    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017
    018package org.apache.commons.io.function;
    019
    020import java.io.IOException;
    021import java.io.UncheckedIOException;
    022import java.util.Objects;
    023import java.util.function.BiFunction;
    024import java.util.function.Function;
    025
    026/**
    027 * Like {@link BiFunction} but throws {@link IOException}.
    028 *
    029 * <p>
    030 * This is a <a href="package-summary.html">functional interface</a> whose functional method is
    031 * {@link #apply(Object, Object)}.
    032 * </p>
    033 *
    034 * @param <T> the type of the first argument to the function
    035 * @param <U> the type of the second argument to the function
    036 * @param <R> the type of the result of the function
    037 *
    038 * @see Function
    039 * @since 2.12.0
    040 */
    041@FunctionalInterface
    042public interface IOBiFunction<T, U, R> {
    043
    044    /**
    045     * Creates a composed function that first applies this function to its input, and then applies the {@code after}
    046     * function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the
    047     * composed function.
    048     *
    049     * @param <V> the type of output of the {@code after} function, and of the composed function
    050     * @param after the function to apply after this function is applied
    051     * @return a composed function that first applies this function and then applies the {@code after} function
    052     * @throws NullPointerException if after is null
    053     */
    054    default <V> IOBiFunction<T, U, V> andThen(final IOFunction<? super R, ? extends V> after) {
    055        Objects.requireNonNull(after);
    056        return (final T t, final U u) -> after.apply(apply(t, u));
    057    }
    058
    059    /**
    060     * Applies this function to the given arguments.
    061     *
    062     * @param t the first function argument
    063     * @param u the second function argument
    064     * @return the function result
    065     * @throws IOException if an I/O error occurs.
    066     */
    067    R apply(T t, U u) throws IOException;
    068
    069    /**
    070     * Creates a {@link BiFunction} for this instance that throws {@link UncheckedIOException} instead of
    071     * {@link IOException}.
    072     *
    073     * @return an UncheckedIOException BiFunction.
    074     */
    075    default BiFunction<T, U, R> asBiFunction() {
    076        return (t, u) -> Uncheck.apply(this, t, u);
    077    }
    078}