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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * particular file as subject to the "Classpath" exception as provided

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 * 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).

 *

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package java.util.function;

import java.util.Objects;

import java.util.Comparator;

/**

 * Represents an operation upon two operands of the same type, producing a result

 * of the same type as the operands.  This is a specialization of

 * {@link BiFunction} for the case where the operands and the result are all of

 * the same type.

 *

 * <p>This is a <a href="package-summary.html">functional interface</a>

 * whose functional method is {@link #apply(Object, Object)}.

 *

 * @param <T> the type of the operands and result of the operator

 *

 * @see BiFunction

 * @see UnaryOperator

 * @since 1.8

 */

@FunctionalInterface

public interface BinaryOperator<T> extends BiFunction<T,T,T> {

    /**

     * Returns a {@link BinaryOperator} which returns the lesser of two elements

     * according to the specified {@code Comparator}.

     *

     * @param <T> the type of the input arguments of the comparator

     * @param comparator a {@code Comparator} for comparing the two values

     * @return a {@code BinaryOperator} which returns the lesser of its operands,

     *         according to the supplied {@code Comparator}

     * @throws NullPointerException if the argument is null

     */

    public static <T> BinaryOperator<T> minBy(Comparator<? super T> comparator) {

        Objects.requireNonNull(comparator);

        return (a, b) -> comparator.compare(a, b) <= 0 ? a : b;

    }

    /**

     * Returns a {@link BinaryOperator} which returns the greater of two elements

     * according to the specified {@code Comparator}.

     *

     * @param <T> the type of the input arguments of the comparator

     * @param comparator a {@code Comparator} for comparing the two values

     * @return a {@code BinaryOperator} which returns the greater of its operands,

     *         according to the supplied {@code Comparator}

     * @throws NullPointerException if the argument is null

     */

    public static <T> BinaryOperator<T> maxBy(Comparator<? super T> comparator) {

        Objects.requireNonNull(comparator);

        return (a, b) -> comparator.compare(a, b) >= 0 ? a : b;

    }

}