001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2026 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.api.DetailAST;
023import com.puppycrawl.tools.checkstyle.api.TokenTypes;
024import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
025import com.puppycrawl.tools.checkstyle.utils.ScopeUtil;
026
027/**
028 * <div>
029 * Checks that local final variable names conform to a specified pattern.
030 *  A catch parameter and resources in try statements are considered to be a local, final variables.
031 * </div>
032 *
033 * <p>
034 * This check does not support final pattern variables. Instead, use
035 * <a href="https://checkstyle.org/checks/naming/patternvariablename.html">
036 * PatternVariableName</a>.
037 * </p>
038 *
039 * @since 3.0
040 */
041public class LocalFinalVariableNameCheck extends AbstractNameCheck {
042
043    /**
044     * A key is pointing to the warning message text in "messages.properties" file.
045     */
046    public static final String MSG_INVALID_PATTERN = "name.invalidPattern";
047
048    /** Creates a new {@code LocalFinalVariableNameCheck} instance. */
049    public LocalFinalVariableNameCheck() {
050        super("^([a-z][a-zA-Z0-9]*|_)$", MSG_INVALID_PATTERN);
051    }
052
053    @Override
054    public int[] getDefaultTokens() {
055        return getAcceptableTokens();
056    }
057
058    @Override
059    public int[] getAcceptableTokens() {
060        return new int[] {
061            TokenTypes.VARIABLE_DEF,
062            TokenTypes.PARAMETER_DEF,
063            TokenTypes.RESOURCE,
064        };
065    }
066
067    @Override
068    public int[] getRequiredTokens() {
069        return CommonUtil.EMPTY_INT_ARRAY;
070    }
071
072    @Override
073    protected final boolean mustCheckName(DetailAST ast) {
074        final DetailAST modifiersAST =
075            ast.findFirstToken(TokenTypes.MODIFIERS);
076        final boolean isFinal = ast.getType() == TokenTypes.RESOURCE
077            || modifiersAST.findFirstToken(TokenTypes.FINAL) != null;
078        return isFinal && ScopeUtil.isLocalVariableDef(ast);
079    }
080
081}