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.coding;
021
022import com.puppycrawl.tools.checkstyle.StatelessCheck;
023import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
024import com.puppycrawl.tools.checkstyle.api.DetailAST;
025import com.puppycrawl.tools.checkstyle.api.TokenTypes;
026
027/**
028 * <div>
029 * Detects empty statements (standalone {@code ";"} semicolon).
030 * Empty statements often introduce bugs that are hard to spot
031 * </div>
032 *
033 * @since 3.1
034 */
035@StatelessCheck
036public class EmptyStatementCheck extends AbstractCheck {
037
038    /**
039     * A key is pointing to the warning message text in "messages.properties"
040     * file.
041     */
042    public static final String MSG_KEY = "empty.statement";
043
044    @Override
045    public int[] getDefaultTokens() {
046        return getRequiredTokens();
047    }
048
049    @Override
050    public int[] getAcceptableTokens() {
051        return getRequiredTokens();
052    }
053
054    @Override
055    public int[] getRequiredTokens() {
056        return new int[] {TokenTypes.EMPTY_STAT};
057    }
058
059    @Override
060    public void visitToken(DetailAST ast) {
061        log(ast, MSG_KEY);
062    }
063
064}