/*
	* Copyright (C) 2003-2019 Paolo Boldi and 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.Comparator;
A class providing static methods and objects that do useful things with
comparators.
/**
 * A class providing static methods and objects that do useful things with
 * comparators.
 */
public final class ObjectComparators {
	private ObjectComparators() {
	}
	
A type-specific comparator mimicking the natural order. /** A type-specific comparator mimicking the natural order. */
	@SuppressWarnings({"unchecked", "rawtypes"})
	protected static class NaturalImplicitComparator implements Comparator, java.io.Serializable {
		private static final long serialVersionUID = 1L;
		@Override
		public final int compare(final Object a, final Object b) {
			return ((Comparable) a).compareTo(b);
		}
		@Override
		public Comparator reversed() {
			return OPPOSITE_COMPARATOR;
		}
		private Object readResolve() {
			return NATURAL_COMPARATOR;
		}
	};
	@SuppressWarnings("rawtypes")
	public static final Comparator NATURAL_COMPARATOR = new NaturalImplicitComparator();
	
A type-specific comparator mimicking the opposite of the natural order. /** A type-specific comparator mimicking the opposite of the natural order. */
	@SuppressWarnings({"unchecked", "rawtypes"})
	protected static class OppositeImplicitComparator implements Comparator, java.io.Serializable {
		private static final long serialVersionUID = 1L;
		@Override
		public final int compare(final Object a, final Object b) {
			return ((Comparable) b).compareTo(a);
		}
		@Override
		public Comparator reversed() {
			return NATURAL_COMPARATOR;
		}
		private Object readResolve() {
			return OPPOSITE_COMPARATOR;
		}
	};
	@SuppressWarnings("rawtypes")
	public static final Comparator OPPOSITE_COMPARATOR = new OppositeImplicitComparator();
	protected static class OppositeComparator<K> implements Comparator<K>, java.io.Serializable {
		private static final long serialVersionUID = 1L;
		final Comparator<K> comparator;
		protected OppositeComparator(final Comparator<K> c) {
			comparator = c;
		}
		@Override
		public final int compare(final K a, final K b) {
			return comparator.compare(b, a);
		}
		@Override
		public final Comparator<K> reversed() {
			return comparator;
		}
	};
	
Returns a comparator representing the opposite order of the given comparator.
Params:
c – 
           a comparator.
Returns:
a comparator representing the opposite order of c./**
	 * Returns a comparator representing the opposite order of the given comparator.
	 *
	 * @param c
	 *            a comparator.
	 * @return a comparator representing the opposite order of {@code c}.
	 */
	public static <K> Comparator<K> oppositeComparator(final Comparator<K> c) {
		if (c instanceof OppositeComparator)
			return ((OppositeComparator<K>) c).comparator;
		return new OppositeComparator<>(c);
	}
}