--- jsr166/src/main/java/util/NavigableSet.java 2005/07/20 02:18:52 1.12 +++ jsr166/src/main/java/util/NavigableSet.java 2012/11/18 18:03:10 1.26 @@ -1,57 +1,67 @@ /* - * 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; -import java.util.*; // for javadoc (till 6280605 is fixed) /** * A {@link SortedSet} extended with navigation methods reporting - * closest matches for given search targets. Methods lower, - * floor, ceiling, and higher return elements + * closest matches for given search targets. Methods {@code lower}, + * {@code floor}, {@code ceiling}, and {@code higher} return elements * respectively less than, less than or equal, greater than or equal, - * and greater than a given element, returning null if there is - * no such element. A NavigableSet may be viewed and traversed - * in either ascending or descending order. The Collection - * iterator method returns an ascending Iterator and - * the additional method descendingIterator returns a - * descending iterator. The performance of ascending traversals is - * likely to be faster than descending traversals. This interface - * additionally defines methods pollFirst and - * pollLast that return and remove the lowest and highest - * element, if one exists, else returning null. - * Methods navigableSubSet, navigableHeadSet, and - * navigableTailSet differ from the similarly named - * SortedSet methods only in their declared return types. - * Subsets of any NavigableSet must implement the - * NavigableSet interface. + * and greater than a given element, returning {@code null} if there + * is no such element. A {@code NavigableSet} may be accessed and + * traversed in either ascending or descending order. The {@code + * descendingSet} method returns a view of the set 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. This interface additionally defines methods + * {@code pollFirst} and {@code pollLast} that return and remove the + * lowest and highest element, if one exists, else returning {@code + * null}. Methods {@code subSet}, {@code headSet}, + * and {@code tailSet} differ from the like-named {@code + * SortedSet} methods in accepting additional arguments describing + * whether lower and upper bounds are inclusive versus exclusive. + * Subsets of any {@code NavigableSet} must implement the {@code + * NavigableSet} interface. * - *
The return values of navigation methods may be ambiguous in - * implementations that permit null elements. However, even + *
The return values of navigation methods may be ambiguous in + * implementations that permit {@code null} elements. However, even * in this case the result can be disambiguated by checking - * contains(null). To avoid such issues, implementations of + * {@code contains(null)}. To avoid such issues, implementations of * this interface are encouraged to not permit insertion of - * null elements. (Note that sorted sets of {@link - * Comparable} elements intrinsically do not permit null.) + * {@code null} elements. (Note that sorted sets of {@link + * Comparable} elements intrinsically do not permit {@code null}.) + * + *
Methods + * {@link #subSet(Object, Object) subSet(E, E)}, + * {@link #headSet(Object) headSet(E)}, and + * {@link #tailSet(Object) tailSet(E)} + * are specified to return {@code SortedSet} to allow existing + * implementations of {@code SortedSet} to be compatibly retrofitted to + * implement {@code NavigableSet}, but extensions and implementations + * of this interface are encouraged to override these methods to return + * {@code NavigableSet}. * *
This interface is a member of the
- *
+ *
* Java Collections Framework.
*
* @author Doug Lea
+ * @author Josh Bloch
* @param The returned set has an ordering equivalent to
+ * {@link Collections#reverseOrder(Comparator) Collections.reverseOrder}(comparator()).
+ * The expression {@code s.descendingSet().descendingSet()} returns a
+ * view of {@code s} essentially equivalent to {@code s}.
+ *
+ * @return a reverse order view of this set
+ */
+ NavigableSet The returned set will throw an IllegalArgumentException
+ * The returned set will throw an {@code IllegalArgumentException}
* on an attempt to insert an element outside its range.
*
- * @param fromElement low endpoint (inclusive) of the returned set
- * @param toElement high endpoint (exclusive) of the returned set
+ * @param fromElement low endpoint of the returned set
+ * @param fromInclusive {@code true} if the low endpoint
+ * is to be included in the returned view
+ * @param toElement high endpoint of the returned set
+ * @param toInclusive {@code true} if the high endpoint
+ * is to be included in the returned view
* @return a view of the portion of this set whose elements range from
- * fromElement, inclusive, to toElement, exclusive
- * @throws ClassCastException if fromElement and
- * toElement cannot be compared to one another using this
+ * {@code fromElement}, inclusive, to {@code toElement}, exclusive
+ * @throws ClassCastException if {@code fromElement} and
+ * {@code toElement} cannot be compared to one another using this
* set's comparator (or, if the set has no comparator, using
* natural ordering). Implementations may, but are not required
- * to, throw this exception if fromElement or
- * toElement cannot be compared to elements currently in
+ * to, throw this exception if {@code fromElement} or
+ * {@code toElement} cannot be compared to elements currently in
* the set.
- * @throws NullPointerException if fromElement or
- * toElement is null and this set does
+ * @throws NullPointerException if {@code fromElement} or
+ * {@code toElement} is null and this set does
* not permit null elements
- * @throws IllegalArgumentException if fromElement is
- * greater than toElement; or if this set itself
- * has a restricted range, and fromElement or
- * toElement lies outside the bounds of the range.
- */
- NavigableSet The returned set will throw an IllegalArgumentException
+ * The returned set will throw an {@code IllegalArgumentException}
* on an attempt to insert an element outside its range.
*
- * @param toElement high endpoint (exclusive) of the returned set
- * @return a view of the portion of this set whose elements are strictly
- * less than toElement
- * @throws ClassCastException if toElement is not compatible
+ * @param toElement high endpoint of the returned set
+ * @param inclusive {@code true} if the high endpoint
+ * is to be included in the returned view
+ * @return a view of the portion of this set whose elements are less than
+ * (or equal to, if {@code inclusive} is true) {@code toElement}
+ * @throws ClassCastException if {@code toElement} is not compatible
* with this set's comparator (or, if the set has no comparator,
- * if toElement does not implement {@link Comparable}).
+ * if {@code toElement} does not implement {@link Comparable}).
* Implementations may, but are not required to, throw this
- * exception if toElement cannot be compared to elements
+ * exception if {@code toElement} cannot be compared to elements
* currently in the set.
- * @throws NullPointerException if toElement is null and
+ * @throws NullPointerException if {@code toElement} is null and
* this set does not permit null elements
* @throws IllegalArgumentException if this set itself has a
- * restricted range, and toElement lies outside the
+ * restricted range, and {@code toElement} lies outside the
* bounds of the range
*/
- NavigableSet The returned set will throw an IllegalArgumentException
+ * The returned set will throw an {@code IllegalArgumentException}
* on an attempt to insert an element outside its range.
*
- * @param fromElement low endpoint (inclusive) of the returned set
+ * @param fromElement low endpoint of the returned set
+ * @param inclusive {@code true} if the low endpoint
+ * is to be included in the returned view
* @return a view of the portion of this set whose elements are greater
- * than or equal to fromElement
- * @throws ClassCastException if fromElement is not compatible
+ * than or equal to {@code fromElement}
+ * @throws ClassCastException if {@code fromElement} is not compatible
* with this set's comparator (or, if the set has no comparator,
- * if fromElement does not implement {@link Comparable}).
+ * if {@code fromElement} does not implement {@link Comparable}).
* Implementations may, but are not required to, throw this
- * exception if fromElement cannot be compared to elements
+ * exception if {@code fromElement} cannot be compared to elements
* currently in the set.
- * @throws NullPointerException if fromElement is null
+ * @throws NullPointerException if {@code fromElement} is null
* and this set does not permit null elements
* @throws IllegalArgumentException if this set itself has a
- * restricted range, and fromElement lies outside the
+ * restricted range, and {@code fromElement} lies outside the
* bounds of the range
*/
- NavigableSet Equivalent to {@code subSet(fromElement, true, toElement, false)}.
+ *
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ * @throws IllegalArgumentException {@inheritDoc}
+ */
+ SortedSet Equivalent to {@code headSet(toElement, false)}.
+ *
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ * @throws IllegalArgumentException {@inheritDoc}
+na */
+ SortedSet Equivalent to {@code tailSet(fromElement, true)}.
+ *
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException {@inheritDoc}
+ * @throws IllegalArgumentException {@inheritDoc}
+ */
+ SortedSet