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root/jsr166/jsr166/src/main/java/util/NavigableMap.java
Revision: 1.24
Committed: Tue Mar 15 19:47:02 2011 UTC (13 years, 1 month ago) by jsr166
Branch: MAIN
CVS Tags: release-1_7_0
Changes since 1.23: +1 -1 lines
Log Message: 
Update Creative Commons license URL in legal notices

File Contents

# User Rev Content
1 dl 1.1 /*
2 dl 1.14 * Written by Doug Lea and Josh Bloch with assistance from members of JCP
3     * JSR-166 Expert Group and released to the public domain, as explained at
4 jsr166 1.24 * http://creativecommons.org/publicdomain/zero/1.0/
5 dl 1.1 */
6    
7     package java.util;
8    
9     /**
10     * A {@link SortedMap} extended with navigation methods returning the
11     * closest matches for given search targets. Methods
12 dl 1.14 * {@code lowerEntry}, {@code floorEntry}, {@code ceilingEntry},
13     * and {@code higherEntry} return {@code Map.Entry} objects
14 dl 1.1 * associated with keys respectively less than, less than or equal,
15     * greater than or equal, and greater than a given key, returning
16 dl 1.14 * {@code null} if there is no such key. Similarly, methods
17     * {@code lowerKey}, {@code floorKey}, {@code ceilingKey}, and
18     * {@code higherKey} return only the associated keys. All of these
19 dl 1.1 * methods are designed for locating, not traversing entries.
20     *
21 dl 1.14 * <p>A {@code NavigableMap} may be accessed and traversed in either
22     * ascending or descending key order. The {@code descendingMap}
23     * method returns a view of the map with the senses of all relational
24     * and directional methods inverted. The performance of ascending
25     * operations and views is likely to be faster than that of descending
26 dl 1.15 * ones. Methods {@code subMap}, {@code headMap},
27     * and {@code tailMap} differ from the like-named {@code
28 dl 1.14 * SortedMap} methods in accepting additional arguments describing
29     * whether lower and upper bounds are inclusive versus exclusive.
30     * Submaps of any {@code NavigableMap} must implement the {@code
31     * NavigableMap} interface.
32 jsr166 1.5 *
33 dl 1.14 * <p>This interface additionally defines methods {@code firstEntry},
34     * {@code pollFirstEntry}, {@code lastEntry}, and
35     * {@code pollLastEntry} that return and/or remove the least and
36     * greatest mappings, if any exist, else returning {@code null}.
37 dl 1.1 *
38 jsr166 1.22 * <p>Implementations of entry-returning methods are expected to
39 dl 1.14 * return {@code Map.Entry} pairs representing snapshots of mappings
40 dl 1.1 * at the time they were produced, and thus generally do <em>not</em>
41 dl 1.14 * support the optional {@code Entry.setValue} method. Note however
42 dl 1.1 * that it is possible to change mappings in the associated map using
43 dl 1.14 * method {@code put}.
44 dl 1.1 *
45 jsr166 1.22 * <p>Methods
46     * {@link #subMap(Object, Object) subMap(K, K)},
47     * {@link #headMap(Object) headMap(K)}, and
48     * {@link #tailMap(Object) tailMap(K)}
49     * are specified to return {@code SortedMap} to allow existing
50     * implementations of {@code SortedMap} to be compatibly retrofitted to
51     * implement {@code NavigableMap}, but extensions and implementations
52     * of this interface are encouraged to override these methods to return
53     * {@code NavigableMap}. Similarly,
54     * {@link #keySet()} can be overriden to return {@code NavigableSet}.
55 jsr166 1.23 *
56 jsr166 1.7 * <p>This interface is a member of the
57 jsr166 1.22 * <a href="{@docRoot}/../technotes/guides/collections/index.html">
58 jsr166 1.7 * Java Collections Framework</a>.
59     *
60 dl 1.1 * @author Doug Lea
61 dl 1.14 * @author Josh Bloch
62 dl 1.1 * @param <K> the type of keys maintained by this map
63 jsr166 1.5 * @param <V> the type of mapped values
64 jsr166 1.6 * @since 1.6
65 dl 1.1 */
66     public interface NavigableMap<K,V> extends SortedMap<K,V> {
67     /**
68 jsr166 1.8 * Returns a key-value mapping associated with the greatest key
69 dl 1.14 * strictly less than the given key, or {@code null} if there is
70 jsr166 1.8 * no such key.
71 jsr166 1.5 *
72 jsr166 1.8 * @param key the key
73 dl 1.14 * @return an entry with the greatest key less than {@code key},
74     * or {@code null} if there is no such key
75 jsr166 1.8 * @throws ClassCastException if the specified key cannot be compared
76     * with the keys currently in the map
77     * @throws NullPointerException if the specified key is null
78     * and this map does not permit null keys
79 dl 1.1 */
80 jsr166 1.8 Map.Entry<K,V> lowerEntry(K key);
81 dl 1.1
82     /**
83 jsr166 1.8 * Returns the greatest key strictly less than the given key, or
84 dl 1.14 * {@code null} if there is no such key.
85 jsr166 1.5 *
86 jsr166 1.8 * @param key the key
87 dl 1.14 * @return the greatest key less than {@code key},
88     * or {@code null} if there is no such key
89 jsr166 1.8 * @throws ClassCastException if the specified key cannot be compared
90     * with the keys currently in the map
91     * @throws NullPointerException if the specified key is null
92     * and this map does not permit null keys
93 dl 1.1 */
94 jsr166 1.8 K lowerKey(K key);
95 dl 1.1
96     /**
97 jsr166 1.8 * Returns a key-value mapping associated with the greatest key
98 dl 1.14 * less than or equal to the given key, or {@code null} if there
99 jsr166 1.8 * is no such key.
100 jsr166 1.5 *
101 jsr166 1.8 * @param key the key
102     * @return an entry with the greatest key less than or equal to
103 dl 1.14 * {@code key}, or {@code null} if there is no such key
104 jsr166 1.8 * @throws ClassCastException if the specified key cannot be compared
105     * with the keys currently in the map
106     * @throws NullPointerException if the specified key is null
107     * and this map does not permit null keys
108 dl 1.1 */
109 jsr166 1.8 Map.Entry<K,V> floorEntry(K key);
110 dl 1.1
111     /**
112 jsr166 1.8 * Returns the greatest key less than or equal to the given key,
113 dl 1.14 * or {@code null} if there is no such key.
114 jsr166 1.5 *
115 jsr166 1.8 * @param key the key
116 dl 1.14 * @return the greatest key less than or equal to {@code key},
117     * or {@code null} if there is no such key
118 jsr166 1.8 * @throws ClassCastException if the specified key cannot be compared
119     * with the keys currently in the map
120     * @throws NullPointerException if the specified key is null
121     * and this map does not permit null keys
122 dl 1.1 */
123 jsr166 1.8 K floorKey(K key);
124 dl 1.1
125     /**
126 jsr166 1.8 * Returns a key-value mapping associated with the least key
127 dl 1.14 * greater than or equal to the given key, or {@code null} if
128 jsr166 1.8 * there is no such key.
129 jsr166 1.5 *
130 jsr166 1.8 * @param key the key
131     * @return an entry with the least key greater than or equal to
132 dl 1.14 * {@code key}, or {@code null} if there is no such key
133 jsr166 1.8 * @throws ClassCastException if the specified key cannot be compared
134     * with the keys currently in the map
135     * @throws NullPointerException if the specified key is null
136     * and this map does not permit null keys
137 dl 1.1 */
138 jsr166 1.8 Map.Entry<K,V> ceilingEntry(K key);
139 dl 1.1
140     /**
141 jsr166 1.8 * Returns the least key greater than or equal to the given key,
142 dl 1.14 * or {@code null} if there is no such key.
143 jsr166 1.5 *
144 jsr166 1.8 * @param key the key
145 dl 1.14 * @return the least key greater than or equal to {@code key},
146     * or {@code null} if there is no such key
147 jsr166 1.8 * @throws ClassCastException if the specified key cannot be compared
148     * with the keys currently in the map
149     * @throws NullPointerException if the specified key is null
150     * and this map does not permit null keys
151 dl 1.1 */
152 jsr166 1.8 K ceilingKey(K key);
153 dl 1.1
154     /**
155     * Returns a key-value mapping associated with the least key
156 dl 1.14 * strictly greater than the given key, or {@code null} if there
157 jsr166 1.8 * is no such key.
158 jsr166 1.5 *
159 jsr166 1.8 * @param key the key
160 dl 1.14 * @return an entry with the least key greater than {@code key},
161     * or {@code null} if there is no such key
162 jsr166 1.8 * @throws ClassCastException if the specified key cannot be compared
163     * with the keys currently in the map
164     * @throws NullPointerException if the specified key is null
165     * and this map does not permit null keys
166 dl 1.1 */
167 dl 1.3 Map.Entry<K,V> higherEntry(K key);
168 dl 1.1
169     /**
170     * Returns the least key strictly greater than the given key, or
171 dl 1.14 * {@code null} if there is no such key.
172 jsr166 1.5 *
173 jsr166 1.8 * @param key the key
174 dl 1.14 * @return the least key greater than {@code key},
175     * or {@code null} if there is no such key
176 jsr166 1.8 * @throws ClassCastException if the specified key cannot be compared
177     * with the keys currently in the map
178     * @throws NullPointerException if the specified key is null
179     * and this map does not permit null keys
180 dl 1.1 */
181 dl 1.3 K higherKey(K key);
182 dl 1.1
183     /**
184     * Returns a key-value mapping associated with the least
185 dl 1.14 * key in this map, or {@code null} if the map is empty.
186 jsr166 1.5 *
187 jsr166 1.8 * @return an entry with the least key,
188 dl 1.14 * or {@code null} if this map is empty
189 dl 1.1 */
190 dl 1.3 Map.Entry<K,V> firstEntry();
191 dl 1.1
192     /**
193     * Returns a key-value mapping associated with the greatest
194 dl 1.14 * key in this map, or {@code null} if the map is empty.
195 jsr166 1.5 *
196 jsr166 1.8 * @return an entry with the greatest key,
197 dl 1.14 * or {@code null} if this map is empty
198 dl 1.1 */
199 dl 1.3 Map.Entry<K,V> lastEntry();
200 dl 1.1
201     /**
202     * Removes and returns a key-value mapping associated with
203 dl 1.14 * the least key in this map, or {@code null} if the map is empty.
204 jsr166 1.5 *
205 jsr166 1.8 * @return the removed first entry of this map,
206 dl 1.14 * or {@code null} if this map is empty
207 dl 1.1 */
208 dl 1.3 Map.Entry<K,V> pollFirstEntry();
209 dl 1.1
210     /**
211     * Removes and returns a key-value mapping associated with
212 dl 1.14 * the greatest key in this map, or {@code null} if the map is empty.
213 jsr166 1.5 *
214 jsr166 1.8 * @return the removed last entry of this map,
215 dl 1.14 * or {@code null} if this map is empty
216 dl 1.1 */
217 dl 1.3 Map.Entry<K,V> pollLastEntry();
218 dl 1.1
219     /**
220 jsr166 1.22 * Returns a reverse order view of the mappings contained in this map.
221     * The descending map is backed by this map, so changes to the map are
222     * reflected in the descending map, and vice-versa. If either map is
223     * modified while an iteration over a collection view of either map
224     * is in progress (except through the iterator's own {@code remove}
225     * operation), the results of the iteration are undefined.
226     *
227     * <p>The returned map has an ordering equivalent to
228     * <tt>{@link Collections#reverseOrder(Comparator) Collections.reverseOrder}(comparator())</tt>.
229     * The expression {@code m.descendingMap().descendingMap()} returns a
230     * view of {@code m} essentially equivalent to {@code m}.
231 dl 1.14 *
232 jsr166 1.22 * @return a reverse order view of this map
233 dl 1.14 */
234     NavigableMap<K,V> descendingMap();
235    
236     /**
237 jsr166 1.22 * Returns a {@link NavigableSet} view of the keys contained in this map.
238     * The set's iterator returns the keys in ascending order.
239     * The set is backed by the map, so changes to the map are reflected in
240     * the set, and vice-versa. If the map is modified while an iteration
241     * over the set is in progress (except through the iterator's own {@code
242     * remove} operation), the results of the iteration are undefined. The
243     * set supports element removal, which removes the corresponding mapping
244     * from the map, via the {@code Iterator.remove}, {@code Set.remove},
245     * {@code removeAll}, {@code retainAll}, and {@code clear} operations.
246     * It does not support the {@code add} or {@code addAll} operations.
247 dl 1.14 *
248 jsr166 1.22 * @return a navigable set view of the keys in this map
249 dl 1.14 */
250     NavigableSet<K> navigableKeySet();
251    
252     /**
253 jsr166 1.22 * Returns a reverse order {@link NavigableSet} view of the keys contained in this map.
254 jsr166 1.8 * The set's iterator returns the keys in descending order.
255 jsr166 1.22 * The set is backed by the map, so changes to the map are reflected in
256     * the set, and vice-versa. If the map is modified while an iteration
257     * over the set is in progress (except through the iterator's own {@code
258     * remove} operation), the results of the iteration are undefined. The
259     * set supports element removal, which removes the corresponding mapping
260     * from the map, via the {@code Iterator.remove}, {@code Set.remove},
261     * {@code removeAll}, {@code retainAll}, and {@code clear} operations.
262     * It does not support the {@code add} or {@code addAll} operations.
263 dl 1.1 *
264 jsr166 1.22 * @return a reverse order navigable set view of the keys in this map
265 dl 1.1 */
266 dl 1.14 NavigableSet<K> descendingKeySet();
267 dl 1.1
268     /**
269     * Returns a view of the portion of this map whose keys range from
270 dl 1.14 * {@code fromKey} to {@code toKey}. If {@code fromKey} and
271     * {@code toKey} are equal, the returned map is empty unless
272     * {@code fromExclusive} and {@code toExclusive} are both true. The
273     * returned map is backed by this map, so changes in the returned map are
274     * reflected in this map, and vice-versa. The returned map supports all
275     * optional map operations that this map supports.
276 dl 1.1 *
277 dl 1.14 * <p>The returned map will throw an {@code IllegalArgumentException}
278     * on an attempt to insert a key outside of its range, or to construct a
279     * submap either of whose endpoints lie outside its range.
280     *
281     * @param fromKey low endpoint of the keys in the returned map
282 jsr166 1.19 * @param fromInclusive {@code true} if the low endpoint
283     * is to be included in the returned view
284 dl 1.14 * @param toKey high endpoint of the keys in the returned map
285 jsr166 1.19 * @param toInclusive {@code true} if the high endpoint
286     * is to be included in the returned view
287 dl 1.1 * @return a view of the portion of this map whose keys range from
288 dl 1.14 * {@code fromKey} to {@code toKey}
289     * @throws ClassCastException if {@code fromKey} and {@code toKey}
290 jsr166 1.8 * cannot be compared to one another using this map's comparator
291     * (or, if the map has no comparator, using natural ordering).
292     * Implementations may, but are not required to, throw this
293 dl 1.14 * exception if {@code fromKey} or {@code toKey}
294 jsr166 1.8 * cannot be compared to keys currently in the map.
295 dl 1.14 * @throws NullPointerException if {@code fromKey} or {@code toKey}
296 jsr166 1.8 * is null and this map does not permit null keys
297 dl 1.14 * @throws IllegalArgumentException if {@code fromKey} is greater than
298     * {@code toKey}; or if this map itself has a restricted
299     * range, and {@code fromKey} or {@code toKey} lies
300 jsr166 1.8 * outside the bounds of the range
301 dl 1.1 */
302 dl 1.15 NavigableMap<K,V> subMap(K fromKey, boolean fromInclusive,
303     K toKey, boolean toInclusive);
304 dl 1.1
305     /**
306 dl 1.14 * Returns a view of the portion of this map whose keys are less than (or
307     * equal to, if {@code inclusive} is true) {@code toKey}. The returned
308     * map is backed by this map, so changes in the returned map are reflected
309     * in this map, and vice-versa. The returned map supports all optional
310     * map operations that this map supports.
311 jsr166 1.8 *
312 dl 1.14 * <p>The returned map will throw an {@code IllegalArgumentException}
313 jsr166 1.8 * on an attempt to insert a key outside its range.
314     *
315 dl 1.14 * @param toKey high endpoint of the keys in the returned map
316 jsr166 1.19 * @param inclusive {@code true} if the high endpoint
317     * is to be included in the returned view
318 dl 1.14 * @return a view of the portion of this map whose keys are less than
319     * (or equal to, if {@code inclusive} is true) {@code toKey}
320     * @throws ClassCastException if {@code toKey} is not compatible
321 dl 1.1 * with this map's comparator (or, if the map has no comparator,
322 dl 1.14 * if {@code toKey} does not implement {@link Comparable}).
323 jsr166 1.8 * Implementations may, but are not required to, throw this
324 dl 1.14 * exception if {@code toKey} cannot be compared to keys
325 jsr166 1.8 * currently in the map.
326 dl 1.14 * @throws NullPointerException if {@code toKey} is null
327 jsr166 1.8 * and this map does not permit null keys
328     * @throws IllegalArgumentException if this map itself has a
329 dl 1.14 * restricted range, and {@code toKey} lies outside the
330 jsr166 1.8 * bounds of the range
331 dl 1.1 */
332 dl 1.15 NavigableMap<K,V> headMap(K toKey, boolean inclusive);
333 dl 1.1
334     /**
335 dl 1.14 * Returns a view of the portion of this map whose keys are greater than (or
336     * equal to, if {@code inclusive} is true) {@code fromKey}. The returned
337     * map is backed by this map, so changes in the returned map are reflected
338     * in this map, and vice-versa. The returned map supports all optional
339     * map operations that this map supports.
340 jsr166 1.8 *
341 dl 1.14 * <p>The returned map will throw an {@code IllegalArgumentException}
342 jsr166 1.8 * on an attempt to insert a key outside its range.
343     *
344 dl 1.14 * @param fromKey low endpoint of the keys in the returned map
345 jsr166 1.19 * @param inclusive {@code true} if the low endpoint
346     * is to be included in the returned view
347 dl 1.14 * @return a view of the portion of this map whose keys are greater than
348     * (or equal to, if {@code inclusive} is true) {@code fromKey}
349     * @throws ClassCastException if {@code fromKey} is not compatible
350 dl 1.1 * with this map's comparator (or, if the map has no comparator,
351 dl 1.14 * if {@code fromKey} does not implement {@link Comparable}).
352 jsr166 1.8 * Implementations may, but are not required to, throw this
353 dl 1.14 * exception if {@code fromKey} cannot be compared to keys
354 jsr166 1.8 * currently in the map.
355 dl 1.14 * @throws NullPointerException if {@code fromKey} is null
356 jsr166 1.8 * and this map does not permit null keys
357     * @throws IllegalArgumentException if this map itself has a
358 dl 1.14 * restricted range, and {@code fromKey} lies outside the
359 jsr166 1.8 * bounds of the range
360 dl 1.1 */
361 dl 1.15 NavigableMap<K,V> tailMap(K fromKey, boolean inclusive);
362 jsr166 1.19
363     /**
364 jsr166 1.22 * {@inheritDoc}
365 jsr166 1.19 *
366 jsr166 1.22 * <p>Equivalent to {@code subMap(fromKey, true, toKey, false)}.
367 jsr166 1.19 *
368     * @throws ClassCastException {@inheritDoc}
369     * @throws NullPointerException {@inheritDoc}
370     * @throws IllegalArgumentException {@inheritDoc}
371     */
372     SortedMap<K,V> subMap(K fromKey, K toKey);
373    
374     /**
375 jsr166 1.22 * {@inheritDoc}
376 jsr166 1.19 *
377 jsr166 1.22 * <p>Equivalent to {@code headMap(toKey, false)}.
378 jsr166 1.19 *
379     * @throws ClassCastException {@inheritDoc}
380     * @throws NullPointerException {@inheritDoc}
381     * @throws IllegalArgumentException {@inheritDoc}
382     */
383     SortedMap<K,V> headMap(K toKey);
384    
385     /**
386 jsr166 1.22 * {@inheritDoc}
387 jsr166 1.19 *
388 jsr166 1.22 * <p>Equivalent to {@code tailMap(fromKey, true)}.
389 jsr166 1.19 *
390     * @throws ClassCastException {@inheritDoc}
391     * @throws NullPointerException {@inheritDoc}
392     * @throws IllegalArgumentException {@inheritDoc}
393     */
394     SortedMap<K,V> tailMap(K fromKey);
395 dl 1.1 }