1 ///////////////////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
3 // Copyright (C) 2001-2025 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.checks;
21
22 import com.puppycrawl.tools.checkstyle.StatelessCheck;
23 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
24 import com.puppycrawl.tools.checkstyle.api.DetailAST;
25 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
26
27 /**
28 * <div>
29 * Checks whether file contains code.
30 * Java compiler is not raising errors on files with no code or all commented out.
31 * Files which are considered to have no code:
32 * </div>
33 *
34 * <ul>
35 * <li>
36 * File with no text
37 * </li>
38 * <li>
39 * File with single-line comment(s)
40 * </li>
41 * <li>
42 * File with a multi line comment(s).
43 * </li>
44 * </ul>
45 *
46 * @since 8.33
47 */
48 @StatelessCheck
49 public class NoCodeInFileCheck extends AbstractCheck {
50
51 /**
52 * A key is pointing to the warning message text in "messages.properties"
53 * file.
54 */
55 public static final String MSG_KEY_NO_CODE = "nocode.in.file";
56
57 /** Line number used to log violation when no AST nodes are present in file. */
58 private static final int DEFAULT_LINE_NUMBER = 1;
59
60 @Override
61 public int[] getDefaultTokens() {
62 return getRequiredTokens();
63 }
64
65 @Override
66 public int[] getAcceptableTokens() {
67 return getRequiredTokens();
68 }
69
70 @Override
71 public int[] getRequiredTokens() {
72 return CommonUtil.EMPTY_INT_ARRAY;
73 }
74
75 @Override
76 public void finishTree(DetailAST ast) {
77 if (ast == null) {
78 log(DEFAULT_LINE_NUMBER, MSG_KEY_NO_CODE);
79 }
80 }
81 }