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 java.util.Locale;
  
  /**
   * This enum represents access modifiers.
   * Access modifiers names are taken from
   * <a href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-6.html#jls-6.6">JLS</a>
   *
   */
  public enum AccessModifierOption {
  
      /** Public access modifier. */
      PUBLIC,
      /** Protected access modifier. */
      PROTECTED,
      /** Package access modifier. */
      PACKAGE,
      /** Private access modifier. */
      PRIVATE;
  
      @Override
      public String toString() {
          return getName();
      }
  
      /**
       * Returns the access modifier name.
       *
       * @return the access modifier name
       */
      private String getName() {
          return name().toLowerCase(Locale.ENGLISH);
      }
  
      /**
       * Factory method which returns an AccessModifier instance that corresponds to the
       * given access modifier name represented as a {@link String}.
       * The access modifier name can be formatted both as lower case or upper case string.
       * For example, passing PACKAGE or package as a modifier name
       * will return {@link AccessModifierOption#PACKAGE}.
       *
       * @param modifierName access modifier name represented as a {@link String}.
       * @return the AccessModifier associated with given access modifier name.
       */
      public static AccessModifierOption getInstance(String modifierName) {
          return valueOf(AccessModifierOption.class, modifierName.trim().toUpperCase(Locale.ENGLISH));
      }
  
  }
  