");
1795 return new DescendingSubMap(m,
1796 false, toKey, toInclusive,
1797 false, fromKey, fromInclusive);
1798 }
1799
1800 public NavigableMap<K,V> headMap(K toKey, boolean inclusive) {
1801 if (!inRange(toKey, inclusive))
1802 throw new IllegalArgumentException("toKey out of range");
1803 return new DescendingSubMap(m,
1804 false, toKey, inclusive,
1805 toEnd, hi, hiInclusive);
1806 }
1807
1808 public NavigableMap<K,V> tailMap(K fromKey, boolean inclusive){
1809 if (!inRange(fromKey, inclusive))
1810 throw new IllegalArgumentException("fromKey out of range");
1811 return new DescendingSubMap(m,
1812 fromStart, lo, loInclusive,
1813 false, fromKey, inclusive);
1814 }
1815
1816 public NavigableMap<K,V> descendingMap() {
1817 NavigableMap<K,V> mv = descendingMapView;
1818 return (mv != null) ? mv :
1819 (descendingMapView =
1820 new AscendingSubMap(m,
1821 fromStart, lo, loInclusive,
1822 toEnd, hi, hiInclusive));
1823 }
1824
1825 Iterator<K> keyIterator() {
1826 return new DescendingSubMapKeyIterator(absHighest(), absLowFence());
1827 }
1828
1829 Iterator<K> descendingKeyIterator() {
1830 return new SubMapKeyIterator(absLowest(), absHighFence());
1831 }
1832
1833 final class DescendingEntrySetView extends EntrySetView {
1834 public Iterator<Map.Entry<K,V>> iterator() {
1835 return new DescendingSubMapEntryIterator(absHighest(), absLowFence());
1836 }
1837 }
1838
1839 public Set<Map.Entry<K,V>> entrySet() {
1840 EntrySetView es = entrySetView;
1841 return (es != null) ? es : new DescendingEntrySetView();
1842 }
1843
1844 TreeMap.Entry<K,V> subLowest() { return absHighest(); }
1845 TreeMap.Entry<K,V> subHighest() { return absLowest(); }
1846 TreeMap.Entry<K,V> subCeiling(K key) { return absFloor(key); }
1847 TreeMap.Entry<K,V> subHigher(K key) { return absLower(key); }
1848 TreeMap.Entry<K,V> subFloor(K key) { return absCeiling(key); }
1849 TreeMap.Entry<K,V> subLower(K key) { return absHigher(key); }
1850 }
1851
1852 /**
1853 * This class exists solely for the sake of serialization
1854 * compatibility with previous releases of TreeMap that did not
1855 * support NavigableMap. It translates an old-version SubMap into
1856 * a new-version AscendingSubMap. This class is never otherwise
1857 * used.
1858 *
1859 * @serial include
1860 */
1861 private class SubMap extends AbstractMap<K,V>
1862 implements SortedMap<K,V>, java.io.Serializable {
1863 private static final long serialVersionUID = -6520786458950516097L;
1864 private boolean fromStart = false, toEnd = false;
1865 private K fromKey, toKey;
1866 private Object readResolve() {
1867 return new AscendingSubMap(TreeMap.this,
1868 fromStart, fromKey, true,
1869 toEnd, toKey, false);
1870 }
1871 public Set<Map.Entry<K,V>> entrySet() { throw new InternalError(); }
1872 public K lastKey() { throw new InternalError(); }
1873 public K firstKey() { throw new InternalError(); }
1874 public SortedMap<K,V> subMap(K fromKey, K toKey) { throw new InternalError(); }
1875 public SortedMap<K,V> headMap(K toKey) { throw new InternalError(); }
1876 public SortedMap<K,V> tailMap(K fromKey) { throw new InternalError(); }
1877 public Comparator<? super K> comparator() { throw new InternalError(); }
1878 }
1879
1880
1881 // Red-black mechanics
1882
1883 private static final boolean RED = false;
1884 private static final boolean BLACK = true;
1885
1886 /**
1887 * Node in the Tree. Doubles as a means to pass key-value pairs back to
1888 * user (see Map.Entry).
1889 */
1890
1891 static final class Entry<K,V> implements Map.Entry<K,V> {
1892 K key;
1893 V value;
1894 Entry<K,V> left = null;
1895 Entry<K,V> right = null;
1896 Entry<K,V> parent;
1897 boolean color = BLACK;
1898
1899 /**
1900 * Make a new cell with given key, value, and parent, and with
1901 * <tt>null</tt> child links, and BLACK color.
1902 */
1903 Entry(K key, V value, Entry<K,V> parent) {
1904 this.key = key;
1905 this.value = value;
1906 this.parent = parent;
1907 }
1908
1909 /**
1910 * Returns the key.
1911 *
1912 * @return the key
1913 */
1914 public K getKey() {
1915 return key;
1916 }
1917
1918 /**
1919 * Returns the value associated with the key.
1920 *
1921 * @return the value associated with the key
1922 */
1923 public V getValue() {
1924 return value;
1925 }
1926
1927 /**
1928 * Replaces the value currently associated with the key with the given
1929 * value.
1930 *
1931 * @return the value associated with the key before this method was
1932 * called
1933 */
1934 public V setValue(V value) {
1935 V oldValue = this.value;
1936 this.value = value;
1937 return oldValue;
1938 }
1939
1940 public boolean equals(Object o) {
1941 if (!(o instanceof Map.Entry))
1942 return false;
1943 Map.Entry<?,?> e = (Map.Entry<?,?>)o;
1944
1945 return valEquals(key,e.getKey()) && valEquals(value,e.getValue());
1946 }
1947
1948 public int hashCode() {
1949 int keyHash = (key==null ? 0 : key.hashCode());
1950 int valueHash = (value==null ? 0 : value.hashCode());
1951 return keyHash ^ valueHash;
1952 }
1953
1954 public String toString() {
1955 return key + "=" + value;
1956 }
1957 }
1958
1959 /**
1960 * Returns the first Entry in the TreeMap (according to the TreeMap's
1961 * key-sort function). Returns null if the TreeMap is empty.
1962 */
1963 final Entry<K,V> getFirstEntry() {
1964 Entry<K,V> p = root;
1965 if (p != null)
1966 while (p.left != null)
1967 p = p.left;
1968 return p;
1969 }
1970
1971 /**
1972 * Returns the last Entry in the TreeMap (according to the TreeMap's
1973 * key-sort function). Returns null if the TreeMap is empty.
1974 */
1975 final Entry<K,V> getLastEntry() {
1976 Entry<K,V> p = root;
1977 if (p != null)
1978 while (p.right != null)
1979 p = p.right;
1980 return p;
1981 }
1982
1983 /**
1984 * Returns the successor of the specified Entry, or null if no such.
1985 */
1986 static <K,V> TreeMap.Entry<K,V> successor(Entry<K,V> t) {
1987 if (t == null)
1988 return null;
1989 else if (t.right != null) {
1990 Entry<K,V> p = t.right;
1991 while (p.left != null)
1992 p = p.left;
1993 return p;
1994 } else {
1995 Entry<K,V> p = t.parent;
1996 Entry<K,V> ch = t;
1997 while (p != null && ch == p.right) {
1998 ch = p;
1999 p = p.parent;
2000 }
2001 return p;
2002 }
2003 }
2004
2005 /**
2006 * Returns the predecessor of the specified Entry, or null if no such.
2007 */
2008 static <K,V> Entry<K,V> predecessor(Entry<K,V> t) {
2009 if (t == null)
2010 return null;
2011 else if (t.left != null) {
2012 Entry<K,V> p = t.left;
2013 while (p.right != null)
2014 p = p.right;
2015 return p;
2016 } else {
2017 Entry<K,V> p = t.parent;
2018 Entry<K,V> ch = t;
2019 while (p != null && ch == p.left) {
2020 ch = p;
2021 p = p.parent;
2022 }
2023 return p;
2024 }
2025 }
2026
2027 /**
2028 * Balancing operations.
2029 *
2030 * Implementations of rebalancings during insertion and deletion are
2031 * slightly different than the CLR version. Rather than using dummy
2032 * nilnodes, we use a set of accessors that deal properly with null. They
2033 * are used to avoid messiness surrounding nullness checks in the main
2034 * algorithms.
2035 */
2036
2037 private static <K,V> boolean colorOf(Entry<K,V> p) {
2038 return (p == null ? BLACK : p.color);
2039 }
2040
2041 private static <K,V> Entry<K,V> parentOf(Entry<K,V> p) {
2042 return (p == null ? null: p.parent);
2043 }
2044
2045 private static <K,V> void setColor(Entry<K,V> p, boolean c) {
2046 if (p != null)
2047 p.color = c;
2048 }
2049
2050 private static <K,V> Entry<K,V> leftOf(Entry<K,V> p) {
2051 return (p == null) ? null: p.left;
2052 }
2053
2054 private static <K,V> Entry<K,V> rightOf(Entry<K,V> p) {
2055 return (p == null) ? null: p.right;
2056 }
2057
2058 /** From CLR */
2059 private void rotateLeft(Entry<K,V> p) {
2060 if (p != null) {
2061 Entry<K,V> r = p.right;
2062 p.right = r.left;
2063 if (r.left != null)
2064 r.left.parent = p;
2065 r.parent = p.parent;
2066 if (p.parent == null)
2067 root = r;
2068 else if (p.parent.left == p)
2069 p.parent.left = r;
2070 else
2071 p.parent.right = r;
2072 r.left = p;
2073 p.parent = r;
2074 }
2075 }
2076
2077 /** From CLR */
2078 private void rotateRight(Entry<K,V> p) {
2079 if (p != null) {
2080 Entry<K,V> l = p.left;
2081 p.left = l.right;
2082 if (l.right != null) l.right.parent = p;
2083 l.parent = p.parent;
2084 if (p.parent == null)
2085 root = l;
2086 else if (p.parent.right == p)
2087 p.parent.right = l;
2088 else p.parent.left = l;
2089 l.right = p;
2090 p.parent = l;
2091 }
2092 }
2093
2094 /** From CLR */
2095 private void fixAfterInsertion(Entry<K,V> x) {
2096 x.color = RED;
2097
2098 while (x != null && x != root && x.parent.color == RED) {
2099 if (parentOf(x) == leftOf(parentOf(parentOf(x)))) {
2100 Entry<K,V> y = rightOf(parentOf(parentOf(x)));
2101 if (colorOf(y) == RED) {
2102 setColor(parentOf(x), BLACK);
2103 setColor(y, BLACK);
2104 setColor(parentOf(parentOf(x)), RED);
2105 x = parentOf(parentOf(x));
2106 } else {
2107 if (x == rightOf(parentOf(x))) {
2108 x = parentOf(x);
2109 rotateLeft(x);
2110 }
2111 setColor(parentOf(x), BLACK);
2112 setColor(parentOf(parentOf(x)), RED);
2113 rotateRight(parentOf(parentOf(x)));
2114 }
2115 } else {
2116 Entry<K,V> y = leftOf(parentOf(parentOf(x)));
2117 if (colorOf(y) == RED) {
2118 setColor(parentOf(x), BLACK);
2119 setColor(y, BLACK);
2120 setColor(parentOf(parentOf(x)), RED);
2121 x = parentOf(parentOf(x));
2122 } else {
2123 if (x == leftOf(parentOf(x))) {
2124 x = parentOf(x);
2125 rotateRight(x);
2126 }
2127 setColor(parentOf(x), BLACK);
2128 setColor(parentOf(parentOf(x)), RED);
2129 rotateLeft(parentOf(parentOf(x)));
2130 }
2131 }
2132 }
2133 root.color = BLACK;
2134 }
2135
2136 /**
2137 * Delete node p, and then rebalance the tree.
2138 */
2139 private void deleteEntry(Entry<K,V> p) {
2140 modCount++;
2141 size--;
2142
2143 // If strictly internal, copy successor's element to p and then make p
2144 // point to successor.
2145 if (p.left != null && p.right != null) {
2146 Entry<K,V> s = successor (p);
2147 p.key = s.key;
2148 p.value = s.value;
2149 p = s;
2150 } // p has 2 children
2151
2152 // Start fixup at replacement node, if it exists.
2153 Entry<K,V> replacement = (p.left != null ? p.left : p.right);
2154
2155 if (replacement != null) {
2156 // Link replacement to parent
2157 replacement.parent = p.parent;
2158 if (p.parent == null)
2159 root = replacement;
2160 else if (p == p.parent.left)
2161 p.parent.left = replacement;
2162 else
2163 p.parent.right = replacement;
2164
2165 // Null out links so they are OK to use by fixAfterDeletion.
2166 p.left = p.right = p.parent = null;
2167
2168 // Fix replacement
2169 if (p.color == BLACK)
2170 fixAfterDeletion(replacement);
2171 } else if (p.parent == null) { // return if we are the only node.
2172 root = null;
2173 } else { // No children. Use self as phantom replacement and unlink.
2174 if (p.color == BLACK)
2175 fixAfterDeletion(p);
2176
2177 if (p.parent != null) {
2178 if (p == p.parent.left)
2179 p.parent.left = null;
2180 else if (p == p.parent.right)
2181 p.parent.right = null;
2182 p.parent = null;
2183 }
2184 }
2185 }
2186
2187 /** From CLR */
2188 private void fixAfterDeletion(Entry<K,V> x) {
2189 while (x != root && colorOf(x) == BLACK) {
2190 if (x == leftOf(parentOf(x))) {
2191 Entry<K,V> sib = rightOf(parentOf(x));
2192
2193 if (colorOf(sib) == RED) {
2194 setColor(sib, BLACK);
2195 setColor(parentOf(x), RED);
2196 rotateLeft(parentOf(x));
2197 sib = rightOf(parentOf(x));
2198 }
2199
2200 if (colorOf(leftOf(sib)) == BLACK &&
2201 colorOf(rightOf(sib)) == BLACK) {
2202 setColor(sib, RED);
2203 x = parentOf(x);
2204 } else {
2205 if (colorOf(rightOf(sib)) == BLACK) {
2206 setColor(leftOf(sib), BLACK);
2207 setColor(sib, RED);
2208 rotateRight(sib);
2209 sib = rightOf(parentOf(x));
2210 }
2211 setColor(sib, colorOf(parentOf(x)));
2212 setColor(parentOf(x), BLACK);
2213 setColor(rightOf(sib), BLACK);
2214 rotateLeft(parentOf(x));
2215 x = root;
2216 }
2217 } else { // symmetric
2218 Entry<K,V> sib = leftOf(parentOf(x));
2219
2220 if (colorOf(sib) == RED) {
2221 setColor(sib, BLACK);
2222 setColor(parentOf(x), RED);
2223 rotateRight(parentOf(x));
2224 sib = leftOf(parentOf(x));
2225 }
2226
2227 if (colorOf(rightOf(sib)) == BLACK &&
2228 colorOf(leftOf(sib)) == BLACK) {
2229 setColor(sib, RED);
2230 x = parentOf(x);
2231 } else {
2232 if (colorOf(leftOf(sib)) == BLACK) {
2233 setColor(rightOf(sib), BLACK);
2234 setColor(sib, RED);
2235 rotateLeft(sib);
2236 sib = leftOf(parentOf(x));
2237 }
2238 setColor(sib, colorOf(parentOf(x)));
2239 setColor(parentOf(x), BLACK);
2240 setColor(leftOf(sib), BLACK);
2241 rotateRight(parentOf(x));
2242 x = root;
2243 }
2244 }
2245 }
2246
2247 setColor(x, BLACK);
2248 }
2249
2250 private static final long serialVersionUID = 919286545866124006L;
2251
2252 /**
2253 * Save the state of the <tt>TreeMap</tt> instance to a stream (i.e.,
2254 * serialize it).
2255 *
2256 * @serialData The <i>size</i> of the TreeMap (the number of key-value
2257 * mappings) is emitted (int), followed by the key (Object)
2258 * and value (Object) for each key-value mapping represented
2259 * by the TreeMap. The key-value mappings are emitted in
2260 * key-order (as determined by the TreeMap's Comparator,
2261 * or by the keys' natural ordering if the TreeMap has no
2262 * Comparator).
2263 */
2264 private void writeObject(java.io.ObjectOutputStream s)
2265 throws java.io.IOException {
2266 // Write out the Comparator and any hidden stuff
2267 s.defaultWriteObject();
2268
2269 // Write out size (number of Mappings)
2270 s.writeInt(size);
2271
2272 // Write out keys and values (alternating)
2273 for (Iterator<Map.Entry<K,V>> i = entrySet().iterator(); i.hasNext(); ) {
2274 Map.Entry<K,V> e = i.next();
2275 s.writeObject(e.getKey());
2276 s.writeObject(e.getValue());
2277 }
2278 }
2279
2280 /**
2281 * Reconstitute the <tt>TreeMap</tt> instance from a stream (i.e.,
2282 * deserialize it).
2283 */
2284 private void readObject(final java.io.ObjectInputStream s)
2285 throws java.io.IOException, ClassNotFoundException {
2286 // Read in the Comparator and any hidden stuff
2287 s.defaultReadObject();
2288
2289 // Read in size
2290 int size = s.readInt();
2291
2292 buildFromSorted(size, null, s, null);
2293 }
2294
2295 /** Intended to be called only from TreeSet.readObject */
2296 void readTreeSet(int size, java.io.ObjectInputStream s, V defaultVal)
2297 throws java.io.IOException, ClassNotFoundException {
2298 buildFromSorted(size, null, s, defaultVal);
2299 }
2300
2301 /** Intended to be called only from TreeSet.addAll */
2302 void addAllForTreeSet(SortedSet<? extends K> set, V defaultVal) {
2303 try {
2304 buildFromSorted(set.size(), set.iterator(), null, defaultVal);
2305 } catch (java.io.IOException cannotHappen) {
2306 } catch (ClassNotFoundException cannotHappen) {
2307 }
2308 }
2309
2310
2311 /**
2312 * Linear time tree building algorithm from sorted data. Can accept keys
2313 * and/or values from iterator or stream. This leads to too many
2314 * parameters, but seems better than alternatives. The four formats
2315 * that this method accepts are:
2316 *
2317 * 1) An iterator of Map.Entries. (it != null, defaultVal == null).
2318 * 2) An iterator of keys. (it != null, defaultVal != null).
2319 * 3) A stream of alternating serialized keys and values.
2320 * (it == null, defaultVal == null).
2321 * 4) A stream of serialized keys. (it == null, defaultVal != null).
2322 *
2323 * It is assumed that the comparator of the TreeMap is already set prior
2324 * to calling this method.
2325 *
2326 * @param size the number of keys (or key-value pairs) to be read from
2327 * the iterator or stream
2328 * @param it If non-null, new entries are created from entries
2329 * or keys read from this iterator.
2330 * @param str If non-null, new entries are created from keys and
2331 * possibly values read from this stream in serialized form.
2332 * Exactly one of it and str should be non-null.
2333 * @param defaultVal if non-null, this default value is used for
2334 * each value in the map. If null, each value is read from
2335 * iterator or stream, as described above.
2336 * @throws IOException propagated from stream reads. This cannot
2337 * occur if str is null.
2338 * @throws ClassNotFoundException propagated from readObject.
2339 * This cannot occur if str is null.
2340 */
2341 private void buildFromSorted(int size, Iterator it,
2342 java.io.ObjectInputStream str,
2343 V defaultVal)
2344 throws java.io.IOException, ClassNotFoundException {
2345 this.size = size;
2346 root = buildFromSorted(0, 0, size-1, computeRedLevel(size),
2347 it, str, defaultVal);
2348 }
2349
2350 /**
2351 * Recursive "helper method" that does the real work of the
2352 * previous method. Identically named parameters have
2353 * identical definitions. Additional parameters are documented below.
2354 * It is assumed that the comparator and size fields of the TreeMap are
2355 * already set prior to calling this method. (It ignores both fields.)
2356 *
2357 * @param level the current level of tree. Initial call should be 0.
2358 * @param lo the first element index of this subtree. Initial should be 0.
2359 * @param hi the last element index of this subtree. Initial should be
2360 * size-1.
2361 * @param redLevel the level at which nodes should be red.
2362 * Must be equal to computeRedLevel for tree of this size.
2363 */
2364 private final Entry<K,V> buildFromSorted(int level, int lo, int hi,
2365 int redLevel,
2366 Iterator it,
2367 java.io.ObjectInputStream str,
2368 V defaultVal)
2369 throws java.io.IOException, ClassNotFoundException {
2370 /*
2371 * Strategy: The root is the middlemost element. To get to it, we
2372 * have to first recursively construct the entire left subtree,
2373 * so as to grab all of its elements. We can then proceed with right
2374 * subtree.
2375 *
2376 * The lo and hi arguments are the minimum and maximum
2377 * indices to pull out of the iterator or stream for current subtree.
2378 * They are not actually indexed, we just proceed sequentially,
2379 * ensuring that items are extracted in corresponding order.
2380 */
2381
2382 if (hi < lo) return null;
2383
2384 int mid = (lo + hi) >>> 1;
2385
2386 Entry<K,V> left = null;
2387 if (lo < mid)
2388 left = buildFromSorted(level+1, lo, mid - 1, redLevel,
2389 it, str, defaultVal);
2390
2391 // extract key and/or value from iterator or stream
2392 K key;
2393 V value;
2394 if (it != null) {
2395 if (defaultVal==null) {
2396 Map.Entry<K,V> entry = (Map.Entry<K,V>)it.next();
2397 key = entry.getKey();
2398 value = entry.getValue();
2399 } else {
2400 key = (K)it.next();
2401 value = defaultVal;
2402 }
2403 } else { // use stream
2404 key = (K) str.readObject();
2405 value = (defaultVal != null ? defaultVal : (V) str.readObject());
2406 }
2407
2408 Entry<K,V> middle = new Entry<K,V>(key, value, null);
2409
2410 // color nodes in non-full bottommost level red
2411 if (level == redLevel)
2412 middle.color = RED;
2413
2414 if (left != null) {
2415 middle.left = left;
2416 left.parent = middle;
2417 }
2418
2419 if (mid < hi) {
2420 Entry<K,V> right = buildFromSorted(level+1, mid+1, hi, redLevel,
2421 it, str, defaultVal);
2422 middle.right = right;
2423 right.parent = middle;
2424 }
2425
2426 return middle;
2427 }
2428
2429 /**
2430 * Find the level down to which to assign all nodes BLACK. This is the
2431 * last `full' level of the complete binary tree produced by
2432 * buildTree. The remaining nodes are colored RED. (This makes a `nice'
2433 * set of color assignments wrt future insertions.) This level number is
2434 * computed by finding the number of splits needed to reach the zeroeth
2435 * node. (The answer is ~lg(N), but in any case must be computed by same
2436 * quick O(lg(N)) loop.)
2437 */
2438 private static int computeRedLevel(int sz) {
2439 int level = 0;
2440 for (int m = sz - 1; m >= 0; m = m / 2 - 1)
2441 level++;
2442 return level;
2443 }
2444 }