/*
* Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*
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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;
}
}