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