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My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

Showing the changes to java/pkg/java/util/TreeSet.java (1 of 18352 files). Show all

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1+/*
2+ * Copyright (c) 1998, 2010, 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 {@link NavigableSet} implementation based on a {@link TreeMap}.
30+ * The elements are ordered using their {@linkplain Comparable natural
31+ * ordering}, or by a {@link Comparator} provided at set creation
32+ * time, depending on which constructor is used.
33+ *
34+ * <p>This implementation provides guaranteed log(n) time cost for the basic
35+ * operations ({@code add}, {@code remove} and {@code contains}).
36+ *
37+ * <p>Note that the ordering maintained by a set (whether or not an explicit
38+ * comparator is provided) must be <i>consistent with equals</i> if it is to
39+ * correctly implement the {@code Set} interface. (See {@code Comparable}
40+ * or {@code Comparator} for a precise definition of <i>consistent with
41+ * equals</i>.) This is so because the {@code Set} interface is defined in
42+ * terms of the {@code equals} operation, but a {@code TreeSet} instance
43+ * performs all element comparisons using its {@code compareTo} (or
44+ * {@code compare}) method, so two elements that are deemed equal by this method
45+ * are, from the standpoint of the set, equal. The behavior of a set
46+ * <i>is</i> well-defined even if its ordering is inconsistent with equals; it
47+ * just fails to obey the general contract of the {@code Set} interface.
48+ *
49+ * <p><strong>Note that this implementation is not synchronized.</strong>
50+ * If multiple threads access a tree set concurrently, and at least one
51+ * of the threads modifies the set, it <i>must</i> be synchronized
52+ * externally. This is typically accomplished by synchronizing on some
53+ * object that naturally encapsulates the set.
54+ * If no such object exists, the set should be "wrapped" using the
55+ * {@link Collections#synchronizedSortedSet Collections.synchronizedSortedSet}
56+ * method. This is best done at creation time, to prevent accidental
57+ * unsynchronized access to the set: <pre>
58+ * SortedSet s = Collections.synchronizedSortedSet(new TreeSet(...));</pre>
59+ *
60+ * <p>The iterators returned by this class's {@code iterator} method are
61+ * <i>fail-fast</i>: if the set is modified at any time after the iterator is
62+ * created, in any way except through the iterator's own {@code remove}
63+ * method, the iterator will throw a {@link ConcurrentModificationException}.
64+ * Thus, in the face of concurrent modification, the iterator fails quickly
65+ * and cleanly, rather than risking arbitrary, non-deterministic behavior at
66+ * an undetermined time in the future.
67+ *
68+ * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
69+ * as it is, generally speaking, impossible to make any hard guarantees in the
70+ * presence of unsynchronized concurrent modification. Fail-fast iterators
71+ * throw {@code ConcurrentModificationException} on a best-effort basis.
72+ * Therefore, it would be wrong to write a program that depended on this
73+ * exception for its correctness: <i>the fail-fast behavior of iterators
74+ * should be used only to detect bugs.</i>
75+ *
76+ * <p>This class is a member of the
77+ * <a href="{@docRoot}/../technotes/guides/collections/index.html">
78+ * Java Collections Framework</a>.
79+ *
80+ * @param <E> the type of elements maintained by this set
81+ *
82+ * @author Josh Bloch
83+ * @see Collection
84+ * @see Set
85+ * @see HashSet
86+ * @see Comparable
87+ * @see Comparator
88+ * @see TreeMap
89+ * @since 1.2
90+ */
91+
92+public class TreeSet<E> extends AbstractSet<E>
93+ implements NavigableSet<E>, Cloneable, java.io.Serializable
94+{
95+ /**
96+ * The backing map.
97+ */
98+ private transient NavigableMap<E,Object> m;
99+
100+ // Dummy value to associate with an Object in the backing Map
101+ private static final Object PRESENT = new Object();
102+
103+ /**
104+ * Constructs a set backed by the specified navigable map.
105+ */
106+ TreeSet(NavigableMap<E,Object> m) {
107+ this.m = m;
108+ }
109+
110+ /**
111+ * Constructs a new, empty tree set, sorted according to the
112+ * natural ordering of its elements. All elements inserted into
113+ * the set must implement the {@link Comparable} interface.
114+ * Furthermore, all such elements must be <i>mutually
115+ * comparable</i>: {@code e1.compareTo(e2)} must not throw a
116+ * {@code ClassCastException} for any elements {@code e1} and
117+ * {@code e2} in the set. If the user attempts to add an element
118+ * to the set that violates this constraint (for example, the user
119+ * attempts to add a string element to a set whose elements are
120+ * integers), the {@code add} call will throw a
121+ * {@code ClassCastException}.
122+ */
123+ public TreeSet() {
124+ this(new TreeMap<E,Object>());
125+ }
126+
127+ /**
128+ * Constructs a new, empty tree set, sorted according to the specified
129+ * comparator. All elements inserted into the set must be <i>mutually
130+ * comparable</i> by the specified comparator: {@code comparator.compare(e1,
131+ * e2)} must not throw a {@code ClassCastException} for any elements
132+ * {@code e1} and {@code e2} in the set. If the user attempts to add
133+ * an element to the set that violates this constraint, the
134+ * {@code add} call will throw a {@code ClassCastException}.
135+ *
136+ * @param comparator the comparator that will be used to order this set.
137+ * If {@code null}, the {@linkplain Comparable natural
138+ * ordering} of the elements will be used.
139+ */
140+ public TreeSet(Comparator<? super E> comparator) {
141+ this(new TreeMap<>(comparator));
142+ }
143+
144+ /**
145+ * Constructs a new tree set containing the elements in the specified
146+ * collection, sorted according to the <i>natural ordering</i> of its
147+ * elements. All elements inserted into the set must implement the
148+ * {@link Comparable} interface. Furthermore, all such elements must be
149+ * <i>mutually comparable</i>: {@code e1.compareTo(e2)} must not throw a
150+ * {@code ClassCastException} for any elements {@code e1} and
151+ * {@code e2} in the set.
152+ *
153+ * @param c collection whose elements will comprise the new set
154+ * @throws ClassCastException if the elements in {@code c} are
155+ * not {@link Comparable}, or are not mutually comparable
156+ * @throws NullPointerException if the specified collection is null
157+ */
158+ public TreeSet(Collection<? extends E> c) {
159+ this();
160+ addAll(c);
161+ }
162+
163+ /**
164+ * Constructs a new tree set containing the same elements and
165+ * using the same ordering as the specified sorted set.
166+ *
167+ * @param s sorted set whose elements will comprise the new set
168+ * @throws NullPointerException if the specified sorted set is null
169+ */
170+ public TreeSet(SortedSet<E> s) {
171+ this(s.comparator());
172+ addAll(s);
173+ }
174+
175+ /**
176+ * Returns an iterator over the elements in this set in ascending order.
177+ *
178+ * @return an iterator over the elements in this set in ascending order
179+ */
180+ public Iterator<E> iterator() {
181+ return m.navigableKeySet().iterator();
182+ }
183+
184+ /**
185+ * Returns an iterator over the elements in this set in descending order.
186+ *
187+ * @return an iterator over the elements in this set in descending order
188+ * @since 1.6
189+ */
190+ public Iterator<E> descendingIterator() {
191+ return m.descendingKeySet().iterator();
192+ }
193+
194+ /**
195+ * @since 1.6
196+ */
197+ public NavigableSet<E> descendingSet() {
198+ return new TreeSet<>(m.descendingMap());
199+ }
200+
201+ /**
202+ * Returns the number of elements in this set (its cardinality).
203+ *
204+ * @return the number of elements in this set (its cardinality)
205+ */
206+ public int size() {
207+ return m.size();
208+ }
209+
210+ /**
211+ * Returns {@code true} if this set contains no elements.
212+ *
213+ * @return {@code true} if this set contains no elements
214+ */
215+ public boolean isEmpty() {
216+ return m.isEmpty();
217+ }
218+
219+ /**
220+ * Returns {@code true} if this set contains the specified element.
221+ * More formally, returns {@code true} if and only if this set
222+ * contains an element {@code e} such that
223+ * <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>.
224+ *
225+ * @param o object to be checked for containment in this set
226+ * @return {@code true} if this set contains the specified element
227+ * @throws ClassCastException if the specified object cannot be compared
228+ * with the elements currently in the set
229+ * @throws NullPointerException if the specified element is null
230+ * and this set uses natural ordering, or its comparator
231+ * does not permit null elements
232+ */
233+ public boolean contains(Object o) {
234+ return m.containsKey(o);
235+ }
236+
237+ /**
238+ * Adds the specified element to this set if it is not already present.
239+ * More formally, adds the specified element {@code e} to this set if
240+ * the set contains no element {@code e2} such that
241+ * <tt>(e==null&nbsp;?&nbsp;e2==null&nbsp;:&nbsp;e.equals(e2))</tt>.
242+ * If this set already contains the element, the call leaves the set
243+ * unchanged and returns {@code false}.
244+ *
245+ * @param e element to be added to this set
246+ * @return {@code true} if this set did not already contain the specified
247+ * element
248+ * @throws ClassCastException if the specified object cannot be compared
249+ * with the elements currently in this set
250+ * @throws NullPointerException if the specified element is null
251+ * and this set uses natural ordering, or its comparator
252+ * does not permit null elements
253+ */
254+ public boolean add(E e) {
255+ return m.put(e, PRESENT)==null;
256+ }
257+
258+ /**
259+ * Removes the specified element from this set if it is present.
260+ * More formally, removes an element {@code e} such that
261+ * <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>,
262+ * if this set contains such an element. Returns {@code true} if
263+ * this set contained the element (or equivalently, if this set
264+ * changed as a result of the call). (This set will not contain the
265+ * element once the call returns.)
266+ *
267+ * @param o object to be removed from this set, if present
268+ * @return {@code true} if this set contained the specified element
269+ * @throws ClassCastException if the specified object cannot be compared
270+ * with the elements currently in this set
271+ * @throws NullPointerException if the specified element is null
272+ * and this set uses natural ordering, or its comparator
273+ * does not permit null elements
274+ */
275+ public boolean remove(Object o) {
276+ return m.remove(o)==PRESENT;
277+ }
278+
279+ /**
280+ * Removes all of the elements from this set.
281+ * The set will be empty after this call returns.
282+ */
283+ public void clear() {
284+ m.clear();
285+ }
286+
287+ /**
288+ * Adds all of the elements in the specified collection to this set.
289+ *
290+ * @param c collection containing elements to be added to this set
291+ * @return {@code true} if this set changed as a result of the call
292+ * @throws ClassCastException if the elements provided cannot be compared
293+ * with the elements currently in the set
294+ * @throws NullPointerException if the specified collection is null or
295+ * if any element is null and this set uses natural ordering, or
296+ * its comparator does not permit null elements
297+ */
298+ public boolean addAll(Collection<? extends E> c) {
299+ // Use linear-time version if applicable
300+ if (m.size()==0 && c.size() > 0 &&
301+ c instanceof SortedSet &&
302+ m instanceof TreeMap) {
303+ SortedSet<? extends E> set = (SortedSet<? extends E>) c;
304+ TreeMap<E,Object> map = (TreeMap<E, Object>) m;
305+ Comparator<? super E> cc = (Comparator<? super E>) set.comparator();
306+ Comparator<? super E> mc = map.comparator();
307+ if (cc==mc || (cc != null && cc.equals(mc))) {
308+ map.addAllForTreeSet(set, PRESENT);
309+ return true;
310+ }
311+ }
312+ return super.addAll(c);
313+ }
314+
315+ /**
316+ * @throws ClassCastException {@inheritDoc}
317+ * @throws NullPointerException if {@code fromElement} or {@code toElement}
318+ * is null and this set uses natural ordering, or its comparator
319+ * does not permit null elements
320+ * @throws IllegalArgumentException {@inheritDoc}
321+ * @since 1.6
322+ */
323+ public NavigableSet<E> subSet(E fromElement, boolean fromInclusive,
324+ E toElement, boolean toInclusive) {
325+ return new TreeSet<>(m.subMap(fromElement, fromInclusive,
326+ toElement, toInclusive));
327+ }
328+
329+ /**
330+ * @throws ClassCastException {@inheritDoc}
331+ * @throws NullPointerException if {@code toElement} is null and
332+ * this set uses natural ordering, or its comparator does
333+ * not permit null elements
334+ * @throws IllegalArgumentException {@inheritDoc}
335+ * @since 1.6
336+ */
337+ public NavigableSet<E> headSet(E toElement, boolean inclusive) {
338+ return new TreeSet<>(m.headMap(toElement, inclusive));
339+ }
340+
341+ /**
342+ * @throws ClassCastException {@inheritDoc}
343+ * @throws NullPointerException if {@code fromElement} is null and
344+ * this set uses natural ordering, or its comparator does
345+ * not permit null elements
346+ * @throws IllegalArgumentException {@inheritDoc}
347+ * @since 1.6
348+ */
349+ public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
350+ return new TreeSet<>(m.tailMap(fromElement, inclusive));
351+ }
352+
353+ /**
354+ * @throws ClassCastException {@inheritDoc}
355+ * @throws NullPointerException if {@code fromElement} or
356+ * {@code toElement} is null and this set uses natural ordering,
357+ * or its comparator does not permit null elements
358+ * @throws IllegalArgumentException {@inheritDoc}
359+ */
360+ public SortedSet<E> subSet(E fromElement, E toElement) {
361+ return subSet(fromElement, true, toElement, false);
362+ }
363+
364+ /**
365+ * @throws ClassCastException {@inheritDoc}
366+ * @throws NullPointerException if {@code toElement} is null
367+ * and this set uses natural ordering, or its comparator does
368+ * not permit null elements
369+ * @throws IllegalArgumentException {@inheritDoc}
370+ */
371+ public SortedSet<E> headSet(E toElement) {
372+ return headSet(toElement, false);
373+ }
374+
375+ /**
376+ * @throws ClassCastException {@inheritDoc}
377+ * @throws NullPointerException if {@code fromElement} is null
378+ * and this set uses natural ordering, or its comparator does
379+ * not permit null elements
380+ * @throws IllegalArgumentException {@inheritDoc}
381+ */
382+ public SortedSet<E> tailSet(E fromElement) {
383+ return tailSet(fromElement, true);
384+ }
385+
386+ public Comparator<? super E> comparator() {
387+ return m.comparator();
388+ }
389+
390+ /**
391+ * @throws NoSuchElementException {@inheritDoc}
392+ */
393+ public E first() {
394+ return m.firstKey();
395+ }
396+
397+ /**
398+ * @throws NoSuchElementException {@inheritDoc}
399+ */
400+ public E last() {
401+ return m.lastKey();
402+ }
403+
404+ // NavigableSet API methods
405+
406+ /**
407+ * @throws ClassCastException {@inheritDoc}
408+ * @throws NullPointerException if the specified element is null
409+ * and this set uses natural ordering, or its comparator
410+ * does not permit null elements
411+ * @since 1.6
412+ */
413+ public E lower(E e) {
414+ return m.lowerKey(e);
415+ }
416+
417+ /**
418+ * @throws ClassCastException {@inheritDoc}
419+ * @throws NullPointerException if the specified element is null
420+ * and this set uses natural ordering, or its comparator
421+ * does not permit null elements
422+ * @since 1.6
423+ */
424+ public E floor(E e) {
425+ return m.floorKey(e);
426+ }
427+
428+ /**
429+ * @throws ClassCastException {@inheritDoc}
430+ * @throws NullPointerException if the specified element is null
431+ * and this set uses natural ordering, or its comparator
432+ * does not permit null elements
433+ * @since 1.6
434+ */
435+ public E ceiling(E e) {
436+ return m.ceilingKey(e);
437+ }
438+
439+ /**
440+ * @throws ClassCastException {@inheritDoc}
441+ * @throws NullPointerException if the specified element is null
442+ * and this set uses natural ordering, or its comparator
443+ * does not permit null elements
444+ * @since 1.6
445+ */
446+ public E higher(E e) {
447+ return m.higherKey(e);
448+ }
449+
450+ /**
451+ * @since 1.6
452+ */
453+ public E pollFirst() {
454+ Map.Entry<E,?> e = m.pollFirstEntry();
455+ return (e == null) ? null : e.getKey();
456+ }
457+
458+ /**
459+ * @since 1.6
460+ */
461+ public E pollLast() {
462+ Map.Entry<E,?> e = m.pollLastEntry();
463+ return (e == null) ? null : e.getKey();
464+ }
465+
466+ /**
467+ * Returns a shallow copy of this {@code TreeSet} instance. (The elements
468+ * themselves are not cloned.)
469+ *
470+ * @return a shallow copy of this set
471+ */
472+ public Object clone() {
473+ TreeSet<E> clone = null;
474+ try {
475+ clone = (TreeSet<E>) super.clone();
476+ } catch (CloneNotSupportedException e) {
477+ throw new InternalError();
478+ }
479+
480+ clone.m = new TreeMap<>(m);
481+ return clone;
482+ }
483+
484+ /**
485+ * Save the state of the {@code TreeSet} instance to a stream (that is,
486+ * serialize it).
487+ *
488+ * @serialData Emits the comparator used to order this set, or
489+ * {@code null} if it obeys its elements' natural ordering
490+ * (Object), followed by the size of the set (the number of
491+ * elements it contains) (int), followed by all of its
492+ * elements (each an Object) in order (as determined by the
493+ * set's Comparator, or by the elements' natural ordering if
494+ * the set has no Comparator).
495+ */
496+ private void writeObject(java.io.ObjectOutputStream s)
497+ throws java.io.IOException {
498+ // Write out any hidden stuff
499+ s.defaultWriteObject();
500+
501+ // Write out Comparator
502+ s.writeObject(m.comparator());
503+
504+ // Write out size
505+ s.writeInt(m.size());
506+
507+ // Write out all elements in the proper order.
508+ for (E e : m.keySet())
509+ s.writeObject(e);
510+ }
511+
512+ /**
513+ * Reconstitute the {@code TreeSet} instance from a stream (that is,
514+ * deserialize it).
515+ */
516+ private void readObject(java.io.ObjectInputStream s)
517+ throws java.io.IOException, ClassNotFoundException {
518+ // Read in any hidden stuff
519+ s.defaultReadObject();
520+
521+ // Read in Comparator
522+ Comparator<? super E> c = (Comparator<? super E>) s.readObject();
523+
524+ // Create backing TreeMap
525+ TreeMap<E,Object> tm;
526+ if (c==null)
527+ tm = new TreeMap<>();
528+ else
529+ tm = new TreeMap<>(c);
530+ m = tm;
531+
532+ // Read in size
533+ int size = s.readInt();
534+
535+ tm.readTreeSet(size, s, PRESENT);
536+ }
537+
538+ private static final long serialVersionUID = -2479143000061671589L;
539+}