/*
	* 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 java.util.SortedSet;
import java.util.NoSuchElementException;
import java.util.Comparator;
A class providing static methods and objects that do useful things with
type-specific sorted sets.
See Also:
Collections/**
 * A class providing static methods and objects that do useful things with
 * type-specific sorted sets.
 *
 * @see java.util.Collections
 */
public final class ObjectSortedSets {
	private ObjectSortedSets() {
	}
	
An immutable class representing the empty sorted set and implementing a
type-specific set interface.

This class may be useful to implement your own in case you subclass a
type-specific sorted set.
/**
	 * An immutable class representing the empty sorted set and implementing a
	 * type-specific set interface.
	 *
	 * <p>
	 * This class may be useful to implement your own in case you subclass a
	 * type-specific sorted set.
	 */
	public static class EmptySet<K> extends ObjectSets.EmptySet<K>
			implements
				ObjectSortedSet<K>,
				java.io.Serializable,
				Cloneable {
		private static final long serialVersionUID = -7046029254386353129L;
		protected EmptySet() {
		}
		@Override
		@SuppressWarnings("unchecked")
		public ObjectBidirectionalIterator<K> iterator(K from) {
			return ObjectIterators.EMPTY_ITERATOR;
		}
		@Override
		@SuppressWarnings("unchecked")
		public ObjectSortedSet<K> subSet(K from, K to) {
			return EMPTY_SET;
		}
		@Override
		@SuppressWarnings("unchecked")
		public ObjectSortedSet<K> headSet(K from) {
			return EMPTY_SET;
		}
		@Override
		@SuppressWarnings("unchecked")
		public ObjectSortedSet<K> tailSet(K to) {
			return EMPTY_SET;
		}
		@Override
		public K first() {
			throw new NoSuchElementException();
		}
		@Override
		public K last() {
			throw new NoSuchElementException();
		}
		@Override
		public Comparator<? super K> comparator() {
			return null;
		}
		@Override
		public Object clone() {
			return EMPTY_SET;
		}
		private Object readResolve() {
			return EMPTY_SET;
		}
	}
	
An empty sorted set (immutable). It is serializable and cloneable.
/**
	 * An empty sorted set (immutable). It is serializable and cloneable.
	 *
	 */
	@SuppressWarnings("rawtypes")
	public static final EmptySet EMPTY_SET = new EmptySet();
	
Returns an empty sorted set (immutable). It is serializable and cloneable.
 This method provides a typesafe access to EMPTY_SET. 
Returns:
an empty sorted set (immutable)./**
	 * Returns an empty sorted set (immutable). It is serializable and cloneable.
	 *
	 * <p>
	 * This method provides a typesafe access to {@link #EMPTY_SET}.
	 * 
	 * @return an empty sorted set (immutable).
	 */
	@SuppressWarnings("unchecked")
	public static <K> ObjectSet<K> emptySet() {
		return EMPTY_SET;
	}
	
A class representing a singleton sorted set.

This class may be useful to implement your own in case you subclass a
type-specific sorted set.
/**
	 * A class representing a singleton sorted set.
	 *
	 * <p>
	 * This class may be useful to implement your own in case you subclass a
	 * type-specific sorted set.
	 */
	public static class Singleton<K> extends ObjectSets.Singleton<K>
			implements
				ObjectSortedSet<K>,
				java.io.Serializable,
				Cloneable {
		private static final long serialVersionUID = -7046029254386353129L;
		final Comparator<? super K> comparator;
		protected Singleton(final K element, final Comparator<? super K> comparator) {
			super(element);
			this.comparator = comparator;
		}
		private Singleton(final K element) {
			this(element, 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 ObjectBidirectionalIterator<K> iterator(K from) {
			ObjectBidirectionalIterator<K> i = iterator();
			if (compare(element, from) <= 0)
				i.next();
			return i;
		}
		@Override
		public Comparator<? super K> comparator() {
			return comparator;
		}
		@Override
		@SuppressWarnings("unchecked")
		public ObjectSortedSet<K> subSet(final K from, final K to) {
			if (compare(from, element) <= 0 && compare(element, to) < 0)
				return this;
			return EMPTY_SET;
		}
		@Override
		@SuppressWarnings("unchecked")
		public ObjectSortedSet<K> headSet(final K to) {
			if (compare(element, to) < 0)
				return this;
			return EMPTY_SET;
		}
		@Override
		@SuppressWarnings("unchecked")
		public ObjectSortedSet<K> tailSet(final K from) {
			if (compare(from, element) <= 0)
				return this;
			return EMPTY_SET;
		}
		@Override
		public K first() {
			return element;
		}
		@Override
		public K last() {
			return element;
		}
	}
	
Returns a type-specific immutable sorted set containing only the specified
element. The returned sorted set is serializable and cloneable.
Params:
element – 
           the only element of the returned sorted set.
Returns:
a type-specific immutable sorted set containing just element./**
	 * Returns a type-specific immutable sorted set containing only the specified
	 * element. The returned sorted set is serializable and cloneable.
	 *
	 * @param element
	 *            the only element of the returned sorted set.
	 * @return a type-specific immutable sorted set containing just {@code element}.
	 */
	public static <K> ObjectSortedSet<K> singleton(final K element) {
		return new Singleton<>(element);
	}
	
Returns a type-specific immutable sorted set containing only the specified
element, and using a specified comparator. The returned sorted set is
serializable and cloneable.
Params:
element – 
           the only element of the returned sorted set.
comparator – 
           the comparator to use in the returned sorted set.
Returns:
a type-specific immutable sorted set containing just element./**
	 * Returns a type-specific immutable sorted set containing only the specified
	 * element, and using a specified comparator. The returned sorted set is
	 * serializable and cloneable.
	 *
	 * @param element
	 *            the only element of the returned sorted set.
	 * @param comparator
	 *            the comparator to use in the returned sorted set.
	 * @return a type-specific immutable sorted set containing just {@code element}.
	 */
	public static <K> ObjectSortedSet<K> singleton(final K element, final Comparator<? super K> comparator) {
		return new Singleton<>(element, comparator);
	}
	
A synchronized wrapper class for sorted sets. /** A synchronized wrapper class for sorted sets. */
	public static class SynchronizedSortedSet<K> extends ObjectSets.SynchronizedSet<K>
			implements
				ObjectSortedSet<K>,
				java.io.Serializable {
		private static final long serialVersionUID = -7046029254386353129L;
		protected final ObjectSortedSet<K> sortedSet;
		protected SynchronizedSortedSet(final ObjectSortedSet<K> s, final Object sync) {
			super(s, sync);
			sortedSet = s;
		}
		protected SynchronizedSortedSet(final ObjectSortedSet<K> s) {
			super(s);
			sortedSet = s;
		}
		@Override
		public Comparator<? super K> comparator() {
			synchronized (sync) {
				return sortedSet.comparator();
			}
		}
		@Override
		public ObjectSortedSet<K> subSet(final K from, final K to) {
			return new SynchronizedSortedSet<>(sortedSet.subSet(from, to), sync);
		}
		@Override
		public ObjectSortedSet<K> headSet(final K to) {
			return new SynchronizedSortedSet<>(sortedSet.headSet(to), sync);
		}
		@Override
		public ObjectSortedSet<K> tailSet(final K from) {
			return new SynchronizedSortedSet<>(sortedSet.tailSet(from), sync);
		}
		@Override
		public ObjectBidirectionalIterator<K> iterator() {
			return sortedSet.iterator();
		}
		@Override
		public ObjectBidirectionalIterator<K> iterator(final K from) {
			return sortedSet.iterator(from);
		}
		@Override
		public K first() {
			synchronized (sync) {
				return sortedSet.first();
			}
		}
		@Override
		public K last() {
			synchronized (sync) {
				return sortedSet.last();
			}
		}
	}
	
Returns a synchronized type-specific sorted set backed by the given
type-specific sorted set.
Params:
s – 
           the sorted set to be wrapped in a synchronized sorted set.
See Also:
Collections.synchronizedSortedSet(SortedSet<Object>)
Returns:
a synchronized view of the specified sorted set./**
	 * Returns a synchronized type-specific sorted set backed by the given
	 * type-specific sorted set.
	 *
	 * @param s
	 *            the sorted set to be wrapped in a synchronized sorted set.
	 * @return a synchronized view of the specified sorted set.
	 * @see java.util.Collections#synchronizedSortedSet(SortedSet)
	 */
	public static <K> ObjectSortedSet<K> synchronize(final ObjectSortedSet<K> s) {
		return new SynchronizedSortedSet<>(s);
	}
	
Returns a synchronized type-specific sorted set backed by the given
type-specific sorted set, using an assigned object to synchronize.
Params:
s – 
           the sorted set to be wrapped in a synchronized sorted set.
sync – 
           an object that will be used to synchronize the access to the
           sorted set.
See Also:
Collections.synchronizedSortedSet(SortedSet<Object>)
Returns:
a synchronized view of the specified sorted set./**
	 * Returns a synchronized type-specific sorted set backed by the given
	 * type-specific sorted set, using an assigned object to synchronize.
	 *
	 * @param s
	 *            the sorted set to be wrapped in a synchronized sorted set.
	 * @param sync
	 *            an object that will be used to synchronize the access to the
	 *            sorted set.
	 * @return a synchronized view of the specified sorted set.
	 * @see java.util.Collections#synchronizedSortedSet(SortedSet)
	 */
	public static <K> ObjectSortedSet<K> synchronize(final ObjectSortedSet<K> s, final Object sync) {
		return new SynchronizedSortedSet<>(s, sync);
	}
	
An unmodifiable wrapper class for sorted sets. /** An unmodifiable wrapper class for sorted sets. */
	public static class UnmodifiableSortedSet<K> extends ObjectSets.UnmodifiableSet<K>
			implements
				ObjectSortedSet<K>,
				java.io.Serializable {
		private static final long serialVersionUID = -7046029254386353129L;
		protected final ObjectSortedSet<K> sortedSet;
		protected UnmodifiableSortedSet(final ObjectSortedSet<K> s) {
			super(s);
			sortedSet = s;
		}
		@Override
		public Comparator<? super K> comparator() {
			return sortedSet.comparator();
		}
		@Override
		public ObjectSortedSet<K> subSet(final K from, final K to) {
			return new UnmodifiableSortedSet<>(sortedSet.subSet(from, to));
		}
		@Override
		public ObjectSortedSet<K> headSet(final K to) {
			return new UnmodifiableSortedSet<>(sortedSet.headSet(to));
		}
		@Override
		public ObjectSortedSet<K> tailSet(final K from) {
			return new UnmodifiableSortedSet<>(sortedSet.tailSet(from));
		}
		@Override
		public ObjectBidirectionalIterator<K> iterator() {
			return ObjectIterators.unmodifiable(sortedSet.iterator());
		}
		@Override
		public ObjectBidirectionalIterator<K> iterator(final K from) {
			return ObjectIterators.unmodifiable(sortedSet.iterator(from));
		}
		@Override
		public K first() {
			return sortedSet.first();
		}
		@Override
		public K last() {
			return sortedSet.last();
		}
	}
	
Returns an unmodifiable type-specific sorted set backed by the given
type-specific sorted set.
Params:
s – 
           the sorted set to be wrapped in an unmodifiable sorted set.
See Also:
Collections.unmodifiableSortedSet(SortedSet<Object>)
Returns:
an unmodifiable view of the specified sorted set./**
	 * Returns an unmodifiable type-specific sorted set backed by the given
	 * type-specific sorted set.
	 *
	 * @param s
	 *            the sorted set to be wrapped in an unmodifiable sorted set.
	 * @return an unmodifiable view of the specified sorted set.
	 * @see java.util.Collections#unmodifiableSortedSet(SortedSet)
	 */
	public static <K> ObjectSortedSet<K> unmodifiable(final ObjectSortedSet<K> s) {
		return new UnmodifiableSortedSet<>(s);
	}
}