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.javadoc;
  
  import java.util.regex.Pattern;
  
  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.FileContents;
  import com.puppycrawl.tools.checkstyle.api.Scope;
  import com.puppycrawl.tools.checkstyle.api.TextBlock;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  import com.puppycrawl.tools.checkstyle.utils.ScopeUtil;
  
  /**
   * <p>
   * Checks that a variable has a Javadoc comment. Ignores {@code serialVersionUID} fields.
   * </p>
   * <ul>
   * <li>
   * Property {@code scope} - Specify the visibility scope where Javadoc comments are checked.
   * Type is {@code com.puppycrawl.tools.checkstyle.api.Scope}.
   * Default value is {@code private}.
   * </li>
   * <li>
   * Property {@code excludeScope} - Specify the visibility scope where Javadoc
   * comments are not checked.
   * Type is {@code com.puppycrawl.tools.checkstyle.api.Scope}.
   * Default value is {@code null}.
   * </li>
   * <li>
   * Property {@code ignoreNamePattern} - Specify the regexp to define variable names to ignore.
   * Type is {@code java.util.regex.Pattern}.
   * Default value is {@code null}.
   * </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#ENUM_CONSTANT_DEF">
   * ENUM_CONSTANT_DEF</a>.
   * </li>
   * </ul>
   * <p>
   * To configure the default check:
   * </p>
   * <pre>
   * &lt;module name="JavadocVariable"/&gt;
   * </pre>
   * <p>
   * By default, this setting will report a violation if
   * there is no javadoc for any scope member.
   * </p>
   * <pre>
   * public class Test {
   *   private int a; // violation, missing javadoc for private member
   *
   *   &#47;**
   *    * Some description here
   *    *&#47;
   *   private int b; // OK
   *   protected int c; // violation, missing javadoc for protected member
   *   public int d; // violation, missing javadoc for public member
   *   &#47;*package*&#47; int e; // violation, missing javadoc for package member
   * }
   * </pre>
   * <p>
   * To configure the check for {@code public} scope:
   * </p>
   * <pre>
   * &lt;module name="JavadocVariable"&gt;
   *   &lt;property name="scope" value="public"/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>This setting will report a violation if there is no javadoc for {@code public} member.</p>
   * <pre>
   * public class Test {
   *   private int a; // OK
   *
   *   &#47;**
   *    * Some description here
   *    *&#47;
   *   private int b; // OK
   *   protected int c; // OK
   *   public int d; // violation, missing javadoc for public member
   *   &#47;*package*&#47; int e; // OK
   * }
   * </pre>
   * <p>
   * To configure the check for members which are in {@code private},
   * but not in {@code protected} scope:
   * </p>
   * <pre>
   * &lt;module name="JavadocVariable"&gt;
   *   &lt;property name="scope" value="private"/&gt;
   *   &lt;property name="excludeScope" value="protected"/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>
   * This setting will report a violation if there is no javadoc for {@code private}
   * member and ignores {@code protected} member.
   * </p>
   * <pre>
   * public class Test {
   *   private int a; // violation, missing javadoc for private member
   *
   *   &#47;**
   *    * Some description here
   *    *&#47;
   *   private int b; // OK
   *   protected int c; // OK
   *   public int d; // OK
   *   &#47;*package*&#47; int e; // violation, missing javadoc for package member
   * }
   * </pre>
   * <p>
   * To ignore absence of Javadoc comments for variables with names {@code log} or {@code logger}:
   * </p>
   * <pre>
   * &lt;module name="JavadocVariable"&gt;
   *   &lt;property name="ignoreNamePattern" value="log|logger"/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>
   * This setting will report a violation if there is no javadoc for any scope
   * member and ignores members with name {@code log} or {@code logger}.
   * </p>
   * <pre>
   * public class Test {
   *   private int a; // violation, missing javadoc for private member
   *
   *   &#47;**
   *    * Some description here
   *    *&#47;
   *   private int b; // OK
   *   protected int c; // violation, missing javadoc for protected member
   *   public int d; // violation, missing javadoc for public member
   *   &#47;*package*&#47; int e; // violation, missing javadoc for package member
   *   private int log; // OK
   *   private int logger; // OK
   * }
   * </pre>
   * <p>
   * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
   * </p>
   * <p>
   * Violation Message Keys:
   * </p>
   * <ul>
   * <li>
   * {@code javadoc.missing}
   * </li>
   * </ul>
   *
   * @since 3.0
   */
  @StatelessCheck
  public class JavadocVariableCheck
      extends AbstractCheck {
  
      /**
       * A key is pointing to the warning message text in "messages.properties"
       * file.
       */
      public static final String MSG_JAVADOC_MISSING = "javadoc.missing";
  
      /** Specify the visibility scope where Javadoc comments are checked. */
      private Scope scope = Scope.PRIVATE;
  
      /** Specify the visibility scope where Javadoc comments are not checked. */
      private Scope excludeScope;
  
      /** Specify the regexp to define variable names to ignore. */
      private Pattern ignoreNamePattern;
  
      /**
       * Setter to specify the visibility scope where Javadoc comments are checked.
       *
       * @param scope a scope.
       */
      public void setScope(Scope scope) {
          this.scope = scope;
      }
  
      /**
       * Setter to specify the visibility scope where Javadoc comments are not checked.
       *
       * @param excludeScope a scope.
       */
      public void setExcludeScope(Scope excludeScope) {
          this.excludeScope = excludeScope;
      }
  
      /**
       * Setter to specify the regexp to define variable names to ignore.
       *
       * @param pattern a pattern.
       */
      public void setIgnoreNamePattern(Pattern pattern) {
          ignoreNamePattern = pattern;
      }
  
      @Override
      public int[] getDefaultTokens() {
          return getAcceptableTokens();
      }
  
      @Override
      public int[] getAcceptableTokens() {
          return new int[] {
              TokenTypes.VARIABLE_DEF,
              TokenTypes.ENUM_CONSTANT_DEF,
          };
      }
  
      /*
       * Skipping enum values is requested.
       * Checkstyle's issue #1669: https://github.com/checkstyle/checkstyle/issues/1669
       */
      @Override
      public int[] getRequiredTokens() {
          return new int[] {
              TokenTypes.VARIABLE_DEF,
          };
      }
  
      // suppress deprecation until https://github.com/checkstyle/checkstyle/issues/11166
      @SuppressWarnings("deprecation")
      @Override
      public void visitToken(DetailAST ast) {
          if (shouldCheck(ast)) {
              final FileContents contents = getFileContents();
              final TextBlock textBlock =
                  contents.getJavadocBefore(ast.getLineNo());
  
              if (textBlock == null) {
                  log(ast, MSG_JAVADOC_MISSING);
              }
          }
      }
  
      /**
       * Decides whether the variable name of an AST is in the ignore list.
       *
       * @param ast the AST to check
       * @return true if the variable name of ast is in the ignore list.
       */
      private boolean isIgnored(DetailAST ast) {
          final String name = ast.findFirstToken(TokenTypes.IDENT).getText();
          return ignoreNamePattern != null && ignoreNamePattern.matcher(name).matches()
              || "serialVersionUID".equals(name);
      }
  
      /**
       * Whether we should check this node.
       *
       * @param ast a given node.
       * @return whether we should check a given node.
       */
      private boolean shouldCheck(final DetailAST ast) {
          boolean result = false;
          if (!ScopeUtil.isInCodeBlock(ast) && !isIgnored(ast)) {
              final Scope customScope = ScopeUtil.getScope(ast);
              final Scope surroundingScope = ScopeUtil.getSurroundingScope(ast);
              result = customScope.isIn(scope) && surroundingScope.isIn(scope)
                  && (excludeScope == null
                      || !customScope.isIn(excludeScope)
                      || !surroundingScope.isIn(excludeScope));
          }
          return result;
      }
  
  }
  