[cvs] / jsr166 / src / main / java / util / NavigableMap.java Repository:
ViewVC logotype

Annotation of /jsr166/src/main/java/util/NavigableMap.java

Parent Directory Parent Directory | Revision Log Revision Log


Revision 1.4 - (view) (download)

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 : dl 1.1 *
34 :     * <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 :     * @author Doug Lea
47 :     * @param <K> the type of keys maintained by this map
48 :     * @param <V> the type of mapped values
49 :     */
50 :     public interface NavigableMap<K,V> extends SortedMap<K,V> {
51 :     /**
52 :     * Returns a key-value mapping associated with the least key
53 :     * greater than or equal to the given key, or <tt>null</tt> if there is
54 :     * no such entry.
55 :     *
56 :     * @param key the key.
57 :     * @return an Entry associated with ceiling of given key, or <tt>null</tt>
58 :     * if there is no such Entry.
59 :     * @throws ClassCastException if key cannot be compared with the keys
60 :     * currently in the map.
61 :     * @throws NullPointerException if key is <tt>null</tt> and this map
62 :     * does not support <tt>null</tt> keys.
63 :     */
64 : dl 1.3 Map.Entry<K,V> ceilingEntry(K key);
65 : dl 1.1
66 :     /**
67 :     * Returns least key greater than or equal to the given key, or
68 :     * <tt>null</tt> if there is no such key.
69 :     *
70 :     * @param key the key.
71 :     * @return the ceiling key, or <tt>null</tt>
72 :     * if there is no such key.
73 :     * @throws ClassCastException if key cannot be compared with the keys
74 :     * currently in the map.
75 :     * @throws NullPointerException if key is <tt>null</tt> and this map
76 :     * does not support <tt>null</tt> keys.
77 :     */
78 : dl 1.3 K ceilingKey(K key);
79 : dl 1.1
80 :     /**
81 :     * Returns a key-value mapping associated with the greatest
82 :     * key strictly less than the given key, or <tt>null</tt> if there is no
83 :     * such entry.
84 :     *
85 :     * @param key the key.
86 :     * @return an Entry with greatest key less than the given
87 :     * key, or <tt>null</tt> if there is no such Entry.
88 :     * @throws ClassCastException if key cannot be compared with the keys
89 :     * currently in the map.
90 :     * @throws NullPointerException if key is <tt>null</tt> and this map
91 :     * does not support <tt>null</tt> keys.
92 :     */
93 : dl 1.3 Map.Entry<K,V> lowerEntry(K key);
94 : dl 1.1
95 :     /**
96 :     * Returns the greatest key strictly less than the given key, or
97 :     * <tt>null</tt> if there is no such key.
98 :     *
99 :     * @param key the key.
100 :     * @return the greatest key less than the given
101 :     * key, or <tt>null</tt> if there is no such key.
102 :     * @throws ClassCastException if key cannot be compared with the keys
103 :     * currently in the map.
104 :     * @throws NullPointerException if key is <tt>null</tt> and this map
105 :     * does not support <tt>null</tt> keys.
106 :     */
107 : dl 1.3 K lowerKey(K key);
108 : dl 1.1
109 :     /**
110 :     * Returns a key-value mapping associated with the greatest key
111 :     * less than or equal to the given key, or <tt>null</tt> if there
112 :     * is no such entry.
113 :     *
114 :     * @param key the key.
115 :     * @return an Entry associated with floor of given key, or <tt>null</tt>
116 :     * if there is no such Entry.
117 :     * @throws ClassCastException if key cannot be compared with the keys
118 :     * currently in the map.
119 :     * @throws NullPointerException if key is <tt>null</tt> and this map
120 :     * does not support <tt>null</tt> keys.
121 :     */
122 : dl 1.3 Map.Entry<K,V> floorEntry(K key);
123 : dl 1.1
124 :     /**
125 :     * Returns the greatest key
126 :     * less than or equal to the given key, or <tt>null</tt> if there
127 :     * is no such key.
128 :     *
129 :     * @param key the key.
130 :     * @return the floor of given key, or <tt>null</tt> if there is no
131 :     * such key.
132 :     * @throws ClassCastException if key cannot be compared with the keys
133 :     * currently in the map.
134 :     * @throws NullPointerException if key is <tt>null</tt> and this map
135 :     * does not support <tt>null</tt> keys.
136 :     */
137 : dl 1.3 K floorKey(K key);
138 : dl 1.1
139 :     /**
140 :     * Returns a key-value mapping associated with the least key
141 :     * strictly greater than the given key, or <tt>null</tt> if there
142 :     * is no such entry.
143 :     *
144 :     * @param key the key.
145 :     * @return an Entry with least key greater than the given key, or
146 :     * <tt>null</tt> if there is no such Entry.
147 :     * @throws ClassCastException if key cannot be compared with the keys
148 :     * currently in the map.
149 :     * @throws NullPointerException if key is <tt>null</tt> and this map
150 :     * does not support <tt>null</tt> keys.
151 :     */
152 : dl 1.3 Map.Entry<K,V> higherEntry(K key);
153 : dl 1.1
154 :     /**
155 :     * Returns the least key strictly greater than the given key, or
156 :     * <tt>null</tt> if there is no such key.
157 :     *
158 :     * @param key the key.
159 :     * @return the least key greater than the given key, or
160 :     * <tt>null</tt> if there is no such key.
161 :     * @throws ClassCastException if key cannot be compared with the keys
162 :     * currently in the map.
163 :     * @throws NullPointerException if key is <tt>null</tt> and this map
164 :     * does not support <tt>null</tt> keys.
165 :     */
166 : dl 1.3 K higherKey(K key);
167 : dl 1.1
168 :     /**
169 :     * Returns a key-value mapping associated with the least
170 :     * key in this map, or <tt>null</tt> if the map is empty.
171 :     *
172 :     * @return an Entry with least key, or <tt>null</tt>
173 :     * if the map is empty.
174 :     */
175 : dl 1.3 Map.Entry<K,V> firstEntry();
176 : dl 1.1
177 :     /**
178 :     * Returns a key-value mapping associated with the greatest
179 :     * key in this map, or <tt>null</tt> if the map is empty.
180 :     *
181 :     * @return an Entry with greatest key, or <tt>null</tt>
182 :     * if the map is empty.
183 :     */
184 : dl 1.3 Map.Entry<K,V> lastEntry();
185 : dl 1.1
186 :     /**
187 :     * Removes and returns a key-value mapping associated with
188 :     * the least key in this map, or <tt>null</tt> if the map is empty.
189 :     *
190 :     * @return the removed first entry of this map, or <tt>null</tt>
191 :     * if the map is empty.
192 :     */
193 : dl 1.3 Map.Entry<K,V> pollFirstEntry();
194 : dl 1.1
195 :     /**
196 :     * Removes and returns a key-value mapping associated with
197 :     * the greatest key in this map, or <tt>null</tt> if the map is empty.
198 :     *
199 :     * @return the removed last entry of this map, or <tt>null</tt>
200 :     * if the map is empty.
201 :     */
202 : dl 1.3 Map.Entry<K,V> pollLastEntry();
203 : dl 1.1
204 :     /**
205 :     * Returns a set view of the keys contained in this map, in
206 :     * descending key order. The set is backed by the map, so changes
207 :     * to the map are reflected in the set, and vice-versa. If the
208 :     * map is modified while an iteration over the set is in progress
209 :     * (except through the iterator's own <tt>remove</tt> operation),
210 :     * the results of the iteration are undefined. The set supports
211 :     * element removal, which removes the corresponding mapping from
212 :     * the map, via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
213 :     * <tt>removeAll</tt> <tt>retainAll</tt>, and <tt>clear</tt>
214 :     * operations. It does not support the add or <tt>addAll</tt>
215 :     * operations.
216 :     *
217 :     * @return a set view of the keys contained in this map.
218 :     */
219 :     Set<K> descendingKeySet();
220 :    
221 :     /**
222 :     * Returns a set view of the mappings contained in this map, in
223 :     * descending key order. Each element in the returned set is a
224 :     * <tt>Map.Entry</tt>. The set is backed by the map, so changes to
225 :     * the map are reflected in the set, and vice-versa. If the map
226 :     * is modified while an iteration over the set is in progress
227 :     * (except through the iterator's own <tt>remove</tt> operation,
228 :     * or through the <tt>setValue</tt> operation on a map entry
229 :     * returned by the iterator) the results of the iteration are
230 :     * undefined. The set supports element removal, which removes the
231 :     * corresponding mapping from the map, via the
232 :     * <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
233 :     * <tt>removeAll</tt>, <tt>retainAll</tt> and <tt>clear</tt>
234 :     * operations. It does not support the <tt>add</tt> or
235 :     * <tt>addAll</tt> operations.
236 :     *
237 :     * @return a set view of the mappings contained in this map.
238 :     */
239 :     Set<Map.Entry<K, V>> descendingEntrySet();
240 :    
241 :     /**
242 :     * Returns a view of the portion of this map whose keys range from
243 :     * <tt>fromKey</tt>, inclusive, to <tt>toKey</tt>, exclusive. (If
244 : dl 1.3 * <tt>fromKey</tt> and <tt>toKey</tt> are equal, the returned
245 :     * navigable map is empty.) The returned navigable map is backed
246 :     * by this map, so changes in the returned navigable map are
247 : dl 1.4 * reflected in this map, and vice-versa.
248 : dl 1.3 *
249 : dl 1.1 * @param fromKey low endpoint (inclusive) of the subMap.
250 :     * @param toKey high endpoint (exclusive) of the subMap.
251 :     *
252 :     * @return a view of the portion of this map whose keys range from
253 :     * <tt>fromKey</tt>, inclusive, to <tt>toKey</tt>, exclusive.
254 :     *
255 :     * @throws ClassCastException if <tt>fromKey</tt> and
256 :     * <tt>toKey</tt> cannot be compared to one another using this
257 :     * map's comparator (or, if the map has no comparator, using
258 :     * natural ordering).
259 :     * @throws IllegalArgumentException if <tt>fromKey</tt> is greater
260 :     * than <tt>toKey</tt>.
261 :     * @throws NullPointerException if <tt>fromKey</tt> or
262 :     * <tt>toKey</tt> is <tt>null</tt> and this map does not support
263 :     * <tt>null</tt> keys.
264 :     */
265 : dl 1.3 NavigableMap<K,V> navigableSubMap(K fromKey, K toKey);
266 : dl 1.1
267 :     /**
268 :     * Returns a view of the portion of this map whose keys are strictly less
269 : dl 1.3 * than <tt>toKey</tt>. The returned navigable map is backed by this map, so
270 :     * changes in the returned navigable map are reflected in this map, and
271 : dl 1.1 * vice-versa.
272 :     * @param toKey high endpoint (exclusive) of the headMap.
273 :     * @return a view of the portion of this map whose keys are strictly
274 :     * less than <tt>toKey</tt>.
275 :     *
276 :     * @throws ClassCastException if <tt>toKey</tt> is not compatible
277 :     * with this map's comparator (or, if the map has no comparator,
278 :     * if <tt>toKey</tt> does not implement <tt>Comparable</tt>).
279 :     * @throws NullPointerException if <tt>toKey</tt> is <tt>null</tt>
280 :     * and this map does not support <tt>null</tt> keys.
281 :     */
282 : dl 1.3 NavigableMap<K,V> navigableHeadMap(K toKey);
283 : dl 1.1
284 :     /**
285 :     * Returns a view of the portion of this map whose keys are
286 : dl 1.3 * greater than or equal to <tt>fromKey</tt>. The returned navigable
287 :     * map is backed by this map, so changes in the returned navigable
288 : dl 1.1 * map are reflected in this map, and vice-versa.
289 :     * @param fromKey low endpoint (inclusive) of the tailMap.
290 :     * @return a view of the portion of this map whose keys are greater
291 :     * than or equal to <tt>fromKey</tt>.
292 :     * @throws ClassCastException if <tt>fromKey</tt> is not compatible
293 :     * with this map's comparator (or, if the map has no comparator,
294 :     * if <tt>fromKey</tt> does not implement <tt>Comparable</tt>).
295 :     * @throws NullPointerException if <tt>fromKey</tt> is <tt>null</tt>
296 :     * and this map does not support <tt>null</tt> keys.
297 :     */
298 : dl 1.3 NavigableMap<K,V> navigableTailMap(K fromKey);
299 : dl 1.1 }

Doug Lea
ViewVC Help
Powered by ViewVC 1.0.8