1 ///////////////////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
3 // Copyright (C) 2001-2024 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.naming;
21
22 import java.util.regex.Pattern;
23
24 import com.puppycrawl.tools.checkstyle.StatelessCheck;
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 * <p>
32 * Checks that package names conform to a specified pattern.
33 * </p>
34 * <p>
35 * The default value of {@code format} for module {@code PackageName} has been chosen to match
36 * the requirements in the
37 * <a href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-6.html#jls-6.5.3">
38 * Java Language specification</a>
39 * and the Sun coding conventions. However, both underscores and uppercase letters are rather
40 * uncommon, so most configurations should probably assign value
41 * {@code ^[a-z]+(\.[a-z][a-z0-9]*)*$} to {@code format} for module {@code PackageName}.
42 * </p>
43 * <ul>
44 * <li>
45 * Property {@code format} - Control the pattern to match valid identifiers.
46 * Type is {@code java.util.regex.Pattern}.
47 * Default value is {@code "^[a-z]+(\.[a-zA-Z_]\w*)*$"}.
48 * </li>
49 * </ul>
50 * <p>
51 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
52 * </p>
53 * <p>
54 * Violation Message Keys:
55 * </p>
56 * <ul>
57 * <li>
58 * {@code name.invalidPattern}
59 * </li>
60 * </ul>
61 *
62 * @since 3.0
63 */
64 @StatelessCheck
65 public class PackageNameCheck
66 extends AbstractCheck {
67
68 /**
69 * A key is pointing to the warning message text in "messages.properties"
70 * file.
71 */
72 public static final String MSG_KEY = "name.invalidPattern";
73
74 /** Control the pattern to match valid identifiers. */
75 // Uppercase letters seem rather uncommon, but they're allowed in
76 // https://docs.oracle.com/javase/specs/
77 // second_edition/html/packages.doc.html#40169
78 private Pattern format = Pattern.compile("^[a-z]+(\\.[a-zA-Z_]\\w*)*$");
79
80 /**
81 * Setter to control the pattern to match valid identifiers.
82 *
83 * @param pattern the new pattern
84 * @since 3.0
85 */
86 public void setFormat(Pattern pattern) {
87 format = pattern;
88 }
89
90 @Override
91 public int[] getDefaultTokens() {
92 return getRequiredTokens();
93 }
94
95 @Override
96 public int[] getAcceptableTokens() {
97 return getRequiredTokens();
98 }
99
100 @Override
101 public int[] getRequiredTokens() {
102 return new int[] {TokenTypes.PACKAGE_DEF};
103 }
104
105 @Override
106 public void visitToken(DetailAST ast) {
107 final DetailAST nameAST = ast.getLastChild().getPreviousSibling();
108 final FullIdent full = FullIdent.createFullIdent(nameAST);
109 if (!format.matcher(full.getText()).find()) {
110 log(full.getDetailAst(),
111 MSG_KEY,
112 full.getText(),
113 format.pattern());
114 }
115 }
116
117 }