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.naming;
21
22 import com.puppycrawl.tools.checkstyle.api.DetailAST;
23 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
24 import com.puppycrawl.tools.checkstyle.utils.ScopeUtil;
25
26 /**
27 * <div>
28 * Checks that local, non-{@code final} variable names conform to a specified pattern.
29 * A catch parameter is considered to be a local variable.
30 * </div>
31 *
32 * <p>
33 * This check does not support pattern variables. Instead, use
34 * <a href="https://checkstyle.org/checks/naming/patternvariablename.html">
35 * PatternVariableName</a>.
36 * </p>
37 * <ul>
38 * <li>
39 * Property {@code allowOneCharVarInForLoop} - Allow one character variable name in
40 * <a href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/for.html">
41 * initialization expressions</a>
42 * in FOR loop if one char variable name is prohibited by {@code format} regexp.
43 * Type is {@code boolean}.
44 * Default value is {@code false}.
45 * </li>
46 * <li>
47 * Property {@code format} - Sets the pattern to match valid identifiers.
48 * Type is {@code java.util.regex.Pattern}.
49 * Default value is {@code "^([a-z][a-zA-Z0-9]*|_)$"}.
50 * </li>
51 * </ul>
52 *
53 * <p>
54 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
55 * </p>
56 *
57 * <p>
58 * Violation Message Keys:
59 * </p>
60 * <ul>
61 * <li>
62 * {@code name.invalidPattern}
63 * </li>
64 * </ul>
65 *
66 * @since 3.0
67 */
68 public class LocalVariableNameCheck
69 extends AbstractNameCheck {
70
71 /**
72 * Allow one character variable name in
73 * <a href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/for.html">
74 * initialization expressions</a>
75 * in FOR loop if one char variable name is prohibited by {@code format} regexp.
76 */
77 private boolean allowOneCharVarInForLoop;
78
79 /** Creates a new {@code LocalVariableNameCheck} instance. */
80 public LocalVariableNameCheck() {
81 super("^([a-z][a-zA-Z0-9]*|_)$");
82 }
83
84 /**
85 * Setter to allow one character variable name in
86 * <a href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/for.html">
87 * initialization expressions</a>
88 * in FOR loop if one char variable name is prohibited by {@code format} regexp.
89 *
90 * @param allow Flag for allowing or not one character name in FOR loop.
91 * @since 5.8
92 */
93 public final void setAllowOneCharVarInForLoop(boolean allow) {
94 allowOneCharVarInForLoop = allow;
95 }
96
97 @Override
98 public int[] getDefaultTokens() {
99 return getRequiredTokens();
100 }
101
102 @Override
103 public int[] getAcceptableTokens() {
104 return getRequiredTokens();
105 }
106
107 @Override
108 public int[] getRequiredTokens() {
109 return new int[] {
110 TokenTypes.VARIABLE_DEF,
111 };
112 }
113
114 @Override
115 protected final boolean mustCheckName(DetailAST ast) {
116 final boolean result;
117 if (allowOneCharVarInForLoop && isForLoopVariable(ast)) {
118 final String variableName = ast.findFirstToken(TokenTypes.IDENT).getText();
119 result = variableName.length() != 1;
120 }
121 else {
122 final DetailAST modifiersAST = ast.findFirstToken(TokenTypes.MODIFIERS);
123 final boolean isFinal = modifiersAST.findFirstToken(TokenTypes.FINAL) != null;
124 result = !isFinal && ScopeUtil.isLocalVariableDef(ast);
125 }
126 return result;
127 }
128
129 /**
130 * Checks if a variable is the loop's one.
131 *
132 * @param variableDef variable definition.
133 * @return true if a variable is the loop's one.
134 */
135 private static boolean isForLoopVariable(DetailAST variableDef) {
136 final int parentType = variableDef.getParent().getType();
137 return parentType == TokenTypes.FOR_INIT
138 || parentType == TokenTypes.FOR_EACH_CLAUSE;
139 }
140
141 }