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My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

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java/pkg/java/nio/file/FileVisitor.java+177−0
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1+/*
2+ * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
3+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4+ *
5+ * This code is free software; you can redistribute it and/or modify it
6+ * under the terms of the GNU General Public License version 2 only, as
7+ * published by the Free Software Foundation. Oracle designates this
8+ * particular file as subject to the "Classpath" exception as provided
9+ * by Oracle in the LICENSE file that accompanied this code.
10+ *
11+ * This code is distributed in the hope that it will be useful, but WITHOUT
12+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14+ * version 2 for more details (a copy is included in the LICENSE file that
15+ * accompanied this code).
16+ *
17+ * You should have received a copy of the GNU General Public License version
18+ * 2 along with this work; if not, write to the Free Software Foundation,
19+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20+ *
21+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22+ * or visit www.oracle.com if you need additional information or have any
23+ * questions.
24+ */
25+
26+package java.nio.file;
27+
28+import java.nio.file.attribute.BasicFileAttributes;
29+import java.io.IOException;
30+
31+/**
32+ * A visitor of files. An implementation of this interface is provided to the
33+ * {@link Files#walkFileTree Files.walkFileTree} methods to visit each file in
34+ * a file tree.
35+ *
36+ * <p> <b>Usage Examples:</b>
37+ * Suppose we want to delete a file tree. In that case, each directory should
38+ * be deleted after the entries in the directory are deleted.
39+ * <pre>
40+ * Path start = ...
41+ * Files.walkFileTree(start, new SimpleFileVisitor&lt;Path&gt;() {
42+ * &#64;Override
43+ * public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
44+ * throws IOException
45+ * {
46+ * Files.delete(file);
47+ * return FileVisitResult.CONTINUE;
48+ * }
49+ * &#64;Override
50+ * public FileVisitResult postVisitDirectory(Path dir, IOException e)
51+ * throws IOException
52+ * {
53+ * if (e == null) {
54+ * Files.delete(dir);
55+ * return FileVisitResult.CONTINUE;
56+ * } else {
57+ * // directory iteration failed
58+ * throw e;
59+ * }
60+ * }
61+ * });
62+ * </pre>
63+ * <p> Furthermore, suppose we want to copy a file tree to a target location.
64+ * In that case, symbolic links should be followed and the target directory
65+ * should be created before the entries in the directory are copied.
66+ * <pre>
67+ * final Path source = ...
68+ * final Path target = ...
69+ *
70+ * Files.walkFileTree(source, EnumSet.of(FileVisitOption.FOLLOW_LINKS), Integer.MAX_VALUE,
71+ * new SimpleFileVisitor&lt;Path&gt;() {
72+ * &#64;Override
73+ * public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
74+ * throws IOException
75+ * {
76+ * Path targetdir = target.resolve(source.relativize(dir));
77+ * try {
78+ * Files.copy(dir, targetdir);
79+ * } catch (FileAlreadyExistsException e) {
80+ * if (!Files.isDirectory(targetdir))
81+ * throw e;
82+ * }
83+ * return CONTINUE;
84+ * }
85+ * &#64;Override
86+ * public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
87+ * throws IOException
88+ * {
89+ * Files.copy(file, target.resolve(source.relativize(file)));
90+ * return CONTINUE;
91+ * }
92+ * });
93+ * </pre>
94+ *
95+ * @since 1.7
96+ */
97+
98+public interface FileVisitor<T> {
99+
100+ /**
101+ * Invoked for a directory before entries in the directory are visited.
102+ *
103+ * <p> If this method returns {@link FileVisitResult#CONTINUE CONTINUE},
104+ * then entries in the directory are visited. If this method returns {@link
105+ * FileVisitResult#SKIP_SUBTREE SKIP_SUBTREE} or {@link
106+ * FileVisitResult#SKIP_SIBLINGS SKIP_SIBLINGS} then entries in the
107+ * directory (and any descendants) will not be visited.
108+ *
109+ * @param dir
110+ * a reference to the directory
111+ * @param attrs
112+ * the directory's basic attributes
113+ *
114+ * @return the visit result
115+ *
116+ * @throws IOException
117+ * if an I/O error occurs
118+ */
119+ FileVisitResult preVisitDirectory(T dir, BasicFileAttributes attrs)
120+ throws IOException;
121+
122+ /**
123+ * Invoked for a file in a directory.
124+ *
125+ * @param file
126+ * a reference to the file
127+ * @param attrs
128+ * the file's basic attributes
129+ *
130+ * @return the visit result
131+ *
132+ * @throws IOException
133+ * if an I/O error occurs
134+ */
135+ FileVisitResult visitFile(T file, BasicFileAttributes attrs)
136+ throws IOException;
137+
138+ /**
139+ * Invoked for a file that could not be visited. This method is invoked
140+ * if the file's attributes could not be read, the file is a directory
141+ * that could not be opened, and other reasons.
142+ *
143+ * @param file
144+ * a reference to the file
145+ * @param exc
146+ * the I/O exception that prevented the file from being visited
147+ *
148+ * @return the visit result
149+ *
150+ * @throws IOException
151+ * if an I/O error occurs
152+ */
153+ FileVisitResult visitFileFailed(T file, IOException exc)
154+ throws IOException;
155+
156+ /**
157+ * Invoked for a directory after entries in the directory, and all of their
158+ * descendants, have been visited. This method is also invoked when iteration
159+ * of the directory completes prematurely (by a {@link #visitFile visitFile}
160+ * method returning {@link FileVisitResult#SKIP_SIBLINGS SKIP_SIBLINGS},
161+ * or an I/O error when iterating over the directory).
162+ *
163+ * @param dir
164+ * a reference to the directory
165+ * @param exc
166+ * {@code null} if the iteration of the directory completes without
167+ * an error; otherwise the I/O exception that caused the iteration
168+ * of the directory to complete prematurely
169+ *
170+ * @return the visit result
171+ *
172+ * @throws IOException
173+ * if an I/O error occurs
174+ */
175+ FileVisitResult postVisitDirectory(T dir, IOException exc)
176+ throws IOException;
177+}