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.naming;
21
22 import com.puppycrawl.tools.checkstyle.StatelessCheck;
23 import com.puppycrawl.tools.checkstyle.api.DetailAST;
24 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
25 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
26
27 /**
28 * <div>
29 * Checks identifiers against a regular expression pattern to detect illegal names. Since this
30 * check uses a pattern to define <i>valid</i> identifiers, users will need to use negative
31 * lookaheads to explicitly ban certain names (e.g., "var") or patterns (e.g., any identifier
32 * containing $) while still allowing all other valid identifiers.
33 * </div>
34 *
35 * @since 8.36
36 */
37 @StatelessCheck
38 public class IllegalIdentifierNameCheck extends AbstractNameCheck {
39
40 /**
41 * Creates a new {@code IllegalIdentifierNameCheck} instance.
42 */
43 public IllegalIdentifierNameCheck() {
44 super("^(?!var$|\\S*\\$)\\S+$");
45 }
46
47 @Override
48 public int[] getDefaultTokens() {
49 return getAcceptableTokens();
50 }
51
52 @Override
53 public int[] getAcceptableTokens() {
54 return new int[] {
55 TokenTypes.CLASS_DEF,
56 TokenTypes.INTERFACE_DEF,
57 TokenTypes.ENUM_DEF,
58 TokenTypes.ANNOTATION_DEF,
59 TokenTypes.ANNOTATION_FIELD_DEF,
60 TokenTypes.PARAMETER_DEF,
61 TokenTypes.VARIABLE_DEF,
62 TokenTypes.METHOD_DEF,
63 TokenTypes.ENUM_CONSTANT_DEF,
64 TokenTypes.PATTERN_VARIABLE_DEF,
65 TokenTypes.RECORD_DEF,
66 TokenTypes.RECORD_COMPONENT_DEF,
67 TokenTypes.LAMBDA,
68 };
69 }
70
71 @Override
72 public int[] getRequiredTokens() {
73 return CommonUtil.EMPTY_INT_ARRAY;
74 }
75
76 @Override
77 protected boolean mustCheckName(DetailAST ast) {
78 return ast.findFirstToken(TokenTypes.IDENT) != null;
79 }
80
81 }