| /* |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * This file is available under and governed by the GNU General Public |
| * License version 2 only, as published by the Free Software Foundation. |
| * However, the following notice accompanied the original version of this |
| * file: |
| * |
| * 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/ |
| */ |
| |
| // BEGIN android-note |
| // removed link to collections framework docs |
| // END android-note |
| |
| package java.util; |
| |
| /** |
| * A {@link SortedSet} extended with navigation methods reporting |
| * closest matches for given search targets. Methods {@link #lower}, |
| * {@link #floor}, {@link #ceiling}, and {@link #higher} return elements |
| * respectively less than, less than or equal, greater than or equal, |
| * and greater than a given element, returning {@code null} if there |
| * is no such element. |
| * |
| * <p>A {@code NavigableSet} may be accessed and traversed in either |
| * ascending or descending order. The {@link #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 {@link |
| * #pollFirst} and {@link #pollLast} that return and remove the lowest |
| * and highest element, if one exists, else returning {@code null}. |
| * Methods |
| * {@link #subSet(Object, boolean, Object, boolean) subSet(E, boolean, E, boolean)}, |
| * {@link #headSet(Object, boolean) headSet(E, boolean)}, and |
| * {@link #tailSet(Object, boolean) tailSet(E, boolean)} |
| * 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. |
| * |
| * <p>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 |
| * {@code contains(null)}. To avoid such issues, implementations of |
| * this interface are encouraged to <em>not</em> permit insertion of |
| * {@code null} elements. (Note that sorted sets of {@link |
| * Comparable} elements intrinsically do not permit {@code null}.) |
| * |
| * <p>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}. |
| * |
| * @author Doug Lea |
| * @author Josh Bloch |
| * @param <E> the type of elements maintained by this set |
| * @since 1.6 |
| */ |
| public interface NavigableSet<E> extends SortedSet<E> { |
| /** |
| * Returns the greatest element in this set strictly less than the |
| * given element, or {@code null} if there is no such element. |
| * |
| * @param e the value to match |
| * @return the greatest element less than {@code e}, |
| * or {@code null} if there is no such element |
| * @throws ClassCastException if the specified element cannot be |
| * compared with the elements currently in the set |
| * @throws NullPointerException if the specified element is null |
| * and this set does not permit null elements |
| */ |
| E lower(E e); |
| |
| /** |
| * Returns the greatest element in this set less than or equal to |
| * the given element, or {@code null} if there is no such element. |
| * |
| * @param e the value to match |
| * @return the greatest element less than or equal to {@code e}, |
| * or {@code null} if there is no such element |
| * @throws ClassCastException if the specified element cannot be |
| * compared with the elements currently in the set |
| * @throws NullPointerException if the specified element is null |
| * and this set does not permit null elements |
| */ |
| E floor(E e); |
| |
| /** |
| * Returns the least element in this set greater than or equal to |
| * the given element, or {@code null} if there is no such element. |
| * |
| * @param e the value to match |
| * @return the least element greater than or equal to {@code e}, |
| * or {@code null} if there is no such element |
| * @throws ClassCastException if the specified element cannot be |
| * compared with the elements currently in the set |
| * @throws NullPointerException if the specified element is null |
| * and this set does not permit null elements |
| */ |
| E ceiling(E e); |
| |
| /** |
| * Returns the least element in this set strictly greater than the |
| * given element, or {@code null} if there is no such element. |
| * |
| * @param e the value to match |
| * @return the least element greater than {@code e}, |
| * or {@code null} if there is no such element |
| * @throws ClassCastException if the specified element cannot be |
| * compared with the elements currently in the set |
| * @throws NullPointerException if the specified element is null |
| * and this set does not permit null elements |
| */ |
| E higher(E e); |
| |
| /** |
| * Retrieves and removes the first (lowest) element, |
| * or returns {@code null} if this set is empty. |
| * |
| * @return the first element, or {@code null} if this set is empty |
| */ |
| E pollFirst(); |
| |
| /** |
| * Retrieves and removes the last (highest) element, |
| * or returns {@code null} if this set is empty. |
| * |
| * @return the last element, or {@code null} if this set is empty |
| */ |
| E pollLast(); |
| |
| /** |
| * Returns an iterator over the elements in this set, in ascending order. |
| * |
| * @return an iterator over the elements in this set, in ascending order |
| */ |
| Iterator<E> iterator(); |
| |
| /** |
| * Returns a reverse order view of the elements contained in this set. |
| * The descending set is backed by this set, so changes to the set are |
| * reflected in the descending set, and vice-versa. If either set is |
| * modified while an iteration over either set is in progress (except |
| * through the iterator's own {@code remove} operation), the results of |
| * the iteration are undefined. |
| * |
| * <p>The returned set has an ordering equivalent to |
| * {@link Collections#reverseOrder(Comparator) Collections.reverseOrder}{@code (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<E> descendingSet(); |
| |
| /** |
| * Returns an iterator over the elements in this set, in descending order. |
| * Equivalent in effect to {@code descendingSet().iterator()}. |
| * |
| * @return an iterator over the elements in this set, in descending order |
| */ |
| Iterator<E> descendingIterator(); |
| |
| /** |
| * Returns a view of the portion of this set whose elements range from |
| * {@code fromElement} to {@code toElement}. If {@code fromElement} and |
| * {@code toElement} are equal, the returned set is empty unless {@code |
| * fromInclusive} and {@code toInclusive} are both true. The returned set |
| * is backed by this set, so changes in the returned set are reflected in |
| * this set, and vice-versa. The returned set supports all optional set |
| * operations that this set supports. |
| * |
| * <p>The returned set will throw an {@code IllegalArgumentException} |
| * on an attempt to insert an element outside its range. |
| * |
| * @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 |
| * {@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 {@code fromElement} or |
| * {@code toElement} cannot be compared to elements currently in |
| * the set. |
| * @throws NullPointerException if {@code fromElement} or |
| * {@code toElement} is null and this set does |
| * not permit null elements |
| * @throws IllegalArgumentException if {@code fromElement} is |
| * greater than {@code toElement}; or if this set itself |
| * has a restricted range, and {@code fromElement} or |
| * {@code toElement} lies outside the bounds of the range. |
| */ |
| NavigableSet<E> subSet(E fromElement, boolean fromInclusive, |
| E toElement, boolean toInclusive); |
| |
| /** |
| * Returns a view of the portion of this set whose elements are less than |
| * (or equal to, if {@code inclusive} is true) {@code toElement}. The |
| * returned set is backed by this set, so changes in the returned set are |
| * reflected in this set, and vice-versa. The returned set supports all |
| * optional set operations that this set supports. |
| * |
| * <p>The returned set will throw an {@code IllegalArgumentException} |
| * on an attempt to insert an element outside its range. |
| * |
| * @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 {@code toElement} does not implement {@link Comparable}). |
| * Implementations may, but are not required to, throw this |
| * exception if {@code toElement} cannot be compared to elements |
| * currently in the set. |
| * @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 {@code toElement} lies outside the |
| * bounds of the range |
| */ |
| NavigableSet<E> headSet(E toElement, boolean inclusive); |
| |
| /** |
| * Returns a view of the portion of this set whose elements are greater |
| * than (or equal to, if {@code inclusive} is true) {@code fromElement}. |
| * The returned set is backed by this set, so changes in the returned set |
| * are reflected in this set, and vice-versa. The returned set supports |
| * all optional set operations that this set supports. |
| * |
| * <p>The returned set will throw an {@code IllegalArgumentException} |
| * on an attempt to insert an element outside its range. |
| * |
| * @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 {@code fromElement} |
| * @throws ClassCastException if {@code fromElement} is not compatible |
| * with this set's comparator (or, if the set has no comparator, |
| * if {@code fromElement} does not implement {@link Comparable}). |
| * Implementations may, but are not required to, throw this |
| * exception if {@code fromElement} cannot be compared to elements |
| * currently in the set. |
| * @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 {@code fromElement} lies outside the |
| * bounds of the range |
| */ |
| NavigableSet<E> tailSet(E fromElement, boolean inclusive); |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>Equivalent to {@code subSet(fromElement, true, toElement, false)}. |
| * |
| * @throws ClassCastException {@inheritDoc} |
| * @throws NullPointerException {@inheritDoc} |
| * @throws IllegalArgumentException {@inheritDoc} |
| */ |
| SortedSet<E> subSet(E fromElement, E toElement); |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>Equivalent to {@code headSet(toElement, false)}. |
| * |
| * @throws ClassCastException {@inheritDoc} |
| * @throws NullPointerException {@inheritDoc} |
| * @throws IllegalArgumentException {@inheritDoc} |
| */ |
| SortedSet<E> headSet(E toElement); |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>Equivalent to {@code tailSet(fromElement, true)}. |
| * |
| * @throws ClassCastException {@inheritDoc} |
| * @throws NullPointerException {@inheritDoc} |
| * @throws IllegalArgumentException {@inheritDoc} |
| */ |
| SortedSet<E> tailSet(E fromElement); |
| |
| /** |
| * {@inheritDoc} |
| * |
| * @implSpec |
| * If this set is not empty, the implementation in this interface returns the result of calling |
| * the {@code pollFirst} method. Otherwise, it throws {@code NoSuchElementException}. |
| * |
| * @throws NoSuchElementException {@inheritDoc} |
| * @throws UnsupportedOperationException {@inheritDoc} |
| * @since 21 |
| */ |
| default E removeFirst() { |
| if (this.isEmpty()) { |
| throw new NoSuchElementException(); |
| } else { |
| return this.pollFirst(); |
| } |
| } |
| |
| /** |
| * {@inheritDoc} |
| * |
| * @implSpec |
| * If this set is not empty, the implementation in this interface returns the result of calling |
| * the {@code pollLast} method. Otherwise, it throws {@code NoSuchElementException}. |
| * |
| * @throws NoSuchElementException {@inheritDoc} |
| * @throws UnsupportedOperationException {@inheritDoc} |
| * @since 21 |
| */ |
| default E removeLast() { |
| if (this.isEmpty()) { |
| throw new NoSuchElementException(); |
| } else { |
| return this.pollLast(); |
| } |
| } |
| |
| /** |
| * {@inheritDoc} |
| * <p> |
| * This method is equivalent to {@link #descendingSet descendingSet}. |
| * |
| * @implSpec |
| * The implementation in this interface returns the result of calling the |
| * {@code descendingSet} method. |
| * |
| * @return a reverse-ordered view of this collection, as a {@code NavigableSet} |
| * @since 21 |
| */ |
| default NavigableSet<E> reversed() { |
| return this.descendingSet(); |
| } |
| } |
