001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2021 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.Arrays;
024
025import com.puppycrawl.tools.checkstyle.StatelessCheck;
026import com.puppycrawl.tools.checkstyle.api.FileText;
027
028/**
029 * <p>
030 * Checks that a source file begins with a specified header.
031 * Property {@code headerFile} specifies a file that contains the required header.
032 * Alternatively, the header specification can be set directly in the
033 * {@code header} property without the need for an external file.
034 * </p>
035 * <p>
036 * Property {@code ignoreLines} specifies the line numbers to ignore when matching
037 * lines in a header file. This property is very useful for supporting headers
038 * that contain copyright dates. For example, consider the following header:
039 * </p>
040 * <pre>
041 * line 1: ////////////////////////////////////////////////////////////////////
042 * line 2: // checkstyle:
043 * line 3: // Checks Java source code for adherence to a set of rules.
044 * line 4: // Copyright (C) 2002  Oliver Burn
045 * line 5: ////////////////////////////////////////////////////////////////////
046 * </pre>
047 * <p>
048 * Since the year information will change over time, you can tell Checkstyle
049 * to ignore line 4 by setting property {@code ignoreLines} to {@code 4}.
050 * </p>
051 * <p>
052 * In default configuration, if header is not specified, the default value
053 * of header is set to {@code null} and the check does not rise any violations.
054 * </p>
055 * <ul>
056 * <li>
057 * Property {@code headerFile} - Specify the name of the file containing the required header.
058 * Type is {@code java.net.URI}.
059 * Default value is {@code null}.
060 * </li>
061 * <li>
062 * Property {@code charset} - Specify the character encoding to use when reading the headerFile.
063 * Type is {@code java.lang.String}.
064 * Default value is {@code the charset property of the parent
065 * <a href="https://checkstyle.org/config.html#Checker">Checker</a> module}.
066 * </li>
067 * <li>
068 * Property {@code header} - Specify the required header specified inline.
069 * Individual header lines must be separated by the string {@code "\n"}
070 * (even on platforms with a different line separator), see examples below.
071 * Type is {@code java.lang.String}.
072 * Default value is {@code null}.
073 * </li>
074 * <li>
075 * Property {@code ignoreLines} - Specify the line numbers to ignore.
076 * Type is {@code int[]}.
077 * Default value is {@code ""}.
078 * </li>
079 * <li>
080 * Property {@code fileExtensions} - Specify the file type extension of files to process.
081 * Type is {@code java.lang.String[]}.
082 * Default value is {@code ""}.
083 * </li>
084 * </ul>
085 * <p>
086 * To configure the check such that no violations arise.
087 * Default values of properties are used.
088 * </p>
089 * <pre>
090 * &lt;module name="Header"/&gt;
091 * </pre>
092 * <p>
093 * To configure the check to use header file {@code "config/java.header"}
094 * and ignore lines {@code 2}, {@code 3}, and {@code 4} and only process Java files:
095 * </p>
096 * <pre>
097 * &lt;module name="Header"&gt;
098 *   &lt;property name="headerFile" value="config/java.header"/&gt;
099 *   &lt;property name="ignoreLines" value="2, 3, 4"/&gt;
100 *   &lt;property name="fileExtensions" value="java"/&gt;
101 * &lt;/module&gt;
102 * </pre>
103 * <p>
104 * To configure the check to verify that each file starts with the header
105 * </p>
106 * <pre>
107 * // Copyright (C) 2004 MyCompany
108 * // All rights reserved
109 * </pre>
110 * <p>
111 * without the need for an external header file:
112 * </p>
113 * <pre>
114 * &lt;module name="Header"&gt;
115 *   &lt;property name="header"
116 *     value="// Copyright (C) 2004 MyCompany\n// All rights reserved"/&gt;
117 * &lt;/module&gt;
118 * </pre>
119 * <p>
120 * Parent is {@code com.puppycrawl.tools.checkstyle.Checker}
121 * </p>
122 * <p>
123 * Violation Message Keys:
124 * </p>
125 * <ul>
126 * <li>
127 * {@code header.mismatch}
128 * </li>
129 * <li>
130 * {@code header.missing}
131 * </li>
132 * </ul>
133 *
134 * @since 6.9
135 */
136@StatelessCheck
137public class HeaderCheck extends AbstractHeaderCheck {
138
139    /**
140     * A key is pointing to the warning message text in "messages.properties"
141     * file.
142     */
143    public static final String MSG_MISSING = "header.missing";
144
145    /**
146     * A key is pointing to the warning message text in "messages.properties"
147     * file.
148     */
149    public static final String MSG_MISMATCH = "header.mismatch";
150
151    /** Empty array to avoid instantiations. */
152    private static final int[] EMPTY_INT_ARRAY = new int[0];
153
154    /** Specify the line numbers to ignore. */
155    private int[] ignoreLines = EMPTY_INT_ARRAY;
156
157    /**
158     * Returns true if lineNo is header lines or false.
159     *
160     * @param lineNo a line number
161     * @return if {@code lineNo} is one of the ignored header lines.
162     */
163    private boolean isIgnoreLine(int lineNo) {
164        return Arrays.binarySearch(ignoreLines, lineNo) >= 0;
165    }
166
167    /**
168     * Checks if a code line matches the required header line.
169     *
170     * @param lineNumber the line number to check against the header
171     * @param line the line contents
172     * @return true if and only if the line matches the required header line
173     */
174    private boolean isMatch(int lineNumber, String line) {
175        // skip lines we are meant to ignore
176        return isIgnoreLine(lineNumber + 1)
177            || getHeaderLines().get(lineNumber).equals(line);
178    }
179
180    /**
181     * Setter to specify the line numbers to ignore.
182     *
183     * @param list comma separated list of line numbers to ignore in header.
184     */
185    public void setIgnoreLines(int... list) {
186        ignoreLines = new int[list.length];
187        System.arraycopy(list, 0, ignoreLines, 0, list.length);
188        Arrays.sort(ignoreLines);
189    }
190
191    @Override
192    protected void processFiltered(File file, FileText fileText) {
193        if (getHeaderLines().size() > fileText.size()) {
194            log(1, MSG_MISSING);
195        }
196        else {
197            for (int i = 0; i < getHeaderLines().size(); i++) {
198                if (!isMatch(i, fileText.get(i))) {
199                    log(i + 1, MSG_MISMATCH, getHeaderLines().get(i));
200                    break;
201                }
202            }
203        }
204    }
205
206    @Override
207    protected void postProcessHeaderLines() {
208        // no code
209    }
210
211}