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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.api.DetailAST;
23  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
24  import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
25  import com.puppycrawl.tools.checkstyle.utils.ScopeUtil;
26  
27  /**
28   * <div>
29   * Checks that local final variable names conform to a specified pattern.
30   *  A catch parameter and resources in try statements
31   * are considered to be a local, final variables.
32   * </div>
33   *
34   * <p>
35   * This check does not support final pattern variables. Instead, use
36   * <a href="https://checkstyle.org/checks/naming/patternvariablename.html">
37   * PatternVariableName</a>.
38   * </p>
39   *
40   * @since 3.0
41   */
42  public class LocalFinalVariableNameCheck
43      extends AbstractNameCheck {
44  
45      /** Creates a new {@code LocalFinalVariableNameCheck} instance. */
46      public LocalFinalVariableNameCheck() {
47          super("^([a-z][a-zA-Z0-9]*|_)$");
48      }
49  
50      @Override
51      public int[] getDefaultTokens() {
52          return getAcceptableTokens();
53      }
54  
55      @Override
56      public int[] getAcceptableTokens() {
57          return new int[] {
58              TokenTypes.VARIABLE_DEF,
59              TokenTypes.PARAMETER_DEF,
60              TokenTypes.RESOURCE,
61          };
62      }
63  
64      @Override
65      public int[] getRequiredTokens() {
66          return CommonUtil.EMPTY_INT_ARRAY;
67      }
68  
69      @Override
70      protected final boolean mustCheckName(DetailAST ast) {
71          final DetailAST modifiersAST =
72              ast.findFirstToken(TokenTypes.MODIFIERS);
73          final boolean isFinal = ast.getType() == TokenTypes.RESOURCE
74              || modifiersAST.findFirstToken(TokenTypes.FINAL) != null;
75          return isFinal && ScopeUtil.isLocalVariableDef(ast);
76      }
77  
78  }