View Javadoc
1   ///////////////////////////////////////////////////////////////////////////////////////////////
2   // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
3   // Copyright (C) 2001-2026 the original author or authors.
4   //
5   // This library is free software; you can redistribute it and/or
6   // modify it under the terms of the GNU Lesser General Public
7   // License as published by the Free Software Foundation; either
8   // version 2.1 of the License, or (at your option) any later version.
9   //
10  // This library is distributed in the hope that it will be useful,
11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  // Lesser General Public License for more details.
14  //
15  // You should have received a copy of the GNU Lesser General Public
16  // License along with this library; if not, write to the Free Software
17  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  ///////////////////////////////////////////////////////////////////////////////////////////////
19  
20  package com.puppycrawl.tools.checkstyle;
21  
22  import java.util.HashSet;
23  import java.util.List;
24  import java.util.Set;
25  
26  import org.antlr.v4.runtime.BufferedTokenStream;
27  import org.antlr.v4.runtime.CommonTokenStream;
28  import org.antlr.v4.runtime.ParserRuleContext;
29  import org.antlr.v4.runtime.Token;
30  import org.antlr.v4.runtime.tree.ParseTree;
31  import org.antlr.v4.runtime.tree.TerminalNode;
32  
33  import com.puppycrawl.tools.checkstyle.api.DetailNode;
34  import com.puppycrawl.tools.checkstyle.api.JavadocCommentsTokenTypes;
35  import com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocNodeImpl;
36  import com.puppycrawl.tools.checkstyle.grammar.javadoc.JavadocCommentsLexer;
37  import com.puppycrawl.tools.checkstyle.grammar.javadoc.JavadocCommentsParser;
38  import com.puppycrawl.tools.checkstyle.grammar.javadoc.JavadocCommentsParserBaseVisitor;
39  import com.puppycrawl.tools.checkstyle.utils.JavadocUtil;
40  
41  /**
42   * Visitor class used to build Checkstyle's Javadoc AST from the parse tree
43   * produced by {@link JavadocCommentsParser}. Each overridden {@code visit...}
44   * method visits children of a parse tree node (subrules) or creates terminal
45   * nodes (tokens), and returns a {@link JavadocNodeImpl} subtree as the result.
46   *
47   * <p>
48   * The order of {@code visit...} methods in {@code JavaAstVisitor.java} and production rules in
49   * {@code JavaLanguageParser.g4} should be consistent to ease maintenance.
50   * </p>
51   *
52   * @see JavadocCommentsLexer
53   * @see JavadocCommentsParser
54   * @see JavadocNodeImpl
55   * @see JavaAstVisitor
56   * @noinspection JavadocReference
57   * @noinspectionreason JavadocReference - References are valid
58   */
59  public class JavadocCommentsAstVisitor extends JavadocCommentsParserBaseVisitor<JavadocNodeImpl> {
60  
61      /**
62       * All Javadoc tag token types.
63       */
64      private static final Set<Integer> JAVADOC_TAG_TYPES = Set.of(
65          JavadocCommentsLexer.CODE,
66          JavadocCommentsLexer.LINK,
67          JavadocCommentsLexer.LINKPLAIN,
68          JavadocCommentsLexer.VALUE,
69          JavadocCommentsLexer.INHERIT_DOC,
70          JavadocCommentsLexer.SUMMARY,
71          JavadocCommentsLexer.SYSTEM_PROPERTY,
72          JavadocCommentsLexer.INDEX,
73          JavadocCommentsLexer.RETURN,
74          JavadocCommentsLexer.LITERAL,
75          JavadocCommentsLexer.SNIPPET,
76          JavadocCommentsLexer.CUSTOM_NAME,
77          JavadocCommentsLexer.AUTHOR,
78          JavadocCommentsLexer.DEPRECATED,
79          JavadocCommentsLexer.PARAM,
80          JavadocCommentsLexer.THROWS,
81          JavadocCommentsLexer.EXCEPTION,
82          JavadocCommentsLexer.SINCE,
83          JavadocCommentsLexer.VERSION,
84          JavadocCommentsLexer.SEE,
85          JavadocCommentsLexer.LITERAL_HIDDEN,
86          JavadocCommentsLexer.USES,
87          JavadocCommentsLexer.PROVIDES,
88          JavadocCommentsLexer.SERIAL,
89          JavadocCommentsLexer.SERIAL_DATA,
90          JavadocCommentsLexer.SERIAL_FIELD
91      );
92  
93      /**
94       * Line number of the Block comment AST that is being parsed.
95       */
96      private final int blockCommentLineNumber;
97  
98      /**
99       * Javadoc Ident.
100      */
101     private final int javadocColumnNumber;
102 
103     /**
104      * Token stream to check for hidden tokens.
105      */
106     private final BufferedTokenStream tokens;
107 
108     /**
109      * A set of token indices used to track which tokens have already had their
110      * hidden tokens added to the AST.
111      */
112     private final Set<Integer> processedTokenIndices = new HashSet<>();
113 
114     /**
115      * Accumulator for consecutive TEXT tokens.
116      * This is used to merge multiple TEXT tokens into a single node.
117      */
118     private final TextAccumulator accumulator = new TextAccumulator();
119 
120     /**
121      * The first non-tight HTML tag encountered in the Javadoc comment, if any.
122      */
123     private DetailNode firstNonTightHtmlTag;
124 
125     /**
126      * Constructs a JavaAstVisitor with given token stream, line number, and column number.
127      *
128      * @param tokens the token stream to check for hidden tokens
129      * @param blockCommentLineNumber the line number of the block comment being parsed
130      * @param javadocColumnNumber the column number of the javadoc indent
131      */
132     public JavadocCommentsAstVisitor(CommonTokenStream tokens,
133                                      int blockCommentLineNumber, int javadocColumnNumber) {
134         this.tokens = tokens;
135         this.blockCommentLineNumber = blockCommentLineNumber;
136         this.javadocColumnNumber = javadocColumnNumber;
137     }
138 
139     @Override
140     public JavadocNodeImpl visitJavadoc(JavadocCommentsParser.JavadocContext ctx) {
141         return buildImaginaryNode(JavadocCommentsTokenTypes.JAVADOC_CONTENT, ctx);
142     }
143 
144     @Override
145     public JavadocNodeImpl visitMainDescription(JavadocCommentsParser.MainDescriptionContext ctx) {
146         return flattenedTree(ctx);
147     }
148 
149     @Override
150     public JavadocNodeImpl visitBlockTag(JavadocCommentsParser.BlockTagContext ctx) {
151         final JavadocNodeImpl blockTagNode =
152                 createImaginary(JavadocCommentsTokenTypes.JAVADOC_BLOCK_TAG);
153         final ParseTree tag = ctx.getChild(0);
154         final Token tagName = (Token) tag.getChild(1).getPayload();
155         final int tokenType = tagName.getType();
156         final JavadocNodeImpl specificTagNode = switch (tokenType) {
157             case JavadocCommentsLexer.AUTHOR ->
158                 buildImaginaryNode(JavadocCommentsTokenTypes.AUTHOR_BLOCK_TAG, ctx);
159             case JavadocCommentsLexer.DEPRECATED ->
160                 buildImaginaryNode(JavadocCommentsTokenTypes.DEPRECATED_BLOCK_TAG, ctx);
161             case JavadocCommentsLexer.RETURN ->
162                 buildImaginaryNode(JavadocCommentsTokenTypes.RETURN_BLOCK_TAG, ctx);
163             case JavadocCommentsLexer.PARAM ->
164                 buildImaginaryNode(JavadocCommentsTokenTypes.PARAM_BLOCK_TAG, ctx);
165             case JavadocCommentsLexer.THROWS ->
166                 buildImaginaryNode(JavadocCommentsTokenTypes.THROWS_BLOCK_TAG, ctx);
167             case JavadocCommentsLexer.EXCEPTION ->
168                 buildImaginaryNode(JavadocCommentsTokenTypes.EXCEPTION_BLOCK_TAG, ctx);
169             case JavadocCommentsLexer.SINCE ->
170                 buildImaginaryNode(JavadocCommentsTokenTypes.SINCE_BLOCK_TAG, ctx);
171             case JavadocCommentsLexer.VERSION ->
172                 buildImaginaryNode(JavadocCommentsTokenTypes.VERSION_BLOCK_TAG, ctx);
173             case JavadocCommentsLexer.SEE ->
174                 buildImaginaryNode(JavadocCommentsTokenTypes.SEE_BLOCK_TAG, ctx);
175             case JavadocCommentsLexer.LITERAL_HIDDEN ->
176                 buildImaginaryNode(JavadocCommentsTokenTypes.HIDDEN_BLOCK_TAG, ctx);
177             case JavadocCommentsLexer.USES ->
178                 buildImaginaryNode(JavadocCommentsTokenTypes.USES_BLOCK_TAG, ctx);
179             case JavadocCommentsLexer.PROVIDES ->
180                 buildImaginaryNode(JavadocCommentsTokenTypes.PROVIDES_BLOCK_TAG, ctx);
181             case JavadocCommentsLexer.SERIAL ->
182                 buildImaginaryNode(JavadocCommentsTokenTypes.SERIAL_BLOCK_TAG, ctx);
183             case JavadocCommentsLexer.SERIAL_DATA ->
184                 buildImaginaryNode(JavadocCommentsTokenTypes.SERIAL_DATA_BLOCK_TAG, ctx);
185             case JavadocCommentsLexer.SERIAL_FIELD ->
186                 buildImaginaryNode(JavadocCommentsTokenTypes.SERIAL_FIELD_BLOCK_TAG, ctx);
187             default ->
188                 buildImaginaryNode(JavadocCommentsTokenTypes.CUSTOM_BLOCK_TAG, ctx);
189         };
190         blockTagNode.addChild(specificTagNode);
191 
192         return blockTagNode;
193     }
194 
195     @Override
196     public JavadocNodeImpl visitAuthorTag(JavadocCommentsParser.AuthorTagContext ctx) {
197         return flattenedTree(ctx);
198     }
199 
200     @Override
201     public JavadocNodeImpl visitDeprecatedTag(JavadocCommentsParser.DeprecatedTagContext ctx) {
202         return flattenedTree(ctx);
203     }
204 
205     @Override
206     public JavadocNodeImpl visitReturnTag(JavadocCommentsParser.ReturnTagContext ctx) {
207         return flattenedTree(ctx);
208     }
209 
210     @Override
211     public JavadocNodeImpl visitParameterTag(JavadocCommentsParser.ParameterTagContext ctx) {
212         return flattenedTree(ctx);
213     }
214 
215     @Override
216     public JavadocNodeImpl visitThrowsTag(JavadocCommentsParser.ThrowsTagContext ctx) {
217         return flattenedTree(ctx);
218     }
219 
220     @Override
221     public JavadocNodeImpl visitExceptionTag(JavadocCommentsParser.ExceptionTagContext ctx) {
222         return flattenedTree(ctx);
223     }
224 
225     @Override
226     public JavadocNodeImpl visitSinceTag(JavadocCommentsParser.SinceTagContext ctx) {
227         return flattenedTree(ctx);
228     }
229 
230     @Override
231     public JavadocNodeImpl visitVersionTag(JavadocCommentsParser.VersionTagContext ctx) {
232         return flattenedTree(ctx);
233     }
234 
235     @Override
236     public JavadocNodeImpl visitSeeTag(JavadocCommentsParser.SeeTagContext ctx) {
237         return flattenedTree(ctx);
238     }
239 
240     @Override
241     public JavadocNodeImpl visitHiddenTag(JavadocCommentsParser.HiddenTagContext ctx) {
242         return flattenedTree(ctx);
243     }
244 
245     @Override
246     public JavadocNodeImpl visitUsesTag(JavadocCommentsParser.UsesTagContext ctx) {
247         return flattenedTree(ctx);
248     }
249 
250     @Override
251     public JavadocNodeImpl visitProvidesTag(JavadocCommentsParser.ProvidesTagContext ctx) {
252         return flattenedTree(ctx);
253     }
254 
255     @Override
256     public JavadocNodeImpl visitSerialTag(JavadocCommentsParser.SerialTagContext ctx) {
257         return flattenedTree(ctx);
258     }
259 
260     @Override
261     public JavadocNodeImpl visitSerialDataTag(JavadocCommentsParser.SerialDataTagContext ctx) {
262         return flattenedTree(ctx);
263     }
264 
265     @Override
266     public JavadocNodeImpl visitSerialFieldTag(JavadocCommentsParser.SerialFieldTagContext ctx) {
267         return flattenedTree(ctx);
268     }
269 
270     @Override
271     public JavadocNodeImpl visitCustomBlockTag(JavadocCommentsParser.CustomBlockTagContext ctx) {
272         return flattenedTree(ctx);
273     }
274 
275     @Override
276     public JavadocNodeImpl visitInlineTag(JavadocCommentsParser.InlineTagContext ctx) {
277         final JavadocNodeImpl inlineTagNode =
278                 createImaginary(JavadocCommentsTokenTypes.JAVADOC_INLINE_TAG);
279         final ParseTree tagContent = ctx.inlineTagContent().getChild(0);
280         final Token tagName = (Token) tagContent.getChild(0).getPayload();
281         final int tokenType = tagName.getType();
282         final JavadocNodeImpl specificTagNode = switch (tokenType) {
283             case JavadocCommentsLexer.CODE ->
284                 buildImaginaryNode(JavadocCommentsTokenTypes.CODE_INLINE_TAG, ctx);
285             case JavadocCommentsLexer.LINK ->
286                 buildImaginaryNode(JavadocCommentsTokenTypes.LINK_INLINE_TAG, ctx);
287             case JavadocCommentsLexer.LINKPLAIN ->
288                 buildImaginaryNode(JavadocCommentsTokenTypes.LINKPLAIN_INLINE_TAG, ctx);
289             case JavadocCommentsLexer.VALUE ->
290                 buildImaginaryNode(JavadocCommentsTokenTypes.VALUE_INLINE_TAG, ctx);
291             case JavadocCommentsLexer.INHERIT_DOC ->
292                 buildImaginaryNode(JavadocCommentsTokenTypes.INHERIT_DOC_INLINE_TAG, ctx);
293             case JavadocCommentsLexer.SUMMARY ->
294                 buildImaginaryNode(JavadocCommentsTokenTypes.SUMMARY_INLINE_TAG, ctx);
295             case JavadocCommentsLexer.SYSTEM_PROPERTY ->
296                 buildImaginaryNode(JavadocCommentsTokenTypes.SYSTEM_PROPERTY_INLINE_TAG, ctx);
297             case JavadocCommentsLexer.INDEX ->
298                 buildImaginaryNode(JavadocCommentsTokenTypes.INDEX_INLINE_TAG, ctx);
299             case JavadocCommentsLexer.RETURN ->
300                 buildImaginaryNode(JavadocCommentsTokenTypes.RETURN_INLINE_TAG, ctx);
301             case JavadocCommentsLexer.LITERAL ->
302                 buildImaginaryNode(JavadocCommentsTokenTypes.LITERAL_INLINE_TAG, ctx);
303             case JavadocCommentsLexer.SNIPPET ->
304                 buildImaginaryNode(JavadocCommentsTokenTypes.SNIPPET_INLINE_TAG, ctx);
305             default -> buildImaginaryNode(JavadocCommentsTokenTypes.CUSTOM_INLINE_TAG, ctx);
306         };
307         inlineTagNode.addChild(specificTagNode);
308 
309         return inlineTagNode;
310     }
311 
312     @Override
313     public JavadocNodeImpl visitInlineTagContent(
314             JavadocCommentsParser.InlineTagContentContext ctx) {
315         return flattenedTree(ctx);
316     }
317 
318     @Override
319     public JavadocNodeImpl visitCodeInlineTag(JavadocCommentsParser.CodeInlineTagContext ctx) {
320         return flattenedTree(ctx);
321     }
322 
323     @Override
324     public JavadocNodeImpl visitLinkPlainInlineTag(
325             JavadocCommentsParser.LinkPlainInlineTagContext ctx) {
326         return flattenedTree(ctx);
327     }
328 
329     @Override
330     public JavadocNodeImpl visitLinkInlineTag(JavadocCommentsParser.LinkInlineTagContext ctx) {
331         return flattenedTree(ctx);
332     }
333 
334     @Override
335     public JavadocNodeImpl visitValueInlineTag(JavadocCommentsParser.ValueInlineTagContext ctx) {
336         return flattenedTree(ctx);
337     }
338 
339     @Override
340     public JavadocNodeImpl visitInheritDocInlineTag(
341             JavadocCommentsParser.InheritDocInlineTagContext ctx) {
342         return flattenedTree(ctx);
343     }
344 
345     @Override
346     public JavadocNodeImpl visitSummaryInlineTag(
347             JavadocCommentsParser.SummaryInlineTagContext ctx) {
348         return flattenedTree(ctx);
349     }
350 
351     @Override
352     public JavadocNodeImpl visitSystemPropertyInlineTag(
353             JavadocCommentsParser.SystemPropertyInlineTagContext ctx) {
354         return flattenedTree(ctx);
355     }
356 
357     @Override
358     public JavadocNodeImpl visitIndexInlineTag(JavadocCommentsParser.IndexInlineTagContext ctx) {
359         return flattenedTree(ctx);
360     }
361 
362     @Override
363     public JavadocNodeImpl visitReturnInlineTag(JavadocCommentsParser.ReturnInlineTagContext ctx) {
364         return flattenedTree(ctx);
365     }
366 
367     @Override
368     public JavadocNodeImpl visitLiteralInlineTag(
369             JavadocCommentsParser.LiteralInlineTagContext ctx) {
370         return flattenedTree(ctx);
371     }
372 
373     @Override
374     public JavadocNodeImpl visitSnippetInlineTag(
375             JavadocCommentsParser.SnippetInlineTagContext ctx) {
376         final JavadocNodeImpl dummyRoot = new JavadocNodeImpl();
377         if (!ctx.snippetAttributes.isEmpty()) {
378             final JavadocNodeImpl snippetAttributes =
379                     createImaginary(JavadocCommentsTokenTypes.SNIPPET_ATTRIBUTES);
380             ctx.snippetAttributes.forEach(snippetAttributeContext -> {
381                 final JavadocNodeImpl snippetAttribute = visit(snippetAttributeContext);
382                 snippetAttributes.addChild(snippetAttribute);
383             });
384             dummyRoot.addChild(snippetAttributes);
385         }
386         if (ctx.COLON() != null) {
387             dummyRoot.addChild(create((Token) ctx.COLON().getPayload()));
388         }
389         if (ctx.snippetBody() != null) {
390             dummyRoot.addChild(visit(ctx.snippetBody()));
391         }
392         return dummyRoot.getFirstChild();
393     }
394 
395     @Override
396     public JavadocNodeImpl visitCustomInlineTag(JavadocCommentsParser.CustomInlineTagContext ctx) {
397         return flattenedTree(ctx);
398     }
399 
400     @Override
401     public JavadocNodeImpl visitReference(JavadocCommentsParser.ReferenceContext ctx) {
402         return buildImaginaryNode(JavadocCommentsTokenTypes.REFERENCE, ctx);
403     }
404 
405     @Override
406     public JavadocNodeImpl visitTypeName(JavadocCommentsParser.TypeNameContext ctx) {
407         return flattenedTree(ctx);
408 
409     }
410 
411     @Override
412     public JavadocNodeImpl visitQualifiedName(JavadocCommentsParser.QualifiedNameContext ctx) {
413         return flattenedTree(ctx);
414     }
415 
416     @Override
417     public JavadocNodeImpl visitTypeArguments(JavadocCommentsParser.TypeArgumentsContext ctx) {
418         return buildImaginaryNode(JavadocCommentsTokenTypes.TYPE_ARGUMENTS, ctx);
419     }
420 
421     @Override
422     public JavadocNodeImpl visitTypeArgument(JavadocCommentsParser.TypeArgumentContext ctx) {
423         return buildImaginaryNode(JavadocCommentsTokenTypes.TYPE_ARGUMENT, ctx);
424     }
425 
426     @Override
427     public JavadocNodeImpl visitMemberReference(JavadocCommentsParser.MemberReferenceContext ctx) {
428         return buildImaginaryNode(JavadocCommentsTokenTypes.MEMBER_REFERENCE, ctx);
429     }
430 
431     @Override
432     public JavadocNodeImpl visitParameterTypeList(
433             JavadocCommentsParser.ParameterTypeListContext ctx) {
434         return buildImaginaryNode(JavadocCommentsTokenTypes.PARAMETER_TYPE_LIST, ctx);
435     }
436 
437     @Override
438     public JavadocNodeImpl visitDescription(JavadocCommentsParser.DescriptionContext ctx) {
439         return buildImaginaryNode(JavadocCommentsTokenTypes.DESCRIPTION, ctx);
440     }
441 
442     @Override
443     public JavadocNodeImpl visitSnippetAttribute(
444             JavadocCommentsParser.SnippetAttributeContext ctx) {
445         return buildImaginaryNode(JavadocCommentsTokenTypes.SNIPPET_ATTRIBUTE, ctx);
446     }
447 
448     @Override
449     public JavadocNodeImpl visitSnippetBody(JavadocCommentsParser.SnippetBodyContext ctx) {
450         return buildImaginaryNode(JavadocCommentsTokenTypes.SNIPPET_BODY, ctx);
451     }
452 
453     @Override
454     public JavadocNodeImpl visitHtmlElement(JavadocCommentsParser.HtmlElementContext ctx) {
455         return buildImaginaryNode(JavadocCommentsTokenTypes.HTML_ELEMENT, ctx);
456     }
457 
458     @Override
459     public JavadocNodeImpl visitVoidElement(JavadocCommentsParser.VoidElementContext ctx) {
460         return buildImaginaryNode(JavadocCommentsTokenTypes.VOID_ELEMENT, ctx);
461     }
462 
463     @Override
464     public JavadocNodeImpl visitTightElement(JavadocCommentsParser.TightElementContext ctx) {
465         return flattenedTree(ctx);
466     }
467 
468     @Override
469     public JavadocNodeImpl visitNonTightElement(JavadocCommentsParser.NonTightElementContext ctx) {
470         if (firstNonTightHtmlTag == null) {
471             final ParseTree htmlTagStart = ctx.getChild(0);
472             final ParseTree tagNameToken = htmlTagStart.getChild(1);
473             firstNonTightHtmlTag = create((Token) tagNameToken.getPayload());
474         }
475         return flattenedTree(ctx);
476     }
477 
478     @Override
479     public JavadocNodeImpl visitSelfClosingElement(
480             JavadocCommentsParser.SelfClosingElementContext ctx) {
481         final JavadocNodeImpl javadocNode =
482                 createImaginary(JavadocCommentsTokenTypes.VOID_ELEMENT);
483         javadocNode.addChild(create((Token) ctx.TAG_OPEN().getPayload()));
484         javadocNode.addChild(create((Token) ctx.TAG_NAME().getPayload()));
485         if (!ctx.htmlAttributes.isEmpty()) {
486             final JavadocNodeImpl htmlAttributes =
487                     createImaginary(JavadocCommentsTokenTypes.HTML_ATTRIBUTES);
488             ctx.htmlAttributes.forEach(htmlAttributeContext -> {
489                 final JavadocNodeImpl htmlAttribute = visit(htmlAttributeContext);
490                 htmlAttributes.addChild(htmlAttribute);
491             });
492             javadocNode.addChild(htmlAttributes);
493         }
494 
495         javadocNode.addChild(create((Token) ctx.TAG_SLASH_CLOSE().getPayload()));
496         return javadocNode;
497     }
498 
499     @Override
500     public JavadocNodeImpl visitHtmlTagStart(JavadocCommentsParser.HtmlTagStartContext ctx) {
501         final JavadocNodeImpl javadocNode =
502                 createImaginary(JavadocCommentsTokenTypes.HTML_TAG_START);
503         javadocNode.addChild(create((Token) ctx.TAG_OPEN().getPayload()));
504         javadocNode.addChild(create((Token) ctx.TAG_NAME().getPayload()));
505         if (!ctx.htmlAttributes.isEmpty()) {
506             final JavadocNodeImpl htmlAttributes =
507                     createImaginary(JavadocCommentsTokenTypes.HTML_ATTRIBUTES);
508             ctx.htmlAttributes.forEach(htmlAttributeContext -> {
509                 final JavadocNodeImpl htmlAttribute = visit(htmlAttributeContext);
510                 htmlAttributes.addChild(htmlAttribute);
511             });
512             javadocNode.addChild(htmlAttributes);
513         }
514 
515         final Token tagClose = (Token) ctx.TAG_CLOSE().getPayload();
516         addHiddenTokensToTheLeft(tagClose, javadocNode);
517         javadocNode.addChild(create(tagClose));
518         return javadocNode;
519     }
520 
521     @Override
522     public JavadocNodeImpl visitHtmlTagEnd(JavadocCommentsParser.HtmlTagEndContext ctx) {
523         return buildImaginaryNode(JavadocCommentsTokenTypes.HTML_TAG_END, ctx);
524     }
525 
526     @Override
527     public JavadocNodeImpl visitHtmlAttribute(JavadocCommentsParser.HtmlAttributeContext ctx) {
528         return buildImaginaryNode(JavadocCommentsTokenTypes.HTML_ATTRIBUTE, ctx);
529     }
530 
531     @Override
532     public JavadocNodeImpl visitHtmlContent(JavadocCommentsParser.HtmlContentContext ctx) {
533         return buildImaginaryNode(JavadocCommentsTokenTypes.HTML_CONTENT, ctx);
534     }
535 
536     @Override
537     public JavadocNodeImpl visitNonTightHtmlContent(
538             JavadocCommentsParser.NonTightHtmlContentContext ctx) {
539         return buildImaginaryNode(JavadocCommentsTokenTypes.HTML_CONTENT, ctx);
540     }
541 
542     @Override
543     public JavadocNodeImpl visitHtmlComment(JavadocCommentsParser.HtmlCommentContext ctx) {
544         return buildImaginaryNode(JavadocCommentsTokenTypes.HTML_COMMENT, ctx);
545     }
546 
547     @Override
548     public JavadocNodeImpl visitHtmlCommentContent(
549             JavadocCommentsParser.HtmlCommentContentContext ctx) {
550         return buildImaginaryNode(JavadocCommentsTokenTypes.HTML_COMMENT_CONTENT, ctx);
551     }
552 
553     /**
554      * Creates an imaginary JavadocNodeImpl of the given token type and
555      * processes all children of the given ParserRuleContext.
556      *
557      * @param tokenType the token type of this JavadocNodeImpl
558      * @param ctx the ParserRuleContext whose children are to be processed
559      * @return new JavadocNodeImpl of given type with processed children
560      */
561     private JavadocNodeImpl buildImaginaryNode(int tokenType, ParserRuleContext ctx) {
562         final JavadocNodeImpl javadocNode = createImaginary(tokenType);
563         processChildren(javadocNode, ctx.children);
564         return javadocNode;
565     }
566 
567     /**
568      * Builds the AST for a particular node, then returns a "flattened" tree
569      * of siblings.
570      *
571      * @param ctx the ParserRuleContext to base tree on
572      * @return flattened DetailAstImpl
573      */
574     private JavadocNodeImpl flattenedTree(ParserRuleContext ctx) {
575         final JavadocNodeImpl dummyNode = new JavadocNodeImpl();
576         processChildren(dummyNode, ctx.children);
577         return dummyNode.getFirstChild();
578     }
579 
580     /**
581      * Adds all the children from the given ParseTree or ParserRuleContext
582      * list to the parent JavadocNodeImpl.
583      *
584      * @param parent   the JavadocNodeImpl to add children to
585      * @param children the list of children to add
586      */
587     private void processChildren(JavadocNodeImpl parent, List<? extends ParseTree> children) {
588         for (ParseTree child : children) {
589             if (child instanceof TerminalNode terminalNode) {
590                 final Token token = (Token) terminalNode.getPayload();
591 
592                 // Add hidden tokens before this token
593                 addHiddenTokensToTheLeft(token, parent);
594 
595                 if (isTextToken(token)) {
596                     accumulator.append(token);
597                 }
598                 else if (token.getType() != Token.EOF) {
599                     parent.addChild(create(token));
600                 }
601             }
602             else {
603                 accumulator.flushTo(parent);
604                 final Token token = ((ParserRuleContext) child).getStart();
605                 addHiddenTokensToTheLeft(token, parent);
606                 parent.addChild(visit(child));
607             }
608         }
609 
610         accumulator.flushTo(parent);
611     }
612 
613     /**
614      * Checks whether a token is a Javadoc text token.
615      *
616      * @param token the token to check
617      * @return true if the token is a text token, false otherwise
618      */
619     private static boolean isTextToken(Token token) {
620         return token.getType() == JavadocCommentsTokenTypes.TEXT;
621     }
622 
623     /**
624      * Adds hidden tokens to the left of the given token to the parent node.
625      * Ensures text accumulation is flushed before adding hidden tokens.
626      * Hidden tokens are only added once per unique token index.
627      *
628      * @param token      the token whose hidden tokens should be added
629      * @param parent     the parent node to which hidden tokens are added
630      */
631     private void addHiddenTokensToTheLeft(Token token, JavadocNodeImpl parent) {
632         final boolean alreadyProcessed = !processedTokenIndices.add(token.getTokenIndex());
633 
634         if (!alreadyProcessed) {
635             final int tokenIndex = token.getTokenIndex();
636             final List<Token> hiddenTokens = tokens.getHiddenTokensToLeft(tokenIndex);
637             if (hiddenTokens != null) {
638                 accumulator.flushTo(parent);
639                 for (Token hiddenToken : hiddenTokens) {
640                     parent.addChild(create(hiddenToken));
641                 }
642             }
643         }
644     }
645 
646     /**
647      * Creates a JavadocNodeImpl from the given token.
648      *
649      * @param token the token to create the JavadocNodeImpl from
650      * @return a new JavadocNodeImpl initialized with the token
651      */
652     private JavadocNodeImpl create(Token token) {
653         final JavadocNodeImpl node = new JavadocNodeImpl();
654         node.initialize(token);
655 
656         // adjust line number to the position of the block comment
657         node.setLineNumber(node.getLineNumber() + blockCommentLineNumber);
658 
659         // adjust first line to indent of /**
660         if (node.getLineNumber() == blockCommentLineNumber) {
661             node.setColumnNumber(node.getColumnNumber() + javadocColumnNumber);
662         }
663 
664         if (isJavadocTag(token.getType())) {
665             node.setType(JavadocCommentsTokenTypes.TAG_NAME);
666         }
667 
668         if (token.getType() == JavadocCommentsLexer.WS) {
669             node.setType(JavadocCommentsTokenTypes.TEXT);
670         }
671 
672         return node;
673     }
674 
675     /**
676      * Checks if the given token type is a Javadoc tag.
677      *
678      * @param type the token type to check
679      * @return true if the token type is a Javadoc tag, false otherwise
680      */
681     private static boolean isJavadocTag(int type) {
682         return JAVADOC_TAG_TYPES.contains(type);
683     }
684 
685     /**
686      * Create a JavadocNodeImpl from a given token and token type. This method
687      * should be used for imaginary nodes only, i.e. 'JAVADOC_INLINE_TAG -&gt; JAVADOC_INLINE_TAG',
688      * where the text on the RHS matches the text on the LHS.
689      *
690      * @param tokenType the token type of this JavadocNodeImpl
691      * @return new JavadocNodeImpl of given type
692      */
693     private JavadocNodeImpl createImaginary(int tokenType) {
694         final JavadocNodeImpl node = new JavadocNodeImpl();
695         node.setType(tokenType);
696         node.setText(JavadocUtil.getTokenName(tokenType));
697         node.setLineNumber(blockCommentLineNumber);
698         node.setColumnNumber(javadocColumnNumber);
699         return node;
700     }
701 
702     /**
703      * Returns the first non-tight HTML tag encountered in the Javadoc comment, if any.
704      *
705      * @return the first non-tight HTML tag, or null if none was found
706      */
707     public DetailNode getFirstNonTightHtmlTag() {
708         return firstNonTightHtmlTag;
709     }
710 
711     /**
712      * A small utility to accumulate consecutive TEXT tokens into one node,
713      * preserving the starting token for accurate location metadata.
714      */
715     private final class TextAccumulator {
716         /**
717          * Buffer to accumulate TEXT token texts.
718          *
719          * @noinspection StringBufferField
720          * @noinspectionreason StringBufferField - We want to reuse the same buffer to avoid
721          */
722         private final StringBuilder buffer = new StringBuilder(256);
723 
724         /**
725          * The first token in the accumulation, used for line/column info.
726          */
727         private Token startToken;
728 
729         /**
730          * Appends a TEXT token's text to the buffer and tracks the first token.
731          *
732          * @param token the token to accumulate
733          */
734         /* package */ void append(Token token) {
735             if (buffer.isEmpty()) {
736                 startToken = token;
737             }
738             buffer.append(token.getText());
739         }
740 
741         /**
742          * Flushes the accumulated buffer into a single {@link JavadocNodeImpl} node
743          * and adds it to the given parent. Clears the buffer after flushing.
744          *
745          * @param parent the parent node to add the new node to
746          */
747         /* package */ void flushTo(JavadocNodeImpl parent) {
748             if (!buffer.isEmpty()) {
749                 final JavadocNodeImpl startNode = create(startToken);
750                 startNode.setText(buffer.toString());
751                 parent.addChild(startNode);
752                 buffer.setLength(0);
753             }
754         }
755     }
756 }