001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2023 the original author or authors.
004//
005// This library is free software; you can redistribute it and/or
006// modify it under the terms of the GNU Lesser General Public
007// License as published by the Free Software Foundation; either
008// version 2.1 of the License, or (at your option) any later version.
009//
010// This library is distributed in the hope that it will be useful,
011// but WITHOUT ANY WARRANTY; without even the implied warranty of
012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013// Lesser General Public License for more details.
014//
015// You should have received a copy of the GNU Lesser General Public
016// License along with this library; if not, write to the Free Software
017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
018///////////////////////////////////////////////////////////////////////////////////////////////
019
020package com.puppycrawl.tools.checkstyle.checks.naming;
021
022import com.puppycrawl.tools.checkstyle.api.DetailAST;
023import com.puppycrawl.tools.checkstyle.api.TokenTypes;
024import com.puppycrawl.tools.checkstyle.utils.AnnotationUtil;
025
026/**
027 * <p>
028 * Checks that method names conform to a specified pattern.
029 * </p>
030 *
031 * <p>Also, checks if a method name has the same name as the residing class.
032 * The default is false (it is not allowed). It is legal in Java to have
033 * method with the same name as a class. As long as a return type is specified
034 * it is a method and not a constructor which it could be easily confused as.
035 * Does not check-style the name of an overridden methods because the developer does not
036 * have a choice in renaming such methods.
037 * </p>
038 *
039 * <ul>
040 * <li>
041 * Property {@code allowClassName} - Controls whether to allow a method name to have the same name
042 * as the residing class name. This is not to be confused with a constructor. An easy mistake is
043 * to place a return type on a constructor declaration which turns it into a method. For example:
044 * <pre>
045 * class MyClass {
046 *     public void MyClass() {} //this is a method
047 *     public MyClass() {} //this is a constructor
048 * }
049 * </pre>
050 * Type is {@code boolean}.
051 * Default value is {@code false}.
052 * </li>
053 * <li>
054 * Property {@code applyToPackage} - Controls whether to apply the check to package-private member.
055 * Type is {@code boolean}.
056 * Default value is {@code true}.
057 * </li>
058 * <li>
059 * Property {@code applyToPrivate} - Controls whether to apply the check to private member.
060 * Type is {@code boolean}.
061 * Default value is {@code true}.
062 * </li>
063 * <li>
064 * Property {@code applyToProtected} - Controls whether to apply the check to protected member.
065 * Type is {@code boolean}.
066 * Default value is {@code true}.
067 * </li>
068 * <li>
069 * Property {@code applyToPublic} - Controls whether to apply the check to public member.
070 * Type is {@code boolean}.
071 * Default value is {@code true}.
072 * </li>
073 * <li>
074 * Property {@code format} - Specifies valid identifiers.
075 * Type is {@code java.util.regex.Pattern}.
076 * Default value is {@code "^[a-z][a-zA-Z0-9]*$"}.
077 * </li>
078 * </ul>
079 * <p>
080 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
081 * </p>
082 * <p>
083 * Violation Message Keys:
084 * </p>
085 * <ul>
086 * <li>
087 * {@code method.name.equals.class.name}
088 * </li>
089 * <li>
090 * {@code name.invalidPattern}
091 * </li>
092 * </ul>
093 *
094 * @since 3.0
095 */
096public class MethodNameCheck
097    extends AbstractAccessControlNameCheck {
098
099    /**
100     * A key is pointing to the warning message text in "messages.properties"
101     * file.
102     */
103    public static final String MSG_KEY = "method.name.equals.class.name";
104
105    /**
106     * Controls whether to allow a method name to have the same name as the residing class name.
107     * This is not to be confused with a constructor. An easy mistake is to place a return type on
108     * a constructor declaration which turns it into a method. For example:
109     * <pre>
110     * class MyClass {
111     *     public void MyClass() {} //this is a method
112     *     public MyClass() {} //this is a constructor
113     * }
114     * </pre>
115     */
116    private boolean allowClassName;
117
118    /** Creates a new {@code MethodNameCheck} instance. */
119    public MethodNameCheck() {
120        super("^[a-z][a-zA-Z0-9]*$");
121    }
122
123    @Override
124    public int[] getDefaultTokens() {
125        return getRequiredTokens();
126    }
127
128    @Override
129    public int[] getAcceptableTokens() {
130        return getRequiredTokens();
131    }
132
133    @Override
134    public int[] getRequiredTokens() {
135        return new int[] {TokenTypes.METHOD_DEF, };
136    }
137
138    @Override
139    public void visitToken(DetailAST ast) {
140        if (!AnnotationUtil.hasOverrideAnnotation(ast)) {
141            // Will check the name against the format.
142            super.visitToken(ast);
143        }
144
145        if (!allowClassName) {
146            final DetailAST method =
147                ast.findFirstToken(TokenTypes.IDENT);
148            // in all cases this will be the classDef type except anon inner
149            // with anon inner classes this will be the Literal_New keyword
150            final DetailAST classDefOrNew = ast.getParent().getParent();
151            final DetailAST classIdent =
152                classDefOrNew.findFirstToken(TokenTypes.IDENT);
153            // Following logic is to handle when a classIdent can not be
154            // found. This is when you have a Literal_New keyword followed
155            // a DOT, which is when you have:
156            // new Outclass.InnerInterface(x) { ... }
157            // Such a rare case, will not have the logic to handle parsing
158            // down the tree looking for the first ident.
159            if (classIdent != null
160                && method.getText().equals(classIdent.getText())) {
161                log(method, MSG_KEY, method.getText());
162            }
163        }
164    }
165
166    /**
167     * Setter to controls whether to allow a method name to have the same name as the residing
168     * class name. This is not to be confused with a constructor. An easy mistake is to place
169     * a return type on a constructor declaration which turns it into a method. For example:
170     * <pre>
171     * class MyClass {
172     *     public void MyClass() {} //this is a method
173     *     public MyClass() {} //this is a constructor
174     * }
175     * </pre>
176     *
177     * @param allowClassName true to allow false to disallow
178     * @since 5.0
179     */
180    public void setAllowClassName(boolean allowClassName) {
181        this.allowClassName = allowClassName;
182    }
183
184}