    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 *      https://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;
    024
    025/**
    026 * Like {@link BiFunction} but throws {@link IOException}.
    027 *
    028 * <p>
    029 * This is a <a href="package-summary.html">functional interface</a> whose functional method is
    030 * {@link #apply(Object, Object)}.
    031 * </p>
    032 *
    033 * @param <T> the type of the first argument to the function.
    034 * @param <U> the type of the second argument to the function.
    035 * @param <R> the type of the result of the function.
    036 * @see BiFunction
    037 * @since 2.12.0
    038 */
    039@FunctionalInterface
    040public interface IOBiFunction<T, U, R> {
    041
    042    /**
    043     * Creates a composed function that first applies this function to its input, and then applies the {@code after}
    044     * function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the
    045     * composed function.
    046     *
    047     * @param <V> the type of output of the {@code after} function, and of the composed function.
    048     * @param after the function to apply after this function is applied.
    049     * @return a composed function that first applies this function and then applies the {@code after} function.
    050     * @throws NullPointerException if after is null.
    051     */
    052    default <V> IOBiFunction<T, U, V> andThen(final IOFunction<? super R, ? extends V> after) {
    053        Objects.requireNonNull(after);
    054        return (final T t, final U u) -> after.apply(apply(t, u));
    055    }
    056
    057    /**
    058     * Applies this function to the given arguments.
    059     *
    060     * @param t the first function argument.
    061     * @param u the second function argument.
    062     * @return the function result.
    063     * @throws IOException if an I/O error occurs.
    064     */
    065    R apply(T t, U u) throws IOException;
    066
    067    /**
    068     * Creates a {@link BiFunction} for this instance that throws {@link UncheckedIOException} instead of
    069     * {@link IOException}.
    070     *
    071     * @return an UncheckedIOException BiFunction.
    072     */
    073    default BiFunction<T, U, R> asBiFunction() {
    074        return (t, u) -> Uncheck.apply(this, t, u);
    075    }
    076}