code: ///////////////////////////////////////////////////////////////////////////////////////////////
  // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
  // Copyright (C) 2001-2023 the original author or authors.
  //
  // This library is free software; you can redistribute it and/or
  // modify it under the terms of the GNU Lesser General Public
  // License as published by the Free Software Foundation; either
  // version 2.1 of the License, or (at your option) any later version.
  //
  // This library is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  // Lesser General Public License for more details.
  //
  // You should have received a copy of the GNU Lesser General Public
  // License along with this library; if not, write to the Free Software
  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  ///////////////////////////////////////////////////////////////////////////////////////////////
  
  package com.puppycrawl.tools.checkstyle.checks.naming;
  
  import com.puppycrawl.tools.checkstyle.api.DetailAST;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
  import com.puppycrawl.tools.checkstyle.utils.ScopeUtil;
  
  /**
   * <p>
   * Checks that local final variable names conform to a specified pattern.
   *  A catch parameter and resources in try statements
   * are considered to be a local, final variables.
   * </p>
   * <ul>
   * <li>
   * Property {@code format} - Specifies valid identifiers.
   * Type is {@code java.util.regex.Pattern}.
   * Default value is {@code "^[a-z][a-zA-Z0-9]*$"}.
   * </li>
   * <li>
   * Property {@code tokens} - tokens to check
   * Type is {@code java.lang.String[]}.
   * Validation type is {@code tokenSet}.
   * Default value is:
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">
   * VARIABLE_DEF</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PARAMETER_DEF">
   * PARAMETER_DEF</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RESOURCE">
   * RESOURCE</a>.
   * </li>
   * </ul>
   * <p>
   * To configure the check:
   * </p>
   * <pre>
   * &lt;module name="LocalFinalVariableName"/&gt;
   * </pre>
   * <p>
   * An example of how to configure the check for names that are only upper case
   * letters and digits is:
   * </p>
   * <pre>
   * &lt;module name="LocalFinalVariableName"&gt;
   *   &lt;property name="format" value="^[A-Z][A-Z0-9]*$"/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>Code Example:</p>
   * <pre>
   * class MyClass {
   *   void MyMethod() {
   *     try {
   *       final int VAR1 = 5; // OK
   *       final int var1 = 10; // violation,  name 'var1' must match pattern "^[A-Z][A-Z0-9]*$"
   *     } catch (Exception ex) {
   *       final int VAR2 = 15; // OK
   *       final int var2 = 20; // violation,  name 'var2' must match pattern "^[A-Z][A-Z0-9]*$"
   *     }
   *   }
   * }
   * </pre>
   * <p>
   * An example of how to configure the check for names of local final parameters and
   * resources in try statements (without checks on variables):
   * </p>
   * <pre>
   * &lt;module name=&quot;LocalFinalVariableName&quot;&gt;
   *   &lt;property name="format" value="^[A-Z][A-Z0-9]*$"/&gt;
   *   &lt;property name="tokens" value="PARAMETER_DEF,RESOURCE"/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>Code Example:</p>
   * <pre>
   * class MyClass {
   *   void MyMethod() {
   *     try(Scanner scanner = new Scanner()) { // violation, name 'scanner' must
   *                                            // match pattern '^[A-Z][A-Z0-9]*$'
   *       final int VAR1 = 5; // OK
   *       final int var1 = 10; // OK
   *     } catch (final Exception ex) { // violation, name 'ex'
   *                                    // must match pattern '^[A-Z][A-Z0-9]*$'
   *       final int VAR2 = 15; // OK
   *       final int var2 = 20; // OK
   *     }
   *   }
   * }
   * </pre>
   * <p>
   * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
   * </p>
   * <p>
   * Violation Message Keys:
   * </p>
   * <ul>
   * <li>
   * {@code name.invalidPattern}
   * </li>
   * </ul>
   *
   * @since 3.0
   */
  public class LocalFinalVariableNameCheck
      extends AbstractNameCheck {
  
      /** Creates a new {@code LocalFinalVariableNameCheck} instance. */
      public LocalFinalVariableNameCheck() {
          super("^[a-z][a-zA-Z0-9]*$");
      }
  
      @Override
      public int[] getDefaultTokens() {
          return getAcceptableTokens();
      }
  
      @Override
      public int[] getAcceptableTokens() {
          return new int[] {
              TokenTypes.VARIABLE_DEF,
              TokenTypes.PARAMETER_DEF,
              TokenTypes.RESOURCE,
          };
      }
  
      @Override
      public int[] getRequiredTokens() {
          return CommonUtil.EMPTY_INT_ARRAY;
      }
  
      @Override
      protected final boolean mustCheckName(DetailAST ast) {
          final DetailAST modifiersAST =
              ast.findFirstToken(TokenTypes.MODIFIERS);
          final boolean isFinal = ast.getType() == TokenTypes.RESOURCE
              || modifiersAST.findFirstToken(TokenTypes.FINAL) != null;
          return isFinal && ScopeUtil.isLocalVariableDef(ast);
      }
  
  }
  