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.whitespace;
21
22 import java.io.File;
23
24 import com.puppycrawl.tools.checkstyle.StatelessCheck;
25 import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
26 import com.puppycrawl.tools.checkstyle.api.FileText;
27
28 /**
29 * <div>
30 * Checks that there are no tab characters ({@code '\t'}) in the source code.
31 * </div>
32 *
33 * <p>
34 * Rationale:
35 * </p>
36 * <ul>
37 * <li>
38 * Developers should not need to configure the tab width of their text editors in order
39 * to be able to read source code.
40 * </li>
41 * <li>
42 * From the Apache jakarta coding standards: In a distributed development environment,
43 * when the commit messages get sent to a mailing list, they are almost impossible to
44 * read if you use tabs.
45 * </li>
46 * </ul>
47 *
48 * <p>
49 * Notes:
50 * When the {@code FileTabCharacter} check is used with the default configuration,
51 * only the first instance of a tab character is reported.
52 * </p>
53 *
54 * @since 5.0
55 */
56 @StatelessCheck
57 public class FileTabCharacterCheck extends AbstractFileSetCheck {
58
59 /**
60 * A key is pointing to the warning message text in "messages.properties"
61 * file.
62 */
63 public static final String MSG_CONTAINS_TAB = "containsTab";
64
65 /**
66 * A key is pointing to the warning message text in "messages.properties"
67 * file.
68 */
69 public static final String MSG_FILE_CONTAINS_TAB = "file.containsTab";
70
71 /** Control whether to report on each line containing a tab, or just the first instance. */
72 private boolean eachLine;
73
74 @Override
75 protected void processFiltered(File file, FileText fileText) {
76 int lineNum = 0;
77 for (int index = 0; index < fileText.size(); index++) {
78 final String line = fileText.get(index);
79 lineNum++;
80 final int tabPosition = line.indexOf('\t');
81 if (tabPosition != -1) {
82 if (eachLine) {
83 log(lineNum, tabPosition, MSG_CONTAINS_TAB);
84 }
85 else {
86 log(lineNum, tabPosition, MSG_FILE_CONTAINS_TAB);
87 break;
88 }
89 }
90 }
91 }
92
93 /**
94 * Setter to control whether to report on each line containing a tab, or just the first
95 * instance.
96 *
97 * @param eachLine Whether report on each line containing a tab.
98 * @since 5.0
99 */
100 public void setEachLine(boolean eachLine) {
101 this.eachLine = eachLine;
102 }
103
104 }