src/jsr166x/NavigableMap.java

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */

package jsr166x;

import java.util.*;

/**
 * A {@link SortedMap} extended with navigation methods returning the
 * closest matches for given search targets. Methods
 * {@code lowerEntry}, {@code floorEntry}, {@code ceilingEntry},
 * and {@code higherEntry} return {@code Map.Entry} objects
 * associated with keys respectively less than, less than or equal,
 * greater than or equal, and greater than a given key, returning
 * {@code null} if there is no such key.  Similarly, methods
 * {@code lowerKey}, {@code floorKey}, {@code ceilingKey}, and
 * {@code higherKey} return only the associated keys. All of these
 * methods are designed for locating, not traversing entries.
 *
 * <p>A {@code NavigableMap} may be viewed and traversed in either
 * ascending or descending key order.  The {@code Map} methods
 * {@code keySet} and {@code entrySet} return ascending views, and
 * the additional methods {@code descendingKeySet} and
 * {@code descendingEntrySet} return descending views. The
 * performance of ascending traversals is likely to be faster than
 * descending traversals.  Notice that it is possible to perform
 * subrannge traversals in either direction using {@code SubMap}.
 *
 * <p>This interface additionally defines methods {@code firstEntry},
 * {@code pollFirstEntry}, {@code lastEntry}, and
 * {@code pollLastEntry} that return and/or remove the least and
 * greatest mappings, if any exist, else returning {@code null}.
 *
 * <p>Implementations of entry-returning methods are expected to
 * return {@code Map.Entry} pairs representing snapshots of mappings
 * at the time they were produced, and thus generally do <em>not</em>
 * support the optional {@code Entry.setValue} method. Note however
 * that it is possible to change mappings in the associated map using
 * method {@code put}.
 *
 * @author Doug Lea
 * @param <K> the type of keys maintained by this map
 * @param <V> the type of mapped values
 */
public interface NavigableMap<K,V> extends SortedMap<K,V> {
    /**
     * Returns a key-value mapping associated with the least key
     * greater than or equal to the given key, or {@code null} if there is
     * no such entry.
     *
     * @param key the key
     * @return an Entry associated with ceiling of given key, or {@code null}
     * if there is no such Entry
     * @throws ClassCastException if key cannot be compared with the keys
     *            currently in the map
     * @throws NullPointerException if key is {@code null} and this map
     * does not support {@code null} keys
     */
    public Map.Entry<K,V> ceilingEntry(K key);

    /**
     * Returns least key greater than or equal to the given key, or
     * {@code null} if there is no such key.
     *
     * @param key the key
     * @return the ceiling key, or {@code null}
     * if there is no such key
     * @throws ClassCastException if key cannot be compared with the keys
     *            currently in the map
     * @throws NullPointerException if key is {@code null} and this map
     * does not support {@code null} keys
     */
    public K ceilingKey(K key);

    /**
     * Returns a key-value mapping associated with the greatest
     * key strictly less than the given key, or {@code null} if there is no
     * such entry.
     *
     * @param key the key
     * @return an Entry with greatest key less than the given
     * key, or {@code null} if there is no such Entry
     * @throws ClassCastException if key cannot be compared with the keys
     *            currently in the map
     * @throws NullPointerException if key is {@code null} and this map
     * does not support {@code null} keys
     */
    public Map.Entry<K,V> lowerEntry(K key);

    /**
     * Returns the greatest key strictly less than the given key, or
     * {@code null} if there is no such key.
     *
     * @param key the key
     * @return the greatest key less than the given
     * key, or {@code null} if there is no such key
     * @throws ClassCastException if key cannot be compared with the keys
     *            currently in the map
     * @throws NullPointerException if key is {@code null} and this map
     * does not support {@code null} keys
     */
    public K lowerKey(K key);

    /**
     * Returns a key-value mapping associated with the greatest key
     * less than or equal to the given key, or {@code null} if there
     * is no such entry.
     *
     * @param key the key
     * @return an Entry associated with floor of given key, or {@code null}
     * if there is no such Entry
     * @throws ClassCastException if key cannot be compared with the keys
     *            currently in the map
     * @throws NullPointerException if key is {@code null} and this map
     * does not support {@code null} keys
     */
    public Map.Entry<K,V> floorEntry(K key);

    /**
     * Returns the greatest key
     * less than or equal to the given key, or {@code null} if there
     * is no such key.
     *
     * @param key the key
     * @return the floor of given key, or {@code null} if there is no
     * such key
     * @throws ClassCastException if key cannot be compared with the keys
     *            currently in the map
     * @throws NullPointerException if key is {@code null} and this map
     * does not support {@code null} keys
     */
    public K floorKey(K key);

    /**
     * Returns a key-value mapping associated with the least key
     * strictly greater than the given key, or {@code null} if there
     * is no such entry.
     *
     * @param key the key
     * @return an Entry with least key greater than the given key, or
     * {@code null} if there is no such Entry
     * @throws ClassCastException if key cannot be compared with the keys
     *            currently in the map
     * @throws NullPointerException if key is {@code null} and this map
     * does not support {@code null} keys
     */
    public Map.Entry<K,V> higherEntry(K key);

    /**
     * Returns the least key strictly greater than the given key, or
     * {@code null} if there is no such key.
     *
     * @param key the key
     * @return the least key greater than the given key, or
     * {@code null} if there is no such key
     * @throws ClassCastException if key cannot be compared with the keys
     *            currently in the map
     * @throws NullPointerException if key is {@code null} and this map
     * does not support {@code null} keys
     */
    public K higherKey(K key);

    /**
     * Returns a key-value mapping associated with the least
     * key in this map, or {@code null} if the map is empty.
     *
     * @return an Entry with least key, or {@code null}
     * if the map is empty
     */
    public Map.Entry<K,V> firstEntry();

    /**
     * Returns a key-value mapping associated with the greatest
     * key in this map, or {@code null} if the map is empty.
     *
     * @return an Entry with greatest key, or {@code null}
     * if the map is empty
     */
    public Map.Entry<K,V> lastEntry();

    /**
     * Removes and returns a key-value mapping associated with
     * the least key in this map, or {@code null} if the map is empty.
     *
     * @return the removed first entry of this map, or {@code null}
     * if the map is empty
     */
    public Map.Entry<K,V> pollFirstEntry();

    /**
     * Removes and returns a key-value mapping associated with
     * the greatest key in this map, or {@code null} if the map is empty.
     *
     * @return the removed last entry of this map, or {@code null}
     * if the map is empty
     */
    public Map.Entry<K,V> pollLastEntry();

    /**
     * Returns a set view of the keys contained in this map, in
     * descending key order.  The set is backed by the map, so changes
     * to the map are reflected in the set, and vice-versa.  If the
     * map is modified while an iteration over the set is in progress
     * (except through the iterator's own {@code remove} operation),
     * the results of the iteration are undefined.  The set supports
     * element removal, which removes the corresponding mapping from
     * the map, via the {@code Iterator.remove}, {@code Set.remove},
     * {@code removeAll} {@code retainAll}, and {@code clear}
     * operations.  It does not support the add or {@code addAll}
     * operations.
     *
     * @return a set view of the keys contained in this map
     */
    Set<K> descendingKeySet();

    /**
     * Returns a set view of the mappings contained in this map, in
     * descending key order.  Each element in the returned set is a
     * {@code Map.Entry}.  The set is backed by the map, so changes to
     * the map are reflected in the set, and vice-versa.  If the map
     * is modified while an iteration over the set is in progress
     * (except through the iterator's own {@code remove} operation,
     * or through the {@code setValue} operation on a map entry
     * returned by the iterator) the results of the iteration are
     * undefined.  The set supports element removal, which removes the
     * corresponding mapping from the map, via the
     * {@code Iterator.remove}, {@code Set.remove},
     * {@code removeAll}, {@code retainAll} and {@code clear}
     * operations.  It does not support the {@code add} or
     * {@code addAll} operations.
     *
     * @return a set view of the mappings contained in this map
     */
    Set<Map.Entry<K, V>> descendingEntrySet();

    /**
     * Returns a view of the portion of this map whose keys range from
     * {@code fromKey}, inclusive, to {@code toKey}, exclusive.  (If
     * {@code fromKey} and {@code toKey} are equal, the returned sorted map
     * is empty.)  The returned sorted map is backed by this map, so changes
     * in the returned sorted map are reflected in this map, and vice-versa.
     *
     * @param fromKey low endpoint (inclusive) of the subMap
     * @param toKey high endpoint (exclusive) of the subMap
     *
     * @return a view of the portion of this map whose keys range from
     * {@code fromKey}, inclusive, to {@code toKey}, exclusive
     *
     * @throws ClassCastException if {@code fromKey} and
     * {@code toKey} cannot be compared to one another using this
     * map's comparator (or, if the map has no comparator, using
     * natural ordering)
     * @throws IllegalArgumentException if {@code fromKey} is greater
     * than {@code toKey}
     * @throws NullPointerException if {@code fromKey} or
     * {@code toKey} is {@code null} and this map does not support
     * {@code null} keys
     */
    public NavigableMap<K,V> subMap(K fromKey, K toKey);

    /**
     * Returns a view of the portion of this map whose keys are strictly less
     * than {@code toKey}.  The returned sorted map is backed by this map, so
     * changes in the returned sorted map are reflected in this map, and
     * vice-versa.
     * @param toKey high endpoint (exclusive) of the headMap
     * @return a view of the portion of this map whose keys are strictly
     *                less than {@code toKey}
     *
     * @throws ClassCastException if {@code toKey} is not compatible
     *         with this map's comparator (or, if the map has no comparator,
     *         if {@code toKey} does not implement {@code Comparable})
     * @throws NullPointerException if {@code toKey} is {@code null}
     * and this map does not support {@code null} keys
     */
    public NavigableMap<K,V> headMap(K toKey);

    /**
     * Returns a view of the portion of this map whose keys are
     * greater than or equal to {@code fromKey}.  The returned sorted
     * map is backed by this map, so changes in the returned sorted
     * map are reflected in this map, and vice-versa.
     * @param fromKey low endpoint (inclusive) of the tailMap
     * @return a view of the portion of this map whose keys are greater
     *                than or equal to {@code fromKey}
     * @throws ClassCastException if {@code fromKey} is not compatible
     *         with this map's comparator (or, if the map has no comparator,
     *         if {@code fromKey} does not implement {@code Comparable})
     * @throws NullPointerException if {@code fromKey} is {@code null}
     * and this map does not support {@code null} keys
     */
    public NavigableMap<K,V> tailMap(K fromKey);
}
Revision:	1.11
Committed:	Wed Jan 16 00:51:11 2013 UTC (11 years, 3 months ago) by jsr166
Branch:	MAIN
Changes since 1.10:	+91 -91 lines
Log Message:	<tt> -> {@code
#	Content
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/publicdomain/zero/1.0/
5	*/
6
7	package jsr166x;
8
9	import java.util.*;
10
11	/**
12	* A {@link SortedMap} extended with navigation methods returning the
13	* closest matches for given search targets. Methods
14	* {@code lowerEntry}, {@code floorEntry}, {@code ceilingEntry},
15	* and {@code higherEntry} return {@code Map.Entry} objects
16	* associated with keys respectively less than, less than or equal,
17	* greater than or equal, and greater than a given key, returning
18	* {@code null} if there is no such key. Similarly, methods
19	* {@code lowerKey}, {@code floorKey}, {@code ceilingKey}, and
20	* {@code higherKey} return only the associated keys. All of these
21	* methods are designed for locating, not traversing entries.
22	*
23	* <p>A {@code NavigableMap} may be viewed and traversed in either
24	* ascending or descending key order. The {@code Map} methods
25	* {@code keySet} and {@code entrySet} return ascending views, and
26	* the additional methods {@code descendingKeySet} and
27	* {@code descendingEntrySet} return descending views. The
28	* performance of ascending traversals is likely to be faster than
29	* descending traversals. Notice that it is possible to perform
30	* subrannge traversals in either direction using {@code SubMap}.
31	*
32	* <p>This interface additionally defines methods {@code firstEntry},
33	* {@code pollFirstEntry}, {@code lastEntry}, and
34	* {@code pollLastEntry} that return and/or remove the least and
35	* greatest mappings, if any exist, else returning {@code null}.
36	*
37	* <p>Implementations of entry-returning methods are expected to
38	* return {@code Map.Entry} pairs representing snapshots of mappings
39	* at the time they were produced, and thus generally do <em>not</em>
40	* support the optional {@code Entry.setValue} method. Note however
41	* that it is possible to change mappings in the associated map using
42	* method {@code put}.
43	*
44	* @author Doug Lea
45	* @param <K> the type of keys maintained by this map
46	* @param <V> the type of mapped values
47	*/
48	public interface NavigableMap<K,V> extends SortedMap<K,V> {
49	/**
50	* Returns a key-value mapping associated with the least key
51	* greater than or equal to the given key, or {@code null} if there is
52	* no such entry.
53	*
54	* @param key the key
55	* @return an Entry associated with ceiling of given key, or {@code null}
56	* if there is no such Entry
57	* @throws ClassCastException if key cannot be compared with the keys
58	* currently in the map
59	* @throws NullPointerException if key is {@code null} and this map
60	* does not support {@code null} keys
61	*/
62	public Map.Entry<K,V> ceilingEntry(K key);
63
64	/**
65	* Returns least key greater than or equal to the given key, or
66	* {@code null} if there is no such key.
67	*
68	* @param key the key
69	* @return the ceiling key, or {@code null}
70	* if there is no such key
71	* @throws ClassCastException if key cannot be compared with the keys
72	* currently in the map
73	* @throws NullPointerException if key is {@code null} and this map
74	* does not support {@code null} keys
75	*/
76	public K ceilingKey(K key);
77
78	/**
79	* Returns a key-value mapping associated with the greatest
80	* key strictly less than the given key, or {@code null} if there is no
81	* such entry.
82	*
83	* @param key the key
84	* @return an Entry with greatest key less than the given
85	* key, or {@code null} if there is no such Entry
86	* @throws ClassCastException if key cannot be compared with the keys
87	* currently in the map
88	* @throws NullPointerException if key is {@code null} and this map
89	* does not support {@code null} keys
90	*/
91	public Map.Entry<K,V> lowerEntry(K key);
92
93	/**
94	* Returns the greatest key strictly less than the given key, or
95	* {@code null} if there is no such key.
96	*
97	* @param key the key
98	* @return the greatest key less than the given
99	* key, or {@code null} if there is no such key
100	* @throws ClassCastException if key cannot be compared with the keys
101	* currently in the map
102	* @throws NullPointerException if key is {@code null} and this map
103	* does not support {@code null} keys
104	*/
105	public K lowerKey(K key);
106
107	/**
108	* Returns a key-value mapping associated with the greatest key
109	* less than or equal to the given key, or {@code null} if there
110	* is no such entry.
111	*
112	* @param key the key
113	* @return an Entry associated with floor of given key, or {@code null}
114	* if there is no such Entry
115	* @throws ClassCastException if key cannot be compared with the keys
116	* currently in the map
117	* @throws NullPointerException if key is {@code null} and this map
118	* does not support {@code null} keys
119	*/
120	public Map.Entry<K,V> floorEntry(K key);
121
122	/**
123	* Returns the greatest key
124	* less than or equal to the given key, or {@code null} if there
125	* is no such key.
126	*
127	* @param key the key
128	* @return the floor of given key, or {@code null} if there is no
129	* such key
130	* @throws ClassCastException if key cannot be compared with the keys
131	* currently in the map
132	* @throws NullPointerException if key is {@code null} and this map
133	* does not support {@code null} keys
134	*/
135	public K floorKey(K key);
136
137	/**
138	* Returns a key-value mapping associated with the least key
139	* strictly greater than the given key, or {@code null} if there
140	* is no such entry.
141	*
142	* @param key the key
143	* @return an Entry with least key greater than the given key, or
144	* {@code null} if there is no such Entry
145	* @throws ClassCastException if key cannot be compared with the keys
146	* currently in the map
147	* @throws NullPointerException if key is {@code null} and this map
148	* does not support {@code null} keys
149	*/
150	public Map.Entry<K,V> higherEntry(K key);
151
152	/**
153	* Returns the least key strictly greater than the given key, or
154	* {@code null} if there is no such key.
155	*
156	* @param key the key
157	* @return the least key greater than the given key, or
158	* {@code null} if there is no such key
159	* @throws ClassCastException if key cannot be compared with the keys
160	* currently in the map
161	* @throws NullPointerException if key is {@code null} and this map
162	* does not support {@code null} keys
163	*/
164	public K higherKey(K key);
165
166	/**
167	* Returns a key-value mapping associated with the least
168	* key in this map, or {@code null} if the map is empty.
169	*
170	* @return an Entry with least key, or {@code null}
171	* if the map is empty
172	*/
173	public Map.Entry<K,V> firstEntry();
174
175	/**
176	* Returns a key-value mapping associated with the greatest
177	* key in this map, or {@code null} if the map is empty.
178	*
179	* @return an Entry with greatest key, or {@code null}
180	* if the map is empty
181	*/
182	public Map.Entry<K,V> lastEntry();
183
184	/**
185	* Removes and returns a key-value mapping associated with
186	* the least key in this map, or {@code null} if the map is empty.
187	*
188	* @return the removed first entry of this map, or {@code null}
189	* if the map is empty
190	*/
191	public Map.Entry<K,V> pollFirstEntry();
192
193	/**
194	* Removes and returns a key-value mapping associated with
195	* the greatest key in this map, or {@code null} if the map is empty.
196	*
197	* @return the removed last entry of this map, or {@code null}
198	* if the map is empty
199	*/
200	public Map.Entry<K,V> pollLastEntry();
201
202	/**
203	* Returns a set view of the keys contained in this map, in
204	* descending key order. The set is backed by the map, so changes
205	* to the map are reflected in the set, and vice-versa. If the
206	* map is modified while an iteration over the set is in progress
207	* (except through the iterator's own {@code remove} operation),
208	* the results of the iteration are undefined. The set supports
209	* element removal, which removes the corresponding mapping from
210	* the map, via the {@code Iterator.remove}, {@code Set.remove},
211	* {@code removeAll} {@code retainAll}, and {@code clear}
212	* operations. It does not support the add or {@code addAll}
213	* operations.
214	*
215	* @return a set view of the keys contained in this map
216	*/
217	Set<K> descendingKeySet();
218
219	/**
220	* Returns a set view of the mappings contained in this map, in
221	* descending key order. Each element in the returned set is a
222	* {@code Map.Entry}. The set is backed by the map, so changes to
223	* the map are reflected in the set, and vice-versa. If the map
224	* is modified while an iteration over the set is in progress
225	* (except through the iterator's own {@code remove} operation,
226	* or through the {@code setValue} operation on a map entry
227	* returned by the iterator) the results of the iteration are
228	* undefined. The set supports element removal, which removes the
229	* corresponding mapping from the map, via the
230	* {@code Iterator.remove}, {@code Set.remove},
231	* {@code removeAll}, {@code retainAll} and {@code clear}
232	* operations. It does not support the {@code add} or
233	* {@code addAll} operations.
234	*
235	* @return a set view of the mappings contained in this map
236	*/
237	Set<Map.Entry<K, V>> descendingEntrySet();
238
239	/**
240	* Returns a view of the portion of this map whose keys range from
241	* {@code fromKey}, inclusive, to {@code toKey}, exclusive. (If
242	* {@code fromKey} and {@code toKey} are equal, the returned sorted map
243	* is empty.) The returned sorted map is backed by this map, so changes
244	* in the returned sorted map are reflected in this map, and vice-versa.
245	*
246	* @param fromKey low endpoint (inclusive) of the subMap
247	* @param toKey high endpoint (exclusive) of the subMap
248	*
249	* @return a view of the portion of this map whose keys range from
250	* {@code fromKey}, inclusive, to {@code toKey}, exclusive
251	*
252	* @throws ClassCastException if {@code fromKey} and
253	* {@code toKey} cannot be compared to one another using this
254	* map's comparator (or, if the map has no comparator, using
255	* natural ordering)
256	* @throws IllegalArgumentException if {@code fromKey} is greater
257	* than {@code toKey}
258	* @throws NullPointerException if {@code fromKey} or
259	* {@code toKey} is {@code null} and this map does not support
260	* {@code null} keys
261	*/
262	public NavigableMap<K,V> subMap(K fromKey, K toKey);
263
264	/**
265	* Returns a view of the portion of this map whose keys are strictly less
266	* than {@code toKey}. The returned sorted map is backed by this map, so
267	* changes in the returned sorted map are reflected in this map, and
268	* vice-versa.
269	* @param toKey high endpoint (exclusive) of the headMap
270	* @return a view of the portion of this map whose keys are strictly
271	* less than {@code toKey}
272	*
273	* @throws ClassCastException if {@code toKey} is not compatible
274	* with this map's comparator (or, if the map has no comparator,
275	* if {@code toKey} does not implement {@code Comparable})
276	* @throws NullPointerException if {@code toKey} is {@code null}
277	* and this map does not support {@code null} keys
278	*/
279	public NavigableMap<K,V> headMap(K toKey);
280
281	/**
282	* Returns a view of the portion of this map whose keys are
283	* greater than or equal to {@code fromKey}. The returned sorted
284	* map is backed by this map, so changes in the returned sorted
285	* map are reflected in this map, and vice-versa.
286	* @param fromKey low endpoint (inclusive) of the tailMap
287	* @return a view of the portion of this map whose keys are greater
288	* than or equal to {@code fromKey}
289	* @throws ClassCastException if {@code fromKey} is not compatible
290	* with this map's comparator (or, if the map has no comparator,
291	* if {@code fromKey} does not implement {@code Comparable})
292	* @throws NullPointerException if {@code fromKey} is {@code null}
293	* and this map does not support {@code null} keys
294	*/
295	public NavigableMap<K,V> tailMap(K fromKey);
296	}