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.Set;
  
  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.AnnotationUtil;
  import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
  import com.puppycrawl.tools.checkstyle.utils.ScopeUtil;
  
  /**
   * <p>
   * Checks for missing Javadoc comments for class, enum, interface, and annotation interface
   * definitions. The scope to verify is specified using the {@code Scope} class and defaults
   * to {@code Scope.PUBLIC}. To verify another scope, set property scope to one of the
   * {@code Scope} constants.
   * </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 public}.
   * </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 skipAnnotations} - specify annotations that allow missed
   * documentation. If annotation is present in target sources in multiple forms of qualified
   * name, all forms should be listed in this property.
   * Type is {@code java.lang.String[]}.
   * Default value is {@code Generated}.
   * </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#INTERFACE_DEF">
   * INTERFACE_DEF</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CLASS_DEF">
   * CLASS_DEF</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_DEF">
   * ENUM_DEF</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ANNOTATION_DEF">
   * ANNOTATION_DEF</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_DEF">
   * RECORD_DEF</a>.
   * </li>
   * </ul>
   * <p>
   * To configure the default check to make sure all public class, enum, interface, and annotation
   * interface, definitions have javadocs:
   * </p>
   * <pre>
   * &lt;module name="MissingJavadocType"/&gt;
   * </pre>
   * <p>
   * Example:
   * </p>
   * <pre>
   * public class PublicClass {} // violation
   * private class PublicClass {}
   * protected class PublicClass {}
   * class PackagePrivateClass {}
   * </pre>
   * <p>
   * To configure the check for {@code private} scope:
   * </p>
   * <pre>
   * &lt;module name="MissingJavadocType"&gt;
   *   &lt;property name="scope" value="private"/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>
   * Example:
   * </p>
   * <pre>
   * public class PublicClass {} // violation
   * private class PublicClass {} // violation
   * protected class PublicClass {} // violation
   * class PackagePrivateClass {} // violation
   * </pre>
   * <p>
   * To configure the check for {@code private} classes only:
   * </p>
   * <pre>
   * &lt;module name="MissingJavadocType"&gt;
   *   &lt;property name="scope" value="private"/&gt;
   *   &lt;property name="excludeScope" value="package"/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>
   * Example:
   * </p>
   * <pre>
   * public class PublicClass {}
   * private class PublicClass {} // violation
   * protected class PublicClass {}
   * class PackagePrivateClass {}
   * </pre>
   * <p>
   * To configure a check that allows missing comments for classes annotated
   * with {@code @SpringBootApplication} and {@code @Configuration}:
   * </p>
   * <pre>
   * &lt;module name="MissingJavadocType"&gt;
   *   &lt;property name="skipAnnotations" value="SpringBootApplication,Configuration"/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>
   * Example:
   * </p>
   * <pre>
   * &#64;SpringBootApplication // no violations about missing comment on class
   * public class Application {}
   *
   * &#64;Configuration // no violations about missing comment on class
   * class DatabaseConfiguration {}
   * </pre>
   * <p>
   * To configure a check that allows missing comments for classes annotated with {@code @Annotation}
   * and {@code @MyClass.Annotation}:
   * </p>
   * <pre>
   * &lt;module name="MissingJavadocType"&gt;
   *   &lt;property name="skipAnnotations" value="Annotation,MyClass.Annotation"/&gt;
   * &lt;/module&gt;
   * </pre>
   * <p>
   * Example:
   * </p>
   * <pre>
   * &#64;Annotation // ok
   * class Class1 {}
   *
   * &#64;MyClass.Annotation // ok
   * class Class2 {}
   *
   * &#64;com.mycompany.MyClass.Annotation // violation, as this form is missed in config
   * class Class3 {}
   * </pre>
   * <p>
   * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
   * </p>
   * <p>
   * Violation Message Keys:
   * </p>
   * <ul>
   * <li>
   * {@code javadoc.missing}
   * </li>
   * </ul>
   *
   * @since 8.20
   */
  @StatelessCheck
  public class MissingJavadocTypeCheck 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.PUBLIC;
      /** Specify the visibility scope where Javadoc comments are not checked. */
      private Scope excludeScope;
  
      /**
       * Specify annotations that allow missed documentation.
       * If annotation is present in target sources in multiple forms of qualified
       * name, all forms should be listed in this property.
       */
      private Set<String> skipAnnotations = Set.of("Generated");
  
      /**
       * 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 annotations that allow missed documentation.
       * If annotation is present in target sources in multiple forms of qualified
       * name, all forms should be listed in this property.
       *
       * @param userAnnotations user's value.
       */
      public void setSkipAnnotations(String... userAnnotations) {
          skipAnnotations = Set.of(userAnnotations);
      }
  
      @Override
      public int[] getDefaultTokens() {
          return getAcceptableTokens();
      }
  
      @Override
      public int[] getAcceptableTokens() {
          return new int[] {
              TokenTypes.INTERFACE_DEF,
              TokenTypes.CLASS_DEF,
              TokenTypes.ENUM_DEF,
              TokenTypes.ANNOTATION_DEF,
              TokenTypes.RECORD_DEF,
          };
      }
  
      @Override
      public int[] getRequiredTokens() {
          return CommonUtil.EMPTY_INT_ARRAY;
      }
  
      // 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 int lineNo = ast.getLineNo();
              final TextBlock textBlock = contents.getJavadocBefore(lineNo);
              if (textBlock == null) {
                  log(ast, MSG_JAVADOC_MISSING);
              }
          }
      }
  
      /**
       * 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) {
          final Scope customScope = ScopeUtil.getScope(ast);
          final Scope surroundingScope = ScopeUtil.getSurroundingScope(ast);
  
          return customScope.isIn(scope)
              && (surroundingScope == null || surroundingScope.isIn(scope))
              && (excludeScope == null
                  || !customScope.isIn(excludeScope)
                  || surroundingScope != null
                  && !surroundingScope.isIn(excludeScope))
              && !AnnotationUtil.containsAnnotation(ast, skipAnnotations);
      }
  
  }
  