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.indentation;
  
  import com.puppycrawl.tools.checkstyle.api.DetailAST;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  
  /**
   * Handler for class definitions.
   *
   */
  public class ClassDefHandler extends BlockParentHandler {
  
      /**
       * Construct an instance of this handler with the given indentation check,
       * abstract syntax tree, and parent handler.
       *
       * @param indentCheck   the indentation check
       * @param ast           the abstract syntax tree
       * @param parent        the parent handler
       */
      public ClassDefHandler(IndentationCheck indentCheck,
                             DetailAST ast,
                             AbstractExpressionHandler parent) {
          super(indentCheck, getHandlerName(ast), ast, parent);
      }
  
      @Override
      protected DetailAST getLeftCurly() {
          return getMainAst().findFirstToken(TokenTypes.OBJBLOCK)
              .findFirstToken(TokenTypes.LCURLY);
      }
  
      @Override
      protected DetailAST getRightCurly() {
          return getMainAst().findFirstToken(TokenTypes.OBJBLOCK)
              .findFirstToken(TokenTypes.RCURLY);
      }
  
      @Override
      protected DetailAST getTopLevelAst() {
          return null;
          // note: ident checked by hand in check indentation;
      }
  
      @Override
      protected DetailAST getListChild() {
          return getMainAst().findFirstToken(TokenTypes.OBJBLOCK);
      }
  
      @Override
      public void checkIndentation() {
          final DetailAST modifiers = getMainAst().findFirstToken(TokenTypes.MODIFIERS);
          if (modifiers.hasChildren()) {
              checkModifiers();
          }
          else {
              if (getMainAst().getType() != TokenTypes.ANNOTATION_DEF) {
                  final DetailAST ident = getMainAst().findFirstToken(TokenTypes.IDENT);
                  final int lineStart = getLineStart(ident);
                  if (!getIndent().isAcceptable(lineStart)) {
                      logError(ident, "ident", lineStart);
                  }
              }
          }
          if (getMainAst().getType() == TokenTypes.ANNOTATION_DEF) {
              final DetailAST atAst = getMainAst().findFirstToken(TokenTypes.AT);
              if (isOnStartOfLine(atAst)) {
                  checkWrappingIndentation(getMainAst(), getListChild(), 0,
                          getIndent().getFirstIndentLevel(), false);
              }
          }
          else {
              checkWrappingIndentation(getMainAst(), getListChild());
          }
          super.checkIndentation();
      }
  
      @Override
      protected int[] getCheckedChildren() {
          return new int[] {
              TokenTypes.EXPR,
              TokenTypes.OBJBLOCK,
              TokenTypes.LITERAL_BREAK,
              TokenTypes.LITERAL_RETURN,
              TokenTypes.LITERAL_THROW,
              TokenTypes.LITERAL_CONTINUE,
          };
      }
  
      /**
       * Creates a handler name for this class according to ast type.
       *
       * @param ast the abstract syntax tree.
       * @return handler name for this class.
       */
      private static String getHandlerName(DetailAST ast) {
          final String name;
          final int tokenType = ast.getType();
  
          switch (tokenType) {
              case TokenTypes.CLASS_DEF:
                  name = "class def";
                  break;
              case TokenTypes.ENUM_DEF:
                  name = "enum def";
                  break;
              case TokenTypes.ANNOTATION_DEF:
                  name = "annotation def";
                  break;
              case TokenTypes.RECORD_DEF:
                  name = "record def";
                  break;
              default:
                  name = "interface def";
          }
  
          return name;
      }
  
  }
  