1 ///////////////////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
3 // Copyright (C) 2001-2025 the original author or authors.
4 //
5 // This library is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU Lesser General Public
7 // License as published by the Free Software Foundation; either
8 // version 2.1 of the License, or (at your option) any later version.
9 //
10 // This library is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 // Lesser General Public License for more details.
14 //
15 // You should have received a copy of the GNU Lesser General Public
16 // License along with this library; if not, write to the Free Software
17 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 ///////////////////////////////////////////////////////////////////////////////////////////////
19
20 package com.puppycrawl.tools.checkstyle.checks.coding;
21
22 import java.io.File;
23
24 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
25 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
26 import com.puppycrawl.tools.checkstyle.api.DetailAST;
27 import com.puppycrawl.tools.checkstyle.api.FullIdent;
28 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
29
30 /**
31 * <div>
32 * Ensures that a class has a package declaration, and (optionally) whether
33 * the package name matches the directory name for the source file.
34 * </div>
35 *
36 * <p>
37 * Rationale: Classes that live in the null package cannot be imported.
38 * Many novice developers are not aware of this.
39 * </p>
40 *
41 * <p>
42 * Packages provide logical namespace to classes and should be stored in
43 * the form of directory levels to provide physical grouping to your classes.
44 * These directories are added to the classpath so that your classes
45 * are visible to JVM when it runs the code.
46 * </p>
47 * <ul>
48 * <li>
49 * Property {@code matchDirectoryStructure} - Control whether to check for
50 * directory and package name match.
51 * Type is {@code boolean}.
52 * Default value is {@code true}.
53 * </li>
54 * </ul>
55 *
56 * <p>
57 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
58 * </p>
59 *
60 * <p>
61 * Violation Message Keys:
62 * </p>
63 * <ul>
64 * <li>
65 * {@code mismatch.package.directory}
66 * </li>
67 * <li>
68 * {@code missing.package.declaration}
69 * </li>
70 * </ul>
71 *
72 * @since 3.2
73 */
74 @FileStatefulCheck
75 public final class PackageDeclarationCheck extends AbstractCheck {
76
77 /**
78 * A key is pointing to the warning message text in "messages.properties"
79 * file.
80 */
81 public static final String MSG_KEY_MISSING = "missing.package.declaration";
82
83 /**
84 * A key is pointing to the warning message text in "messages.properties"
85 * file.
86 */
87 public static final String MSG_KEY_MISMATCH = "mismatch.package.directory";
88
89 /** Is package defined. */
90 private boolean defined;
91
92 /** Control whether to check for directory and package name match. */
93 private boolean matchDirectoryStructure = true;
94
95 /**
96 * Setter to control whether to check for directory and package name match.
97 *
98 * @param matchDirectoryStructure the new value.
99 * @since 7.6.1
100 */
101 public void setMatchDirectoryStructure(boolean matchDirectoryStructure) {
102 this.matchDirectoryStructure = matchDirectoryStructure;
103 }
104
105 @Override
106 public int[] getDefaultTokens() {
107 return getRequiredTokens();
108 }
109
110 @Override
111 public int[] getRequiredTokens() {
112 return new int[] {TokenTypes.PACKAGE_DEF};
113 }
114
115 @Override
116 public int[] getAcceptableTokens() {
117 return getRequiredTokens();
118 }
119
120 @Override
121 public void beginTree(DetailAST ast) {
122 defined = false;
123 }
124
125 @Override
126 public void finishTree(DetailAST ast) {
127 if (!defined && ast != null) {
128 log(ast, MSG_KEY_MISSING);
129 }
130 }
131
132 @Override
133 public void visitToken(DetailAST ast) {
134 defined = true;
135
136 if (matchDirectoryStructure) {
137 final DetailAST packageNameAst = ast.getLastChild().getPreviousSibling();
138 final FullIdent fullIdent = FullIdent.createFullIdent(packageNameAst);
139 final String packageName = fullIdent.getText().replace('.', File.separatorChar);
140
141 final String directoryName = getDirectoryName();
142
143 if (!directoryName.endsWith(packageName)) {
144 log(ast, MSG_KEY_MISMATCH, packageName);
145 }
146 }
147 }
148
149 /**
150 * Returns the directory name this file is in.
151 *
152 * @return Directory name.
153 */
154 private String getDirectoryName() {
155 final String fileName = getFilePath();
156 final int lastSeparatorPos = fileName.lastIndexOf(File.separatorChar);
157 return fileName.substring(0, lastSeparatorPos);
158 }
159
160 }