/*
 * Copyright (C) 2020 MicroEJ Corp. - EDC compliance and optimizations.
 * 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/
 */

package java.util;

import ej.annotation.Nullable;

/**
 * A {@link SortedMap} extended with navigation methods returning the closest matches for given search targets. Methods
 * {@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 {@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.
 *
 * <p>
 * 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.
 *
 * <p>
 * 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}.
 *
 * <p>
 * Implementations of entry-returning methods are expected to return {@code Map.Entry} pairs representing snapshots of
 * mappings at the time they were produced, and thus generally do <em>not</em> support the optional
 * {@code Entry.setValue} method. Note however that it is possible to change mappings in the associated map using method
 * {@code put}.
 *
 * <p>
 * Methods {@link #subMap(Object, Object) subMap(K, K)}, {@link #headMap(Object) headMap(K)}, and
 * {@link #tailMap(Object) tailMap(K)} are specified to return {@code SortedMap} to allow existing implementations of
 * {@code SortedMap} to be compatibly retrofitted to implement {@code NavigableMap}, but extensions and implementations
 * of this interface are encouraged to override these methods to return {@code NavigableMap}. Similarly,
 * {@link #keySet()} can be overriden to return {@code NavigableSet}.
 *
 * <p>
 * This interface is a member of the <a href="{@docRoot}/../technotes/guides/collections/index.html"> Java Collections
 * Framework</a>.
 *
 * @author Doug Lea
 * @author Josh Bloch
 * @param <K>
 *            the type of keys maintained by this map
 * @param <V>
 *            the type of mapped values
 * @since 1.6
 */
public interface NavigableMap<K, V> extends SortedMap<K, V> {
	/**
	 * 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
	 */
	@Nullable
	Map.Entry<K, V> lowerEntry(K 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 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
	 */
	@Nullable
	K lowerKey(K key);

	/**
	 * 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
	 */
	@Nullable
	Map.Entry<K, V> floorEntry(K 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 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
	 */
	@Nullable
	K floorKey(K key);

	/**
	 * 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
	 */
	@Nullable
	Map.Entry<K, V> 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
	 */
	@Nullable
	K ceilingKey(K key);

	/**
	 * Returns a key-value mapping associated with the least key 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
	 */
	@Nullable
	Map.Entry<K, V> higherEntry(K key);

	/**
	 * Returns the least key strictly greater than the given key, or {@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
	 */
	@Nullable
	K higherKey(K key);

	/**
	 * Returns a key-value mapping associated with the least 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
	 */
	@Nullable
	Map.Entry<K, V> firstEntry();

	/**
	 * Returns a key-value mapping associated with the greatest 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
	 */
	@Nullable
	Map.Entry<K, V> lastEntry();

	/**
	 * Removes and returns a key-value mapping associated with 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
	 */
	@Nullable
	Map.Entry<K, V> pollFirstEntry();

	/**
	 * Removes and returns a key-value mapping associated with the greatest key in this map, or {@code null} if the map
	 * is empty.
	 *
	 * @return the removed last entry of this map, or {@code null} if this map is empty
	 */
	@Nullable
	Map.Entry<K, V> pollLastEntry();

	/**
	 * Returns a reverse order view of the mappings contained in this map. 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 either map is in progress (except through the iterator's own {@code remove}
	 * operation), the results of the iteration are undefined.
	 *
	 * <p>
	 * The returned map has an ordering equivalent to
	 * <tt>{@link Collections#reverseOrder(Comparator) Collections.reverseOrder}(comparator())</tt>. The expression
	 * {@code m.descendingMap().descendingMap()} returns a view of {@code m} essentially equivalent to {@code m}.
	 *
	 * @return a reverse order view of this map
	 */
	NavigableMap<K, V> descendingMap();

	/**
	 * Returns a {@link NavigableSet} 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 navigable set view of the keys in this map
	 */
	NavigableSet<K> navigableKeySet();

	/**
	 * Returns a reverse order {@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 {@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 reverse order navigable set view of the keys in this map
	 */
	NavigableSet<K> descendingKeySet();

	/**
	 * Returns a view of the portion of this map whose keys range from {@code fromKey} to {@code toKey}. If
	 * {@code fromKey} and {@code toKey} are equal, the returned map is empty unless {@code fromInclusive} and
	 * {@code toInclusive} 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.
	 *
	 * <p>
	 * 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
	 *            {@code true} if the low endpoint is to be included in the returned view
	 * @param toKey
	 *            high endpoint of the keys in the returned map
	 * @param toInclusive
	 *            {@code true} if the high endpoint is to be included in the returned view
	 * @return a view of the portion of this map whose keys range from {@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<K, V> 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.
	 *
	 * <p>
	 * 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
	 *            {@code true} if the high endpoint 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
	 *             {@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<K, V> 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.
	 *
	 * <p>
	 * 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
	 *            {@code true} if the low endpoint 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
	 *             {@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<K, V> tailMap(K fromKey, boolean inclusive);

	/**
	 * {@inheritDoc}
	 *
	 * <p>
	 * Equivalent to {@code subMap(fromKey, true, toKey, false)}.
	 *
	 * @throws ClassCastException
	 *             {@inheritDoc}
	 * @throws NullPointerException
	 *             {@inheritDoc}
	 * @throws IllegalArgumentException
	 *             {@inheritDoc}
	 */
	@Override
	SortedMap<K, V> subMap(K fromKey, K toKey);

	/**
	 * {@inheritDoc}
	 *
	 * <p>
	 * Equivalent to {@code headMap(toKey, false)}.
	 *
	 * @throws ClassCastException
	 *             {@inheritDoc}
	 * @throws NullPointerException
	 *             {@inheritDoc}
	 * @throws IllegalArgumentException
	 *             {@inheritDoc}
	 */
	@Override
	SortedMap<K, V> headMap(K toKey);

	/**
	 * {@inheritDoc}
	 *
	 * <p>
	 * Equivalent to {@code tailMap(fromKey, true)}.
	 *
	 * @throws ClassCastException
	 *             {@inheritDoc}
	 * @throws NullPointerException
	 *             {@inheritDoc}
	 * @throws IllegalArgumentException
	 *             {@inheritDoc}
	 */
	@Override
	SortedMap<K, V> tailMap(K fromKey);
}