1 /*
2 * SPDX-FileCopyrightText: Copyright (c) 2011-2025 Yegor Bugayenko
3 * SPDX-License-Identifier: MIT
4 */
5 package com.qulice.checkstyle;
6
7 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
8 import com.puppycrawl.tools.checkstyle.api.DetailAST;
9 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
10 import java.util.regex.Matcher;
11 import java.util.regex.Pattern;
12
13 /**
14 * C++ style inline comment is not allowed.
15 * Use //-style comment instead.
16 * @since 0.18
17 */
18 public final class SingleLineCommentCheck extends AbstractCheck {
19
20 /**
21 * Pattern for check.
22 * It is not final as it is initialized from the configuration.
23 */
24 private Pattern format = Pattern.compile("^$");
25
26 /**
27 * The message to report for a match.
28 * It is not final as it is initialized from the configuration.
29 */
30 private String message = "";
31
32 /**
33 * Comment line.
34 * It is not final because the visitToken method is called many times
35 * during the class under test and the field is reinitialized with a new object.
36 */
37 @SuppressWarnings("PMD.AvoidStringBufferField")
38 private final StringBuilder line = new StringBuilder();
39
40 /**
41 * When inside a block comment, holds begin line number.
42 */
43 private int begin;
44
45 @Override
46 public boolean isCommentNodesRequired() {
47 return true;
48 }
49
50 @Override
51 public int[] getDefaultTokens() {
52 return new int[]{
53 TokenTypes.BLOCK_COMMENT_BEGIN,
54 TokenTypes.COMMENT_CONTENT,
55 TokenTypes.BLOCK_COMMENT_END,
56 };
57 }
58
59 @Override
60 public int[] getAcceptableTokens() {
61 return this.getDefaultTokens();
62 }
63
64 @Override
65 public int[] getRequiredTokens() {
66 return this.getDefaultTokens();
67 }
68
69 @Override
70 public void visitToken(final DetailAST ast) {
71 if (ast.getType() == TokenTypes.BLOCK_COMMENT_BEGIN) {
72 this.line.setLength(0);
73 this.line.append(ast.getText());
74 this.begin = ast.getLineNo();
75 } else if (ast.getType() == TokenTypes.COMMENT_CONTENT) {
76 this.line.append(ast.getText());
77 } else {
78 this.line.append(ast.getText());
79 final Matcher matcher = this.format.matcher(this.line.toString());
80 if (matcher.matches() && this.singleLineCStyleComment(ast)) {
81 this.log(ast, this.message);
82 }
83 }
84 }
85
86 /**
87 * The method is called from checkstyle to configure this class.
88 * The parameter is set from the checks.xml file
89 * <module name="com.qulice.checkstyle.SingleLineCommentCheck"/> and
90 * <property name="format" value=" this regexp "/> property
91 *
92 * @param fmt Validatig regexp.
93 */
94 public void setFormat(final String fmt) {
95 this.format = Pattern.compile(fmt);
96 }
97
98 /**
99 * The method is called from checkstyle to configure this class.
100 * The parameter is set from the checks.xml file
101 * <module name="com.qulice.checkstyle.SingleLineCommentCheck"/> and
102 * <property name="message" value="This kind of comment is not allowed."/>
103 * property
104 *
105 * @param msg Error message.
106 */
107 public void setMessage(final String msg) {
108 this.message = msg;
109 }
110
111 /**
112 * Checks for the end of a comment line.
113 * @param ast Checkstyle's AST nodes.
114 * @return True if this is the end of the comment
115 * and the starting line number is equal to the ending line number.
116 */
117 private boolean singleLineCStyleComment(final DetailAST ast) {
118 return ast.getType() == TokenTypes.BLOCK_COMMENT_END && this.begin == ast.getLineNo();
119 }
120 }