/*
	* Copyright (C) 2002-2019 Sebastiano Vigna
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	*     http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
package it.unimi.dsi.fastutil.objects;
import it.unimi.dsi.fastutil.objects.ObjectBidirectionalIterable;
import it.unimi.dsi.fastutil.objects.ObjectBidirectionalIterator;
import it.unimi.dsi.fastutil.objects.ObjectSortedSet;
import it.unimi.dsi.fastutil.objects.ObjectSortedSets;
import it.unimi.dsi.fastutil.objects.Object2ObjectSortedMap.FastSortedEntrySet;
import java.util.Comparator;
import java.util.Map;
import java.util.SortedMap;
import java.util.NoSuchElementException;
A class providing static methods and objects that do useful things with
type-specific sorted maps.
See Also:
Collections/**
 * A class providing static methods and objects that do useful things with
 * type-specific sorted maps.
 *
 * @see java.util.Collections
 */
public final class Object2ObjectSortedMaps {
	private Object2ObjectSortedMaps() {
	}
	
Returns a comparator for entries based on a given comparator on keys.
Params:
comparator – 
           a comparator on keys.
Returns:
the associated comparator on entries./**
	 * Returns a comparator for entries based on a given comparator on keys.
	 *
	 * @param comparator
	 *            a comparator on keys.
	 * @return the associated comparator on entries.
	 */
	public static <K> Comparator<? super Map.Entry<K, ?>> entryComparator(final Comparator<? super K> comparator) {
		return (Comparator<Map.Entry<K, ?>>) (x, y) -> comparator.compare((x.getKey()), (y.getKey()));
	}
	
Returns a bidirectional iterator that will be 
fast, if possible, on the entry set of the provided map. 
Params:
map – 
           a map from which we will try to extract a (fast) bidirectional
           iterator on the entry set.
Returns:
a bidirectional iterator on the entry set of the given map that will
        be fast, if possible.
Since:
8.0.0/**
	 * Returns a bidirectional iterator that will be {@linkplain FastSortedEntrySet
	 * fast}, if possible, on the {@linkplain Map#entrySet() entry set} of the
	 * provided {@code map}.
	 * 
	 * @param map
	 *            a map from which we will try to extract a (fast) bidirectional
	 *            iterator on the entry set.
	 * @return a bidirectional iterator on the entry set of the given map that will
	 *         be fast, if possible.
	 * @since 8.0.0
	 */
	@SuppressWarnings("unchecked")
	public static <K, V> ObjectBidirectionalIterator<Object2ObjectMap.Entry<K, V>> fastIterator(
			Object2ObjectSortedMap<K, V> map) {
		final ObjectSortedSet<Object2ObjectMap.Entry<K, V>> entries = map.object2ObjectEntrySet();
		return entries instanceof Object2ObjectSortedMap.FastSortedEntrySet
				? ((Object2ObjectSortedMap.FastSortedEntrySet<K, V>) entries).fastIterator()
				: entries.iterator();
	}
	
Returns an iterable yielding a bidirectional iterator that will be fast, if possible, on the entry set of the provided map. 
Params:
map – 
           a map from which we will try to extract an iterable yielding a
           (fast) bidirectional iterator on the entry set.
Returns:
an iterable yielding a bidirectional iterator on the entry set of the
        given map that will be fast, if possible.
Since:
8.0.0/**
	 * Returns an iterable yielding a bidirectional iterator that will be
	 * {@linkplain FastSortedEntrySet fast}, if possible, on the
	 * {@linkplain Map#entrySet() entry set} of the provided {@code map}.
	 * 
	 * @param map
	 *            a map from which we will try to extract an iterable yielding a
	 *            (fast) bidirectional iterator on the entry set.
	 * @return an iterable yielding a bidirectional iterator on the entry set of the
	 *         given map that will be fast, if possible.
	 * @since 8.0.0
	 */
	@SuppressWarnings("unchecked")
	public static <K, V> ObjectBidirectionalIterable<Object2ObjectMap.Entry<K, V>> fastIterable(
			Object2ObjectSortedMap<K, V> map) {
		final ObjectSortedSet<Object2ObjectMap.Entry<K, V>> entries = map.object2ObjectEntrySet();
		return entries instanceof Object2ObjectSortedMap.FastSortedEntrySet
				? ((Object2ObjectSortedMap.FastSortedEntrySet<K, V>) entries)::fastIterator
				: entries;
	}
	
An immutable class representing an empty type-specific sorted map.

This class may be useful to implement your own in case you subclass a
type-specific sorted map.
/**
	 * An immutable class representing an empty type-specific sorted map.
	 *
	 * <p>
	 * This class may be useful to implement your own in case you subclass a
	 * type-specific sorted map.
	 */
	public static class EmptySortedMap<K, V> extends Object2ObjectMaps.EmptyMap<K, V>
			implements
				Object2ObjectSortedMap<K, V>,
				java.io.Serializable,
				Cloneable {
		private static final long serialVersionUID = -7046029254386353129L;
		protected EmptySortedMap() {
		}
		@Override
		public Comparator<? super K> comparator() {
			return null;
		}
		@SuppressWarnings("unchecked")
		@Override
		public ObjectSortedSet<Object2ObjectMap.Entry<K, V>> object2ObjectEntrySet() {
			return ObjectSortedSets.EMPTY_SET;
		}
		
{@inheritDoc} /** {@inheritDoc} */
		@Override
		@SuppressWarnings("unchecked")
		public ObjectSortedSet<Map.Entry<K, V>> entrySet() {
			return ObjectSortedSets.EMPTY_SET;
		}
		@SuppressWarnings("unchecked")
		@Override
		public ObjectSortedSet<K> keySet() {
			return ObjectSortedSets.EMPTY_SET;
		}
		@SuppressWarnings("unchecked")
		@Override
		public Object2ObjectSortedMap<K, V> subMap(final K from, final K to) {
			return EMPTY_MAP;
		}
		@SuppressWarnings("unchecked")
		@Override
		public Object2ObjectSortedMap<K, V> headMap(final K to) {
			return EMPTY_MAP;
		}
		@SuppressWarnings("unchecked")
		@Override
		public Object2ObjectSortedMap<K, V> tailMap(final K from) {
			return EMPTY_MAP;
		}
		@Override
		public K firstKey() {
			throw new NoSuchElementException();
		}
		@Override
		public K lastKey() {
			throw new NoSuchElementException();
		}
	}
	
An empty sorted map (immutable). It is serializable and cloneable.
/**
	 * An empty sorted map (immutable). It is serializable and cloneable.
	 */
	@SuppressWarnings("rawtypes")
	public static final EmptySortedMap EMPTY_MAP = new EmptySortedMap();
	
Returns an empty sorted map (immutable). It is serializable and cloneable.
 This method provides a typesafe access to EMPTY_MAP. 
Returns:
an empty sorted map (immutable)./**
	 * Returns an empty sorted map (immutable). It is serializable and cloneable.
	 *
	 * <p>
	 * This method provides a typesafe access to {@link #EMPTY_MAP}.
	 * 
	 * @return an empty sorted map (immutable).
	 */
	@SuppressWarnings("unchecked")
	public static <K, V> Object2ObjectSortedMap<K, V> emptyMap() {
		return EMPTY_MAP;
	}
	
An immutable class representing a type-specific singleton sorted map.

This class may be useful to implement your own in case you subclass a
type-specific sorted map.
/**
	 * An immutable class representing a type-specific singleton sorted map.
	 *
	 * <p>
	 * This class may be useful to implement your own in case you subclass a
	 * type-specific sorted map.
	 */
	public static class Singleton<K, V> extends Object2ObjectMaps.Singleton<K, V>
			implements
				Object2ObjectSortedMap<K, V>,
				java.io.Serializable,
				Cloneable {
		private static final long serialVersionUID = -7046029254386353129L;
		protected final Comparator<? super K> comparator;
		protected Singleton(final K key, final V value, Comparator<? super K> comparator) {
			super(key, value);
			this.comparator = comparator;
		}
		protected Singleton(final K key, final V value) {
			this(key, value, null);
		}
		@SuppressWarnings("unchecked")
		final int compare(final K k1, final K k2) {
			return comparator == null ? (((Comparable<K>) (k1)).compareTo(k2)) : comparator.compare(k1, k2);
		}
		@Override
		public Comparator<? super K> comparator() {
			return comparator;
		}
		@SuppressWarnings("unchecked")
		@Override
		public ObjectSortedSet<Object2ObjectMap.Entry<K, V>> object2ObjectEntrySet() {
			if (entries == null)
				entries = ObjectSortedSets.singleton(new AbstractObject2ObjectMap.BasicEntry<>(key, value),
						entryComparator(comparator));
			return (ObjectSortedSet<Object2ObjectMap.Entry<K, V>>) entries;
		}
		
{@inheritDoc} /** {@inheritDoc} */
		@Override
		@SuppressWarnings({"rawtypes", "unchecked"})
		public ObjectSortedSet<Map.Entry<K, V>> entrySet() {
			return (ObjectSortedSet) object2ObjectEntrySet();
		}
		@Override
		public ObjectSortedSet<K> keySet() {
			if (keys == null)
				keys = ObjectSortedSets.singleton(key, comparator);
			return (ObjectSortedSet<K>) keys;
		}
		@SuppressWarnings("unchecked")
		@Override
		public Object2ObjectSortedMap<K, V> subMap(final K from, final K to) {
			if (compare(from, key) <= 0 && compare(key, to) < 0)
				return this;
			return EMPTY_MAP;
		}
		@SuppressWarnings("unchecked")
		@Override
		public Object2ObjectSortedMap<K, V> headMap(final K to) {
			if (compare(key, to) < 0)
				return this;
			return EMPTY_MAP;
		}
		@SuppressWarnings("unchecked")
		@Override
		public Object2ObjectSortedMap<K, V> tailMap(final K from) {
			if (compare(from, key) <= 0)
				return this;
			return EMPTY_MAP;
		}
		@Override
		public K firstKey() {
			return key;
		}
		@Override
		public K lastKey() {
			return key;
		}
	}
	
Returns a type-specific immutable sorted map containing only the specified
pair. The returned sorted map is serializable and cloneable.

Note that albeit the returned map is immutable, its default return value may
be changed.
Params:
key – 
           the only key of the returned sorted map.
value – 
           the only value of the returned sorted map.
Returns:
a type-specific immutable sorted map containing just the pair &lt;key,value&gt;./**
	 * Returns a type-specific immutable sorted map containing only the specified
	 * pair. The returned sorted map is serializable and cloneable.
	 *
	 * <p>
	 * Note that albeit the returned map is immutable, its default return value may
	 * be changed.
	 *
	 * @param key
	 *            the only key of the returned sorted map.
	 * @param value
	 *            the only value of the returned sorted map.
	 * @return a type-specific immutable sorted map containing just the pair
	 *         {@code &lt;key,value&gt;}.
	 */
	public static <K, V> Object2ObjectSortedMap<K, V> singleton(final K key, V value) {
		return new Singleton<>((key), (value));
	}
	
RETURNS a type-specific immutable sorted map containing only the specified
pair. The returned sorted map is serializable and cloneable.

Note that albeit the returned map is immutable, its default return value may
be changed.
Params:
key – 
           the only key of the returned sorted map.
value – 
           the only value of the returned sorted map.
comparator – 
           the comparator to use in the returned sorted map.
Returns:
a type-specific immutable sorted map containing just the pair &lt;key,value&gt;./**
	 * RETURNS a type-specific immutable sorted map containing only the specified
	 * pair. The returned sorted map is serializable and cloneable.
	 *
	 * <p>
	 * Note that albeit the returned map is immutable, its default return value may
	 * be changed.
	 *
	 * @param key
	 *            the only key of the returned sorted map.
	 * @param value
	 *            the only value of the returned sorted map.
	 * @param comparator
	 *            the comparator to use in the returned sorted map.
	 * @return a type-specific immutable sorted map containing just the pair
	 *         {@code &lt;key,value&gt;}.
	 */
	public static <K, V> Object2ObjectSortedMap<K, V> singleton(final K key, V value,
			Comparator<? super K> comparator) {
		return new Singleton<>((key), (value), comparator);
	}
	
A synchronized wrapper class for sorted maps. /** A synchronized wrapper class for sorted maps. */
	public static class SynchronizedSortedMap<K, V> extends Object2ObjectMaps.SynchronizedMap<K, V>
			implements
				Object2ObjectSortedMap<K, V>,
				java.io.Serializable {
		private static final long serialVersionUID = -7046029254386353129L;
		protected final Object2ObjectSortedMap<K, V> sortedMap;
		protected SynchronizedSortedMap(final Object2ObjectSortedMap<K, V> m, final Object sync) {
			super(m, sync);
			sortedMap = m;
		}
		protected SynchronizedSortedMap(final Object2ObjectSortedMap<K, V> m) {
			super(m);
			sortedMap = m;
		}
		@Override
		public Comparator<? super K> comparator() {
			synchronized (sync) {
				return sortedMap.comparator();
			}
		}
		@Override
		public ObjectSortedSet<Object2ObjectMap.Entry<K, V>> object2ObjectEntrySet() {
			if (entries == null)
				entries = ObjectSortedSets.synchronize(sortedMap.object2ObjectEntrySet(), sync);
			return (ObjectSortedSet<Object2ObjectMap.Entry<K, V>>) entries;
		}
		
{@inheritDoc} /** {@inheritDoc} */
		@Override
		@SuppressWarnings({"rawtypes", "unchecked"})
		public ObjectSortedSet<Map.Entry<K, V>> entrySet() {
			return (ObjectSortedSet) object2ObjectEntrySet();
		}
		@Override
		public ObjectSortedSet<K> keySet() {
			if (keys == null)
				keys = ObjectSortedSets.synchronize(sortedMap.keySet(), sync);
			return (ObjectSortedSet<K>) keys;
		}
		@Override
		public Object2ObjectSortedMap<K, V> subMap(final K from, final K to) {
			return new SynchronizedSortedMap<>(sortedMap.subMap(from, to), sync);
		}
		@Override
		public Object2ObjectSortedMap<K, V> headMap(final K to) {
			return new SynchronizedSortedMap<>(sortedMap.headMap(to), sync);
		}
		@Override
		public Object2ObjectSortedMap<K, V> tailMap(final K from) {
			return new SynchronizedSortedMap<>(sortedMap.tailMap(from), sync);
		}
		@Override
		public K firstKey() {
			synchronized (sync) {
				return sortedMap.firstKey();
			}
		}
		@Override
		public K lastKey() {
			synchronized (sync) {
				return sortedMap.lastKey();
			}
		}
	}
	
Returns a synchronized type-specific sorted map backed by the given
type-specific sorted map.
Params:
m – 
           the sorted map to be wrapped in a synchronized sorted map.
See Also:
Collections.synchronizedSortedMap(SortedMap<Object,Object>)
Returns:
a synchronized view of the specified sorted map./**
	 * Returns a synchronized type-specific sorted map backed by the given
	 * type-specific sorted map.
	 *
	 * @param m
	 *            the sorted map to be wrapped in a synchronized sorted map.
	 * @return a synchronized view of the specified sorted map.
	 * @see java.util.Collections#synchronizedSortedMap(SortedMap)
	 */
	public static <K, V> Object2ObjectSortedMap<K, V> synchronize(final Object2ObjectSortedMap<K, V> m) {
		return new SynchronizedSortedMap<>(m);
	}
	
Returns a synchronized type-specific sorted map backed by the given
type-specific sorted map, using an assigned object to synchronize.
Params:
m – 
           the sorted map to be wrapped in a synchronized sorted map.
sync – 
           an object that will be used to synchronize the access to the
           sorted sorted map.
See Also:
Collections.synchronizedSortedMap(SortedMap<Object,Object>)
Returns:
a synchronized view of the specified sorted map./**
	 * Returns a synchronized type-specific sorted map backed by the given
	 * type-specific sorted map, using an assigned object to synchronize.
	 *
	 * @param m
	 *            the sorted map to be wrapped in a synchronized sorted map.
	 * @param sync
	 *            an object that will be used to synchronize the access to the
	 *            sorted sorted map.
	 * @return a synchronized view of the specified sorted map.
	 * @see java.util.Collections#synchronizedSortedMap(SortedMap)
	 */
	public static <K, V> Object2ObjectSortedMap<K, V> synchronize(final Object2ObjectSortedMap<K, V> m,
			final Object sync) {
		return new SynchronizedSortedMap<>(m, sync);
	}
	
An unmodifiable wrapper class for sorted maps. /** An unmodifiable wrapper class for sorted maps. */
	public static class UnmodifiableSortedMap<K, V> extends Object2ObjectMaps.UnmodifiableMap<K, V>
			implements
				Object2ObjectSortedMap<K, V>,
				java.io.Serializable {
		private static final long serialVersionUID = -7046029254386353129L;
		protected final Object2ObjectSortedMap<K, V> sortedMap;
		protected UnmodifiableSortedMap(final Object2ObjectSortedMap<K, V> m) {
			super(m);
			sortedMap = m;
		}
		@Override
		public Comparator<? super K> comparator() {
			return sortedMap.comparator();
		}
		@Override
		public ObjectSortedSet<Object2ObjectMap.Entry<K, V>> object2ObjectEntrySet() {
			if (entries == null)
				entries = ObjectSortedSets.unmodifiable(sortedMap.object2ObjectEntrySet());
			return (ObjectSortedSet<Object2ObjectMap.Entry<K, V>>) entries;
		}
		
{@inheritDoc} /** {@inheritDoc} */
		@Override
		@SuppressWarnings({"rawtypes", "unchecked"})
		public ObjectSortedSet<Map.Entry<K, V>> entrySet() {
			return (ObjectSortedSet) object2ObjectEntrySet();
		}
		@Override
		public ObjectSortedSet<K> keySet() {
			if (keys == null)
				keys = ObjectSortedSets.unmodifiable(sortedMap.keySet());
			return (ObjectSortedSet<K>) keys;
		}
		@Override
		public Object2ObjectSortedMap<K, V> subMap(final K from, final K to) {
			return new UnmodifiableSortedMap<>(sortedMap.subMap(from, to));
		}
		@Override
		public Object2ObjectSortedMap<K, V> headMap(final K to) {
			return new UnmodifiableSortedMap<>(sortedMap.headMap(to));
		}
		@Override
		public Object2ObjectSortedMap<K, V> tailMap(final K from) {
			return new UnmodifiableSortedMap<>(sortedMap.tailMap(from));
		}
		@Override
		public K firstKey() {
			return sortedMap.firstKey();
		}
		@Override
		public K lastKey() {
			return sortedMap.lastKey();
		}
	}
	
Returns an unmodifiable type-specific sorted map backed by the given
type-specific sorted map.
Params:
m – 
           the sorted map to be wrapped in an unmodifiable sorted map.
See Also:
Collections.unmodifiableSortedMap(SortedMap<Object,? extends Object>)
Returns:
an unmodifiable view of the specified sorted map./**
	 * Returns an unmodifiable type-specific sorted map backed by the given
	 * type-specific sorted map.
	 *
	 * @param m
	 *            the sorted map to be wrapped in an unmodifiable sorted map.
	 * @return an unmodifiable view of the specified sorted map.
	 * @see java.util.Collections#unmodifiableSortedMap(SortedMap)
	 */
	public static <K, V> Object2ObjectSortedMap<K, V> unmodifiable(final Object2ObjectSortedMap<K, V> m) {
		return new UnmodifiableSortedMap<>(m);
	}
}