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.function.UnaryOperator;
023
024/**
025 * Like {@link UnaryOperator} but throws {@link IOException}.
026 *
027 * @param <T> the type of the operand and result of the operator.
028 *
029 * @see UnaryOperator
030 * @see IOFunction
031 * @since 2.12.0
032 */
033@FunctionalInterface
034public interface IOUnaryOperator<T> extends IOFunction<T, T> {
035
036    /**
037     * Creates a unary operator that always returns its input argument.
038     *
039     * @param <T> the type of the input and output of the operator.
040     * @return a unary operator that always returns its input argument.
041     */
042    static <T> IOUnaryOperator<T> identity() {
043        return t -> t;
044    }
045
046    /**
047     * Creates a {@link UnaryOperator} for this instance that throws {@link UncheckedIOException} instead of
048     * {@link IOException}.
049     *
050     * @return an unchecked BiFunction.
051     */
052    default UnaryOperator<T> asUnaryOperator() {
053        return t -> Uncheck.apply(this, t);
054    }
055
056}