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 * <p>
29 * Detects empty statements (standalone {@code ";"} semicolon).
30 * Empty statements often introduce bugs that are hard to spot
31 * </p>
32 * <p>
33 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
34 * </p>
35 * <p>
36 * Violation Message Keys:
37 * </p>
38 * <ul>
39 * <li>
40 * {@code empty.statement}
41 * </li>
42 * </ul>
43 *
44 * @since 3.1
45 */
46 @StatelessCheck
47 public class EmptyStatementCheck extends AbstractCheck {
48
49 /**
50 * A key is pointing to the warning message text in "messages.properties"
51 * file.
52 */
53 public static final String MSG_KEY = "empty.statement";
54
55 @Override
56 public int[] getDefaultTokens() {
57 return getRequiredTokens();
58 }
59
60 @Override
61 public int[] getAcceptableTokens() {
62 return getRequiredTokens();
63 }
64
65 @Override
66 public int[] getRequiredTokens() {
67 return new int[] {TokenTypes.EMPTY_STAT};
68 }
69
70 @Override
71 public void visitToken(DetailAST ast) {
72 log(ast, MSG_KEY);
73 }
74
75 }