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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.commons.io.file;
19  
20  import java.io.IOException;
21  import java.nio.file.FileVisitResult;
22  import java.nio.file.Path;
23  import java.nio.file.SimpleFileVisitor;
24  import java.util.Objects;
25  
26  import org.apache.commons.io.build.AbstractSupplier;
27  import org.apache.commons.io.function.IOBiFunction;
28  
29  /**
30   * A {@link SimpleFileVisitor} typed to a {@link Path}.
31   *
32   * @since 2.7
33   */
34  public abstract class SimplePathVisitor extends SimpleFileVisitor<Path> implements PathVisitor {
35  
36      /**
37       * Abstracts builder for subclasses.
38       *
39       * @param <T> The SimplePathVisitor type.
40       * @param <B> The builder type.
41       * @since 2.19.0
42       */
43      protected abstract static class AbstractBuilder<T, B extends AbstractSupplier<T, B>> extends AbstractSupplier<T, B> {
44  
45          private IOBiFunction<Path, IOException, FileVisitResult> visitFileFailedFunction;
46  
47          /**
48           * Constructs a new builder for subclasses.
49           */
50          public AbstractBuilder() {
51              // empty.
52          }
53  
54          IOBiFunction<Path, IOException, FileVisitResult> getVisitFileFailedFunction() {
55              return visitFileFailedFunction;
56          }
57  
58          /**
59           * Sets the function to call on {@link #visitFileFailed(Path, IOException)}.
60           * <p>
61           * Defaults to {@link SimpleFileVisitor#visitFileFailed(Object, IOException)} on construction.
62           * </p>
63           *
64           * @param visitFileFailedFunction the function to call on {@link #visitFileFailed(Path, IOException)}.
65           * @return this instance.
66           */
67          public B setVisitFileFailedFunction(final IOBiFunction<Path, IOException, FileVisitResult> visitFileFailedFunction) {
68              this.visitFileFailedFunction = visitFileFailedFunction;
69              return asThis();
70          }
71  
72      }
73  
74      private final IOBiFunction<Path, IOException, FileVisitResult> visitFileFailedFunction;
75  
76      /**
77       * Constructs a new instance.
78       */
79      protected SimplePathVisitor() {
80          this.visitFileFailedFunction = super::visitFileFailed;
81      }
82  
83      /**
84       * Constructs a new instance.
85       *
86       * @param builder The builder provided by a subclass.
87       */
88      SimplePathVisitor(final AbstractBuilder<?, ?> builder) {
89          this.visitFileFailedFunction = builder.visitFileFailedFunction != null ? builder.visitFileFailedFunction : super::visitFileFailed;
90      }
91  
92      /**
93       * Constructs a new instance.
94       *
95       * @param visitFileFailedFunction Called on {@link #visitFileFailed(Path, IOException)}.
96       */
97      protected SimplePathVisitor(final IOBiFunction<Path, IOException, FileVisitResult> visitFileFailedFunction) {
98          this.visitFileFailedFunction = Objects.requireNonNull(visitFileFailedFunction, "visitFileFailedFunction");
99      }
100 
101     @Override
102     public FileVisitResult visitFileFailed(final Path file, final IOException exc) throws IOException {
103         return visitFileFailedFunction.apply(file, exc);
104     }
105 }