    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.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 {@code 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}