IllegalIdentifierNameCheck.java
////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2021 the original author or authors.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
////////////////////////////////////////////////////////////////////////////////
package com.puppycrawl.tools.checkstyle.checks.naming;
import com.puppycrawl.tools.checkstyle.StatelessCheck;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
/**
* <p>
* Checks identifiers with a regular expression for a set of illegal names, such as those
* that are restricted or contextual keywords. Examples include "yield", "record", "_", and
* "var". Please read more at
* <a href="https://docs.oracle.com/javase/specs/jls/se14/html/jls-3.html#jls-3.9">
* Java Language Specification</a> to get to know more about restricted keywords. Since this
* check uses a regular expression to specify valid identifiers, users can also prohibit the usage
* of certain symbols, such as "$", or any non-ascii character.
* </p>
* <ul>
* <li>
* Property {@code format} - Specifies valid identifiers.
* Type is {@code java.util.regex.Pattern}.
* Default value is {@code "(?i)^(?!(record|yield|var|permits|sealed|_)$).+$"}.
* </li>
* <li>
* Property {@code tokens} - tokens to check
* Type is {@code java.lang.String[]}.
* Validation type is {@code tokenSet}.
* Default value is:
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CLASS_DEF">
* CLASS_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INTERFACE_DEF">
* INTERFACE_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_DEF">
* ENUM_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ANNOTATION_DEF">
* ANNOTATION_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ANNOTATION_FIELD_DEF">
* ANNOTATION_FIELD_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PARAMETER_DEF">
* PARAMETER_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">
* VARIABLE_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#METHOD_DEF">
* METHOD_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_CONSTANT_DEF">
* ENUM_CONSTANT_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PATTERN_VARIABLE_DEF">
* PATTERN_VARIABLE_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_DEF">
* RECORD_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_COMPONENT_DEF">
* RECORD_COMPONENT_DEF</a>,
* <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LAMBDA">
* LAMBDA</a>.
* </li>
* </ul>
* <p>
* To configure the check:
* </p>
* <p>Configuration:</p>
* <pre>
* <module name="IllegalIdentifierName"/>
* </pre>
* <p>
* Example:
* </p>
* <pre>
* public class TestClass {
* public static void main(String... args) {
* var var = 4; // violation, "var" should not be used as an identifier.
* int record = 15; // violation, "record" should not be used as an identifier.
* String yield = "yield"; // violation, "yield" should not be used as an identifier.
*
* record Record // violation, "Record" should not be used as an identifier.
* (Record record) { // violation, "record" should not be used as an identifier.
* }
*
* String yieldString = "yieldString"; // ok, part of another word
* record MyRecord(){} // ok, part of another word
* var variable = 2; // ok, part of another word
* String _; // violation, underscore should not be used as an identifier.
* }
* }
* </pre>
* <p>
* To configure the check to include "open" and "transitive" in the set of illegal identifiers:
* </p>
* <p>Configuration:</p>
* <pre>
* <module name="IllegalIdentifierName">
* <property name="format" value="(?i)^(?!(record|yield|var
* |permits|sealed|open|transitive|_)$).+$"/>
* </module>
* </pre>
* <p>Example:</p>
* <pre>
* public class TestClass {
* public static void main(String... args) {
*
* int open = 4; // violation, "open" should not be used as an identifier
* Object transitive = "transitive"; // violation, "transitive" should not
* // be used as an identifier
*
* int openInt = 4; // ok, "open" is part of another word
* Object transitiveObject = "transitiveObject"; // ok, "transitive" is part of another word
* }
* }
* </pre>
* <p>
* Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
* </p>
* <p>
* Violation Message Keys:
* </p>
* <ul>
* <li>
* {@code name.invalidPattern}
* </li>
* </ul>
*
* @since 8.36
*/
@StatelessCheck
public class IllegalIdentifierNameCheck extends AbstractNameCheck {
/**
* Creates a new {@code IllegalIdentifierNameCheck} instance.
*/
public IllegalIdentifierNameCheck() {
super("(?i)^(?!(record|yield|var|permits|sealed|_)$).+$");
}
@Override
public int[] getDefaultTokens() {
return getAcceptableTokens();
}
@Override
public int[] getAcceptableTokens() {
return new int[] {
TokenTypes.CLASS_DEF,
TokenTypes.INTERFACE_DEF,
TokenTypes.ENUM_DEF,
TokenTypes.ANNOTATION_DEF,
TokenTypes.ANNOTATION_FIELD_DEF,
TokenTypes.PARAMETER_DEF,
TokenTypes.VARIABLE_DEF,
TokenTypes.METHOD_DEF,
TokenTypes.ENUM_CONSTANT_DEF,
TokenTypes.PATTERN_VARIABLE_DEF,
TokenTypes.RECORD_DEF,
TokenTypes.RECORD_COMPONENT_DEF,
TokenTypes.LAMBDA,
};
}
@Override
public int[] getRequiredTokens() {
return CommonUtil.EMPTY_INT_ARRAY;
}
@Override
protected boolean mustCheckName(DetailAST ast) {
return ast.findFirstToken(TokenTypes.IDENT) != null;
}
}