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.AnnotationUtil;
25
26 /**
27 * <div>
28 * Checks that method names conform to a specified pattern.
29 * </div>
30 *
31 * <p>Also, checks if a method name has the same name as the residing class.
32 * The default is false (it is not allowed). It is legal in Java to have
33 * method with the same name as a class. As long as a return type is specified
34 * it is a method and not a constructor which it could be easily confused as.
35 * Does not check-style the name of an overridden methods because the developer does not
36 * have a choice in renaming such methods.
37 * </p>
38 *
39 * <ul>
40 * <li>
41 * Property {@code allowClassName} - Control whether to allow a method name to have the same name
42 * as the enclosing class name. Setting this property {@code false} helps to avoid
43 * confusion between constructors and methods.
44 * Type is {@code boolean}.
45 * Default value is {@code false}.
46 * </li>
47 * <li>
48 * Property {@code applyToPackage} - Control if check should apply to package-private members.
49 * Type is {@code boolean}.
50 * Default value is {@code true}.
51 * Since version 5.1
52 * </li>
53 * <li>
54 * Property {@code applyToPrivate} - Control if check should apply to private members.
55 * Type is {@code boolean}.
56 * Default value is {@code true}.
57 * Since version 5.1
58 * </li>
59 * <li>
60 * Property {@code applyToProtected} - Control if check should apply to protected members.
61 * Type is {@code boolean}.
62 * Default value is {@code true}.
63 * Since version 5.1
64 * </li>
65 * <li>
66 * Property {@code applyToPublic} - Control if check should apply to public members.
67 * Type is {@code boolean}.
68 * Default value is {@code true}.
69 * Since version 5.1
70 * </li>
71 * <li>
72 * Property {@code format} - Sets the pattern to match valid identifiers.
73 * Type is {@code java.util.regex.Pattern}.
74 * Default value is {@code "^[a-z][a-zA-Z0-9]*$"}.
75 * </li>
76 * </ul>
77 *
78 * <p>
79 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
80 * </p>
81 *
82 * <p>
83 * Violation Message Keys:
84 * </p>
85 * <ul>
86 * <li>
87 * {@code method.name.equals.class.name}
88 * </li>
89 * <li>
90 * {@code name.invalidPattern}
91 * </li>
92 * </ul>
93 *
94 * @since 3.0
95 */
96 public class MethodNameCheck
97 extends AbstractAccessControlNameCheck {
98
99 /**
100 * A key is pointing to the warning message text in "messages.properties"
101 * file.
102 */
103 public static final String MSG_KEY = "method.name.equals.class.name";
104
105 /**
106 * Control whether to allow a method name to have the same name as the enclosing class name.
107 * Setting this property {@code false} helps to avoid confusion
108 * between constructors and methods.
109 */
110 private boolean allowClassName;
111
112 /** Creates a new {@code MethodNameCheck} instance. */
113 public MethodNameCheck() {
114 super("^[a-z][a-zA-Z0-9]*$");
115 }
116
117 @Override
118 public int[] getDefaultTokens() {
119 return getRequiredTokens();
120 }
121
122 @Override
123 public int[] getAcceptableTokens() {
124 return getRequiredTokens();
125 }
126
127 @Override
128 public int[] getRequiredTokens() {
129 return new int[] {TokenTypes.METHOD_DEF, };
130 }
131
132 @Override
133 public void visitToken(DetailAST ast) {
134 if (!AnnotationUtil.hasOverrideAnnotation(ast)) {
135 // Will check the name against the format.
136 super.visitToken(ast);
137 }
138
139 if (!allowClassName) {
140 final DetailAST method =
141 ast.findFirstToken(TokenTypes.IDENT);
142 // in all cases this will be the classDef type except anon inner
143 // with anon inner classes this will be the Literal_New keyword
144 final DetailAST classDefOrNew = ast.getParent().getParent();
145 final DetailAST classIdent =
146 classDefOrNew.findFirstToken(TokenTypes.IDENT);
147 // Following logic is to handle when a classIdent can not be
148 // found. This is when you have a Literal_New keyword followed
149 // a DOT, which is when you have:
150 // new Outclass.InnerInterface(x) { ... }
151 // Such a rare case, will not have the logic to handle parsing
152 // down the tree looking for the first ident.
153 if (classIdent != null
154 && method.getText().equals(classIdent.getText())) {
155 log(method, MSG_KEY, method.getText());
156 }
157 }
158 }
159
160 /**
161 * Setter to control whether to allow a method name to have the same name
162 * as the enclosing class name. Setting this property {@code false}
163 * helps to avoid confusion between constructors and methods.
164 *
165 * @param allowClassName true to allow false to disallow
166 * @since 5.0
167 */
168 public void setAllowClassName(boolean allowClassName) {
169 this.allowClassName = allowClassName;
170 }
171
172 }