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A lightweight alternative to Java 8 sequential Stream

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/*
 * Copyright 2016 Daniel Skogquist Åborg
 *
 * 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 org.d2ab.collection;

import java.util.Comparator;

import static java.util.Comparator.naturalOrder;
import static java.util.Comparator.nullsFirst;

/**
 * Utilities for comparators.
 */
public abstract class Comparators {
	@SuppressWarnings("unchecked")
	private static final Comparator NATURAL_ORDER_NULLS_FIRST = nullsFirst((Comparator) naturalOrder());

	/**
	 * @return a {@link Comparator} comparing objects using their natural order, and sorting {@code nulls} first.
	 */
	@SuppressWarnings("unchecked")
	public static  Comparator naturalOrderNullsFirst() {
		return (Comparator) NATURAL_ORDER_NULLS_FIRST;
	}
}