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 *
48 * @since 3.2
49 */
50 @FileStatefulCheck
51 public final class PackageDeclarationCheck extends AbstractCheck {
52
53 /**
54 * A key is pointing to the warning message text in "messages.properties"
55 * file.
56 */
57 public static final String MSG_KEY_MISSING = "missing.package.declaration";
58
59 /**
60 * A key is pointing to the warning message text in "messages.properties"
61 * file.
62 */
63 public static final String MSG_KEY_MISMATCH = "mismatch.package.directory";
64
65 /** Is package defined. */
66 private boolean defined;
67
68 /** Control whether to check for directory and package name match. */
69 private boolean matchDirectoryStructure = true;
70
71 /**
72 * Setter to control whether to check for directory and package name match.
73 *
74 * @param matchDirectoryStructure the new value.
75 * @since 7.6.1
76 */
77 public void setMatchDirectoryStructure(boolean matchDirectoryStructure) {
78 this.matchDirectoryStructure = matchDirectoryStructure;
79 }
80
81 @Override
82 public int[] getDefaultTokens() {
83 return getRequiredTokens();
84 }
85
86 @Override
87 public int[] getRequiredTokens() {
88 return new int[] {TokenTypes.PACKAGE_DEF};
89 }
90
91 @Override
92 public int[] getAcceptableTokens() {
93 return getRequiredTokens();
94 }
95
96 @Override
97 public void beginTree(DetailAST ast) {
98 defined = false;
99 }
100
101 @Override
102 public void finishTree(DetailAST ast) {
103 if (!defined && ast != null) {
104 log(ast, MSG_KEY_MISSING);
105 }
106 }
107
108 @Override
109 public void visitToken(DetailAST ast) {
110 defined = true;
111
112 if (matchDirectoryStructure) {
113 final DetailAST packageNameAst = ast.getLastChild().getPreviousSibling();
114 final FullIdent fullIdent = FullIdent.createFullIdent(packageNameAst);
115 final String packageName = fullIdent.getText().replace('.', File.separatorChar);
116
117 final String directoryName = getDirectoryName();
118
119 if (!directoryName.endsWith(packageName)) {
120 log(ast, MSG_KEY_MISMATCH, packageName);
121 }
122 }
123 }
124
125 /**
126 * Returns the directory name this file is in.
127 *
128 * @return Directory name.
129 */
130 private String getDirectoryName() {
131 final String fileName = getFilePath();
132 final int lastSeparatorPos = fileName.lastIndexOf(File.separatorChar);
133 return fileName.substring(0, lastSeparatorPos);
134 }
135
136 }