001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2024 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.ScopeUtil;
025
026/**
027 * <div>
028 * Checks that local, non-{@code final} variable names conform to a specified pattern.
029 * A catch parameter is considered to be
030 * a local variable.
031 * </div>
032 *
033 * <p>
034 * This check does not support pattern variables. Instead, use
035 * <a href="https://checkstyle.org/checks/naming/patternvariablename.html#PatternVariableName">
036 * PatternVariableName</a>.
037 * </p>
038 * <ul>
039 * <li>
040 * Property {@code allowOneCharVarInForLoop} - Allow one character variable name in
041 * <a href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/for.html">
042 * initialization expressions</a>
043 * in FOR loop if one char variable name is prohibited by {@code format} regexp.
044 * Type is {@code boolean}.
045 * Default value is {@code false}.
046 * </li>
047 * <li>
048 * Property {@code format} - Sets the pattern to match valid identifiers.
049 * Type is {@code java.util.regex.Pattern}.
050 * Default value is {@code "^([a-z][a-zA-Z0-9]*|_)$"}.
051 * </li>
052 * </ul>
053 *
054 * <p>
055 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
056 * </p>
057 *
058 * <p>
059 * Violation Message Keys:
060 * </p>
061 * <ul>
062 * <li>
063 * {@code name.invalidPattern}
064 * </li>
065 * </ul>
066 *
067 * @since 3.0
068 */
069public class LocalVariableNameCheck
070    extends AbstractNameCheck {
071
072    /**
073     * Allow one character variable name in
074     * <a href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/for.html">
075     * initialization expressions</a>
076     * in FOR loop if one char variable name is prohibited by {@code format} regexp.
077     */
078    private boolean allowOneCharVarInForLoop;
079
080    /** Creates a new {@code LocalVariableNameCheck} instance. */
081    public LocalVariableNameCheck() {
082        super("^([a-z][a-zA-Z0-9]*|_)$");
083    }
084
085    /**
086     * Setter to allow one character variable name in
087     * <a href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/for.html">
088     * initialization expressions</a>
089     * in FOR loop if one char variable name is prohibited by {@code format} regexp.
090     *
091     * @param allow Flag for allowing or not one character name in FOR loop.
092     * @since 5.8
093     */
094    public final void setAllowOneCharVarInForLoop(boolean allow) {
095        allowOneCharVarInForLoop = allow;
096    }
097
098    @Override
099    public int[] getDefaultTokens() {
100        return getRequiredTokens();
101    }
102
103    @Override
104    public int[] getAcceptableTokens() {
105        return getRequiredTokens();
106    }
107
108    @Override
109    public int[] getRequiredTokens() {
110        return new int[] {
111            TokenTypes.VARIABLE_DEF,
112        };
113    }
114
115    @Override
116    protected final boolean mustCheckName(DetailAST ast) {
117        final boolean result;
118        if (allowOneCharVarInForLoop && isForLoopVariable(ast)) {
119            final String variableName = ast.findFirstToken(TokenTypes.IDENT).getText();
120            result = variableName.length() != 1;
121        }
122        else {
123            final DetailAST modifiersAST = ast.findFirstToken(TokenTypes.MODIFIERS);
124            final boolean isFinal = modifiersAST.findFirstToken(TokenTypes.FINAL) != null;
125            result = !isFinal && ScopeUtil.isLocalVariableDef(ast);
126        }
127        return result;
128    }
129
130    /**
131     * Checks if a variable is the loop's one.
132     *
133     * @param variableDef variable definition.
134     * @return true if a variable is the loop's one.
135     */
136    private static boolean isForLoopVariable(DetailAST variableDef) {
137        final int parentType = variableDef.getParent().getType();
138        return parentType == TokenTypes.FOR_INIT
139                || parentType == TokenTypes.FOR_EACH_CLAUSE;
140    }
141
142}