/*
 * 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;

/**
 * Represents a function that accepts two arguments and produces a result.
 * This is the two-arity specialization of {@link Function}.
 *
 * <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 first argument to the function
 * @param <U> the type of the second argument to the function
 * @param <R> the type of the result of the function
 *
 * @see Function
 * @since 1.8
 */
@FunctionalInterface
public interface BiFunction<T, U, R> {

 /**
 * Applies this function to the given arguments.
 *
 * @param t the first function argument
 * @param u the second function argument
 * @return the function result
 */
 R apply(T t, U u);

 /**
 * Returns a composed function that first applies this function to
 * its input, and then applies the {@code after} function to the result.
 * If evaluation of either function throws an exception, it is relayed to
 * the caller of the composed function.
 *
 * @param <V> the type of output of the {@code after} function, and of the
 * composed function
 * @param after the function to apply after this function is applied
 * @return a composed function that first applies this function and then
 * applies the {@code after} function
 * @throws NullPointerException if after is null
 */
 default <V> BiFunction<T, U, V> andThen(Function<? super R, ? extends V> after) {
 Objects.requireNonNull(after);
 return (T t, U u) -> after.apply(apply(t, u));
 }
}