1 ///////////////////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
3 // Copyright (C) 2001-2024 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 * <p>
34 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
35 * </p>
36 *
37 * <p>
38 * Violation Message Keys:
39 * </p>
40 * <ul>
41 * <li>
42 * {@code empty.statement}
43 * </li>
44 * </ul>
45 *
46 * @since 3.1
47 */
48 @StatelessCheck
49 public class EmptyStatementCheck extends AbstractCheck {
50
51 /**
52 * A key is pointing to the warning message text in "messages.properties"
53 * file.
54 */
55 public static final String MSG_KEY = "empty.statement";
56
57 @Override
58 public int[] getDefaultTokens() {
59 return getRequiredTokens();
60 }
61
62 @Override
63 public int[] getAcceptableTokens() {
64 return getRequiredTokens();
65 }
66
67 @Override
68 public int[] getRequiredTokens() {
69 return new int[] {TokenTypes.EMPTY_STAT};
70 }
71
72 @Override
73 public void visitToken(DetailAST ast) {
74 log(ast, MSG_KEY);
75 }
76
77 }