LocalFinalVariableNameCheck.java

///////////////////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
// Copyright (C) 2001-2024 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.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
import com.puppycrawl.tools.checkstyle.utils.ScopeUtil;

/**
 * <p>
 * Checks that local final variable names conform to a specified pattern.
 *  A catch parameter and resources in try statements
 * are considered to be a local, final variables.
 * </p>
 * <p>
 * This check does not support final pattern variables. Instead, use
 * <a href="https://checkstyle.org/checks/naming/patternvariablename.html#PatternVariableName">
 * PatternVariableName</a>.
 * </p>
 * <ul>
 * <li>
 * Property {@code format} - Sets the pattern to match valid identifiers.
 * Type is {@code java.util.regex.Pattern}.
 * Default value is {@code "^([a-z][a-zA-Z0-9]*|_)$"}.
 * </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#VARIABLE_DEF">
 * VARIABLE_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#RESOURCE">
 * RESOURCE</a>.
 * </li>
 * </ul>
 * <p>
 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
 * </p>
 * <p>
 * Violation Message Keys:
 * </p>
 * <ul>
 * <li>
 * {@code name.invalidPattern}
 * </li>
 * </ul>
 *
 * @since 3.0
 */
public class LocalFinalVariableNameCheck
    extends AbstractNameCheck {

    /** Creates a new {@code LocalFinalVariableNameCheck} instance. */
    public LocalFinalVariableNameCheck() {
        super("^([a-z][a-zA-Z0-9]*|_)$");
    }

    @Override
    public int[] getDefaultTokens() {
        return getAcceptableTokens();
    }

    @Override
    public int[] getAcceptableTokens() {
        return new int[] {
            TokenTypes.VARIABLE_DEF,
            TokenTypes.PARAMETER_DEF,
            TokenTypes.RESOURCE,
        };
    }

    @Override
    public int[] getRequiredTokens() {
        return CommonUtil.EMPTY_INT_ARRAY;
    }

    @Override
    protected final boolean mustCheckName(DetailAST ast) {
        final DetailAST modifiersAST =
            ast.findFirstToken(TokenTypes.MODIFIERS);
        final boolean isFinal = ast.getType() == TokenTypes.RESOURCE
            || modifiersAST.findFirstToken(TokenTypes.FINAL) != null;
        return isFinal && ScopeUtil.isLocalVariableDef(ast);
    }

}