001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2019 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 * Default value is {@code false}.
051 * </li>
052 * <li>
053 * Property {@code fileExtensions} - Specify file type extension of files to process.
054 * Default value is {@code all files}.
055 * </li>
056 * </ul>
057 * <p>
058 * To configure the check to report on the first instance in each file:
059 * </p>
060 * <pre>
061 * &lt;module name=&quot;FileTabCharacter&quot;/&gt;
062 * </pre>
063 * <p>
064 * To configure the check to report on each line in each file:
065 * </p>
066 * <pre>
067 * &lt;module name=&quot;FileTabCharacter&quot;&gt;
068 *   &lt;property name=&quot;eachLine&quot; value=&quot;true&quot;/&gt;
069 * &lt;/module&gt;
070 * </pre>
071 *
072 * @since 5.0
073 */
074@StatelessCheck
075public class FileTabCharacterCheck extends AbstractFileSetCheck {
076
077    /**
078     * A key is pointing to the warning message text in "messages.properties"
079     * file.
080     */
081    public static final String MSG_CONTAINS_TAB = "containsTab";
082
083    /**
084     * A key is pointing to the warning message text in "messages.properties"
085     * file.
086     */
087    public static final String MSG_FILE_CONTAINS_TAB = "file.containsTab";
088
089    /** Control whether to report on each line containing a tab, or just the first instance. */
090    private boolean eachLine;
091
092    @Override
093    protected void processFiltered(File file, FileText fileText) {
094        int lineNum = 0;
095        for (int index = 0; index < fileText.size(); index++) {
096            final String line = fileText.get(index);
097            lineNum++;
098            final int tabPosition = line.indexOf('\t');
099            if (tabPosition != -1) {
100                if (eachLine) {
101                    log(lineNum, tabPosition, MSG_CONTAINS_TAB);
102                }
103                else {
104                    log(lineNum, tabPosition, MSG_FILE_CONTAINS_TAB);
105                    break;
106                }
107            }
108        }
109    }
110
111    /**
112     * Setter to control whether to report on each line containing a tab, or just the first
113     * instance.
114     * @param eachLine Whether report on each line containing a tab.
115     */
116    public void setEachLine(boolean eachLine) {
117        this.eachLine = eachLine;
118    }
119
120}