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.ScopeUtil;
  
  /**
   * <p>
   * Checks that constant names conform to a specified pattern.
   * A <em>constant</em> is a <strong>static</strong> and <strong>final</strong>
   * field or an interface/annotation field, except
   * <strong>serialVersionUID</strong> and <strong>serialPersistentFields
   * </strong>.
   * </p>
   * <ul>
   * <li>
   * Property {@code format} - Specifies valid identifiers.
   * Type is {@code java.util.regex.Pattern}.
   * Default value is {@code "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$"}.
   * </li>
   * <li>
   * Property {@code applyToPublic} - Controls whether to apply the check to public member.
   * Type is {@code boolean}.
   * Default value is {@code true}.
   * </li>
   * <li>
   * Property {@code applyToProtected} - Controls whether to apply the check to protected member.
   * Type is {@code boolean}.
   * Default value is {@code true}.
   * </li>
   * <li>
   * Property {@code applyToPackage} - Controls whether to apply the check to package-private member.
   * Type is {@code boolean}.
   * Default value is {@code true}.
   * </li>
   * <li>
   * Property {@code applyToPrivate} - Controls whether to apply the check to private member.
   * Type is {@code boolean}.
   * Default value is {@code true}.
   * </li>
   * </ul>
   * <p>
   * To configure the check:
   * </p>
   * <pre>
   * &lt;module name="ConstantName"/&gt;
   * </pre>
   * <p>Example:</p>
   * <pre>
   * class Example1 {
   *   public final static int FIRST_CONSTANT1 = 10;
   *   protected final static int SECOND_CONSTANT2 = 100;
   *   final static int third_Constant3 = 1000; // violation 'must match pattern'
   *   private final static int fourth_Const4 = 50; // violation 'must match pattern'
   *   public final static int log = 10; // violation 'must match pattern'
   *   protected final static int logger = 50; // violation 'must match pattern'
   *   final static int loggerMYSELF = 5; // violation 'must match pattern'
   *   final static int MYSELF = 100;
   *   protected final static int myselfConstant = 1; // violation 'must match pattern'
   * }
   * </pre>
   * <p>
   * The following configuration apart from names allowed by default allows {@code log}
   * or {@code logger}:
   * </p>
   * <pre>
   * &lt;module name=&quot;ConstantName&quot;&gt;
   *   &lt;property name=&quot;format&quot;
   *     value=&quot;^log(ger)?$|^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$&quot;/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>Code Example:</p>
   * <pre>
   * class Example2 {
   *   public final static int FIRST_CONSTANT1 = 10;
   *   protected final static int SECOND_CONSTANT2 = 100;
   *   final static int third_Constant3 = 1000; // violation 'must match pattern'
   *   private final static int fourth_Const4 = 50; // violation 'must match pattern'
   *   public final static int log = 10;
   *   protected final static int logger = 50;
   *   final static int loggerMYSELF = 5; // violation 'must match pattern'
   *   final static int MYSELF = 100;
   *   protected final static int myselfConstant = 1; // violation 'must match pattern'
   * }
   * </pre>
   * <p>
   * The following configuration skip validation on
   * public constant field and protected constant field.
   * </p>
   * <pre>
   * &lt;module name=&quot;ConstantName&quot;&gt;
   *   &lt;property name="applyToPublic" value="false"/&gt;
   *   &lt;property name="applyToProtected" value="false"/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>Code Example:</p>
   * <pre>
   * class Example3 {
   *   public final static int FIRST_CONSTANT1 = 10;
   *   protected final static int SECOND_CONSTANT2 = 100;
   *   final static int third_Constant3 = 1000; // violation 'must match pattern'
   *   private final static int fourth_Const4 = 50; // violation 'must match pattern'
   *   public final static int log = 10;
   *   protected final static int logger = 50;
   *   final static int loggerMYSELF = 5; // violation 'must match pattern'
   *   final static int MYSELF = 100;
   *   protected final static int myselfConstant = 1;
   * }
   * </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 ConstantNameCheck
      extends AbstractAccessControlNameCheck {
  
      /** Creates a new {@code ConstantNameCheck} instance. */
      public ConstantNameCheck() {
          super("^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$");
      }
  
      @Override
      public int[] getDefaultTokens() {
          return getRequiredTokens();
      }
  
      @Override
      public int[] getAcceptableTokens() {
          return getRequiredTokens();
      }
  
      @Override
      public int[] getRequiredTokens() {
          return new int[] {TokenTypes.VARIABLE_DEF};
      }
  
      @Override
      protected final boolean mustCheckName(DetailAST ast) {
          boolean returnValue = false;
  
          final DetailAST modifiersAST =
              ast.findFirstToken(TokenTypes.MODIFIERS);
          final boolean isStaticFinal =
              modifiersAST.findFirstToken(TokenTypes.LITERAL_STATIC) != null
                  && modifiersAST.findFirstToken(TokenTypes.FINAL) != null
              || ScopeUtil.isInAnnotationBlock(ast)
              || ScopeUtil.isInInterfaceBlock(ast);
          if (isStaticFinal && shouldCheckInScope(modifiersAST)
                          && !ScopeUtil.isInCodeBlock(ast)) {
              // Handle the serialVersionUID and serialPersistentFields constants
              // which are used for Serialization. Cannot enforce rules on it. :-)
              final DetailAST nameAST = ast.findFirstToken(TokenTypes.IDENT);
              if (!"serialVersionUID".equals(nameAST.getText())
                  && !"serialPersistentFields".equals(nameAST.getText())) {
                  returnValue = true;
              }
          }
  
          return returnValue;
      }
  
  }
  