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1 : dl 1.1 /*
2 :     * Written by Doug Lea with assistance from members of JCP JSR-166
3 :     * Expert Group and released to the public domain, as explained at
4 :     * http://creativecommons.org/licenses/publicdomain
5 :     */
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 :     * <tt>lowerEntry</tt>, <tt>floorEntry</tt>, <tt>ceilingEntry</tt>,
13 :     * and <tt>higherEntry</tt> return <tt>Map.Entry</tt> objects
14 :     * associated with keys respectively less than, less than or equal,
15 :     * greater than or equal, and greater than a given key, returning
16 :     * <tt>null</tt> if there is no such key. Similarly, methods
17 :     * <tt>lowerKey</tt>, <tt>floorKey</tt>, <tt>ceilingKey</tt>, and
18 :     * <tt>higherKey</tt> return only the associated keys. All of these
19 :     * methods are designed for locating, not traversing entries.
20 :     *
21 :     * <p>A <tt>NavigableMap</tt> may be viewed and traversed in either
22 :     * ascending or descending key order. The <tt>Map</tt> methods
23 :     * <tt>keySet</tt> and <tt>entrySet</tt> return ascending views, and
24 :     * the additional methods <tt>descendingKeySet</tt> and
25 :     * <tt>descendingEntrySet</tt> return descending views. The
26 :     * performance of ascending traversals is likely to be faster than
27 :     * descending traversals. Notice that it is possible to perform
28 : dl 1.4 * subrange traversals in either direction using <tt>navigableSubMap</tt>.
29 :     * Methods <tt>navigableSubMap</tt>, <tt>navigableHeadMap</tt>, and
30 :     * <tt>navigableTailMap</tt> differ from the similarly named
31 :     * <tt>SortedMap</tt> methods only in that the returned maps
32 :     * are guaranteed to obey the <tt>NavigableMap</tt> interface.
33 : jsr166 1.5 *
34 : dl 1.1 * <p>This interface additionally defines methods <tt>firstEntry</tt>,
35 :     * <tt>pollFirstEntry</tt>, <tt>lastEntry</tt>, and
36 :     * <tt>pollLastEntry</tt> that return and/or remove the least and
37 :     * greatest mappings, if any exist, else returning <tt>null</tt>.
38 :     *
39 :     * <p> Implementations of entry-returning methods are expected to
40 :     * return <tt>Map.Entry</tt> pairs representing snapshots of mappings
41 :     * at the time they were produced, and thus generally do <em>not</em>
42 :     * support the optional <tt>Entry.setValue</tt> method. Note however
43 :     * that it is possible to change mappings in the associated map using
44 :     * method <tt>put</tt>.
45 :     *
46 : jsr166 1.7 * <p>This interface is a member of the
47 :     * <a href="{@docRoot}/../guide/collections/index.html">
48 :     * Java Collections Framework</a>.
49 :     *
50 : dl 1.1 * @author Doug Lea
51 :     * @param <K> the type of keys maintained by this map
52 : jsr166 1.5 * @param <V> the type of mapped values
53 : jsr166 1.6 * @since 1.6
54 : dl 1.1 */
55 :     public interface NavigableMap<K,V> extends SortedMap<K,V> {
56 :     /**
57 : jsr166 1.8 * Returns a key-value mapping associated with the greatest key
58 :     * strictly less than the given key, or <tt>null</tt> if there is
59 :     * no such key.
60 : jsr166 1.5 *
61 : jsr166 1.8 * @param key the key
62 :     * @return an entry with the greatest key less than <tt>key</tt>,
63 :     * or <tt>null</tt> if there is no such key
64 :     * @throws ClassCastException if the specified key cannot be compared
65 :     * with the keys currently in the map
66 :     * @throws NullPointerException if the specified key is null
67 :     * and this map does not permit null keys
68 : dl 1.1 */
69 : jsr166 1.8 Map.Entry<K,V> lowerEntry(K key);
70 : dl 1.1
71 :     /**
72 : jsr166 1.8 * Returns the greatest key strictly less than the given key, or
73 : dl 1.1 * <tt>null</tt> if there is no such key.
74 : jsr166 1.5 *
75 : jsr166 1.8 * @param key the key
76 :     * @return the greatest key less than <tt>key</tt>,
77 :     * or <tt>null</tt> if there is no such key
78 :     * @throws ClassCastException if the specified key cannot be compared
79 :     * with the keys currently in the map
80 :     * @throws NullPointerException if the specified key is null
81 :     * and this map does not permit null keys
82 : dl 1.1 */
83 : jsr166 1.8 K lowerKey(K key);
84 : dl 1.1
85 :     /**
86 : jsr166 1.8 * Returns a key-value mapping associated with the greatest key
87 :     * less than or equal to the given key, or <tt>null</tt> if there
88 :     * is no such key.
89 : jsr166 1.5 *
90 : jsr166 1.8 * @param key the key
91 :     * @return an entry with the greatest key less than or equal to
92 :     * <tt>key</tt>, or <tt>null</tt> if there is no such key
93 :     * @throws ClassCastException if the specified key cannot be compared
94 :     * with the keys currently in the map
95 :     * @throws NullPointerException if the specified key is null
96 :     * and this map does not permit null keys
97 : dl 1.1 */
98 : jsr166 1.8 Map.Entry<K,V> floorEntry(K key);
99 : dl 1.1
100 :     /**
101 : jsr166 1.8 * Returns the greatest key less than or equal to the given key,
102 :     * or <tt>null</tt> if there is no such key.
103 : jsr166 1.5 *
104 : jsr166 1.8 * @param key the key
105 :     * @return the greatest key less than or equal to <tt>key</tt>,
106 :     * or <tt>null</tt> if there is no such key
107 :     * @throws ClassCastException if the specified key cannot be compared
108 :     * with the keys currently in the map
109 :     * @throws NullPointerException if the specified key is null
110 :     * and this map does not permit null keys
111 : dl 1.1 */
112 : jsr166 1.8 K floorKey(K key);
113 : dl 1.1
114 :     /**
115 : jsr166 1.8 * Returns a key-value mapping associated with the least key
116 :     * greater than or equal to the given key, or <tt>null</tt> if
117 :     * there is no such key.
118 : jsr166 1.5 *
119 : jsr166 1.8 * @param key the key
120 :     * @return an entry with the least key greater than or equal to
121 :     * <tt>key</tt>, or <tt>null</tt> if there is no such key
122 :     * @throws ClassCastException if the specified key cannot be compared
123 :     * with the keys currently in the map
124 :     * @throws NullPointerException if the specified key is null
125 :     * and this map does not permit null keys
126 : dl 1.1 */
127 : jsr166 1.8 Map.Entry<K,V> ceilingEntry(K key);
128 : dl 1.1
129 :     /**
130 : jsr166 1.8 * Returns the least key greater than or equal to the given key,
131 :     * or <tt>null</tt> if there is no such key.
132 : jsr166 1.5 *
133 : jsr166 1.8 * @param key the key
134 :     * @return the least key greater than or equal to <tt>key</tt>,
135 :     * or <tt>null</tt> if there is no such key
136 :     * @throws ClassCastException if the specified key cannot be compared
137 :     * with the keys currently in the map
138 :     * @throws NullPointerException if the specified key is null
139 :     * and this map does not permit null keys
140 : dl 1.1 */
141 : jsr166 1.8 K ceilingKey(K key);
142 : dl 1.1
143 :     /**
144 :     * Returns a key-value mapping associated with the least key
145 :     * strictly greater than the given key, or <tt>null</tt> if there
146 : jsr166 1.8 * is no such key.
147 : jsr166 1.5 *
148 : jsr166 1.8 * @param key the key
149 :     * @return an entry with the least key greater than <tt>key</tt>,
150 :     * or <tt>null</tt> if there is no such key
151 :     * @throws ClassCastException if the specified key cannot be compared
152 :     * with the keys currently in the map
153 :     * @throws NullPointerException if the specified key is null
154 :     * and this map does not permit null keys
155 : dl 1.1 */
156 : dl 1.3 Map.Entry<K,V> higherEntry(K key);
157 : dl 1.1
158 :     /**
159 :     * Returns the least key strictly greater than the given key, or
160 :     * <tt>null</tt> if there is no such key.
161 : jsr166 1.5 *
162 : jsr166 1.8 * @param key the key
163 :     * @return the least key greater than <tt>key</tt>,
164 :     * or <tt>null</tt> if there is no such key
165 :     * @throws ClassCastException if the specified key cannot be compared
166 :     * with the keys currently in the map
167 :     * @throws NullPointerException if the specified key is null
168 :     * and this map does not permit null keys
169 : dl 1.1 */
170 : dl 1.3 K higherKey(K key);
171 : dl 1.1
172 :     /**
173 :     * Returns a key-value mapping associated with the least
174 :     * key in this map, or <tt>null</tt> if the map is empty.
175 : jsr166 1.5 *
176 : jsr166 1.8 * @return an entry with the least key,
177 :     * or <tt>null</tt> if this map is empty
178 : dl 1.1 */
179 : dl 1.3 Map.Entry<K,V> firstEntry();
180 : dl 1.1
181 :     /**
182 :     * Returns a key-value mapping associated with the greatest
183 :     * key in this map, or <tt>null</tt> if the map is empty.
184 : jsr166 1.5 *
185 : jsr166 1.8 * @return an entry with the greatest key,
186 :     * or <tt>null</tt> if this map is empty
187 : dl 1.1 */
188 : dl 1.3 Map.Entry<K,V> lastEntry();
189 : dl 1.1
190 :     /**
191 :     * Removes and returns a key-value mapping associated with
192 :     * the least key in this map, or <tt>null</tt> if the map is empty.
193 : jsr166 1.5 *
194 : jsr166 1.8 * @return the removed first entry of this map,
195 :     * or <tt>null</tt> if this map is empty
196 : dl 1.1 */
197 : dl 1.3 Map.Entry<K,V> pollFirstEntry();
198 : dl 1.1
199 :     /**
200 :     * Removes and returns a key-value mapping associated with
201 :     * the greatest key in this map, or <tt>null</tt> if the map is empty.
202 : jsr166 1.5 *
203 : jsr166 1.8 * @return the removed last entry of this map,
204 :     * or <tt>null</tt> if this map is empty
205 : dl 1.1 */
206 : dl 1.3 Map.Entry<K,V> pollLastEntry();
207 : dl 1.1
208 :     /**
209 : jsr166 1.8 * Returns a {@link Set} view of the keys contained in this map.
210 :     * The set's iterator returns the keys in descending order.
211 :     * The set is backed by the map, so changes to the map are
212 :     * reflected in the set, and vice-versa. If the map is modified
213 :     * while an iteration over the set is in progress (except through
214 :     * the iterator's own <tt>remove</tt> operation), the results of
215 :     * the iteration are undefined. The set supports element removal,
216 :     * which removes the corresponding mapping from the map, via the
217 :     * <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
218 : jsr166 1.9 * <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
219 :     * operations. It does not support the <tt>add</tt> or <tt>addAll</tt>
220 : dl 1.1 * operations.
221 :     *
222 : jsr166 1.8 * @return a set view of the keys contained in this map, sorted in
223 :     * descending order
224 : dl 1.1 */
225 :     Set<K> descendingKeySet();
226 :    
227 :     /**
228 : jsr166 1.8 * Returns a {@link Set} view of the mappings contained in this map.
229 :     * The set's iterator returns the entries in descending key order.
230 :     * The set is backed by the map, so changes to the map are
231 :     * reflected in the set, and vice-versa. If the map is modified
232 :     * while an iteration over the set is in progress (except through
233 :     * the iterator's own <tt>remove</tt> operation, or through the
234 :     * <tt>setValue</tt> operation on a map entry returned by the
235 :     * iterator) the results of the iteration are undefined. The set
236 :     * supports element removal, which removes the corresponding
237 :     * mapping from the map, via the <tt>Iterator.remove</tt>,
238 :     * <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt> and
239 :     * <tt>clear</tt> operations. It does not support the
240 :     * <tt>add</tt> or <tt>addAll</tt> operations.
241 : dl 1.1 *
242 : jsr166 1.8 * @return a set view of the mappings contained in this map,
243 :     * sorted in descending key order
244 : dl 1.1 */
245 :     Set<Map.Entry<K, V>> descendingEntrySet();
246 :    
247 :     /**
248 :     * Returns a view of the portion of this map whose keys range from
249 :     * <tt>fromKey</tt>, inclusive, to <tt>toKey</tt>, exclusive. (If
250 : jsr166 1.8 * <tt>fromKey</tt> and <tt>toKey</tt> are equal, the returned map
251 :     * is empty.) The returned map is backed by this map, so changes
252 :     * in the returned map are reflected in this map, and vice-versa.
253 :     * The returned map supports all optional map operations that this
254 :     * map supports.
255 : dl 1.3 *
256 : jsr166 1.8 * <p>The returned map will throw an <tt>IllegalArgumentException</tt>
257 :     * on an attempt to insert a key outside its range.
258 : dl 1.1 *
259 : jsr166 1.8 * @param fromKey low endpoint (inclusive) of the keys in the returned map
260 :     * @param toKey high endpoint (exclusive) of the keys in the returned map
261 : dl 1.1 * @return a view of the portion of this map whose keys range from
262 : jsr166 1.8 * <tt>fromKey</tt>, inclusive, to <tt>toKey</tt>, exclusive
263 :     * @throws ClassCastException if <tt>fromKey</tt> and <tt>toKey</tt>
264 :     * cannot be compared to one another using this map's comparator
265 :     * (or, if the map has no comparator, using natural ordering).
266 :     * Implementations may, but are not required to, throw this
267 :     * exception if <tt>fromKey</tt> or <tt>toKey</tt>
268 :     * cannot be compared to keys currently in the map.
269 :     * @throws NullPointerException if <tt>fromKey</tt> or <tt>toKey</tt>
270 :     * is null and this map does not permit null keys
271 :     * @throws IllegalArgumentException if <tt>fromKey</tt> is greater than
272 :     * <tt>toKey</tt>; or if this map itself has a restricted
273 :     * range, and <tt>fromKey</tt> or <tt>toKey</tt> lies
274 :     * outside the bounds of the range
275 : dl 1.1 */
276 : dl 1.3 NavigableMap<K,V> navigableSubMap(K fromKey, K toKey);
277 : dl 1.1
278 :     /**
279 : jsr166 1.8 * Returns a view of the portion of this map whose keys are
280 :     * strictly less than <tt>toKey</tt>. The returned map is backed
281 :     * by this map, so changes in the returned map are reflected in
282 :     * this map, and vice-versa. The returned map supports all
283 :     * optional map operations that this map supports.
284 :     *
285 :     * <p>The returned map will throw an <tt>IllegalArgumentException</tt>
286 :     * on an attempt to insert a key outside its range.
287 :     *
288 :     * @param toKey high endpoint (exclusive) of the keys in the returned map
289 : dl 1.1 * @return a view of the portion of this map whose keys are strictly
290 : jsr166 1.8 * less than <tt>toKey</tt>
291 : dl 1.1 * @throws ClassCastException if <tt>toKey</tt> is not compatible
292 :     * with this map's comparator (or, if the map has no comparator,
293 : jsr166 1.8 * if <tt>toKey</tt> does not implement {@link Comparable}).
294 :     * Implementations may, but are not required to, throw this
295 :     * exception if <tt>toKey</tt> cannot be compared to keys
296 :     * currently in the map.
297 :     * @throws NullPointerException if <tt>toKey</tt> is null
298 :     * and this map does not permit null keys
299 :     * @throws IllegalArgumentException if this map itself has a
300 :     * restricted range, and <tt>toKey</tt> lies outside the
301 :     * bounds of the range
302 : dl 1.1 */
303 : dl 1.3 NavigableMap<K,V> navigableHeadMap(K toKey);
304 : dl 1.1
305 :     /**
306 :     * Returns a view of the portion of this map whose keys are
307 : jsr166 1.8 * greater than or equal to <tt>fromKey</tt>. The returned map is
308 :     * backed by this map, so changes in the returned map are
309 :     * reflected in this map, and vice-versa. The returned map
310 :     * supports all optional map operations that this map supports.
311 :     *
312 :     * <p>The returned map will throw an <tt>IllegalArgumentException</tt>
313 :     * on an attempt to insert a key outside its range.
314 :     *
315 :     * @param fromKey low endpoint (inclusive) of the keys in the returned map
316 : dl 1.1 * @return a view of the portion of this map whose keys are greater
317 : jsr166 1.8 * than or equal to <tt>fromKey</tt>
318 : dl 1.1 * @throws ClassCastException if <tt>fromKey</tt> is not compatible
319 :     * with this map's comparator (or, if the map has no comparator,
320 : jsr166 1.8 * if <tt>fromKey</tt> does not implement {@link Comparable}).
321 :     * Implementations may, but are not required to, throw this
322 :     * exception if <tt>fromKey</tt> cannot be compared to keys
323 :     * currently in the map.
324 :     * @throws NullPointerException if <tt>fromKey</tt> is null
325 :     * and this map does not permit null keys
326 :     * @throws IllegalArgumentException if this map itself has a
327 :     * restricted range, and <tt>fromKey</tt> lies outside the
328 :     * bounds of the range
329 : dl 1.1 */
330 : jsr166 1.8 NavigableMap<K,V> navigableTailMap(K fromKey);
331 : dl 1.1 }

Doug Lea
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