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.coding;
  
  import com.puppycrawl.tools.checkstyle.StatelessCheck;
  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
  import com.puppycrawl.tools.checkstyle.api.DetailAST;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
  
  /**
   * <p>
   *  Checks that enum definition does not contain a trailing comma.
   *  Rationale: JLS allows trailing commas in arrays and enumerations, but does not allow
   *  them in other locations. To unify the coding style, the use of trailing commas should
   *  be prohibited.
   * </p>
   * <pre>
   * enum Foo1 {
   *   FOO,
   *   BAR;
   * }
   * </pre>
   * <p>
   *  The check demands that there should not be any comma after last constant in
   *  enum definition.
   * </p>
   * <pre>
   * enum Foo1 {
   *   FOO,
   *   BAR, //violation
   * }
   * </pre>
   * <p>
   * To configure the check:
   * </p>
   * <pre>
   * &lt;module name=&quot;NoEnumTrailingComma&quot;/&gt;
   * </pre>
   * <p>
   * Which results in the following violations:
   * </p>
   * <pre>
   * enum Foo1 {
   *   FOO,
   *   BAR; //OK
   * }
   * enum Foo2 {
   *   FOO,
   *   BAR //OK
   * }
   * enum Foo3 {
   *   FOO,
   *   BAR, //violation
   * }
   * enum Foo4 {
   *   FOO,
   *   BAR, // violation
   *   ;
   * }
   * enum Foo5 {
   *   FOO,
   *   BAR,; // violation
   * }
   * enum Foo6 { FOO, BAR,; } // violation
   * enum Foo7 { FOO, BAR, } // violation
   * enum Foo8 {
   *   FOO,
   *   BAR // OK
   *   ;
   * }
   * enum Foo9 { FOO, BAR; } // OK
   * enum Foo10 { FOO, BAR } // OK
   * </pre>
   * <p>
   * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
   * </p>
   * <p>
   * Violation Message Keys:
   * </p>
   * <ul>
   * <li>
   * {@code no.enum.trailing.comma}
   * </li>
   * </ul>
   *
   * @since 8.29
   */
  @StatelessCheck
  public class NoEnumTrailingCommaCheck extends AbstractCheck {
  
      /**
       * A key is pointing to the warning message text in "messages.properties"
       * file.
       */
      public static final String MSG_KEY = "no.enum.trailing.comma";
  
      @Override
      public int[] getDefaultTokens() {
          return getRequiredTokens();
      }
  
      @Override
      public int[] getAcceptableTokens() {
          return getRequiredTokens();
      }
  
      @Override
      public int[] getRequiredTokens() {
          return new int[] {TokenTypes.ENUM_DEF};
      }
  
      @Override
      public void visitToken(DetailAST detailAST) {
          final DetailAST enumBlock = detailAST.findFirstToken(TokenTypes.OBJBLOCK);
          TokenUtil.findFirstTokenByPredicate(enumBlock,
              node -> TokenUtil.isOfType(node, TokenTypes.SEMI, TokenTypes.RCURLY))
              .map(DetailAST::getPreviousSibling)
              .filter(token -> token.getType() == TokenTypes.COMMA)
              .ifPresent(comma -> log(comma, MSG_KEY));
      }
  }
  