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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  }