001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2024 the original author or authors.
004//
005// This library is free software; you can redistribute it and/or
006// modify it under the terms of the GNU Lesser General Public
007// License as published by the Free Software Foundation; either
008// version 2.1 of the License, or (at your option) any later version.
009//
010// This library is distributed in the hope that it will be useful,
011// but WITHOUT ANY WARRANTY; without even the implied warranty of
012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013// Lesser General Public License for more details.
014//
015// You should have received a copy of the GNU Lesser General Public
016// License along with this library; if not, write to the Free Software
017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
018///////////////////////////////////////////////////////////////////////////////////////////////
019
020package com.puppycrawl.tools.checkstyle.checks.whitespace;
021
022import java.io.File;
023
024import com.puppycrawl.tools.checkstyle.StatelessCheck;
025import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
026import com.puppycrawl.tools.checkstyle.api.FileText;
027
028/**
029 * <p>
030 * Checks that there are no tab characters ({@code '\t'}) in the source code.
031 * </p>
032 * <p>
033 * Rationale:
034 * </p>
035 * <ul>
036 * <li>
037 * Developers should not need to configure the tab width of their text editors in order
038 * to be able to read source code.
039 * </li>
040 * <li>
041 * From the Apache jakarta coding standards: In a distributed development environment,
042 * when the commit messages get sent to a mailing list, they are almost impossible to
043 * read if you use tabs.
044 * </li>
045 * </ul>
046 * <ul>
047 * <li>
048 * Property {@code eachLine} - Control whether to report on each line containing a tab,
049 * or just the first instance.
050 * Type is {@code boolean}.
051 * Default value is {@code false}.
052 * </li>
053 * <li>
054 * Property {@code fileExtensions} - Specify the file extensions of the files to process.
055 * Type is {@code java.lang.String[]}.
056 * Default value is {@code ""}.
057 * </li>
058 * </ul>
059 * <p>
060 * Parent is {@code com.puppycrawl.tools.checkstyle.Checker}
061 * </p>
062 * <p>
063 * Violation Message Keys:
064 * </p>
065 * <ul>
066 * <li>
067 * {@code containsTab}
068 * </li>
069 * <li>
070 * {@code file.containsTab}
071 * </li>
072 * </ul>
073 *
074 * @since 5.0
075 */
076@StatelessCheck
077public class FileTabCharacterCheck extends AbstractFileSetCheck {
078
079    /**
080     * A key is pointing to the warning message text in "messages.properties"
081     * file.
082     */
083    public static final String MSG_CONTAINS_TAB = "containsTab";
084
085    /**
086     * A key is pointing to the warning message text in "messages.properties"
087     * file.
088     */
089    public static final String MSG_FILE_CONTAINS_TAB = "file.containsTab";
090
091    /** Control whether to report on each line containing a tab, or just the first instance. */
092    private boolean eachLine;
093
094    @Override
095    protected void processFiltered(File file, FileText fileText) {
096        int lineNum = 0;
097        for (int index = 0; index < fileText.size(); index++) {
098            final String line = fileText.get(index);
099            lineNum++;
100            final int tabPosition = line.indexOf('\t');
101            if (tabPosition != -1) {
102                if (eachLine) {
103                    log(lineNum, tabPosition, MSG_CONTAINS_TAB);
104                }
105                else {
106                    log(lineNum, tabPosition, MSG_FILE_CONTAINS_TAB);
107                    break;
108                }
109            }
110        }
111    }
112
113    /**
114     * Setter to control whether to report on each line containing a tab, or just the first
115     * instance.
116     *
117     * @param eachLine Whether report on each line containing a tab.
118     * @since 5.0
119     */
120    public void setEachLine(boolean eachLine) {
121        this.eachLine = eachLine;
122    }
123
124}