/* * 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; // BEGIN android-note // removed link to collections framework docs // END android-note /** * 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. * *
A {@code NavigableMap} may be accessed and traversed in either * ascending or descending key order. The {@code 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 {@code subMap}, {@code headMap}, * and {@code tailMap} 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 {@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}. * *
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 {@code Entry.setValue} method. Note however * that it is possible to change mappings in the associated map using * 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 {@code NavigableSet}.
*
* @author Doug Lea
* @author Josh Bloch
* @param The returned map has an ordering equivalent to
* {@link Collections#reverseOrder(Comparator) Collections.reverseOrder}(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 {@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
* {@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 {@code fromKey} or {@code toKey}
* cannot be compared to keys currently in the map.
* @throws NullPointerException if {@code fromKey} or {@code toKey}
* is null and this map does not permit null keys
* @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 {@code IllegalArgumentException}
* on an attempt to insert a key outside its range.
*
* @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 {@code toKey} does not implement {@link Comparable}).
* Implementations may, but are not required to, throw this
* exception if {@code toKey} cannot be compared to keys
* currently in the map.
* @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 {@code toKey} lies outside the
* bounds of the range
*/
NavigableMap The returned map will throw an {@code IllegalArgumentException}
* on an attempt to insert a key outside its range.
*
* @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 {@code fromKey} does not implement {@link Comparable}).
* Implementations may, but are not required to, throw this
* exception if {@code fromKey} cannot be compared to keys
* currently in the map.
* @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 {@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