1 /* 2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. Oracle designates this 7 * particular file as subject to the "Classpath" exception as provided 8 * by Oracle in the LICENSE file that accompanied this code. 9 * 10 * This code is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13 * version 2 for more details (a copy is included in the LICENSE file that 14 * accompanied this code). 15 * 16 * You should have received a copy of the GNU General Public License version 17 * 2 along with this work; if not, write to the Free Software Foundation, 18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 19 * 20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 21 * or visit www.oracle.com if you need additional information or have any 22 * questions. 23 */ 24 25 /* 26 * This file is available under and governed by the GNU General Public 27 * License version 2 only, as published by the Free Software Foundation. 28 * However, the following notice accompanied the original version of this 29 * file: 30 * Written by Doug Lea and Josh Bloch with assistance from members of JCP 31 * JSR-166 Expert Group and released to the public domain, as explained at 32 * http://creativecommons.org/publicdomain/zero/1.0/ 33 */ 34 35 package java.util; 36 37 // BEGIN android-note 38 // removed link to collections framework docs 39 // END android-note 40 41 /** 42 * A {@link SortedMap} extended with navigation methods returning the 43 * closest matches for given search targets. Methods 44 * {@link #lowerEntry}, {@link #floorEntry}, {@link #ceilingEntry}, 45 * and {@link #higherEntry} return {@code Map.Entry} objects 46 * associated with keys respectively less than, less than or equal, 47 * greater than or equal, and greater than a given key, returning 48 * {@code null} if there is no such key. Similarly, methods 49 * {@link #lowerKey}, {@link #floorKey}, {@link #ceilingKey}, and 50 * {@link #higherKey} return only the associated keys. All of these 51 * methods are designed for locating, not traversing entries. 52 * 53 * <p>A {@code NavigableMap} may be accessed and traversed in either 54 * ascending or descending key order. The {@link #descendingMap} 55 * method returns a view of the map with the senses of all relational 56 * and directional methods inverted. The performance of ascending 57 * operations and views is likely to be faster than that of descending 58 * ones. Methods 59 * {@link #subMap(Object, boolean, Object, boolean) subMap(K, boolean, K, boolean)}, 60 * {@link #headMap(Object, boolean) headMap(K, boolean)}, and 61 * {@link #tailMap(Object, boolean) tailMap(K, boolean)} 62 * differ from the like-named {@code SortedMap} methods in accepting 63 * additional arguments describing whether lower and upper bounds are 64 * inclusive versus exclusive. Submaps of any {@code NavigableMap} 65 * must implement the {@code NavigableMap} interface. 66 * 67 * <p>This interface additionally defines methods {@link #firstEntry}, 68 * {@link #pollFirstEntry}, {@link #lastEntry}, and 69 * {@link #pollLastEntry} that return and/or remove the least and 70 * greatest mappings, if any exist, else returning {@code null}. 71 * 72 * <p>Implementations of entry-returning methods are expected to 73 * return {@code Map.Entry} pairs representing snapshots of mappings 74 * at the time they were produced, and thus generally do <em>not</em> 75 * support the optional {@code Entry.setValue} method. Note however 76 * that it is possible to change mappings in the associated map using 77 * method {@code put}. 78 * 79 * <p>Methods 80 * {@link #subMap(Object, Object) subMap(K, K)}, 81 * {@link #headMap(Object) headMap(K)}, and 82 * {@link #tailMap(Object) tailMap(K)} 83 * are specified to return {@code SortedMap} to allow existing 84 * implementations of {@code SortedMap} to be compatibly retrofitted to 85 * implement {@code NavigableMap}, but extensions and implementations 86 * of this interface are encouraged to override these methods to return 87 * {@code NavigableMap}. Similarly, 88 * {@link #keySet()} can be overridden to return {@link NavigableSet}. 89 * 90 * @author Doug Lea 91 * @author Josh Bloch 92 * @param <K> the type of keys maintained by this map 93 * @param <V> the type of mapped values 94 * @since 1.6 95 */ 96 public interface NavigableMap<K,V> extends SortedMap<K,V> { 97 /** 98 * Returns a key-value mapping associated with the greatest key 99 * strictly less than the given key, or {@code null} if there is 100 * no such key. 101 * 102 * @param key the key 103 * @return an entry with the greatest key less than {@code key}, 104 * or {@code null} if there is no such key 105 * @throws ClassCastException if the specified key cannot be compared 106 * with the keys currently in the map 107 * @throws NullPointerException if the specified key is null 108 * and this map does not permit null keys 109 */ lowerEntry(K key)110 Map.Entry<K,V> lowerEntry(K key); 111 112 /** 113 * Returns the greatest key strictly less than the given key, or 114 * {@code null} if there is no such key. 115 * 116 * @param key the key 117 * @return the greatest key less than {@code key}, 118 * or {@code null} if there is no such key 119 * @throws ClassCastException if the specified key cannot be compared 120 * with the keys currently in the map 121 * @throws NullPointerException if the specified key is null 122 * and this map does not permit null keys 123 */ lowerKey(K key)124 K lowerKey(K key); 125 126 /** 127 * Returns a key-value mapping associated with the greatest key 128 * less than or equal to the given key, or {@code null} if there 129 * is no such key. 130 * 131 * @param key the key 132 * @return an entry with the greatest key less than or equal to 133 * {@code key}, or {@code null} if there is no such key 134 * @throws ClassCastException if the specified key cannot be compared 135 * with the keys currently in the map 136 * @throws NullPointerException if the specified key is null 137 * and this map does not permit null keys 138 */ floorEntry(K key)139 Map.Entry<K,V> floorEntry(K key); 140 141 /** 142 * Returns the greatest key less than or equal to the given key, 143 * or {@code null} if there is no such key. 144 * 145 * @param key the key 146 * @return the greatest key less than or equal to {@code key}, 147 * or {@code null} if there is no such key 148 * @throws ClassCastException if the specified key cannot be compared 149 * with the keys currently in the map 150 * @throws NullPointerException if the specified key is null 151 * and this map does not permit null keys 152 */ floorKey(K key)153 K floorKey(K key); 154 155 /** 156 * Returns a key-value mapping associated with the least key 157 * greater than or equal to the given key, or {@code null} if 158 * there is no such key. 159 * 160 * @param key the key 161 * @return an entry with the least key greater than or equal to 162 * {@code key}, or {@code null} if there is no such key 163 * @throws ClassCastException if the specified key cannot be compared 164 * with the keys currently in the map 165 * @throws NullPointerException if the specified key is null 166 * and this map does not permit null keys 167 */ ceilingEntry(K key)168 Map.Entry<K,V> ceilingEntry(K key); 169 170 /** 171 * Returns the least key greater than or equal to the given key, 172 * or {@code null} if there is no such key. 173 * 174 * @param key the key 175 * @return the least key greater than or equal to {@code key}, 176 * or {@code null} if there is no such key 177 * @throws ClassCastException if the specified key cannot be compared 178 * with the keys currently in the map 179 * @throws NullPointerException if the specified key is null 180 * and this map does not permit null keys 181 */ ceilingKey(K key)182 K ceilingKey(K key); 183 184 /** 185 * Returns a key-value mapping associated with the least key 186 * strictly greater than the given key, or {@code null} if there 187 * is no such key. 188 * 189 * @param key the key 190 * @return an entry with the least key greater than {@code key}, 191 * or {@code null} if there is no such key 192 * @throws ClassCastException if the specified key cannot be compared 193 * with the keys currently in the map 194 * @throws NullPointerException if the specified key is null 195 * and this map does not permit null keys 196 */ higherEntry(K key)197 Map.Entry<K,V> higherEntry(K key); 198 199 /** 200 * Returns the least key strictly greater than the given key, or 201 * {@code null} if there is no such key. 202 * 203 * @param key the key 204 * @return the least key greater than {@code key}, 205 * or {@code null} if there is no such key 206 * @throws ClassCastException if the specified key cannot be compared 207 * with the keys currently in the map 208 * @throws NullPointerException if the specified key is null 209 * and this map does not permit null keys 210 */ higherKey(K key)211 K higherKey(K key); 212 213 /** 214 * Returns a key-value mapping associated with the least 215 * key in this map, or {@code null} if the map is empty. 216 * 217 * @return an entry with the least key, 218 * or {@code null} if this map is empty 219 */ firstEntry()220 Map.Entry<K,V> firstEntry(); 221 222 /** 223 * Returns a key-value mapping associated with the greatest 224 * key in this map, or {@code null} if the map is empty. 225 * 226 * @return an entry with the greatest key, 227 * or {@code null} if this map is empty 228 */ lastEntry()229 Map.Entry<K,V> lastEntry(); 230 231 /** 232 * Removes and returns a key-value mapping associated with 233 * the least key in this map, or {@code null} if the map is empty. 234 * 235 * @return the removed first entry of this map, 236 * or {@code null} if this map is empty 237 */ pollFirstEntry()238 Map.Entry<K,V> pollFirstEntry(); 239 240 /** 241 * Removes and returns a key-value mapping associated with 242 * the greatest key in this map, or {@code null} if the map is empty. 243 * 244 * @return the removed last entry of this map, 245 * or {@code null} if this map is empty 246 */ pollLastEntry()247 Map.Entry<K,V> pollLastEntry(); 248 249 /** 250 * Returns a reverse order view of the mappings contained in this map. 251 * The descending map is backed by this map, so changes to the map are 252 * reflected in the descending map, and vice-versa. If either map is 253 * modified while an iteration over a collection view of either map 254 * is in progress (except through the iterator's own {@code remove} 255 * operation), the results of the iteration are undefined. 256 * 257 * <p>The returned map has an ordering equivalent to 258 * {@link Collections#reverseOrder(Comparator) Collections.reverseOrder}{@code (comparator())}. 259 * The expression {@code m.descendingMap().descendingMap()} returns a 260 * view of {@code m} essentially equivalent to {@code m}. 261 * 262 * @return a reverse order view of this map 263 */ descendingMap()264 NavigableMap<K,V> descendingMap(); 265 266 /** 267 * Returns a {@link NavigableSet} view of the keys contained in this map. 268 * The set's iterator returns the keys in ascending order. 269 * The set is backed by the map, so changes to the map are reflected in 270 * the set, and vice-versa. If the map is modified while an iteration 271 * over the set is in progress (except through the iterator's own {@code 272 * remove} operation), the results of the iteration are undefined. The 273 * set supports element removal, which removes the corresponding mapping 274 * from the map, via the {@code Iterator.remove}, {@code Set.remove}, 275 * {@code removeAll}, {@code retainAll}, and {@code clear} operations. 276 * It does not support the {@code add} or {@code addAll} operations. 277 * 278 * @return a navigable set view of the keys in this map 279 */ navigableKeySet()280 NavigableSet<K> navigableKeySet(); 281 282 /** 283 * Returns a reverse order {@link NavigableSet} view of the keys contained in this map. 284 * The set's iterator returns the keys in descending order. 285 * The set is backed by the map, so changes to the map are reflected in 286 * the set, and vice-versa. If the map is modified while an iteration 287 * over the set is in progress (except through the iterator's own {@code 288 * remove} operation), the results of the iteration are undefined. The 289 * set supports element removal, which removes the corresponding mapping 290 * from the map, via the {@code Iterator.remove}, {@code Set.remove}, 291 * {@code removeAll}, {@code retainAll}, and {@code clear} operations. 292 * It does not support the {@code add} or {@code addAll} operations. 293 * 294 * @return a reverse order navigable set view of the keys in this map 295 */ descendingKeySet()296 NavigableSet<K> descendingKeySet(); 297 298 /** 299 * Returns a view of the portion of this map whose keys range from 300 * {@code fromKey} to {@code toKey}. If {@code fromKey} and 301 * {@code toKey} are equal, the returned map is empty unless 302 * {@code fromInclusive} and {@code toInclusive} are both true. The 303 * returned map is backed by this map, so changes in the returned map are 304 * reflected in this map, and vice-versa. The returned map supports all 305 * optional map operations that this map supports. 306 * 307 * <p>The returned map will throw an {@code IllegalArgumentException} 308 * on an attempt to insert a key outside of its range, or to construct a 309 * submap either of whose endpoints lie outside its range. 310 * 311 * @param fromKey low endpoint of the keys in the returned map 312 * @param fromInclusive {@code true} if the low endpoint 313 * is to be included in the returned view 314 * @param toKey high endpoint of the keys in the returned map 315 * @param toInclusive {@code true} if the high endpoint 316 * is to be included in the returned view 317 * @return a view of the portion of this map whose keys range from 318 * {@code fromKey} to {@code toKey} 319 * @throws ClassCastException if {@code fromKey} and {@code toKey} 320 * cannot be compared to one another using this map's comparator 321 * (or, if the map has no comparator, using natural ordering). 322 * Implementations may, but are not required to, throw this 323 * exception if {@code fromKey} or {@code toKey} 324 * cannot be compared to keys currently in the map. 325 * @throws NullPointerException if {@code fromKey} or {@code toKey} 326 * is null and this map does not permit null keys 327 * @throws IllegalArgumentException if {@code fromKey} is greater than 328 * {@code toKey}; or if this map itself has a restricted 329 * range, and {@code fromKey} or {@code toKey} lies 330 * outside the bounds of the range 331 */ subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive)332 NavigableMap<K,V> subMap(K fromKey, boolean fromInclusive, 333 K toKey, boolean toInclusive); 334 335 /** 336 * Returns a view of the portion of this map whose keys are less than (or 337 * equal to, if {@code inclusive} is true) {@code toKey}. The returned 338 * map is backed by this map, so changes in the returned map are reflected 339 * in this map, and vice-versa. The returned map supports all optional 340 * map operations that this map supports. 341 * 342 * <p>The returned map will throw an {@code IllegalArgumentException} 343 * on an attempt to insert a key outside its range. 344 * 345 * @param toKey high endpoint of the keys in the returned map 346 * @param inclusive {@code true} if the high endpoint 347 * is to be included in the returned view 348 * @return a view of the portion of this map whose keys are less than 349 * (or equal to, if {@code inclusive} is true) {@code toKey} 350 * @throws ClassCastException if {@code toKey} is not compatible 351 * with this map's comparator (or, if the map has no comparator, 352 * if {@code toKey} does not implement {@link Comparable}). 353 * Implementations may, but are not required to, throw this 354 * exception if {@code toKey} cannot be compared to keys 355 * currently in the map. 356 * @throws NullPointerException if {@code toKey} is null 357 * and this map does not permit null keys 358 * @throws IllegalArgumentException if this map itself has a 359 * restricted range, and {@code toKey} lies outside the 360 * bounds of the range 361 */ headMap(K toKey, boolean inclusive)362 NavigableMap<K,V> headMap(K toKey, boolean inclusive); 363 364 /** 365 * Returns a view of the portion of this map whose keys are greater than (or 366 * equal to, if {@code inclusive} is true) {@code fromKey}. The returned 367 * map is backed by this map, so changes in the returned map are reflected 368 * in this map, and vice-versa. The returned map supports all optional 369 * map operations that this map supports. 370 * 371 * <p>The returned map will throw an {@code IllegalArgumentException} 372 * on an attempt to insert a key outside its range. 373 * 374 * @param fromKey low endpoint of the keys in the returned map 375 * @param inclusive {@code true} if the low endpoint 376 * is to be included in the returned view 377 * @return a view of the portion of this map whose keys are greater than 378 * (or equal to, if {@code inclusive} is true) {@code fromKey} 379 * @throws ClassCastException if {@code fromKey} is not compatible 380 * with this map's comparator (or, if the map has no comparator, 381 * if {@code fromKey} does not implement {@link Comparable}). 382 * Implementations may, but are not required to, throw this 383 * exception if {@code fromKey} cannot be compared to keys 384 * currently in the map. 385 * @throws NullPointerException if {@code fromKey} is null 386 * and this map does not permit null keys 387 * @throws IllegalArgumentException if this map itself has a 388 * restricted range, and {@code fromKey} lies outside the 389 * bounds of the range 390 */ tailMap(K fromKey, boolean inclusive)391 NavigableMap<K,V> tailMap(K fromKey, boolean inclusive); 392 393 /** 394 * {@inheritDoc} 395 * 396 * <p>Equivalent to {@code subMap(fromKey, true, toKey, false)}. 397 * 398 * @throws ClassCastException {@inheritDoc} 399 * @throws NullPointerException {@inheritDoc} 400 * @throws IllegalArgumentException {@inheritDoc} 401 */ subMap(K fromKey, K toKey)402 SortedMap<K,V> subMap(K fromKey, K toKey); 403 404 /** 405 * {@inheritDoc} 406 * 407 * <p>Equivalent to {@code headMap(toKey, false)}. 408 * 409 * @throws ClassCastException {@inheritDoc} 410 * @throws NullPointerException {@inheritDoc} 411 * @throws IllegalArgumentException {@inheritDoc} 412 */ headMap(K toKey)413 SortedMap<K,V> headMap(K toKey); 414 415 /** 416 * {@inheritDoc} 417 * 418 * <p>Equivalent to {@code tailMap(fromKey, true)}. 419 * 420 * @throws ClassCastException {@inheritDoc} 421 * @throws NullPointerException {@inheritDoc} 422 * @throws IllegalArgumentException {@inheritDoc} 423 */ tailMap(K fromKey)424 SortedMap<K,V> tailMap(K fromKey); 425 } 426