001: package j2me.util;
002:
003: /*
004: * Written by Doug Lea and Josh Bloch with assistance from members of JCP
005: * JSR-166 Expert Group and released to the public domain, as explained at
006: * http://creativecommons.org/licenses/publicdomain
007: */
008:
009: import j2me.util.Map;
010: import j2me.util.SortedMap;
011:
012: /**
013: * A {@link java.util.SortedMap} extended with navigation methods returning the
014: * closest matches for given search targets. Methods
015: * {@code lowerEntry}, {@code floorEntry}, {@code ceilingEntry},
016: * and {@code higherEntry} return {@code Map.Entry} objects
017: * associated with keys respectively less than, less than or equal,
018: * greater than or equal, and greater than a given key, returning
019: * {@code null} if there is no such key. Similarly, methods
020: * {@code lowerKey}, {@code floorKey}, {@code ceilingKey}, and
021: * {@code higherKey} return only the associated keys. All of these
022: * methods are designed for locating, not traversing entries.
023: *
024: * <p>A {@code NavigableMap} may be accessed and traversed in either
025: * ascending or descending key order. The {@code descendingMap}
026: * method returns a view of the map with the senses of all relational
027: * and directional methods inverted. The performance of ascending
028: * operations and views is likely to be faster than that of descending
029: * ones. Methods {@code subMap}, {@code headMap},
030: * and {@code tailMap} differ from the like-named {@code
031: * SortedMap} methods in accepting additional arguments describing
032: * whether lower and upper bounds are inclusive versus exclusive.
033: * Submaps of any {@code NavigableMap} must implement the {@code
034: * NavigableMap} interface.
035: *
036: * <p>This interface additionally defines methods {@code firstEntry},
037: * {@code pollFirstEntry}, {@code lastEntry}, and
038: * {@code pollLastEntry} that return and/or remove the least and
039: * greatest mappings, if any exist, else returning {@code null}.
040: *
041: * <p>Implementations of entry-returning methods are expected to
042: * return {@code Map.Entry} pairs representing snapshots of mappings
043: * at the time they were produced, and thus generally do <em>not</em>
044: * support the optional {@code Entry.setValue} method. Note however
045: * that it is possible to change mappings in the associated map using
046: * method {@code put}.
047: *
048: * <p>Methods
049: * {@link #subMap(Object, Object) subMap(K, K)},
050: * {@link #headMap(Object) headMap(K)}, and
051: * {@link #tailMap(Object) tailMap(K)}
052: * are specified to return {@code SortedMap} to allow existing
053: * implementations of {@code SortedMap} to be compatibly retrofitted to
054: * implement {@code NavigableMap}, but extensions and implementations
055: * of this interface are encouraged to override these methods to return
056: * {@code NavigableMap}. Similarly,
057: * {@link #keySet()} can be overriden to return {@code NavigableSet}.
058: *
059: * <p>This interface is a member of the
060: * <a href="{@docRoot}/../technotes/guides/collections/index.html">
061: * Java Collections Framework</a>.
062: *
063: * @author Doug Lea
064: * @author Josh Bloch
065: * @since 1.6
066: */
067: public interface NavigableMap extends SortedMap {
068: /**
069: * Returns a key-value mapping associated with the greatest key
070: * strictly less than the given key, or {@code null} if there is
071: * no such key.
072: *
073: * @param key the key
074: * @return an entry with the greatest key less than {@code key},
075: * or {@code null} if there is no such key
076: * @throws ClassCastException if the specified key cannot be compared
077: * with the keys currently in the map
078: * @throws NullPointerException if the specified key is null
079: * and this map does not permit null keys
080: */
081: Map.Entry lowerEntry(Object key);
082:
083: /**
084: * Returns the greatest key strictly less than the given key, or
085: * {@code null} if there is no such key.
086: *
087: * @param key the key
088: * @return the greatest key less than {@code key},
089: * or {@code null} if there is no such key
090: * @throws ClassCastException if the specified key cannot be compared
091: * with the keys currently in the map
092: * @throws NullPointerException if the specified key is null
093: * and this map does not permit null keys
094: */
095: Object lowerKey(Object key);
096:
097: /**
098: * Returns a key-value mapping associated with the greatest key
099: * less than or equal to the given key, or {@code null} if there
100: * is no such key.
101: *
102: * @param key the key
103: * @return an entry with the greatest key less than or equal to
104: * {@code key}, 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: */
110: Map.Entry floorEntry(Object key);
111:
112: /**
113: * Returns the greatest key less than or equal to the given key,
114: * or {@code null} if there is no such key.
115: *
116: * @param key the key
117: * @return the greatest key less than or equal to {@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: */
124: Object floorKey(Object key);
125:
126: /**
127: * Returns a key-value mapping associated with the least key
128: * greater than or equal to the given key, or {@code null} if
129: * there is no such key.
130: *
131: * @param key the key
132: * @return an entry with the least key greater 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: */
139: Map.Entry ceilingEntry(Object key);
140:
141: /**
142: * Returns the least key greater 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 least key greater 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: */
153: Object ceilingKey(Object key);
154:
155: /**
156: * Returns a key-value mapping associated with the least key
157: * strictly greater than the given key, or {@code null} if there
158: * is no such key.
159: *
160: * @param key the key
161: * @return an entry with the least key greater than {@code key},
162: * 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: */
168: Map.Entry higherEntry(Object key);
169:
170: /**
171: * Returns the least key strictly greater than the given key, or
172: * {@code null} if there is no such key.
173: *
174: * @param key the key
175: * @return the least key greater than {@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: */
182: Object higherKey(Object key);
183:
184: /**
185: * Returns a key-value mapping associated with the least
186: * key in this map, or {@code null} if the map is empty.
187: *
188: * @return an entry with the least key,
189: * or {@code null} if this map is empty
190: */
191: Map.Entry firstEntry();
192:
193: /**
194: * Returns a key-value mapping associated with the greatest
195: * key in this map, or {@code null} if the map is empty.
196: *
197: * @return an entry with the greatest key,
198: * or {@code null} if this map is empty
199: */
200: Map.Entry lastEntry();
201:
202: /**
203: * Removes and returns a key-value mapping associated with
204: * the least key in this map, or {@code null} if the map is empty.
205: *
206: * @return the removed first entry of this map,
207: * or {@code null} if this map is empty
208: */
209: Map.Entry pollFirstEntry();
210:
211: /**
212: * Removes and returns a key-value mapping associated with
213: * the greatest key in this map, or {@code null} if the map is empty.
214: *
215: * @return the removed last entry of this map,
216: * or {@code null} if this map is empty
217: */
218: Map.Entry pollLastEntry();
219:
220: /**
221: * Returns a reverse order view of the mappings contained in this map.
222: * The descending map is backed by this map, so changes to the map are
223: * reflected in the descending map, and vice-versa. If either map is
224: * modified while an iteration over a collection view of either map
225: * is in progress (except through the iterator's own {@code remove}
226: * operation), the results of the iteration are undefined.
227: *
228: * <p>The returned map has an ordering equivalent to
229: * <tt>{@link Collections#reverseOrder(Comparator) Collections.reverseOrder}(comparator())</tt>.
230: * The expression {@code m.descendingMap().descendingMap()} returns a
231: * view of {@code m} essentially equivalent to {@code m}.
232: *
233: * @return a reverse order view of this map
234: */
235: NavigableMap descendingMap();
236:
237: /**
238: * Returns a {@link NavigableSet} view of the keys contained in this map.
239: * The set's iterator returns the keys in ascending order.
240: * The set is backed by the map, so changes to the map are reflected in
241: * the set, and vice-versa. If the map is modified while an iteration
242: * over the set is in progress (except through the iterator's own {@code
243: * remove} operation), the results of the iteration are undefined. The
244: * set supports element removal, which removes the corresponding mapping
245: * from the map, via the {@code Iterator.remove}, {@code Set.remove},
246: * {@code removeAll}, {@code retainAll}, and {@code clear} operations.
247: * It does not support the {@code add} or {@code addAll} operations.
248: *
249: * @return a navigable set view of the keys in this map
250: */
251: NavigableSet navigableKeySet();
252:
253: /**
254: * Returns a reverse order {@link NavigableSet} view of the keys contained in this map.
255: * The set's iterator returns the keys in descending order.
256: * The set is backed by the map, so changes to the map are reflected in
257: * the set, and vice-versa. If the map is modified while an iteration
258: * over the set is in progress (except through the iterator's own {@code
259: * remove} operation), the results of the iteration are undefined. The
260: * set supports element removal, which removes the corresponding mapping
261: * from the map, via the {@code Iterator.remove}, {@code Set.remove},
262: * {@code removeAll}, {@code retainAll}, and {@code clear} operations.
263: * It does not support the {@code add} or {@code addAll} operations.
264: *
265: * @return a reverse order navigable set view of the keys in this map
266: */
267: NavigableSet descendingKeySet();
268:
269: /**
270: * Returns a view of the portion of this map whose keys range from
271: * {@code fromKey} to {@code toKey}. If {@code fromKey} and
272: * {@code toKey} are equal, the returned map is empty unless
273: * {@code fromExclusive} and {@code toExclusive} are both true. The
274: * returned map is backed by this map, so changes in the returned map are
275: * reflected in this map, and vice-versa. The returned map supports all
276: * optional map operations that this map supports.
277: *
278: * <p>The returned map will throw an {@code IllegalArgumentException}
279: * on an attempt to insert a key outside of its range, or to construct a
280: * submap either of whose endpoints lie outside its range.
281: *
282: * @param fromKey low endpoint of the keys in the returned map
283: * @param fromInclusive {@code true} if the low endpoint
284: * is to be included in the returned view
285: * @param toKey high endpoint of the keys in the returned map
286: * @param toInclusive {@code true} if the high endpoint
287: * is to be included in the returned view
288: * @return a view of the portion of this map whose keys range from
289: * {@code fromKey} to {@code toKey}
290: * @throws ClassCastException if {@code fromKey} and {@code toKey}
291: * cannot be compared to one another using this map's comparator
292: * (or, if the map has no comparator, using natural ordering).
293: * Implementations may, but are not required to, throw this
294: * exception if {@code fromKey} or {@code toKey}
295: * cannot be compared to keys currently in the map.
296: * @throws NullPointerException if {@code fromKey} or {@code toKey}
297: * is null and this map does not permit null keys
298: * @throws IllegalArgumentException if {@code fromKey} is greater than
299: * {@code toKey}; or if this map itself has a restricted
300: * range, and {@code fromKey} or {@code toKey} lies
301: * outside the bounds of the range
302: */
303: NavigableMap subMap(Object fromKey, boolean fromInclusive,
304: Object toKey, boolean toInclusive);
305:
306: /**
307: * Returns a view of the portion of this map whose keys are less than (or
308: * equal to, if {@code inclusive} is true) {@code toKey}. The returned
309: * map is backed by this map, so changes in the returned map are reflected
310: * in this map, and vice-versa. The returned map supports all optional
311: * map operations that this map supports.
312: *
313: * <p>The returned map will throw an {@code IllegalArgumentException}
314: * on an attempt to insert a key outside its range.
315: *
316: * @param toKey high endpoint of the keys in the returned map
317: * @param inclusive {@code true} if the high endpoint
318: * is to be included in the returned view
319: * @return a view of the portion of this map whose keys are less than
320: * (or equal to, if {@code inclusive} is true) {@code toKey}
321: * @throws ClassCastException if {@code toKey} is not compatible
322: * with this map's comparator (or, if the map has no comparator,
323: * if {@code toKey} does not implement {@link java.lang.Comparable}).
324: * Implementations may, but are not required to, throw this
325: * exception if {@code toKey} cannot be compared to keys
326: * currently in the map.
327: * @throws NullPointerException if {@code toKey} is null
328: * and this map does not permit null keys
329: * @throws IllegalArgumentException if this map itself has a
330: * restricted range, and {@code toKey} lies outside the
331: * bounds of the range
332: */
333: NavigableMap headMap(Object toKey, boolean inclusive);
334:
335: /**
336: * Returns a view of the portion of this map whose keys are greater than (or
337: * equal to, if {@code inclusive} is true) {@code fromKey}. 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 fromKey low endpoint of the keys in the returned map
346: * @param inclusive {@code true} if the low endpoint
347: * is to be included in the returned view
348: * @return a view of the portion of this map whose keys are greater than
349: * (or equal to, if {@code inclusive} is true) {@code fromKey}
350: * @throws ClassCastException if {@code fromKey} is not compatible
351: * with this map's comparator (or, if the map has no comparator,
352: * if {@code fromKey} does not implement {@link java.lang.Comparable}).
353: * Implementations may, but are not required to, throw this
354: * exception if {@code fromKey} cannot be compared to keys
355: * currently in the map.
356: * @throws NullPointerException if {@code fromKey} 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 fromKey} lies outside the
360: * bounds of the range
361: */
362: NavigableMap tailMap(Object fromKey, boolean inclusive);
363:
364: /**
365: * {@inheritDoc}
366: *
367: * <p>Equivalent to {@code subMap(fromKey, true, toKey, false)}.
368: *
369: * @throws ClassCastException {@inheritDoc}
370: * @throws NullPointerException {@inheritDoc}
371: * @throws IllegalArgumentException {@inheritDoc}
372: */
373: SortedMap subMap(Object fromKey, Object toKey);
374:
375: /**
376: * {@inheritDoc}
377: *
378: * <p>Equivalent to {@code headMap(toKey, false)}.
379: *
380: * @throws ClassCastException {@inheritDoc}
381: * @throws NullPointerException {@inheritDoc}
382: * @throws IllegalArgumentException {@inheritDoc}
383: */
384: SortedMap headMap(Object toKey);
385:
386: /**
387: * {@inheritDoc}
388: *
389: * <p>Equivalent to {@code tailMap(fromKey, true)}.
390: *
391: * @throws ClassCastException {@inheritDoc}
392: * @throws NullPointerException {@inheritDoc}
393: * @throws IllegalArgumentException {@inheritDoc}
394: */
395: SortedMap tailMap(Object fromKey);
396: }
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