1 ////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code for adherence to a set of rules.
3 // Copyright (C) 2001-2019 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 format specified
33 * by the format property.
34 * </p>
35 * <p>
36 * The default value of {@code format} for module {@code PackageName} has been chosen to match
37 * the requirements in the
38 * <a href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-6.html#jls-6.5.3">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]*)*$} to {@code format} for module {@code PackageName}.
42 * </p>
43 * <ul>
44 * <li>
45 * Property {@code format} - Specifies valid identifiers. Default value is
46 * {@code "^[a-z]+(\.[a-zA-Z_][a-zA-Z0-9_]*)*$"}.
47 * </li>
48 * </ul>
49 * <p>
50 * An example of how to configure the check is:
51 * </p>
52 * <pre>
53 * <module name="PackageName"/>
54 * </pre>
55 * <p>
56 * An example of how to configure the check to ensure with packages start with a lowercase letter
57 * and only contains lowercase letters or numbers is:
58 * </p>
59 * <pre>
60 * <module name="PackageName">
61 * <property name="format"
62 * value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
63 * </module>
64 * </pre>
65 *
66 * @since 3.0
67 */
68 @StatelessCheck
69 public class PackageNameCheck
70 extends AbstractCheck {
71
72 /**
73 * A key is pointing to the warning message text in "messages.properties"
74 * file.
75 */
76 public static final String MSG_KEY = "name.invalidPattern";
77
78 /** Specifies valid identifiers. */
79 // Uppercase letters seem rather uncommon, but they're allowed in
80 // https://docs.oracle.com/javase/specs/
81 // second_edition/html/packages.doc.html#40169
82 private Pattern format = Pattern.compile("^[a-z]+(\\.[a-zA-Z_][a-zA-Z0-9_]*)*$");
83
84 /**
85 * Setter to specifies valid identifiers.
86 * @param pattern the new pattern
87 */
88 public void setFormat(Pattern pattern) {
89 format = pattern;
90 }
91
92 @Override
93 public int[] getDefaultTokens() {
94 return getRequiredTokens();
95 }
96
97 @Override
98 public int[] getAcceptableTokens() {
99 return getRequiredTokens();
100 }
101
102 @Override
103 public int[] getRequiredTokens() {
104 return new int[] {TokenTypes.PACKAGE_DEF};
105 }
106
107 @Override
108 public void visitToken(DetailAST ast) {
109 final DetailAST nameAST = ast.getLastChild().getPreviousSibling();
110 final FullIdent full = FullIdent.createFullIdent(nameAST);
111 if (!format.matcher(full.getText()).find()) {
112 log(full.getDetailAst(),
113 MSG_KEY,
114 full.getText(),
115 format.pattern());
116 }
117 }
118
119 }