1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.maven.plugin.compiler;
20
21 import java.io.Closeable;
22 import java.io.IOException;
23 import java.nio.file.Files;
24 import java.nio.file.Path;
25
26 /**
27 * Helper class for removing the directory having a module name.
28 * This hack is used when the {@code --module-source-path} compiler option is used
29 * but we still want to reproduce the directory layout of Maven 3.
30 * This hack is not used when the new {@code <source>} elements is used instead.
31 *
32 * <p>The code in this class is useful only when {@link AbstractCompilerMojo#SUPPORT_LEGACY} is true.
33 * This class can be fully deleted if a future version permanently set above-cited flag to false.</p>
34 */
35 final class ModuleDirectoryRemover implements Closeable {
36 /**
37 * The output directory expected by Maven 3.
38 * Example: {@code target/classes/META-INF/versions/21}.
39 */
40 private final Path mavenTarget;
41
42 /**
43 * The output directory where {@code javac} will write the classes.
44 * Example: {@code target/classes/META-INF/versions/21/org.foo.bar}.
45 */
46 private final Path javacTarget;
47
48 /**
49 * A temporary directory used as an intermediate step for avoiding name clash.
50 * Example: {@code target/classes/META-INF/versions/org.foo.bar}.
51 */
52 private final Path interTarget;
53
54 /**
55 * Temporarily renames the given output directory for matching the layout of {@code javac} output.
56 *
57 * @param outputDirectory the output directory (must exist)
58 * @param moduleName the name of the module
59 * @throws IOException if an error occurred while renaming the output directory
60 */
61 private ModuleDirectoryRemover(Path outputDirectory, String moduleName) throws IOException {
62 mavenTarget = outputDirectory;
63 interTarget = Files.move(outputDirectory, outputDirectory.resolveSibling(moduleName));
64 javacTarget = Files.createDirectory(outputDirectory).resolve(moduleName);
65 Files.move(interTarget, javacTarget);
66 }
67
68 /**
69 * Temporarily renames the given output directory for matching the layout of {@code javac} output.
70 *
71 * @param outputDirectory the output directory (must exist)
72 * @param moduleName the name of the module, or {@code null} if none
73 * @return a handler for restoring the directory to its original name, or {@code null} if there is no renaming
74 * @throws IOException if an error occurred while renaming the output directory
75 */
76 static ModuleDirectoryRemover create(Path outputDirectory, String moduleName) throws IOException {
77 return (moduleName != null) ? new ModuleDirectoryRemover(outputDirectory, moduleName) : null;
78 }
79
80 /**
81 * Restores the output directory to its original name.
82 * Note: contrarily to {@link Closeable} contract, this method is not idempotent:
83 * it cannot be executed twice. However, this is okay for the usage in this package.
84 *
85 * @throws IOException if an error occurred while renaming the output directory
86 */
87 @Override
88 public void close() throws IOException {
89 Files.move(javacTarget, interTarget);
90 Files.delete(mavenTarget);
91 Files.move(interTarget, mavenTarget);
92 }
93 }