1 ///////////////////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
3 // Copyright (C) 2001-2025 the original author or authors.
4 //
5 // This library is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU Lesser General Public
7 // License as published by the Free Software Foundation; either
8 // version 2.1 of the License, or (at your option) any later version.
9 //
10 // This library is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 // Lesser General Public License for more details.
14 //
15 // You should have received a copy of the GNU Lesser General Public
16 // License along with this library; if not, write to the Free Software
17 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 ///////////////////////////////////////////////////////////////////////////////////////////////
19
20 package com.puppycrawl.tools.checkstyle.checks.coding;
21
22 import com.puppycrawl.tools.checkstyle.StatelessCheck;
23 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
24 import com.puppycrawl.tools.checkstyle.api.DetailAST;
25 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
26
27 /**
28 * <div>
29 * Detects empty statements (standalone {@code ";"} semicolon).
30 * Empty statements often introduce bugs that are hard to spot
31 * </div>
32 *
33 * @since 3.1
34 */
35 @StatelessCheck
36 public class EmptyStatementCheck extends AbstractCheck {
37
38 /**
39 * A key is pointing to the warning message text in "messages.properties"
40 * file.
41 */
42 public static final String MSG_KEY = "empty.statement";
43
44 @Override
45 public int[] getDefaultTokens() {
46 return getRequiredTokens();
47 }
48
49 @Override
50 public int[] getAcceptableTokens() {
51 return getRequiredTokens();
52 }
53
54 @Override
55 public int[] getRequiredTokens() {
56 return new int[] {TokenTypes.EMPTY_STAT};
57 }
58
59 @Override
60 public void visitToken(DetailAST ast) {
61 log(ast, MSG_KEY);
62 }
63
64 }