001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2022 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.naming;
021
022import com.puppycrawl.tools.checkstyle.StatelessCheck;
023import com.puppycrawl.tools.checkstyle.api.DetailAST;
024import com.puppycrawl.tools.checkstyle.api.TokenTypes;
025import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
026
027/**
028 * <p>
029 * Checks identifiers with a pattern for a set of illegal names, such as those
030 * that are restricted or contextual keywords. Examples include "yield", "record", "_", and
031 * "var". Please read more at
032 * <a href="https://docs.oracle.com/javase/specs/jls/se14/html/jls-3.html#jls-3.9">
033 * Java Language Specification</a> to get to know more about restricted keywords. Since this
034 * check uses a pattern to specify valid identifiers, users can also prohibit the usage
035 * of certain symbols, such as "$", or any non-ascii character.
036 * </p>
037 * <ul>
038 * <li>
039 * Property {@code format} - Specifies valid identifiers.
040 * Type is {@code java.util.regex.Pattern}.
041 * Default value is {@code "(?i)^(?!(record|yield|var|permits|sealed|_)$).+$"}.
042 * </li>
043 * <li>
044 * Property {@code tokens} - tokens to check
045 * Type is {@code java.lang.String[]}.
046 * Validation type is {@code tokenSet}.
047 * Default value is:
048 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CLASS_DEF">
049 * CLASS_DEF</a>,
050 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INTERFACE_DEF">
051 * INTERFACE_DEF</a>,
052 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_DEF">
053 * ENUM_DEF</a>,
054 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ANNOTATION_DEF">
055 * ANNOTATION_DEF</a>,
056 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ANNOTATION_FIELD_DEF">
057 * ANNOTATION_FIELD_DEF</a>,
058 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PARAMETER_DEF">
059 * PARAMETER_DEF</a>,
060 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">
061 * VARIABLE_DEF</a>,
062 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#METHOD_DEF">
063 * METHOD_DEF</a>,
064 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_CONSTANT_DEF">
065 * ENUM_CONSTANT_DEF</a>,
066 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PATTERN_VARIABLE_DEF">
067 * PATTERN_VARIABLE_DEF</a>,
068 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_DEF">
069 * RECORD_DEF</a>,
070 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_COMPONENT_DEF">
071 * RECORD_COMPONENT_DEF</a>,
072 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LAMBDA">
073 * LAMBDA</a>.
074 * </li>
075 * </ul>
076 * <p>
077 * To configure the check:
078 * </p>
079 * <p>Configuration:</p>
080 * <pre>
081 * &lt;module name="IllegalIdentifierName"/&gt;
082 * </pre>
083 * <p>
084 * Example:
085 * </p>
086 * <pre>
087 * public class TestClass {
088 *     public static void main(String... args) {
089 *         var var = 4; // violation, "var" should not be used as an identifier.
090 *         int record = 15; // violation, "record" should not be used as an identifier.
091 *         String yield = "yield"; // violation, "yield" should not be used as an identifier.
092 *
093 *         record Record // violation, "Record" should not be used as an identifier.
094 *             (Record record) { // violation, "record" should not be used as an identifier.
095 *         }
096 *
097 *         String yieldString = "yieldString"; // ok, part of another word
098 *         record MyRecord(){} // ok, part of another word
099 *         var variable = 2; // ok, part of another word
100 *         String _; // violation, underscore should not be used as an identifier.
101 *     }
102 * }
103 * </pre>
104 * <p>
105 * To configure the check to include "open" and "transitive" in the set of illegal identifiers:
106 * </p>
107 * <p>Configuration:</p>
108 * <pre>
109 * &lt;module name="IllegalIdentifierName"&gt;
110 *     &lt;property name="format" value="(?i)^(?!(record|yield|var
111 *                        |permits|sealed|open|transitive|_)$).+$"/&gt;
112 * &lt;/module&gt;
113 * </pre>
114 * <p>Example:</p>
115 * <pre>
116 * public class TestClass {
117 *     public static void main(String... args) {
118 *
119 *         int open = 4; // violation, "open" should not be used as an identifier
120 *         Object transitive = "transitive"; // violation, "transitive" should not
121 *                                                // be used as an identifier
122 *
123 *         int openInt = 4; // ok, "open" is part of another word
124 *         Object transitiveObject = "transitiveObject"; // ok, "transitive" is part of another word
125 *     }
126 * }
127 * </pre>
128 * <p>
129 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
130 * </p>
131 * <p>
132 * Violation Message Keys:
133 * </p>
134 * <ul>
135 * <li>
136 * {@code name.invalidPattern}
137 * </li>
138 * </ul>
139 *
140 * @since 8.36
141 */
142@StatelessCheck
143public class IllegalIdentifierNameCheck extends AbstractNameCheck {
144
145    /**
146     * Creates a new {@code IllegalIdentifierNameCheck} instance.
147     */
148    public IllegalIdentifierNameCheck() {
149        super("(?i)^(?!(record|yield|var|permits|sealed|_)$).+$");
150    }
151
152    @Override
153    public int[] getDefaultTokens() {
154        return getAcceptableTokens();
155    }
156
157    @Override
158    public int[] getAcceptableTokens() {
159        return new int[] {
160            TokenTypes.CLASS_DEF,
161            TokenTypes.INTERFACE_DEF,
162            TokenTypes.ENUM_DEF,
163            TokenTypes.ANNOTATION_DEF,
164            TokenTypes.ANNOTATION_FIELD_DEF,
165            TokenTypes.PARAMETER_DEF,
166            TokenTypes.VARIABLE_DEF,
167            TokenTypes.METHOD_DEF,
168            TokenTypes.ENUM_CONSTANT_DEF,
169            TokenTypes.PATTERN_VARIABLE_DEF,
170            TokenTypes.RECORD_DEF,
171            TokenTypes.RECORD_COMPONENT_DEF,
172            TokenTypes.LAMBDA,
173        };
174    }
175
176    @Override
177    public int[] getRequiredTokens() {
178        return CommonUtil.EMPTY_INT_ARRAY;
179    }
180
181    @Override
182    protected boolean mustCheckName(DetailAST ast) {
183        return ast.findFirstToken(TokenTypes.IDENT) != null;
184    }
185
186}