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.header;
021
022import java.io.File;
023import java.util.BitSet;
024
025import com.puppycrawl.tools.checkstyle.StatelessCheck;
026import com.puppycrawl.tools.checkstyle.api.FileText;
027import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
028
029/**
030 * <div>
031 * Checks that a source file begins with a specified header.
032 * Property {@code headerFile} specifies a file that contains the required header.
033 * Alternatively, the header specification can be set directly in the
034 * {@code header} property without the need for an external file.
035 * </div>
036 *
037 * <p>
038 * Property {@code ignoreLines} specifies the line numbers to ignore when matching
039 * lines in a header file. This property is very useful for supporting headers
040 * that contain copyright dates. For example, consider the following header:
041 * </p>
042 * <pre>
043 * line 1: ////////////////////////////////////////////////////////////////////
044 * line 2: // checkstyle:
045 * line 3: // Checks Java source code for adherence to a set of rules.
046 * line 4: // Copyright (C) 2002  Oliver Burn
047 * line 5: ////////////////////////////////////////////////////////////////////
048 * </pre>
049 *
050 * <p>
051 * Since the year information will change over time, you can tell Checkstyle
052 * to ignore line 4 by setting property {@code ignoreLines} to {@code 4}.
053 * </p>
054 *
055 * <p>
056 * In default configuration, if header is not specified, the default value
057 * of header is set to {@code null} and the check does not rise any violations.
058 * </p>
059 * <ul>
060 * <li>
061 * Property {@code charset} - Specify the character encoding to use when reading the headerFile.
062 * Type is {@code java.lang.String}.
063 * Default value is {@code the charset property of the parent
064 * <a href="https://checkstyle.org/config.html#Checker">Checker</a> module}.
065 * </li>
066 * <li>
067 * Property {@code fileExtensions} - Specify the file extensions of the files to process.
068 * Type is {@code java.lang.String[]}.
069 * Default value is {@code ""}.
070 * </li>
071 * <li>
072 * Property {@code header} - Specify the required header specified inline.
073 * Individual header lines must be separated by the string {@code "\n"}
074 * (even on platforms with a different line separator).
075 * Type is {@code java.lang.String}.
076 * Default value is {@code null}.
077 * </li>
078 * <li>
079 * Property {@code headerFile} - Specify the name of the file containing the required header.
080 * Type is {@code java.net.URI}.
081 * Default value is {@code null}.
082 * </li>
083 * <li>
084 * Property {@code ignoreLines} - Specify the line numbers to ignore.
085 * Type is {@code int[]}.
086 * Default value is {@code ""}.
087 * </li>
088 * </ul>
089 *
090 * <p>
091 * Parent is {@code com.puppycrawl.tools.checkstyle.Checker}
092 * </p>
093 *
094 * <p>
095 * Violation Message Keys:
096 * </p>
097 * <ul>
098 * <li>
099 * {@code header.mismatch}
100 * </li>
101 * <li>
102 * {@code header.missing}
103 * </li>
104 * </ul>
105 *
106 * @since 6.9
107 */
108@StatelessCheck
109public class HeaderCheck extends AbstractHeaderCheck {
110
111    /**
112     * A key is pointing to the warning message text in "messages.properties"
113     * file.
114     */
115    public static final String MSG_MISSING = "header.missing";
116
117    /**
118     * A key is pointing to the warning message text in "messages.properties"
119     * file.
120     */
121    public static final String MSG_MISMATCH = "header.mismatch";
122
123    /** Specify the line numbers to ignore. */
124    private BitSet ignoreLines = new BitSet();
125
126    /**
127     * Returns true if lineNo is header lines or false.
128     *
129     * @param lineNo a line number
130     * @return if {@code lineNo} is one of the ignored header lines.
131     */
132    private boolean isIgnoreLine(int lineNo) {
133        return ignoreLines.get(lineNo);
134    }
135
136    /**
137     * Checks if a code line matches the required header line.
138     *
139     * @param lineNumber the line number to check against the header
140     * @param line the line contents
141     * @return true if and only if the line matches the required header line
142     */
143    private boolean isMatch(int lineNumber, String line) {
144        // skip lines we are meant to ignore
145        return isIgnoreLine(lineNumber + 1)
146            || getHeaderLines().get(lineNumber).equals(line);
147    }
148
149    /**
150     * Setter to specify the line numbers to ignore.
151     *
152     * @param lines line numbers to ignore in header.
153     * @since 3.2
154     */
155    public void setIgnoreLines(int... lines) {
156        ignoreLines = TokenUtil.asBitSet(lines);
157    }
158
159    @Override
160    protected void processFiltered(File file, FileText fileText) {
161        if (getHeaderLines().size() > fileText.size()) {
162            log(1, MSG_MISSING);
163        }
164        else {
165            for (int i = 0; i < getHeaderLines().size(); i++) {
166                if (!isMatch(i, fileText.get(i))) {
167                    log(i + 1, MSG_MISMATCH, getHeaderLines().get(i));
168                    break;
169                }
170            }
171        }
172    }
173
174    @Override
175    protected void postProcessHeaderLines() {
176        // no code
177    }
178
179}