/library/java/util/SortedMap.java
Java | 284 lines | 12 code | 11 blank | 261 comment | 0 complexity | b071a0ca06e11a00847e0fbd8c19e5bf MD5 | raw file
- /*
- * Copyright (c) 1998, 2006, Oracle and/or its affiliates. All rights reserved.
- * 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.
- */
- package java.util;
- /**
- * A {@link Map} that further provides a <em>total ordering</em> on its keys.
- * The map is ordered according to the {@linkplain Comparable natural
- * ordering} of its keys, or by a {@link Comparator} typically
- * provided at sorted map creation time. This order is reflected when
- * iterating over the sorted map's collection views (returned by the
- * {@code entrySet}, {@code keySet} and {@code values} methods).
- * Several additional operations are provided to take advantage of the
- * ordering. (This interface is the map analogue of {@link SortedSet}.)
- *
- * <p>All keys inserted into a sorted map must implement the {@code Comparable}
- * interface (or be accepted by the specified comparator). Furthermore, all
- * such keys must be <em>mutually comparable</em>: {@code k1.compareTo(k2)} (or
- * {@code comparator.compare(k1, k2)}) must not throw a
- * {@code ClassCastException} for any keys {@code k1} and {@code k2} in
- * the sorted map. Attempts to violate this restriction will cause the
- * offending method or constructor invocation to throw a
- * {@code ClassCastException}.
- *
- * <p>Note that the ordering maintained by a sorted map (whether or not an
- * explicit comparator is provided) must be <em>consistent with equals</em> if
- * the sorted map is to correctly implement the {@code Map} interface. (See
- * the {@code Comparable} interface or {@code Comparator} interface for a
- * precise definition of <em>consistent with equals</em>.) This is so because
- * the {@code Map} interface is defined in terms of the {@code equals}
- * operation, but a sorted map performs all key comparisons using its
- * {@code compareTo} (or {@code compare}) method, so two keys that are
- * deemed equal by this method are, from the standpoint of the sorted map,
- * equal. The behavior of a tree map <em>is</em> well-defined even if its
- * ordering is inconsistent with equals; it just fails to obey the general
- * contract of the {@code Map} interface.
- *
- * <p>All general-purpose sorted map implementation classes should provide four
- * "standard" constructors. It is not possible to enforce this recommendation
- * though as required constructors cannot be specified by interfaces. The
- * expected "standard" constructors for all sorted map implementations are:
- * <ol>
- * <li>A void (no arguments) constructor, which creates an empty sorted map
- * sorted according to the natural ordering of its keys.</li>
- * <li>A constructor with a single argument of type {@code Comparator}, which
- * creates an empty sorted map sorted according to the specified comparator.</li>
- * <li>A constructor with a single argument of type {@code Map}, which creates
- * a new map with the same key-value mappings as its argument, sorted
- * according to the keys' natural ordering.</li>
- * <li>A constructor with a single argument of type {@code SortedMap}, which
- * creates a new sorted map with the same key-value mappings and the same
- * ordering as the input sorted map.</li>
- * </ol>
- *
- * <p><strong>Note</strong>: several methods return submaps with restricted key
- * ranges. Such ranges are <em>half-open</em>, that is, they include their low
- * endpoint but not their high endpoint (where applicable). If you need a
- * <em>closed range</em> (which includes both endpoints), and the key type
- * allows for calculation of the successor of a given key, merely request
- * the subrange from {@code lowEndpoint} to
- * {@code successor(highEndpoint)}. For example, suppose that {@code m}
- * is a map whose keys are strings. The following idiom obtains a view
- * containing all of the key-value mappings in {@code m} whose keys are
- * between {@code low} and {@code high}, inclusive:<pre>
- * SortedMap<String, V> sub = m.subMap(low, high+"\0");</pre>
- *
- * A similar technique can be used to generate an <em>open range</em>
- * (which contains neither endpoint). The following idiom obtains a
- * view containing all of the key-value mappings in {@code m} whose keys
- * are between {@code low} and {@code high}, exclusive:<pre>
- * SortedMap<String, V> sub = m.subMap(low+"\0", high);</pre>
- *
- * <p>This interface is a member of the
- * <a href="{@docRoot}/../technotes/guides/collections/index.html">
- * Java Collections Framework</a>.
- *
- * @param <K> the type of keys maintained by this map
- * @param <V> the type of mapped values
- *
- * @author Josh Bloch
- * @see Map
- * @see TreeMap
- * @see SortedSet
- * @see Comparator
- * @see Comparable
- * @see Collection
- * @see ClassCastException
- * @since 1.2
- */
- public interface SortedMap<K,V> extends Map<K,V> {
- /**
- * Returns the comparator used to order the keys in this map, or
- * {@code null} if this map uses the {@linkplain Comparable
- * natural ordering} of its keys.
- *
- * @return the comparator used to order the keys in this map,
- * or {@code null} if this map uses the natural ordering
- * of its keys
- */
- Comparator<? super K> comparator();
- /**
- * Returns a view of the portion of this map whose keys range from
- * {@code fromKey}, inclusive, to {@code toKey}, exclusive. (If
- * {@code fromKey} and {@code toKey} are equal, the returned map
- * is empty.) 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.
- *
- * <p>The returned map will throw an {@code IllegalArgumentException}
- * on an attempt to insert a key outside its range.
- *
- * @param fromKey low endpoint (inclusive) of the keys in the returned map
- * @param toKey high endpoint (exclusive) of the keys in the returned map
- * @return a view of the portion of this map whose keys range from
- * {@code fromKey}, inclusive, to {@code toKey}, exclusive
- * @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
- */
- SortedMap<K,V> subMap(K fromKey, K toKey);
- /**
- * Returns a view of the portion of this map whose keys are
- * strictly less than {@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.
- *
- * <p>The returned map will throw an {@code IllegalArgumentException}
- * on an attempt to insert a key outside its range.
- *
- * @param toKey high endpoint (exclusive) of the keys in the returned map
- * @return a view of the portion of this map whose keys are strictly
- * less than {@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
- */
- SortedMap<K,V> headMap(K toKey);
- /**
- * Returns a view of the portion of this map whose keys are
- * greater than or equal to {@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.
- *
- * <p>The returned map will throw an {@code IllegalArgumentException}
- * on an attempt to insert a key outside its range.
- *
- * @param fromKey low endpoint (inclusive) of the keys in the returned map
- * @return a view of the portion of this map whose keys are greater
- * than or equal to {@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
- */
- SortedMap<K,V> tailMap(K fromKey);
- /**
- * Returns the first (lowest) key currently in this map.
- *
- * @return the first (lowest) key currently in this map
- * @throws NoSuchElementException if this map is empty
- */
- K firstKey();
- /**
- * Returns the last (highest) key currently in this map.
- *
- * @return the last (highest) key currently in this map
- * @throws NoSuchElementException if this map is empty
- */
- K lastKey();
- /**
- * Returns a {@link Set} view of the keys contained in this map.
- * The set's iterator returns the keys in ascending 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 {@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 set view of the keys contained in this map, sorted in
- * ascending order
- */
- Set<K> keySet();
- /**
- * Returns a {@link Collection} view of the values contained in this map.
- * The collection's iterator returns the values in ascending order
- * of the corresponding keys.
- * The collection is backed by the map, so changes to the map are
- * reflected in the collection, and vice-versa. If the map is
- * modified while an iteration over the collection is in progress
- * (except through the iterator's own {@code remove} operation),
- * the results of the iteration are undefined. The collection
- * supports element removal, which removes the corresponding
- * mapping from the map, via the {@code Iterator.remove},
- * {@code Collection.remove}, {@code removeAll},
- * {@code retainAll} and {@code clear} operations. It does not
- * support the {@code add} or {@code addAll} operations.
- *
- * @return a collection view of the values contained in this map,
- * sorted in ascending key order
- */
- Collection<V> values();
- /**
- * Returns a {@link Set} view of the mappings contained in this map.
- * The set's iterator returns the entries in ascending 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 {@code remove} operation, or through the
- * {@code 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 {@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 set view of the mappings contained in this map,
- * sorted in ascending key order
- */
- Set<Map.Entry<K, V>> entrySet();
- }