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}