1 |
dl |
1.1 |
/* |
2 |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
3 |
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* Expert Group and released to the public domain, as explained at |
4 |
jsr166 |
1.12 |
* http://creativecommons.org/publicdomain/zero/1.0/ |
5 |
dl |
1.1 |
*/ |
6 |
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7 |
jsr166 |
1.7 |
package jsr166x; |
8 |
dl |
1.1 |
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9 |
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import java.util.*; |
10 |
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import java.util.concurrent.*; |
11 |
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12 |
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/** |
13 |
dl |
1.2 |
* A scalable concurrent {@link NavigableSet} implementation based on |
14 |
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* a {@link ConcurrentSkipListMap}. This class maintains a set in |
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* ascending order, sorted according to the <i>natural order</i> for |
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* the element's class (see {@link Comparable}), or by the comparator |
17 |
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* provided at creation time, depending on which constructor is |
18 |
jsr166 |
1.16 |
* used. |
19 |
dl |
1.1 |
* |
20 |
jsr166 |
1.16 |
* <p>This implementation provides expected average <i>log(n)</i> time |
21 |
jsr166 |
1.17 |
* cost for the {@code contains}, {@code add}, and {@code remove} |
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dl |
1.1 |
* operations and their variants. Insertion, removal, and access |
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* operations safely execute concurrently by multiple |
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* threads. Iterators are <i>weakly consistent</i>, returning elements |
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* reflecting the state of the set at some point at or since the |
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* creation of the iterator. They do <em>not</em> throw {@link |
27 |
dl |
1.6 |
* ConcurrentModificationException}, and may proceed concurrently with |
28 |
dl |
1.1 |
* other operations. |
29 |
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* |
30 |
jsr166 |
1.17 |
* <p>Beware that, unlike in most collections, the {@code size} |
31 |
dl |
1.4 |
* method is <em>not</em> a constant-time operation. Because of the |
32 |
dl |
1.1 |
* asynchronous nature of these sets, determining the current number |
33 |
dl |
1.4 |
* of elements requires a traversal of the elements. Additionally, the |
34 |
jsr166 |
1.17 |
* bulk operations {@code addAll}, {@code removeAll}, |
35 |
jsr166 |
1.18 |
* {@code retainAll}, and {@code containsAll} are <em>not</em> |
36 |
dl |
1.4 |
* guaranteed to be performed atomically. For example, an iterator |
37 |
jsr166 |
1.17 |
* operating concurrently with an {@code addAll} operation might view |
38 |
dl |
1.4 |
* only some of the added elements. |
39 |
dl |
1.1 |
* |
40 |
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* <p>This class and its iterators implement all of the |
41 |
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* <em>optional</em> methods of the {@link Set} and {@link Iterator} |
42 |
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* interfaces. Like most other concurrent collection implementations, |
43 |
jsr166 |
1.17 |
* this class does not permit the use of {@code null} elements. |
44 |
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* because {@code null} arguments and return values cannot be reliably |
45 |
dl |
1.1 |
* distinguished from the absence of elements. |
46 |
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* |
47 |
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* @author Doug Lea |
48 |
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* @param <E> the type of elements maintained by this set |
49 |
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*/ |
50 |
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public class ConcurrentSkipListSet<E> |
51 |
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extends AbstractSet<E> |
52 |
dl |
1.2 |
implements NavigableSet<E>, Cloneable, java.io.Serializable { |
53 |
dl |
1.1 |
|
54 |
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private static final long serialVersionUID = -2479143111061671589L; |
55 |
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56 |
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/** |
57 |
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* The underlying map. Uses Boolean.TRUE as value for each |
58 |
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* element. Note that this class relies on default serialization, |
59 |
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* which is a little wasteful in saving all of the useless value |
60 |
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* fields of underlying map, but enables this field to be declared |
61 |
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* final, which is necessary for thread safety. |
62 |
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*/ |
63 |
jsr166 |
1.7 |
private final ConcurrentSkipListMap<E,Object> m; |
64 |
dl |
1.1 |
|
65 |
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/** |
66 |
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* Constructs a new, empty set, sorted according to the elements' natural |
67 |
jsr166 |
1.7 |
* order. |
68 |
dl |
1.1 |
*/ |
69 |
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public ConcurrentSkipListSet() { |
70 |
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m = new ConcurrentSkipListMap<E,Object>(); |
71 |
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} |
72 |
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73 |
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/** |
74 |
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* Constructs a new, empty set, sorted according to the specified |
75 |
jsr166 |
1.7 |
* comparator. |
76 |
dl |
1.1 |
* |
77 |
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* @param c the comparator that will be used to sort this set. A |
78 |
jsr166 |
1.17 |
* {@code null} value indicates that the elements' <i>natural |
79 |
dl |
1.1 |
* ordering</i> should be used. |
80 |
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*/ |
81 |
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public ConcurrentSkipListSet(Comparator<? super E> c) { |
82 |
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m = new ConcurrentSkipListMap<E,Object>(c); |
83 |
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} |
84 |
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85 |
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/** |
86 |
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* Constructs a new set containing the elements in the specified |
87 |
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* collection, sorted according to the elements' <i>natural order</i>. |
88 |
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* |
89 |
jsr166 |
1.15 |
* @param c The elements that will comprise the new set |
90 |
dl |
1.1 |
* |
91 |
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* @throws ClassCastException if the elements in the specified |
92 |
jsr166 |
1.15 |
* collection are not comparable, or are not mutually comparable |
93 |
dl |
1.4 |
* @throws NullPointerException if the specified collection is |
94 |
jsr166 |
1.17 |
* {@code null} |
95 |
dl |
1.1 |
*/ |
96 |
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public ConcurrentSkipListSet(Collection<? extends E> c) { |
97 |
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m = new ConcurrentSkipListMap<E,Object>(); |
98 |
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addAll(c); |
99 |
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} |
100 |
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101 |
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/** |
102 |
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* Constructs a new set containing the same elements as the specified |
103 |
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* sorted set, sorted according to the same ordering. |
104 |
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* |
105 |
jsr166 |
1.15 |
* @param s sorted set whose elements will comprise the new set |
106 |
dl |
1.4 |
* @throws NullPointerException if the specified sorted set is |
107 |
jsr166 |
1.17 |
* {@code null} |
108 |
dl |
1.1 |
*/ |
109 |
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public ConcurrentSkipListSet(SortedSet<E> s) { |
110 |
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m = new ConcurrentSkipListMap<E,Object>(s.comparator()); |
111 |
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addAll(s); |
112 |
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} |
113 |
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114 |
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/** |
115 |
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* Returns a shallow copy of this set. (The elements themselves |
116 |
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* are not cloned.) |
117 |
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* |
118 |
jsr166 |
1.15 |
* @return a shallow copy of this set |
119 |
dl |
1.1 |
*/ |
120 |
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public Object clone() { |
121 |
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ConcurrentSkipListSet<E> clone = null; |
122 |
jsr166 |
1.8 |
try { |
123 |
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clone = (ConcurrentSkipListSet<E>) super.clone(); |
124 |
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} catch (CloneNotSupportedException e) { |
125 |
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throw new InternalError(); |
126 |
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} |
127 |
dl |
1.1 |
|
128 |
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clone.m.initialize(); |
129 |
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clone.addAll(this); |
130 |
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return clone; |
131 |
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} |
132 |
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133 |
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/* ---------------- Set operations -------------- */ |
134 |
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135 |
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/** |
136 |
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* Returns the number of elements in this set. If this set |
137 |
jsr166 |
1.17 |
* contains more than {@code Integer.MAX_VALUE} elements, it |
138 |
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* returns {@code Integer.MAX_VALUE}. |
139 |
dl |
1.1 |
* |
140 |
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* <p>Beware that, unlike in most collections, this method is |
141 |
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* <em>NOT</em> a constant-time operation. Because of the |
142 |
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* asynchronous nature of these sets, determining the current |
143 |
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* number of elements requires traversing them all to count them. |
144 |
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* Additionally, it is possible for the size to change during |
145 |
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* execution of this method, in which case the returned result |
146 |
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* will be inaccurate. Thus, this method is typically not very |
147 |
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* useful in concurrent applications. |
148 |
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* |
149 |
jsr166 |
1.15 |
* @return the number of elements in this set |
150 |
dl |
1.1 |
*/ |
151 |
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public int size() { |
152 |
jsr166 |
1.8 |
return m.size(); |
153 |
dl |
1.1 |
} |
154 |
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155 |
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/** |
156 |
jsr166 |
1.17 |
* Returns {@code true} if this set contains no elements. |
157 |
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* @return {@code true} if this set contains no elements |
158 |
dl |
1.1 |
*/ |
159 |
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public boolean isEmpty() { |
160 |
jsr166 |
1.8 |
return m.isEmpty(); |
161 |
dl |
1.1 |
} |
162 |
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163 |
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/** |
164 |
jsr166 |
1.17 |
* Returns {@code true} if this set contains the specified element. |
165 |
dl |
1.1 |
* |
166 |
jsr166 |
1.15 |
* @param o the object to be checked for containment in this set |
167 |
jsr166 |
1.17 |
* @return {@code true} if this set contains the specified element |
168 |
dl |
1.1 |
* |
169 |
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* @throws ClassCastException if the specified object cannot be compared |
170 |
jsr166 |
1.15 |
* with the elements currently in the set |
171 |
jsr166 |
1.17 |
* @throws NullPointerException if o is {@code null} |
172 |
dl |
1.1 |
*/ |
173 |
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public boolean contains(Object o) { |
174 |
jsr166 |
1.8 |
return m.containsKey(o); |
175 |
dl |
1.1 |
} |
176 |
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177 |
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/** |
178 |
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* Adds the specified element to this set if it is not already present. |
179 |
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* |
180 |
jsr166 |
1.15 |
* @param o element to be added to this set |
181 |
jsr166 |
1.17 |
* @return {@code true} if the set did not already contain the specified |
182 |
jsr166 |
1.15 |
* element |
183 |
dl |
1.1 |
* |
184 |
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* @throws ClassCastException if the specified object cannot be compared |
185 |
jsr166 |
1.15 |
* with the elements currently in the set |
186 |
jsr166 |
1.17 |
* @throws NullPointerException if o is {@code null} |
187 |
dl |
1.1 |
*/ |
188 |
|
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public boolean add(E o) { |
189 |
jsr166 |
1.8 |
return m.putIfAbsent(o, Boolean.TRUE) == null; |
190 |
dl |
1.1 |
} |
191 |
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|
192 |
|
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/** |
193 |
|
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* Removes the specified element from this set if it is present. |
194 |
|
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* |
195 |
jsr166 |
1.15 |
* @param o object to be removed from this set, if present |
196 |
jsr166 |
1.17 |
* @return {@code true} if the set contained the specified element |
197 |
dl |
1.1 |
* |
198 |
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* @throws ClassCastException if the specified object cannot be compared |
199 |
jsr166 |
1.15 |
* with the elements currently in the set |
200 |
jsr166 |
1.17 |
* @throws NullPointerException if o is {@code null} |
201 |
dl |
1.1 |
*/ |
202 |
|
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public boolean remove(Object o) { |
203 |
jsr166 |
1.8 |
return m.removep(o); |
204 |
dl |
1.1 |
} |
205 |
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|
206 |
|
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/** |
207 |
|
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* Removes all of the elements from this set. |
208 |
|
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*/ |
209 |
|
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public void clear() { |
210 |
jsr166 |
1.8 |
m.clear(); |
211 |
dl |
1.1 |
} |
212 |
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|
213 |
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/** |
214 |
|
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* Returns an iterator over the elements in this set. The elements |
215 |
|
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* are returned in ascending order. |
216 |
|
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* |
217 |
jsr166 |
1.15 |
* @return an iterator over the elements in this set |
218 |
dl |
1.1 |
*/ |
219 |
|
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public Iterator<E> iterator() { |
220 |
jsr166 |
1.8 |
return m.keyIterator(); |
221 |
dl |
1.1 |
} |
222 |
dl |
1.4 |
|
223 |
dl |
1.5 |
/** |
224 |
|
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* Returns an iterator over the elements in this set. The elements |
225 |
|
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* are returned in descending order. |
226 |
|
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* |
227 |
jsr166 |
1.15 |
* @return an iterator over the elements in this set |
228 |
dl |
1.5 |
*/ |
229 |
|
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public Iterator<E> descendingIterator() { |
230 |
jsr166 |
1.8 |
return m.descendingKeyIterator(); |
231 |
dl |
1.5 |
} |
232 |
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|
233 |
dl |
1.4 |
/* ---------------- AbstractSet Overrides -------------- */ |
234 |
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|
235 |
|
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/** |
236 |
|
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* Compares the specified object with this set for equality. Returns |
237 |
jsr166 |
1.17 |
* {@code true} if the specified object is also a set, the two sets |
238 |
dl |
1.4 |
* have the same size, and every member of the specified set is |
239 |
|
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* contained in this set (or equivalently, every member of this set is |
240 |
|
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* contained in the specified set). This definition ensures that the |
241 |
|
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* equals method works properly across different implementations of the |
242 |
|
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* set interface. |
243 |
|
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* |
244 |
jsr166 |
1.15 |
* @param o Object to be compared for equality with this set |
245 |
jsr166 |
1.17 |
* @return {@code true} if the specified Object is equal to this set |
246 |
dl |
1.4 |
*/ |
247 |
|
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public boolean equals(Object o) { |
248 |
|
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// Override AbstractSet version to avoid calling size() |
249 |
jsr166 |
1.8 |
if (o == this) |
250 |
|
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return true; |
251 |
|
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if (!(o instanceof Set)) |
252 |
|
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return false; |
253 |
|
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Collection c = (Collection) o; |
254 |
dl |
1.4 |
try { |
255 |
|
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return containsAll(c) && c.containsAll(this); |
256 |
jsr166 |
1.13 |
} catch (ClassCastException unused) { |
257 |
dl |
1.4 |
return false; |
258 |
jsr166 |
1.9 |
} catch (NullPointerException unused) { |
259 |
dl |
1.4 |
return false; |
260 |
|
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} |
261 |
|
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} |
262 |
jsr166 |
1.7 |
|
263 |
dl |
1.4 |
/** |
264 |
|
|
* Removes from this set all of its elements that are contained in |
265 |
|
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* the specified collection. If the specified collection is also |
266 |
|
|
* a set, this operation effectively modifies this set so that its |
267 |
|
|
* value is the <i>asymmetric set difference</i> of the two sets. |
268 |
|
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* |
269 |
|
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* @param c collection that defines which elements will be removed from |
270 |
jsr166 |
1.15 |
* this set |
271 |
jsr166 |
1.17 |
* @return {@code true} if this set changed as a result of the call |
272 |
jsr166 |
1.7 |
* |
273 |
dl |
1.4 |
* @throws ClassCastException if the types of one or more elements in this |
274 |
|
|
* set are incompatible with the specified collection |
275 |
|
|
* @throws NullPointerException if the specified collection, or any |
276 |
jsr166 |
1.17 |
* of its elements are {@code null} |
277 |
dl |
1.4 |
*/ |
278 |
|
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public boolean removeAll(Collection<?> c) { |
279 |
|
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// Override AbstractSet version to avoid unnecessary call to size() |
280 |
|
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boolean modified = false; |
281 |
|
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for (Iterator<?> i = c.iterator(); i.hasNext(); ) |
282 |
|
|
if (remove(i.next())) |
283 |
|
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modified = true; |
284 |
|
|
return modified; |
285 |
|
|
} |
286 |
jsr166 |
1.7 |
|
287 |
dl |
1.1 |
/* ---------------- Relational operations -------------- */ |
288 |
|
|
|
289 |
|
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/** |
290 |
|
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* Returns an element greater than or equal to the given element, or |
291 |
jsr166 |
1.17 |
* {@code null} if there is no such element. |
292 |
jsr166 |
1.7 |
* |
293 |
dl |
1.1 |
* @param o the value to match |
294 |
dl |
1.4 |
* @return an element greater than or equal to given element, or |
295 |
jsr166 |
1.17 |
* {@code null} if there is no such element |
296 |
dl |
1.1 |
* @throws ClassCastException if o cannot be compared with the elements |
297 |
jsr166 |
1.15 |
* currently in the set |
298 |
jsr166 |
1.17 |
* @throws NullPointerException if o is {@code null} |
299 |
dl |
1.1 |
*/ |
300 |
|
|
public E ceiling(E o) { |
301 |
|
|
return m.ceilingKey(o); |
302 |
|
|
} |
303 |
|
|
|
304 |
|
|
/** |
305 |
dl |
1.4 |
* Returns an element strictly less than the given element, or |
306 |
jsr166 |
1.17 |
* {@code null} if there is no such element. |
307 |
jsr166 |
1.7 |
* |
308 |
dl |
1.1 |
* @param o the value to match |
309 |
|
|
* @return the greatest element less than the given element, or |
310 |
jsr166 |
1.17 |
* {@code null} if there is no such element |
311 |
dl |
1.1 |
* @throws ClassCastException if o cannot be compared with the elements |
312 |
jsr166 |
1.15 |
* currently in the set |
313 |
jsr166 |
1.17 |
* @throws NullPointerException if o is {@code null} |
314 |
dl |
1.1 |
*/ |
315 |
|
|
public E lower(E o) { |
316 |
|
|
return m.lowerKey(o); |
317 |
|
|
} |
318 |
|
|
|
319 |
|
|
/** |
320 |
dl |
1.4 |
* Returns an element less than or equal to the given element, or |
321 |
jsr166 |
1.17 |
* {@code null} if there is no such element. |
322 |
jsr166 |
1.7 |
* |
323 |
dl |
1.1 |
* @param o the value to match |
324 |
|
|
* @return the greatest element less than or equal to given |
325 |
jsr166 |
1.17 |
* element, or {@code null} if there is no such element |
326 |
dl |
1.1 |
* @throws ClassCastException if o cannot be compared with the elements |
327 |
jsr166 |
1.15 |
* currently in the set |
328 |
jsr166 |
1.17 |
* @throws NullPointerException if o is {@code null} |
329 |
dl |
1.1 |
*/ |
330 |
|
|
public E floor(E o) { |
331 |
|
|
return m.floorKey(o); |
332 |
|
|
} |
333 |
|
|
|
334 |
|
|
/** |
335 |
dl |
1.4 |
* Returns an element strictly greater than the given element, or |
336 |
jsr166 |
1.17 |
* {@code null} if there is no such element. |
337 |
jsr166 |
1.7 |
* |
338 |
dl |
1.1 |
* @param o the value to match |
339 |
|
|
* @return the least element greater than the given element, or |
340 |
jsr166 |
1.17 |
* {@code null} if there is no such element |
341 |
dl |
1.1 |
* @throws ClassCastException if o cannot be compared with the elements |
342 |
jsr166 |
1.15 |
* currently in the set |
343 |
jsr166 |
1.17 |
* @throws NullPointerException if o is {@code null} |
344 |
dl |
1.1 |
*/ |
345 |
|
|
public E higher(E o) { |
346 |
|
|
return m.higherKey(o); |
347 |
|
|
} |
348 |
|
|
|
349 |
dl |
1.2 |
/** |
350 |
|
|
* Retrieves and removes the first (lowest) element. |
351 |
|
|
* |
352 |
jsr166 |
1.17 |
* @return the least element, or {@code null} if empty |
353 |
dl |
1.2 |
*/ |
354 |
|
|
public E pollFirst() { |
355 |
dl |
1.5 |
return m.pollFirstKey(); |
356 |
dl |
1.2 |
} |
357 |
|
|
|
358 |
|
|
/** |
359 |
|
|
* Retrieves and removes the last (highest) element. |
360 |
|
|
* |
361 |
jsr166 |
1.17 |
* @return the last element, or {@code null} if empty |
362 |
dl |
1.2 |
*/ |
363 |
|
|
public E pollLast() { |
364 |
dl |
1.5 |
return m.pollLastKey(); |
365 |
dl |
1.2 |
} |
366 |
|
|
|
367 |
|
|
|
368 |
dl |
1.1 |
/* ---------------- SortedSet operations -------------- */ |
369 |
|
|
|
370 |
|
|
|
371 |
|
|
/** |
372 |
jsr166 |
1.17 |
* Returns the comparator used to order this set, or {@code null} |
373 |
dl |
1.1 |
* if this set uses its elements natural ordering. |
374 |
|
|
* |
375 |
jsr166 |
1.17 |
* @return the comparator used to order this set, or {@code null} |
376 |
jsr166 |
1.15 |
* if this set uses its elements natural ordering |
377 |
dl |
1.1 |
*/ |
378 |
|
|
public Comparator<? super E> comparator() { |
379 |
|
|
return m.comparator(); |
380 |
|
|
} |
381 |
|
|
|
382 |
|
|
/** |
383 |
|
|
* Returns the first (lowest) element currently in this set. |
384 |
|
|
* |
385 |
jsr166 |
1.15 |
* @return the first (lowest) element currently in this set |
386 |
|
|
* @throws NoSuchElementException sorted set is empty |
387 |
dl |
1.1 |
*/ |
388 |
|
|
public E first() { |
389 |
|
|
return m.firstKey(); |
390 |
|
|
} |
391 |
|
|
|
392 |
|
|
/** |
393 |
|
|
* Returns the last (highest) element currently in this set. |
394 |
|
|
* |
395 |
jsr166 |
1.15 |
* @return the last (highest) element currently in this set |
396 |
|
|
* @throws NoSuchElementException sorted set is empty |
397 |
dl |
1.1 |
*/ |
398 |
|
|
public E last() { |
399 |
|
|
return m.lastKey(); |
400 |
|
|
} |
401 |
|
|
|
402 |
dl |
1.4 |
|
403 |
|
|
|
404 |
dl |
1.1 |
/** |
405 |
|
|
* Returns a view of the portion of this set whose elements range from |
406 |
jsr166 |
1.17 |
* {@code fromElement}, inclusive, to {@code toElement}, exclusive. (If |
407 |
|
|
* {@code fromElement} and {@code toElement} are equal, the returned |
408 |
dl |
1.1 |
* sorted set is empty.) The returned sorted set is backed by this set, |
409 |
|
|
* so changes in the returned sorted set are reflected in this set, and |
410 |
jsr166 |
1.7 |
* vice-versa. |
411 |
jsr166 |
1.15 |
* @param fromElement low endpoint (inclusive) of the subSet |
412 |
|
|
* @param toElement high endpoint (exclusive) of the subSet |
413 |
dl |
1.1 |
* @return a view of the portion of this set whose elements range from |
414 |
jsr166 |
1.17 |
* {@code fromElement}, inclusive, to {@code toElement}, |
415 |
jsr166 |
1.15 |
* exclusive |
416 |
jsr166 |
1.17 |
* @throws ClassCastException if {@code fromElement} and |
417 |
|
|
* {@code toElement} cannot be compared to one another using |
418 |
dl |
1.1 |
* this set's comparator (or, if the set has no comparator, |
419 |
jsr166 |
1.15 |
* using natural ordering) |
420 |
jsr166 |
1.17 |
* @throws IllegalArgumentException if {@code fromElement} is |
421 |
|
|
* greater than {@code toElement} |
422 |
|
|
* @throws NullPointerException if {@code fromElement} or |
423 |
|
|
* {@code toElement} is {@code null} |
424 |
dl |
1.1 |
*/ |
425 |
dl |
1.2 |
public NavigableSet<E> subSet(E fromElement, E toElement) { |
426 |
jsr166 |
1.8 |
return new ConcurrentSkipListSubSet<E>(m, fromElement, toElement); |
427 |
dl |
1.1 |
} |
428 |
|
|
|
429 |
|
|
/** |
430 |
|
|
* Returns a view of the portion of this set whose elements are strictly |
431 |
jsr166 |
1.17 |
* less than {@code toElement}. The returned sorted set is backed by |
432 |
dl |
1.1 |
* this set, so changes in the returned sorted set are reflected in this |
433 |
jsr166 |
1.7 |
* set, and vice-versa. |
434 |
jsr166 |
1.15 |
* @param toElement high endpoint (exclusive) of the headSet |
435 |
dl |
1.1 |
* @return a view of the portion of this set whose elements are strictly |
436 |
jsr166 |
1.15 |
* less than toElement |
437 |
jsr166 |
1.17 |
* @throws ClassCastException if {@code toElement} is not compatible |
438 |
dl |
1.1 |
* with this set's comparator (or, if the set has no comparator, |
439 |
jsr166 |
1.17 |
* if {@code toElement} does not implement {@code Comparable}) |
440 |
|
|
* @throws NullPointerException if {@code toElement} is {@code null} |
441 |
dl |
1.1 |
*/ |
442 |
dl |
1.2 |
public NavigableSet<E> headSet(E toElement) { |
443 |
jsr166 |
1.8 |
return new ConcurrentSkipListSubSet<E>(m, null, toElement); |
444 |
dl |
1.1 |
} |
445 |
|
|
|
446 |
|
|
|
447 |
|
|
/** |
448 |
|
|
* Returns a view of the portion of this set whose elements are |
449 |
jsr166 |
1.17 |
* greater than or equal to {@code fromElement}. The returned |
450 |
dl |
1.1 |
* sorted set is backed by this set, so changes in the returned |
451 |
|
|
* sorted set are reflected in this set, and vice-versa. |
452 |
jsr166 |
1.15 |
* @param fromElement low endpoint (inclusive) of the tailSet |
453 |
dl |
1.1 |
* @return a view of the portion of this set whose elements are |
454 |
jsr166 |
1.17 |
* greater than or equal to {@code fromElement} |
455 |
|
|
* @throws ClassCastException if {@code fromElement} is not |
456 |
dl |
1.1 |
* compatible with this set's comparator (or, if the set has no |
457 |
jsr166 |
1.17 |
* comparator, if {@code fromElement} does not implement |
458 |
|
|
* {@code Comparable}) |
459 |
|
|
* @throws NullPointerException if {@code fromElement} is {@code null} |
460 |
dl |
1.1 |
*/ |
461 |
dl |
1.2 |
public NavigableSet<E> tailSet(E fromElement) { |
462 |
jsr166 |
1.8 |
return new ConcurrentSkipListSubSet<E>(m, fromElement, null); |
463 |
dl |
1.1 |
} |
464 |
dl |
1.2 |
|
465 |
|
|
/** |
466 |
|
|
* Subsets returned by {@link ConcurrentSkipListSet} subset operations |
467 |
|
|
* represent a subrange of elements of their underlying |
468 |
|
|
* sets. Instances of this class support all methods of their |
469 |
|
|
* underlying sets, differing in that elements outside their range are |
470 |
|
|
* ignored, and attempts to add elements outside their ranges result |
471 |
|
|
* in {@link IllegalArgumentException}. Instances of this class are |
472 |
jsr166 |
1.17 |
* constructed only using the {@code subSet}, {@code headSet}, and |
473 |
|
|
* {@code tailSet} methods of their underlying sets. |
474 |
dl |
1.2 |
*/ |
475 |
jsr166 |
1.7 |
static class ConcurrentSkipListSubSet<E> |
476 |
|
|
extends AbstractSet<E> |
477 |
dl |
1.2 |
implements NavigableSet<E>, java.io.Serializable { |
478 |
|
|
|
479 |
|
|
private static final long serialVersionUID = -7647078645896651609L; |
480 |
|
|
|
481 |
dl |
1.5 |
/** The underlying submap */ |
482 |
dl |
1.2 |
private final ConcurrentSkipListMap.ConcurrentSkipListSubMap<E,Object> s; |
483 |
jsr166 |
1.7 |
|
484 |
dl |
1.2 |
/** |
485 |
jsr166 |
1.7 |
* Creates a new submap. |
486 |
jsr166 |
1.17 |
* @param fromElement inclusive least value, or {@code null} if from start |
487 |
|
|
* @param toElement exclusive upper bound or {@code null} if to end |
488 |
dl |
1.2 |
* @throws IllegalArgumentException if fromElement and toElement |
489 |
jsr166 |
1.10 |
* non-null and fromElement greater than toElement |
490 |
dl |
1.2 |
*/ |
491 |
jsr166 |
1.7 |
ConcurrentSkipListSubSet(ConcurrentSkipListMap<E,Object> map, |
492 |
dl |
1.2 |
E fromElement, E toElement) { |
493 |
dl |
1.5 |
s = new ConcurrentSkipListMap.ConcurrentSkipListSubMap<E,Object> |
494 |
|
|
(map, fromElement, toElement); |
495 |
dl |
1.2 |
} |
496 |
|
|
|
497 |
dl |
1.5 |
// subsubset construction |
498 |
dl |
1.2 |
|
499 |
dl |
1.5 |
public NavigableSet<E> subSet(E fromElement, E toElement) { |
500 |
dl |
1.2 |
if (!s.inOpenRange(fromElement) || !s.inOpenRange(toElement)) |
501 |
|
|
throw new IllegalArgumentException("element out of range"); |
502 |
jsr166 |
1.7 |
return new ConcurrentSkipListSubSet<E>(s.getMap(), |
503 |
dl |
1.2 |
fromElement, toElement); |
504 |
|
|
} |
505 |
|
|
|
506 |
|
|
public NavigableSet<E> headSet(E toElement) { |
507 |
|
|
E least = s.getLeast(); |
508 |
|
|
if (!s.inOpenRange(toElement)) |
509 |
|
|
throw new IllegalArgumentException("element out of range"); |
510 |
jsr166 |
1.7 |
return new ConcurrentSkipListSubSet<E>(s.getMap(), |
511 |
dl |
1.2 |
least, toElement); |
512 |
|
|
} |
513 |
jsr166 |
1.7 |
|
514 |
dl |
1.2 |
public NavigableSet<E> tailSet(E fromElement) { |
515 |
|
|
E fence = s.getFence(); |
516 |
|
|
if (!s.inOpenRange(fromElement)) |
517 |
|
|
throw new IllegalArgumentException("element out of range"); |
518 |
jsr166 |
1.7 |
return new ConcurrentSkipListSubSet<E>(s.getMap(), |
519 |
dl |
1.2 |
fromElement, fence); |
520 |
|
|
} |
521 |
dl |
1.5 |
|
522 |
|
|
// relays to submap methods |
523 |
|
|
|
524 |
|
|
public int size() { return s.size(); } |
525 |
|
|
public boolean isEmpty() { return s.isEmpty(); } |
526 |
|
|
public boolean contains(Object o) { return s.containsKey(o); } |
527 |
|
|
public void clear() { s.clear(); } |
528 |
|
|
public E first() { return s.firstKey(); } |
529 |
|
|
public E last() { return s.lastKey(); } |
530 |
|
|
public E ceiling(E o) { return s.ceilingKey(o); } |
531 |
|
|
public E lower(E o) { return s.lowerKey(o); } |
532 |
|
|
public E floor(E o) { return s.floorKey(o); } |
533 |
|
|
public E higher(E o) { return s.higherKey(o); } |
534 |
|
|
public boolean remove(Object o) { return s.remove(o)==Boolean.TRUE; } |
535 |
|
|
public boolean add(E o) { return s.put(o, Boolean.TRUE)==null; } |
536 |
|
|
public Comparator<? super E> comparator() { return s.comparator(); } |
537 |
|
|
public Iterator<E> iterator() { return s.keySet().iterator(); } |
538 |
|
|
public Iterator<E> descendingIterator() { |
539 |
|
|
return s.descendingKeySet().iterator(); |
540 |
|
|
} |
541 |
jsr166 |
1.7 |
public E pollFirst() { |
542 |
dl |
1.5 |
Map.Entry<E,?> e = s.pollFirstEntry(); |
543 |
jsr166 |
1.11 |
return (e == null) ? null : e.getKey(); |
544 |
dl |
1.5 |
} |
545 |
|
|
public E pollLast() { |
546 |
|
|
Map.Entry<E,?> e = s.pollLastEntry(); |
547 |
jsr166 |
1.11 |
return (e == null) ? null : e.getKey(); |
548 |
dl |
1.5 |
} |
549 |
|
|
|
550 |
dl |
1.2 |
} |
551 |
jsr166 |
1.7 |
} |