001/////////////////////////////////////////////////////////////////////////////////////////////// 002// checkstyle: Checks Java source code and other text files for adherence to a set of rules. 003// Copyright (C) 2001-2024 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 * <p> 034 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker} 035 * </p> 036 * 037 * <p> 038 * Violation Message Keys: 039 * </p> 040 * <ul> 041 * <li> 042 * {@code empty.statement} 043 * </li> 044 * </ul> 045 * 046 * @since 3.1 047 */ 048@StatelessCheck 049public class EmptyStatementCheck extends AbstractCheck { 050 051 /** 052 * A key is pointing to the warning message text in "messages.properties" 053 * file. 054 */ 055 public static final String MSG_KEY = "empty.statement"; 056 057 @Override 058 public int[] getDefaultTokens() { 059 return getRequiredTokens(); 060 } 061 062 @Override 063 public int[] getAcceptableTokens() { 064 return getRequiredTokens(); 065 } 066 067 @Override 068 public int[] getRequiredTokens() { 069 return new int[] {TokenTypes.EMPTY_STAT}; 070 } 071 072 @Override 073 public void visitToken(DetailAST ast) { 074 log(ast, MSG_KEY); 075 } 076 077}