001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2025 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 * <div>
029 * Checks identifiers against a regular expression pattern to detect illegal names. Since this
030 * check uses a pattern to define <i>valid</i> identifiers, users will need to use negative
031 * lookaheads to explicitly ban certain names (e.g., "var") or patterns (e.g., any identifier
032 * containing $) while still allowing all other valid identifiers.
033 * </div>
034 *
035 * <ul>
036 * <li>
037 * Property {@code format} - Sets the pattern to match valid identifiers.
038 * Type is {@code java.util.regex.Pattern}.
039 * Default value is {@code "^(?!var$|\S*\$)\S+$"}.
040 * </li>
041 * <li>
042 * Property {@code tokens} - tokens to check
043 * Type is {@code java.lang.String[]}.
044 * Validation type is {@code tokenSet}.
045 * Default value is:
046 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CLASS_DEF">
047 * CLASS_DEF</a>,
048 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INTERFACE_DEF">
049 * INTERFACE_DEF</a>,
050 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_DEF">
051 * ENUM_DEF</a>,
052 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ANNOTATION_DEF">
053 * ANNOTATION_DEF</a>,
054 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ANNOTATION_FIELD_DEF">
055 * ANNOTATION_FIELD_DEF</a>,
056 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PARAMETER_DEF">
057 * PARAMETER_DEF</a>,
058 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">
059 * VARIABLE_DEF</a>,
060 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#METHOD_DEF">
061 * METHOD_DEF</a>,
062 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_CONSTANT_DEF">
063 * ENUM_CONSTANT_DEF</a>,
064 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PATTERN_VARIABLE_DEF">
065 * PATTERN_VARIABLE_DEF</a>,
066 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_DEF">
067 * RECORD_DEF</a>,
068 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_COMPONENT_DEF">
069 * RECORD_COMPONENT_DEF</a>,
070 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LAMBDA">
071 * LAMBDA</a>.
072 * </li>
073 * </ul>
074 *
075 * <p>
076 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
077 * </p>
078 *
079 * <p>
080 * Violation Message Keys:
081 * </p>
082 * <ul>
083 * <li>
084 * {@code name.invalidPattern}
085 * </li>
086 * </ul>
087 *
088 * @since 8.36
089 */
090@StatelessCheck
091public class IllegalIdentifierNameCheck extends AbstractNameCheck {
092
093    /**
094     * Creates a new {@code IllegalIdentifierNameCheck} instance.
095     */
096    public IllegalIdentifierNameCheck() {
097        super("^(?!var$|\\S*\\$)\\S+$");
098    }
099
100    @Override
101    public int[] getDefaultTokens() {
102        return getAcceptableTokens();
103    }
104
105    @Override
106    public int[] getAcceptableTokens() {
107        return new int[] {
108            TokenTypes.CLASS_DEF,
109            TokenTypes.INTERFACE_DEF,
110            TokenTypes.ENUM_DEF,
111            TokenTypes.ANNOTATION_DEF,
112            TokenTypes.ANNOTATION_FIELD_DEF,
113            TokenTypes.PARAMETER_DEF,
114            TokenTypes.VARIABLE_DEF,
115            TokenTypes.METHOD_DEF,
116            TokenTypes.ENUM_CONSTANT_DEF,
117            TokenTypes.PATTERN_VARIABLE_DEF,
118            TokenTypes.RECORD_DEF,
119            TokenTypes.RECORD_COMPONENT_DEF,
120            TokenTypes.LAMBDA,
121        };
122    }
123
124    @Override
125    public int[] getRequiredTokens() {
126        return CommonUtil.EMPTY_INT_ARRAY;
127    }
128
129    @Override
130    protected boolean mustCheckName(DetailAST ast) {
131        return ast.findFirstToken(TokenTypes.IDENT) != null;
132    }
133
134}