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