001//////////////////////////////////////////////////////////////////////////////// 002// checkstyle: Checks Java source code for adherence to a set of rules. 003// Copyright (C) 2001-2020 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 regular expression 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 regular expression 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 * </li> 073 * </ul> 074 * <p> 075 * To configure the check: 076 * </p> 077 * <p>Configuration:</p> 078 * <pre> 079 * <module name="IllegalIdentifierName"/> 080 * </pre> 081 * <p> 082 * Example: 083 * </p> 084 * <pre> 085 * public class TestClass { 086 * public static void main(String... args) { 087 * var var = 4; // violation, "var" should not be used as an identifier. 088 * int record = 15; // violation, "record" should not be used as an identifier. 089 * String yield = "yield"; // violation, "yield" should not be used as an identifier. 090 * 091 * record Record // violation, "Record" should not be used as an identifier. 092 * (Record record) { // violation, "record" should not be used as an identifier. 093 * } 094 * 095 * String yieldString = "yieldString"; // ok, part of another word 096 * record MyRecord(){} // ok, part of another word 097 * var variable = 2; // ok, part of another word 098 * String _; // violation, underscore should not be used as an identifier. 099 * } 100 * } 101 * </pre> 102 * <p> 103 * To configure the check to include "open" and "transitive" in the set of illegal identifiers: 104 * </p> 105 * <p>Configuration:</p> 106 * <pre> 107 * <module name="IllegalIdentifierName"> 108 * <property name="format" value="(?i)^(?!(record|yield|var 109 * |permits|sealed|open|transitive|_)$).+$"/> 110 * </module> 111 * </pre> 112 * <p>Example:</p> 113 * <pre> 114 * public class TestClass { 115 * public static void main(String... args) { 116 * 117 * int open = 4; // violation, "open" should not be used as an identifier 118 * Object transitive = "transitive"; // violation, "transitive" should not 119 * // be used as an identifier 120 * 121 * int openInt = 4; // ok, "open" is part of another word 122 * Object transitiveObject = "transitiveObject"; // ok, "transitive" is part of another word 123 * } 124 * } 125 * </pre> 126 * <p> 127 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker} 128 * </p> 129 * <p> 130 * Violation Message Keys: 131 * </p> 132 * <ul> 133 * <li> 134 * {@code name.invalidPattern} 135 * </li> 136 * </ul> 137 * 138 * @since 8.36 139 */ 140@StatelessCheck 141public class IllegalIdentifierNameCheck extends AbstractNameCheck { 142 143 /** 144 * Creates a new {@code IllegalIdentifierNameCheck} instance. 145 */ 146 public IllegalIdentifierNameCheck() { 147 super("(?i)^(?!(record|yield|var|permits|sealed|_)$).+$"); 148 } 149 150 @Override 151 public int[] getDefaultTokens() { 152 return getAcceptableTokens(); 153 } 154 155 @Override 156 public int[] getAcceptableTokens() { 157 return new int[] { 158 TokenTypes.CLASS_DEF, 159 TokenTypes.INTERFACE_DEF, 160 TokenTypes.ENUM_DEF, 161 TokenTypes.ANNOTATION_DEF, 162 TokenTypes.ANNOTATION_FIELD_DEF, 163 TokenTypes.PARAMETER_DEF, 164 TokenTypes.VARIABLE_DEF, 165 TokenTypes.METHOD_DEF, 166 TokenTypes.ENUM_CONSTANT_DEF, 167 TokenTypes.PATTERN_VARIABLE_DEF, 168 TokenTypes.RECORD_DEF, 169 TokenTypes.RECORD_COMPONENT_DEF, 170 }; 171 } 172 173 @Override 174 public int[] getRequiredTokens() { 175 return CommonUtil.EMPTY_INT_ARRAY; 176 } 177 178 @Override 179 protected boolean mustCheckName(DetailAST ast) { 180 return ast.findFirstToken(TokenTypes.IDENT) != null; 181 } 182 183}