--- jsr166/src/main/java/util/NavigableMap.java 2005/05/03 02:52:07 1.7
+++ jsr166/src/main/java/util/NavigableMap.java 2006/04/20 20:34:37 1.15
@@ -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
*/
@@ -9,296 +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 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 {@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 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 {@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
* @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.
+ * 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 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.
+ * @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
*/
- Map.Entry ceilingEntry(K key);
+ Map.Entry lowerEntry(K key);
/**
- * Returns least key greater than or equal to the given key, or
- * null if there is no such 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 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.
+ * @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
*/
- K ceilingKey(K key);
+ K lowerKey(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.
+ * 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 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.
+ * @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
*/
- Map.Entry lowerEntry(K key);
+ Map.Entry floorEntry(K key);
/**
- * Returns the greatest key strictly less than the given key, or
- * null if there is no such 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 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.
+ * @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
*/
- K lowerKey(K key);
+ K floorKey(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.
+ * 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 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.
+ * @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
*/
- Map.Entry floorEntry(K key);
+ Map.Entry ceilingEntry(K key);
/**
- * Returns the greatest key
- * less than or equal to the given key, or null if there
- * is no such 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 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.
+ * @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 floorKey(K key);
+ 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.
+ * strictly greater than the given key, or {@code null} if there
+ * is no such key.
*
- * @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.
+ * @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
*/
Map.Entry higherEntry(K key);
/**
* Returns the least key strictly greater than the given key, or
- * null if there is no such key.
+ * {@code 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.
+ * @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
*/
K higherKey(K key);
/**
* Returns a key-value mapping associated with the least
- * key in this map, or null if the map is empty.
+ * key in this map, or {@code null} if the map is empty.
*
- * @return an Entry with least key, or null
- * if the map is empty.
+ * @return an entry with the least key,
+ * or {@code null} if this map is empty
*/
Map.Entry firstEntry();
/**
* Returns a key-value mapping associated with the greatest
- * key in this map, or null if the map is empty.
+ * key in this map, or {@code null} if the map is empty.
*
- * @return an Entry with greatest key, or null
- * if the map is empty.
+ * @return an entry with the greatest key,
+ * or {@code null} if this map is empty
*/
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.
+ * the least key in this map, or {@code null} if the map is empty.
*
- * @return the removed first entry of this map, or null
- * if the map is empty.
+ * @return the removed first entry of this map,
+ * or {@code null} if this map is empty
*/
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.
+ * the greatest key in this map, or {@code null} if the map is empty.
*
- * @return the removed last entry of this map, or null
- * if the map is empty.
+ * @return the removed last entry of this map,
+ * or {@code null} if this map is empty
*/
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.
- *
- * @return a set view of the keys contained in this map.
- */
- Set descendingKeySet();
-
- /**
- * 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 set, 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
- * navigable map is empty.) The returned navigable map is backed
- * by this map, so changes in the returned navigable 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 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 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 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.
- */
- NavigableMap navigableSubMap(K fromKey, K toKey);
-
- /**
- * Returns a view of the portion of this map whose keys are strictly less
- * than toKey. The returned navigable map is backed by this map, so
- * changes in the returned navigable 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.
- *
- * @throws ClassCastException if toKey is not compatible
+ * {@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.
+ *
+ * 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 true if the high endpoint ({@code toKey}) is
+ * to be included in the 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.
- */
- NavigableMap navigableHeadMap(K toKey);
-
- /**
- * Returns a view of the portion of this map whose keys are
- * greater than or equal to fromKey. The returned navigable
- * map is backed by this map, so changes in the returned navigable
- * 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 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
*/
- NavigableMap navigableTailMap(K fromKey);
+ NavigableMap tailMap(K fromKey, boolean inclusive);
}