--- jsr166/src/main/java/util/NavigableMap.java 2005/05/18 01:39:35 1.9 +++ jsr166/src/main/java/util/NavigableMap.java 2018/10/01 00:10:53 1.32 @@ -1,7 +1,7 @@ /* - * 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/licenses/publicdomain + * Written by Doug Lea and Josh Bloch 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 java.util; @@ -9,45 +9,58 @@ package java.util; /** * A {@link SortedMap} extended with navigation methods returning the * closest matches for given search targets. Methods - * lowerEntry, floorEntry, ceilingEntry, - * and higherEntry return Map.Entry objects + * {@link #lowerEntry}, {@link #floorEntry}, {@link #ceilingEntry}, + * and {@link #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 - * null if there is no such key. Similarly, methods - * lowerKey, floorKey, ceilingKey, and - * higherKey return only the associated keys. All of these + * {@code null} if there is no such key. Similarly, methods + * {@link #lowerKey}, {@link #floorKey}, {@link #ceilingKey}, and + * {@link #higherKey} return only the associated keys. All of these * methods are designed for locating, not traversing entries. * - *
A NavigableMap may be viewed and traversed in either - * ascending or descending key order. The Map methods - * keySet and entrySet return ascending views, and - * the additional methods descendingKeySet and - * descendingEntrySet return descending views. The - * performance of ascending traversals is likely to be faster than - * descending traversals. Notice that it is possible to perform - * subrange traversals in either direction using navigableSubMap. - * Methods navigableSubMap, navigableHeadMap, and - * navigableTailMap differ from the similarly named - * SortedMap methods only in that the returned maps - * are guaranteed to obey the NavigableMap interface. + *
A {@code NavigableMap} may be accessed and traversed in either + * ascending or descending key order. The {@link #descendingMap} + * method returns a view of the map with the senses of all relational + * and directional methods inverted. The performance of ascending + * operations and views is likely to be faster than that of descending + * ones. Methods + * {@link #subMap(Object, boolean, Object, boolean) subMap(K, boolean, K, boolean)}, + * {@link #headMap(Object, boolean) headMap(K, boolean)}, and + * {@link #tailMap(Object, boolean) tailMap(K, boolean)} + * differ from the like-named {@code SortedMap} methods in accepting + * additional arguments describing whether lower and upper bounds are + * inclusive versus exclusive. Submaps of any {@code NavigableMap} + * must implement the {@code NavigableMap} interface. * - *
This interface additionally defines methods firstEntry, - * pollFirstEntry, lastEntry, and - * pollLastEntry that return and/or remove the least and - * greatest mappings, if any exist, else returning null. + *
This interface additionally defines methods {@link #firstEntry}, + * {@link #pollFirstEntry}, {@link #lastEntry}, and + * {@link #pollLastEntry} that return and/or remove the least and + * greatest mappings, if any exist, else returning {@code null}. * - *
Implementations of entry-returning methods are expected to - * return Map.Entry pairs representing snapshots of mappings + *
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 not - * support the optional Entry.setValue method. Note however + * support the optional {@code Entry.setValue} method. Note however * that it is possible to change mappings in the associated map using - * method put. + * method {@code put}. + * + *
Methods + * {@link #subMap(Object, Object) subMap(K, K)}, + * {@link #headMap(Object) headMap(K)}, and + * {@link #tailMap(Object) tailMap(K)} + * are specified to return {@code SortedMap} to allow existing + * implementations of {@code SortedMap} to be compatibly retrofitted to + * implement {@code NavigableMap}, but extensions and implementations + * of this interface are encouraged to override these methods to return + * {@code NavigableMap}. Similarly, + * {@link #keySet()} can be overridden to return {@link NavigableSet}. * *
This interface is a member of the
- *
+ *
* Java Collections Framework.
*
* @author Doug Lea
+ * @author Josh Bloch
* @param The returned map has an ordering equivalent to
+ * {@link Collections#reverseOrder(Comparator) Collections.reverseOrder}{@code (comparator())}.
+ * The expression {@code m.descendingMap().descendingMap()} returns a
+ * view of {@code m} essentially equivalent to {@code m}.
+ *
+ * @return a reverse order view of this map
+ */
+ NavigableMap The returned map will throw an IllegalArgumentException
- * on an attempt to insert a key outside its range.
+ * {@code fromKey} to {@code toKey}. If {@code fromKey} and
+ * {@code toKey} are equal, the returned map is empty unless
+ * {@code fromInclusive} and {@code toInclusive} are both true. The
+ * returned map is backed by this map, so changes in the returned map are
+ * reflected in this map, and vice-versa. The returned map supports all
+ * optional map operations that this map supports.
*
- * @param fromKey low endpoint (inclusive) of the keys in the returned map
- * @param toKey high endpoint (exclusive) of the keys in the returned map
+ * The returned map will throw an {@code IllegalArgumentException}
+ * on an attempt to insert a key outside of its range, or to construct a
+ * submap either of whose endpoints lie outside its range.
+ *
+ * @param fromKey low endpoint of the keys in the returned map
+ * @param fromInclusive {@code true} if the low endpoint
+ * is to be included in the returned view
+ * @param toKey high endpoint of the keys in the returned map
+ * @param toInclusive {@code true} if the high endpoint
+ * is to be included in the returned view
* @return a view of the portion of this map whose keys range from
- * fromKey, inclusive, to toKey, exclusive
- * @throws ClassCastException if fromKey and toKey
+ * {@code fromKey} to {@code toKey}
+ * @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).
* Implementations may, but are not required to, throw this
- * exception if fromKey or toKey
+ * exception if {@code fromKey} or {@code toKey}
* cannot be compared to keys currently in the map.
- * @throws NullPointerException if fromKey or toKey
+ * @throws NullPointerException if {@code fromKey} or {@code toKey}
* is null and this map does not permit null keys
- * @throws IllegalArgumentException if fromKey is greater than
- * toKey; or if this map itself has a restricted
- * range, and fromKey or toKey lies
+ * @throws IllegalArgumentException if {@code fromKey} is greater than
+ * {@code toKey}; or if this map itself has a restricted
+ * range, and {@code fromKey} or {@code toKey} lies
* outside the bounds of the range
*/
- NavigableMap The returned map will throw an IllegalArgumentException
+ * The returned map will throw an {@code IllegalArgumentException}
* on an attempt to insert a key outside its range.
*
- * @param toKey high endpoint (exclusive) of the keys in the returned map
- * @return a view of the portion of this map whose keys are strictly
- * less than toKey
- * @throws ClassCastException if toKey is not compatible
+ * @param toKey high endpoint of the keys in the returned map
+ * @param inclusive {@code true} if the high endpoint
+ * is to be included in the returned view
+ * @return a view of the portion of this map whose keys are less than
+ * (or equal to, if {@code inclusive} is true) {@code toKey}
+ * @throws ClassCastException if {@code toKey} is not compatible
* with this map's comparator (or, if the map has no comparator,
- * if toKey does not implement {@link Comparable}).
+ * if {@code toKey} does not implement {@link Comparable}).
* Implementations may, but are not required to, throw this
- * exception if toKey cannot be compared to keys
+ * exception if {@code toKey} cannot be compared to keys
* currently in the map.
- * @throws NullPointerException if toKey is null
+ * @throws NullPointerException if {@code toKey} is null
* and this map does not permit null keys
* @throws IllegalArgumentException if this map itself has a
- * restricted range, and toKey lies outside the
+ * restricted range, and {@code toKey} lies outside the
* bounds of the range
*/
- NavigableMap The returned map will throw an IllegalArgumentException
+ * The returned map will throw an {@code IllegalArgumentException}
* on an attempt to insert a key outside its range.
*
- * @param fromKey low endpoint (inclusive) of the keys in the returned map
- * @return a view of the portion of this map whose keys are greater
- * than or equal to fromKey
- * @throws ClassCastException if fromKey is not compatible
+ * @param fromKey low endpoint of the keys in the returned map
+ * @param inclusive {@code true} if the low endpoint
+ * is to be included in the returned view
+ * @return a view of the portion of this map whose keys are greater than
+ * (or equal to, if {@code inclusive} is true) {@code fromKey}
+ * @throws ClassCastException if {@code fromKey} is not compatible
* with this map's comparator (or, if the map has no comparator,
- * if fromKey does not implement {@link Comparable}).
+ * if {@code fromKey} does not implement {@link Comparable}).
* Implementations may, but are not required to, throw this
- * exception if fromKey cannot be compared to keys
+ * exception if {@code fromKey} cannot be compared to keys
* currently in the map.
- * @throws NullPointerException if fromKey is null
+ * @throws NullPointerException if {@code fromKey} is null
* and this map does not permit null keys
* @throws IllegalArgumentException if this map itself has a
- * restricted range, and fromKey lies outside the
+ * restricted range, and {@code fromKey} lies outside the
* bounds of the range
*/
- NavigableMap Equivalent to {@code subMap(fromKey, true, toKey, false)}.
+ *
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ * @throws IllegalArgumentException {@inheritDoc}
+ */
+ SortedMap Equivalent to {@code headMap(toKey, false)}.
+ *
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ * @throws IllegalArgumentException {@inheritDoc}
+ */
+ SortedMap Equivalent to {@code tailMap(fromKey, true)}.
+ *
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ * @throws IllegalArgumentException {@inheritDoc}
+ */
+ SortedMap