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.file;
019
020import java.io.IOException;
021import java.nio.file.FileVisitResult;
022import java.nio.file.Path;
023import java.nio.file.SimpleFileVisitor;
024import java.util.Objects;
025
026import org.apache.commons.io.build.AbstractSupplier;
027import org.apache.commons.io.function.IOBiFunction;
028
029/**
030 * A {@link SimpleFileVisitor} typed to a {@link Path}.
031 *
032 * @since 2.7
033 */
034public abstract class SimplePathVisitor extends SimpleFileVisitor<Path> implements PathVisitor {
035
036    /**
037     * Abstracts builder for subclasses.
038     *
039     * @param <T> The SimplePathVisitor type.
040     * @param <B> The builder type.
041     * @since 2.19.0
042     */
043    protected abstract static class AbstractBuilder<T, B extends AbstractSupplier<T, B>> extends AbstractSupplier<T, B> {
044
045        private IOBiFunction<Path, IOException, FileVisitResult> visitFileFailedFunction;
046
047        /**
048         * Constructs a new builder for subclasses.
049         */
050        public AbstractBuilder() {
051            // empty.
052        }
053
054        IOBiFunction<Path, IOException, FileVisitResult> getVisitFileFailedFunction() {
055            return visitFileFailedFunction;
056        }
057
058        /**
059         * Sets the function to call on {@link #visitFileFailed(Path, IOException)}.
060         * <p>
061         * Defaults to {@link SimpleFileVisitor#visitFileFailed(Object, IOException)} on construction.
062         * </p>
063         *
064         * @param visitFileFailedFunction the function to call on {@link #visitFileFailed(Path, IOException)}.
065         * @return this instance.
066         */
067        public B setVisitFileFailedFunction(final IOBiFunction<Path, IOException, FileVisitResult> visitFileFailedFunction) {
068            this.visitFileFailedFunction = visitFileFailedFunction;
069            return asThis();
070        }
071
072    }
073
074    private final IOBiFunction<Path, IOException, FileVisitResult> visitFileFailedFunction;
075
076    /**
077     * Constructs a new instance.
078     */
079    protected SimplePathVisitor() {
080        this.visitFileFailedFunction = super::visitFileFailed;
081    }
082
083    /**
084     * Constructs a new instance.
085     *
086     * @param builder The builder provided by a subclass.
087     */
088    SimplePathVisitor(final AbstractBuilder<?, ?> builder) {
089        this.visitFileFailedFunction = builder.visitFileFailedFunction != null ? builder.visitFileFailedFunction : super::visitFileFailed;
090    }
091
092    /**
093     * Constructs a new instance.
094     *
095     * @param visitFileFailedFunction Called on {@link #visitFileFailed(Path, IOException)}.
096     */
097    protected SimplePathVisitor(final IOBiFunction<Path, IOException, FileVisitResult> visitFileFailedFunction) {
098        this.visitFileFailedFunction = Objects.requireNonNull(visitFileFailedFunction, "visitFileFailedFunction");
099    }
100
101    @Override
102    public FileVisitResult visitFileFailed(final Path file, final IOException exc) throws IOException {
103        return visitFileFailedFunction.apply(file, exc);
104    }
105}