--- jsr166/src/main/java/util/NavigableMap.java 2005/03/08 17:52:02 1.2 +++ jsr166/src/main/java/util/NavigableMap.java 2006/04/21 03:53:57 1.17 @@ -1,6 +1,6 @@ /* - * Written by Doug Lea with assistance from members of JCP JSR-166 - * Expert Group and released to the public domain, as explained at + * 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/licenses/publicdomain */ @@ -9,286 +9,342 @@ 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 + * {@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 - * 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 + * {@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 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 SubMap. - * - *

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. + *

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 Map.Entry pairs representing snapshots of mappings + * 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}. + * + *

This interface is a member of the + * + * Java Collections Framework. * * @author Doug Lea + * @author Josh Bloch * @param the type of keys maintained by this map - * @param the type of mapped values + * @param the type of mapped values + * @since 1.6 */ public interface NavigableMap extends SortedMap { /** - * Returns a key-value mapping associated with the least key - * greater than or equal to the given key, or null if there is - * no such entry. - * - * @param key the key. - * @return an Entry associated with ceiling of given key, or 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 null and this map - * does not support null keys. - */ - public Map.Entry ceilingEntry(K key); - - /** - * Returns least key greater than or equal to the given key, or - * null if there is no such key. - * - * @param key the key. - * @return the ceiling key, or 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 null and this map - * does not support null keys. + * Returns a key-value mapping associated with the greatest key + * strictly less than the given key, or {@code null} if there is + * no such key. + * + * @param key the key + * @return an entry with the greatest key less than {@code key}, + * or {@code null} if there is no such key + * @throws ClassCastException if the specified key cannot be compared + * with the keys currently in the map + * @throws NullPointerException if the specified key is null + * and this map does not permit null keys */ - public K ceilingKey(K key); + Map.Entry lowerEntry(K key); /** - * Returns a key-value mapping associated with the greatest - * key strictly less than the given key, or null if there is no - * such entry. - * - * @param key the key. - * @return an Entry with greatest key less than the given - * key, or 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 null and this map - * does not support null keys. + * 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 {@code key}, + * or {@code null} if there is no such key + * @throws ClassCastException if the specified key cannot be compared + * with the keys currently in the map + * @throws NullPointerException if the specified key is null + * and this map does not permit null keys */ - public Map.Entry lowerEntry(K key); + K lowerKey(K key); /** - * Returns the greatest key strictly less than the given key, or - * null if there is no such key. - * - * @param key the key. - * @return the greatest key less than the given - * key, or 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 null and this map - * does not support null keys. + * 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 key. + * + * @param key the key + * @return an entry with the greatest key less than or equal to + * {@code key}, or {@code null} if there is no such key + * @throws ClassCastException if the specified key cannot be compared + * with the keys currently in the map + * @throws NullPointerException if the specified key is null + * and this map does not permit null keys */ - public K lowerKey(K key); + Map.Entry floorEntry(K key); /** - * Returns a key-value mapping associated with the greatest key - * less than or equal to the given key, or null if there - * is no such entry. - * - * @param key the key. - * @return an Entry associated with floor of given key, or 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 null and this map - * does not support null keys. + * 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 greatest key less than or equal to {@code key}, + * or {@code null} if there is no such key + * @throws ClassCastException if the specified key cannot be compared + * with the keys currently in the map + * @throws NullPointerException if the specified key is null + * and this map does not permit null keys */ - public Map.Entry floorEntry(K key); + K floorKey(K key); /** - * Returns the greatest key - * less than or equal to the given key, or null if there - * is no such key. - * - * @param key the key. - * @return the floor of given key, or 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 null and this map - * does not support null keys. + * 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 key. + * + * @param key the key + * @return an entry with the least key greater than or equal to + * {@code key}, or {@code null} if there is no such key + * @throws ClassCastException if the specified key cannot be compared + * with the keys currently in the map + * @throws NullPointerException if the specified key is null + * and this map does not permit null keys */ - public K floorKey(K key); + Map.Entry ceilingEntry(K key); + + /** + * Returns the 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 least key greater than or equal to {@code key}, + * or {@code null} if there is no such key + * @throws ClassCastException if the specified key cannot be compared + * with the keys currently in the map + * @throws NullPointerException if the specified key is null + * and this map does not permit null keys + */ + K ceilingKey(K key); /** * Returns a key-value mapping associated with the least key - * strictly greater than the given key, or null if there - * is no such entry. - * - * @param key the key. - * @return an Entry with least key greater than the given key, or - * 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 null and this map - * does not support null keys. + * strictly greater than the given key, or {@code null} if there + * is no such key. + * + * @param key the key + * @return an entry with the least key greater than {@code key}, + * or {@code null} if there is no such key + * @throws ClassCastException if the specified key cannot be compared + * with the keys currently in the map + * @throws NullPointerException if the specified key is null + * and this map does not permit null keys */ - public Map.Entry higherEntry(K key); + Map.Entry higherEntry(K key); /** * Returns the least key strictly greater than the given key, or - * null if there is no such key. - * - * @param key the key. - * @return the least key greater than the given key, or - * 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 null and this map - * does not support null keys. + * {@code null} if there is no such key. + * + * @param key the key + * @return the least key greater than {@code key}, + * or {@code null} if there is no such key + * @throws ClassCastException if the specified key cannot be compared + * with the keys currently in the map + * @throws NullPointerException if the specified key is null + * and this map does not permit null keys */ - public K higherKey(K key); + K higherKey(K key); /** * Returns a key-value mapping associated with the least - * key in this map, or null if the map is empty. - * - * @return an Entry with least key, or null - * if the map is empty. + * key in this map, or {@code null} if the map is empty. + * + * @return an entry with the least key, + * or {@code null} if this map is empty */ - public Map.Entry firstEntry(); + Map.Entry firstEntry(); /** * Returns a key-value mapping associated with the greatest - * key in this map, or null if the map is empty. - * - * @return an Entry with greatest key, or null - * if the map is empty. + * key in this map, or {@code null} if the map is empty. + * + * @return an entry with the greatest key, + * or {@code null} if this map is empty */ - public Map.Entry lastEntry(); + Map.Entry lastEntry(); /** * Removes and returns a key-value mapping associated with - * the least key in this map, or null if the map is empty. - * - * @return the removed first entry of this map, or null - * if the map is empty. + * 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 this map is empty */ - public Map.Entry pollFirstEntry(); + Map.Entry pollFirstEntry(); /** * Removes and returns a key-value mapping associated with - * the greatest key in this map, or null if the map is empty. - * - * @return the removed last entry of this map, or null - * if the map is empty. - */ - public Map.Entry 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 remove operation), - * the results of the iteration are undefined. The set supports - * element removal, which removes the corresponding mapping from - * the map, via the Iterator.remove, Set.remove, - * removeAll retainAll, and clear - * operations. It does not support the add or addAll - * operations. + * the greatest key in this map, or {@code null} if the map is empty. * - * @return a set view of the keys contained in this map. + * @return the removed last entry of this map, + * or {@code null} if this map is empty */ - Set descendingKeySet(); + Map.Entry pollLastEntry(); /** - * Returns a set view of the mappings contained in this map, in - * descending key order. Each element in the returned set is a - * 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 remove operation, - * or through the 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 + * Returns a {@link NavigableMap} view of the mappings contained in this + * map in descending order. The descending map is backed by this map, so + * changes to the map are reflected in the descending map, and vice-versa. + * If either map is modified while an iteration over a collection view of + * the other map is in progress (except through the iterator's own + * {@code remove} operation), the results of the iteration are undefined. + * + * @return a navigable map view of the mappings contained in this map, + * sorted in descending order + */ + NavigableMap descendingMap(); + + /** + * Returns a navigable set view of the keys contained in this navigable + * map. 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 {@code add} or + * {@code addAll} operations. + * + * @return a navigable set view of the keys contained in this navigable map + */ + NavigableSet navigableKeySet(); + + /** + * Returns a {@link NavigableSet} view of the keys contained in this map. + * The set's iterator returns the keys in descending 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 remove operation), the results of + * the iteration are undefined. The set supports element removal, + * which removes the corresponding mapping from the map, via the * Iterator.remove, Set.remove, - * removeAll, retainAll and clear - * operations. It does not support the add or - * addAll operations. + * removeAll, retainAll, and clear + * operations. It does not support the add or addAll + * operations. * - * @return a set view of the mappings contained in this map. + * @return a set view of the keys contained in this map, sorted in + * descending order */ - Set> descendingEntrySet(); + NavigableSet descendingKeySet(); /** * Returns a view of the portion of this map whose keys range from - * fromKey, inclusive, to toKey, exclusive. (If - * fromKey and 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. + * {@code fromKey} to {@code toKey}. If {@code fromKey} and + * {@code toKey} are equal, the returned map is empty unless + * {@code fromExclusive} and {@code toExclusive} 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. * + *

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 true if the low endpoint ({@code fromKey}) is + * to be included in the returned view + * @param toKey high endpoint of the keys in the returned map + * @param toInclusive true if the high endpoint ({@code toKey}) 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. + * {@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 subMap(K fromKey, boolean fromInclusive, + K toKey, boolean toInclusive); + + /** + * Returns a view of the portion of this map whose keys are less than (or + * equal to, if {@code inclusive} is true) {@code toKey}. 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. * - * @throws ClassCastException if fromKey and - * 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 fromKey is greater - * than toKey. - * @throws NullPointerException if fromKey or - * toKey is null and this map does not support - * null keys. - */ - public NavigableMap subMap(K fromKey, K toKey); - - /** - * Returns a view of the portion of this map whose keys are strictly less - * than 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 toKey. + *

The returned map will throw an {@code IllegalArgumentException} + * on an attempt to insert a key outside its range. * - * @throws ClassCastException if toKey is not compatible + * @param toKey high endpoint of the keys in the returned map + * @param inclusive true if the high endpoint ({@code toKey}) 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 Comparable). - * @throws NullPointerException if toKey is null - * and this map does not support null keys. - */ - public NavigableMap headMap(K toKey); - - /** - * Returns a view of the portion of this map whose keys are - * greater than or equal to 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 fromKey. - * @throws ClassCastException if fromKey is not compatible + * 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 headMap(K toKey, boolean inclusive); + + /** + * Returns a view of the portion of this map whose keys are greater than (or + * equal to, if {@code inclusive} is true) {@code fromKey}. 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. + * + *

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 true if the low endpoint ({@code fromKey}) 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 Comparable). - * @throws NullPointerException if fromKey is null - * and this map does not support null keys. + * 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 */ - public NavigableMap tailMap(K fromKey); + NavigableMap tailMap(K fromKey, boolean inclusive); }