///////////////////////////////////////////////////////////////////////////////////////////////
   // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
   // Copyright (C) 2001-2025 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.whitespace;
  
  import java.util.ArrayList;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Optional;
  
  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.TokenTypes;
  import com.puppycrawl.tools.checkstyle.utils.CheckUtil;
  import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
  import com.puppycrawl.tools.checkstyle.utils.JavadocUtil;
  import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
  
  /**
   * <div>
   * Checks for empty line separators before package, all import declarations,
   * fields, constructors, methods, nested classes,
   * static initializers and instance initializers.
   * </div>
   *
   * <p>
   * Checks for empty line separators before not only statements but
   * implementation and documentation comments and blocks as well.
   * </p>
   *
   * <p>
   * ATTENTION: empty line separator is required between token siblings,
   * not after line where token is found.
   * If token does not have a sibling of the same type, then empty line
   * is required at its end (for example for CLASS_DEF it is after '}').
   * Also, trailing comments are skipped.
   * </p>
   * <ul>
   * <li>
   * Property {@code allowMultipleEmptyLines} - Allow multiple empty lines between class members.
   * Type is {@code boolean}.
   * Default value is {@code true}.
   * </li>
   * <li>
   * Property {@code allowMultipleEmptyLinesInsideClassMembers} - Allow multiple
   * empty lines inside class members.
   * Type is {@code boolean}.
   * Default value is {@code true}.
   * </li>
   * <li>
   * Property {@code allowNoEmptyLineBetweenFields} - Allow no empty line between fields.
   * Type is {@code boolean}.
   * Default value is {@code false}.
   * </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#PACKAGE_DEF">
   * PACKAGE_DEF</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#IMPORT">
   * IMPORT</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#STATIC_IMPORT">
   * STATIC_IMPORT</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#INTERFACE_DEF">
   * INTERFACE_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#STATIC_INIT">
   * STATIC_INIT</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INSTANCE_INIT">
   * INSTANCE_INIT</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#METHOD_DEF">
   * METHOD_DEF</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CTOR_DEF">
   * CTOR_DEF</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">
   * VARIABLE_DEF</a>,
   * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_DEF">
  * RECORD_DEF</a>,
  * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#COMPACT_CTOR_DEF">
  * COMPACT_CTOR_DEF</a>.
  * </li>
  * </ul>
  *
  * <p>
  * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
  * </p>
  *
  * <p>
  * Violation Message Keys:
  * </p>
  * <ul>
  * <li>
  * {@code empty.line.separator}
  * </li>
  * <li>
  * {@code empty.line.separator.multiple.lines}
  * </li>
  * <li>
  * {@code empty.line.separator.multiple.lines.after}
  * </li>
  * <li>
  * {@code empty.line.separator.multiple.lines.inside}
  * </li>
  * </ul>
  *
  * @since 5.8
  */
 @StatelessCheck
 public class EmptyLineSeparatorCheck extends AbstractCheck {
 
     /**
      * A key is pointing to the warning message empty.line.separator in "messages.properties"
      * file.
      */
     public static final String MSG_SHOULD_BE_SEPARATED = "empty.line.separator";
 
     /**
      * A key is pointing to the warning message empty.line.separator.multiple.lines
      *  in "messages.properties"
      * file.
      */
     public static final String MSG_MULTIPLE_LINES = "empty.line.separator.multiple.lines";
 
     /**
      * A key is pointing to the warning message empty.line.separator.lines.after
      * in "messages.properties" file.
      */
     public static final String MSG_MULTIPLE_LINES_AFTER =
             "empty.line.separator.multiple.lines.after";
 
     /**
      * A key is pointing to the warning message empty.line.separator.multiple.lines.inside
      * in "messages.properties" file.
      */
     public static final String MSG_MULTIPLE_LINES_INSIDE =
             "empty.line.separator.multiple.lines.inside";
 
     /** Allow no empty line between fields. */
     private boolean allowNoEmptyLineBetweenFields;
 
     /** Allow multiple empty lines between class members. */
     private boolean allowMultipleEmptyLines = true;
 
     /** Allow multiple empty lines inside class members. */
     private boolean allowMultipleEmptyLinesInsideClassMembers = true;
 
     /**
      * Setter to allow no empty line between fields.
      *
      * @param allow
      *        User's value.
      * @since 5.8
      */
     public final void setAllowNoEmptyLineBetweenFields(boolean allow) {
         allowNoEmptyLineBetweenFields = allow;
     }
 
     /**
      * Setter to allow multiple empty lines between class members.
      *
      * @param allow User's value.
      * @since 6.3
      */
     public void setAllowMultipleEmptyLines(boolean allow) {
         allowMultipleEmptyLines = allow;
     }
 
     /**
      * Setter to allow multiple empty lines inside class members.
      *
      * @param allow User's value.
      * @since 6.18
      */
     public void setAllowMultipleEmptyLinesInsideClassMembers(boolean allow) {
         allowMultipleEmptyLinesInsideClassMembers = allow;
     }
 
     @Override
     public boolean isCommentNodesRequired() {
         return true;
     }
 
     @Override
     public int[] getDefaultTokens() {
         return getAcceptableTokens();
     }
 
     @Override
     public int[] getAcceptableTokens() {
         return new int[] {
             TokenTypes.PACKAGE_DEF,
             TokenTypes.IMPORT,
             TokenTypes.STATIC_IMPORT,
             TokenTypes.CLASS_DEF,
             TokenTypes.INTERFACE_DEF,
             TokenTypes.ENUM_DEF,
             TokenTypes.STATIC_INIT,
             TokenTypes.INSTANCE_INIT,
             TokenTypes.METHOD_DEF,
             TokenTypes.CTOR_DEF,
             TokenTypes.VARIABLE_DEF,
             TokenTypes.RECORD_DEF,
             TokenTypes.COMPACT_CTOR_DEF,
         };
     }
 
     @Override
     public int[] getRequiredTokens() {
         return CommonUtil.EMPTY_INT_ARRAY;
     }
 
     @Override
     public void visitToken(DetailAST ast) {
         checkComments(ast);
         if (hasMultipleLinesBefore(ast)) {
             log(ast, MSG_MULTIPLE_LINES, ast.getText());
         }
         if (!allowMultipleEmptyLinesInsideClassMembers) {
             processMultipleLinesInside(ast);
         }
         if (ast.getType() == TokenTypes.PACKAGE_DEF) {
             checkCommentInModifiers(ast);
         }
         DetailAST nextToken = ast.getNextSibling();
         while (nextToken != null && TokenUtil.isCommentType(nextToken.getType())) {
             nextToken = nextToken.getNextSibling();
         }
         if (nextToken != null) {
             checkToken(ast, nextToken);
         }
     }
 
     /**
      * Checks that token and next token are separated.
      *
      * @param ast token to validate
      * @param nextToken next sibling of the token
      */
     private void checkToken(DetailAST ast, DetailAST nextToken) {
         final int astType = ast.getType();
 
         switch (astType) {
             case TokenTypes.VARIABLE_DEF -> processVariableDef(ast, nextToken);
 
             case TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT -> processImport(ast, nextToken);
 
             case TokenTypes.PACKAGE_DEF -> processPackage(ast, nextToken);
 
             default -> {
                 if (nextToken.getType() == TokenTypes.RCURLY) {
                     if (hasNotAllowedTwoEmptyLinesBefore(nextToken)) {
                         final DetailAST result = getLastElementBeforeEmptyLines(
                                 ast, nextToken.getLineNo()
                         );
                         log(result, MSG_MULTIPLE_LINES_AFTER, result.getText());
                     }
                 }
                 else if (!hasEmptyLineAfter(ast)) {
                     log(nextToken, MSG_SHOULD_BE_SEPARATED, nextToken.getText());
                 }
             }
         }
     }
 
     /**
      * Checks that packageDef token is separated from comment in modifiers.
      *
      * @param packageDef package def token
      */
     private void checkCommentInModifiers(DetailAST packageDef) {
         final Optional<DetailAST> comment = findCommentUnder(packageDef);
         comment.ifPresent(commentValue -> {
             log(commentValue, MSG_SHOULD_BE_SEPARATED, commentValue.getText());
         });
     }
 
     /**
      * Log violation in case there are multiple empty lines inside constructor,
      * initialization block or method.
      *
      * @param ast the ast to check.
      */
     private void processMultipleLinesInside(DetailAST ast) {
         final int astType = ast.getType();
         if (isClassMemberBlock(astType)) {
             final List<Integer> emptyLines = getEmptyLines(ast);
             final List<Integer> emptyLinesToLog = getEmptyLinesToLog(emptyLines);
             for (Integer lineNo : emptyLinesToLog) {
                 log(getLastElementBeforeEmptyLines(ast, lineNo), MSG_MULTIPLE_LINES_INSIDE);
             }
         }
     }
 
     /**
      * Returns the element after which empty lines exist.
      *
      * @param ast the ast to check.
      * @param line the empty line which gives violation.
      * @return The DetailAST after which empty lines are present.
      */
     private static DetailAST getLastElementBeforeEmptyLines(DetailAST ast, int line) {
         DetailAST result = ast;
         if (ast.getFirstChild().getLineNo() <= line) {
             result = ast.getFirstChild();
             while (result.getNextSibling() != null
                     && result.getNextSibling().getLineNo() <= line) {
                 result = result.getNextSibling();
             }
             if (result.hasChildren()) {
                 result = getLastElementBeforeEmptyLines(result, line);
             }
         }
 
         if (result.getNextSibling() != null) {
             final Optional<DetailAST> postFixNode = getPostFixNode(result.getNextSibling());
             if (postFixNode.isPresent()) {
                 // A post fix AST will always have a sibling METHOD CALL
                 // METHOD CALL will at least have two children
                 // The first child is DOT in case of POSTFIX which have at least 2 children
                 // First child of DOT again puts us back to normal AST tree which will
                 // recurse down below from here
                 final DetailAST firstChildAfterPostFix = postFixNode.orElseThrow();
                 result = getLastElementBeforeEmptyLines(firstChildAfterPostFix, line);
             }
         }
         return result;
     }
 
     /**
      * Gets postfix Node from AST if present.
      *
      * @param ast the AST used to get postfix Node.
      * @return Optional postfix node.
      */
     private static Optional<DetailAST> getPostFixNode(DetailAST ast) {
         Optional<DetailAST> result = Optional.empty();
         if (ast.getType() == TokenTypes.EXPR
             // EXPR always has at least one child
             && ast.getFirstChild().getType() == TokenTypes.METHOD_CALL) {
             // METHOD CALL always has at two least child
             final DetailAST node = ast.getFirstChild().getFirstChild();
             if (node.getType() == TokenTypes.DOT) {
                 result = Optional.of(node);
             }
         }
         return result;
     }
 
     /**
      * Whether the AST is a class member block.
      *
      * @param astType the AST to check.
      * @return true if the AST is a class member block.
      */
     private static boolean isClassMemberBlock(int astType) {
         return TokenUtil.isOfType(astType,
             TokenTypes.STATIC_INIT, TokenTypes.INSTANCE_INIT, TokenTypes.METHOD_DEF,
             TokenTypes.CTOR_DEF, TokenTypes.COMPACT_CTOR_DEF);
     }
 
     /**
      * Get list of empty lines.
      *
      * @param ast the ast to check.
      * @return list of line numbers for empty lines.
      */
     private List<Integer> getEmptyLines(DetailAST ast) {
         final DetailAST lastToken = ast.getLastChild().getLastChild();
         int lastTokenLineNo = 0;
         if (lastToken != null) {
             // -1 as count starts from 0
             // -2 as last token line cannot be empty, because it is a RCURLY
             lastTokenLineNo = lastToken.getLineNo() - 2;
         }
         final List<Integer> emptyLines = new ArrayList<>();
 
         for (int lineNo = ast.getLineNo(); lineNo <= lastTokenLineNo; lineNo++) {
             if (CommonUtil.isBlank(getLine(lineNo))) {
                 emptyLines.add(lineNo);
             }
         }
         return emptyLines;
     }
 
     /**
      * Get list of empty lines to log.
      *
      * @param emptyLines list of empty lines.
      * @return list of empty lines to log.
      */
     private static List<Integer> getEmptyLinesToLog(Iterable<Integer> emptyLines) {
         final List<Integer> emptyLinesToLog = new ArrayList<>();
         int previousEmptyLineNo = -1;
         for (int emptyLineNo : emptyLines) {
             if (previousEmptyLineNo + 1 == emptyLineNo) {
                 emptyLinesToLog.add(previousEmptyLineNo);
             }
             previousEmptyLineNo = emptyLineNo;
         }
         return emptyLinesToLog;
     }
 
     /**
      * Whether the token has not allowed multiple empty lines before.
      *
      * @param ast the ast to check.
      * @return true if the token has not allowed multiple empty lines before.
      */
     private boolean hasMultipleLinesBefore(DetailAST ast) {
         return (ast.getType() != TokenTypes.VARIABLE_DEF || isTypeField(ast))
                 && hasNotAllowedTwoEmptyLinesBefore(ast);
     }
 
     /**
      * Process Package.
      *
      * @param ast token
      * @param nextToken next token
      */
     private void processPackage(DetailAST ast, DetailAST nextToken) {
         if (ast.getLineNo() > 1 && !hasEmptyLineBefore(ast)) {
             if (CheckUtil.isPackageInfo(getFilePath())) {
                 if (!ast.getFirstChild().hasChildren() && !isPrecededByJavadoc(ast)) {
                     log(ast, MSG_SHOULD_BE_SEPARATED, ast.getText());
                 }
             }
             else {
                 log(ast, MSG_SHOULD_BE_SEPARATED, ast.getText());
             }
         }
         if (isLineEmptyAfterPackage(ast)) {
             final DetailAST elementAst = getViolationAstForPackage(ast);
             log(elementAst, MSG_SHOULD_BE_SEPARATED, elementAst.getText());
         }
         else if (!hasEmptyLineAfter(ast)) {
             log(nextToken, MSG_SHOULD_BE_SEPARATED, nextToken.getText());
         }
     }
 
     /**
      * Checks if there is another element at next line of package declaration.
      *
      * @param ast Package ast.
      * @return true, if there is an element.
      */
     private static boolean isLineEmptyAfterPackage(DetailAST ast) {
         DetailAST nextElement = ast;
         final int lastChildLineNo = ast.getLastChild().getLineNo();
         while (nextElement.getLineNo() < lastChildLineNo + 1
                 && nextElement.getNextSibling() != null) {
             nextElement = nextElement.getNextSibling();
         }
         return nextElement.getLineNo() == lastChildLineNo + 1;
     }
 
     /**
      * Gets the Ast on which violation is to be given for package declaration.
      *
      * @param ast Package ast.
      * @return Violation ast.
      */
     private static DetailAST getViolationAstForPackage(DetailAST ast) {
         DetailAST nextElement = ast;
         final int lastChildLineNo = ast.getLastChild().getLineNo();
         while (nextElement.getLineNo() < lastChildLineNo + 1) {
             nextElement = nextElement.getNextSibling();
         }
         return nextElement;
     }
 
     /**
      * Process Import.
      *
      * @param ast token
      * @param nextToken next token
      */
     private void processImport(DetailAST ast, DetailAST nextToken) {
         if (!TokenUtil.isOfType(nextToken, TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT)
             && !hasEmptyLineAfter(ast)) {
             log(nextToken, MSG_SHOULD_BE_SEPARATED, nextToken.getText());
         }
     }
 
     /**
      * Process Variable.
      *
      * @param ast token
      * @param nextToken next Token
      */
     private void processVariableDef(DetailAST ast, DetailAST nextToken) {
         if (isTypeField(ast) && !hasEmptyLineAfter(ast)
                 && isViolatingEmptyLineBetweenFieldsPolicy(nextToken)) {
             log(nextToken, MSG_SHOULD_BE_SEPARATED,
                     nextToken.getText());
         }
     }
 
     /**
      * Checks whether token placement violates policy of empty line between fields.
      *
      * @param detailAST token to be analyzed
      * @return true if policy is violated and warning should be raised; false otherwise
      */
     private boolean isViolatingEmptyLineBetweenFieldsPolicy(DetailAST detailAST) {
         return detailAST.getType() != TokenTypes.RCURLY
                 && (!allowNoEmptyLineBetweenFields
                     || !TokenUtil.isOfType(detailAST, TokenTypes.COMMA, TokenTypes.VARIABLE_DEF));
     }
 
     /**
      * Checks if a token has empty two previous lines and multiple empty lines is not allowed.
      *
      * @param token DetailAST token
      * @return true, if token has empty two lines before and allowMultipleEmptyLines is false
      */
     private boolean hasNotAllowedTwoEmptyLinesBefore(DetailAST token) {
         return !allowMultipleEmptyLines && hasEmptyLineBefore(token)
                 && isPrePreviousLineEmpty(token);
     }
 
     /**
      * Check if group of comments located right before token has more than one previous empty line.
      *
      * @param token DetailAST token
      */
     private void checkComments(DetailAST token) {
         if (!allowMultipleEmptyLines) {
             if (TokenUtil.isOfType(token,
                 TokenTypes.PACKAGE_DEF, TokenTypes.IMPORT,
                 TokenTypes.STATIC_IMPORT, TokenTypes.STATIC_INIT)) {
                 DetailAST previousNode = token.getPreviousSibling();
                 while (isCommentInBeginningOfLine(previousNode)) {
                     if (hasEmptyLineBefore(previousNode) && isPrePreviousLineEmpty(previousNode)) {
                         log(previousNode, MSG_MULTIPLE_LINES, previousNode.getText());
                     }
                     previousNode = previousNode.getPreviousSibling();
                 }
             }
             else {
                 checkCommentsInsideToken(token);
             }
         }
     }
 
     /**
      * Check if group of comments located at the start of token has more than one previous empty
      * line.
      *
      * @param token DetailAST token
      */
     private void checkCommentsInsideToken(DetailAST token) {
         final List<DetailAST> childNodes = new LinkedList<>();
         DetailAST childNode = token.getLastChild();
         while (childNode != null) {
             if (childNode.getType() == TokenTypes.MODIFIERS) {
                 for (DetailAST node = token.getFirstChild().getLastChild();
                          node != null;
                          node = node.getPreviousSibling()) {
                     if (isCommentInBeginningOfLine(node)) {
                         childNodes.add(node);
                     }
                 }
             }
             else if (isCommentInBeginningOfLine(childNode)) {
                 childNodes.add(childNode);
             }
             childNode = childNode.getPreviousSibling();
         }
         for (DetailAST node : childNodes) {
             if (hasEmptyLineBefore(node) && isPrePreviousLineEmpty(node)) {
                 log(node, MSG_MULTIPLE_LINES, node.getText());
             }
         }
     }
 
     /**
      * Checks if a token has empty pre-previous line.
      *
      * @param token DetailAST token.
      * @return true, if token has empty lines before.
      */
     private boolean isPrePreviousLineEmpty(DetailAST token) {
         boolean result = false;
         final int lineNo = token.getLineNo();
         // 3 is the number of the pre-previous line because the numbering starts from zero.
         final int number = 3;
         if (lineNo >= number) {
             final String prePreviousLine = getLine(lineNo - number);
 
             result = CommonUtil.isBlank(prePreviousLine);
             final boolean previousLineIsEmpty = CommonUtil.isBlank(getLine(lineNo - 2));
 
             if (previousLineIsEmpty && result) {
                 result = true;
             }
             else if (token.findFirstToken(TokenTypes.TYPE) != null) {
                 result = isTwoPrecedingPreviousLinesFromCommentEmpty(token);
             }
         }
         return result;
 
     }
 
     /**
      * Checks if token has two preceding lines empty, starting from its describing comment.
      *
      * @param token token checked.
      * @return true, if both previous and pre-previous lines from dependent comment are empty
      */
     private boolean isTwoPrecedingPreviousLinesFromCommentEmpty(DetailAST token) {
         boolean upToPrePreviousLinesEmpty = false;
 
         for (DetailAST typeChild = token.findFirstToken(TokenTypes.TYPE).getLastChild();
              typeChild != null; typeChild = typeChild.getPreviousSibling()) {
 
             if (isTokenNotOnPreviousSiblingLines(typeChild, token)) {
 
                 final String commentBeginningPreviousLine =
                     getLine(typeChild.getLineNo() - 2);
                 final String commentBeginningPrePreviousLine =
                     getLine(typeChild.getLineNo() - 3);
 
                 if (CommonUtil.isBlank(commentBeginningPreviousLine)
                     && CommonUtil.isBlank(commentBeginningPrePreviousLine)) {
                     upToPrePreviousLinesEmpty = true;
                     break;
                 }
 
             }
 
         }
 
         return upToPrePreviousLinesEmpty;
     }
 
     /**
      * Checks if token is not placed on the realm of previous sibling of token's parent.
      *
      * @param token token checked.
      * @param parentToken parent token.
      * @return true, if child token doesn't occupy parent token's previous sibling's realm.
      */
     private static boolean isTokenNotOnPreviousSiblingLines(DetailAST token,
                                                             DetailAST parentToken) {
         DetailAST previousSibling = parentToken.getPreviousSibling();
         for (DetailAST astNode = previousSibling; astNode != null;
              astNode = astNode.getLastChild()) {
             previousSibling = astNode;
         }
 
         return token.getLineNo() != previousSibling.getLineNo();
     }
 
     /**
      * Checks if token have empty line after.
      *
      * @param token token.
      * @return true if token have empty line after.
      */
     private boolean hasEmptyLineAfter(DetailAST token) {
         DetailAST lastToken = token.getLastChild().getLastChild();
         if (lastToken == null) {
             lastToken = token.getLastChild();
         }
         DetailAST nextToken = token.getNextSibling();
         if (TokenUtil.isCommentType(nextToken.getType())) {
             nextToken = nextToken.getNextSibling();
         }
         // Start of the next token
         final int nextBegin = nextToken.getLineNo();
         // End of current token.
         final int currentEnd = lastToken.getLineNo();
         return hasEmptyLine(currentEnd + 1, nextBegin - 1);
     }
 
     /**
      * Finds comment in next sibling of given packageDef.
      *
      * @param packageDef token to check
      * @return comment under the token
      */
     private static Optional<DetailAST> findCommentUnder(DetailAST packageDef) {
         return Optional.ofNullable(packageDef.getNextSibling())
             .map(sibling -> sibling.findFirstToken(TokenTypes.MODIFIERS))
             .map(DetailAST::getFirstChild)
             .filter(token -> TokenUtil.isCommentType(token.getType()))
             .filter(comment -> comment.getLineNo() == packageDef.getLineNo() + 1);
     }
 
     /**
      * Checks, whether there are empty lines within the specified line range. Line numbering is
      * started from 1 for parameter values
      *
      * @param startLine number of the first line in the range
      * @param endLine number of the second line in the range
      * @return {@code true} if found any blank line within the range, {@code false}
      *         otherwise
      */
     private boolean hasEmptyLine(int startLine, int endLine) {
         // Initial value is false - blank line not found
         boolean result = false;
         for (int line = startLine; line <= endLine; line++) {
             // Check, if the line is blank. Lines are numbered from 0, so subtract 1
             if (CommonUtil.isBlank(getLine(line - 1))) {
                 result = true;
                 break;
             }
         }
         return result;
     }
 
     /**
      * Checks if a token has an empty line before.
      *
      * @param token token.
      * @return true, if token have empty line before.
      */
     private boolean hasEmptyLineBefore(DetailAST token) {
         boolean result = false;
         final int lineNo = token.getLineNo();
         if (lineNo != 1) {
             // [lineNo - 2] is the number of the previous line as the numbering starts from zero.
             final String lineBefore = getLine(lineNo - 2);
 
             if (CommonUtil.isBlank(lineBefore)) {
                 result = true;
             }
             else if (token.findFirstToken(TokenTypes.TYPE) != null) {
                 for (DetailAST typeChild = token.findFirstToken(TokenTypes.TYPE).getLastChild();
                      typeChild != null && !result && typeChild.getLineNo() > 1;
                      typeChild = typeChild.getPreviousSibling()) {
 
                     final String commentBeginningPreviousLine =
                         getLine(typeChild.getLineNo() - 2);
                     result = CommonUtil.isBlank(commentBeginningPreviousLine);
 
                 }
             }
         }
         return result;
     }
 
     /**
      * Check if token is comment, which starting in beginning of line.
      *
      * @param comment comment token for check.
      * @return true, if token is comment, which starting in beginning of line.
      */
     private boolean isCommentInBeginningOfLine(DetailAST comment) {
         // comment.getLineNo() - 1 is the number of the previous line as the numbering starts
         // from zero.
         boolean result = false;
         if (comment != null) {
             final String lineWithComment = getLine(comment.getLineNo() - 1).trim();
             result = lineWithComment.startsWith("//") || lineWithComment.startsWith("/*");
         }
         return result;
     }
 
     /**
      * Check if token is preceded by javadoc comment.
      *
      * @param token token for check.
      * @return true, if token is preceded by javadoc comment.
      */
     private static boolean isPrecededByJavadoc(DetailAST token) {
         boolean result = false;
         final DetailAST previous = token.getPreviousSibling();
         if (previous.getType() == TokenTypes.BLOCK_COMMENT_BEGIN
                 && JavadocUtil.isJavadocComment(previous.getFirstChild().getText())) {
             result = true;
         }
         return result;
     }
 
     /**
      * If variable definition is a type field.
      *
      * @param variableDef variable definition.
      * @return true variable definition is a type field.
      */
     private static boolean isTypeField(DetailAST variableDef) {
         return TokenUtil.isTypeDeclaration(variableDef.getParent().getParent().getType());
     }
 
 }