LocalVariableNameCheck.java
///////////////////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
// Copyright (C) 2001-2024 the original author or authors.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
///////////////////////////////////////////////////////////////////////////////////////////////
package com.puppycrawl.tools.checkstyle.checks.naming;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
import com.puppycrawl.tools.checkstyle.utils.ScopeUtil;
/**
* <p>
* Checks that local, non-{@code final} variable names conform to a specified pattern.
* A catch parameter is considered to be
* a local variable.
* </p>
* <p>
* This check does not support pattern variables. Instead, use
* <a href="https://checkstyle.org/checks/naming/patternvariablename.html#PatternVariableName">
* PatternVariableName</a>.
* </p>
* <ul>
* <li>
* Property {@code allowOneCharVarInForLoop} - Allow one character variable name in
* <a href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/for.html">
* initialization expressions</a>
* in FOR loop if one char variable name is prohibited by {@code format} regexp.
* Type is {@code boolean}.
* Default value is {@code false}.
* </li>
* <li>
* Property {@code format} - Sets the pattern to match valid identifiers.
* Type is {@code java.util.regex.Pattern}.
* Default value is {@code "^([a-z][a-zA-Z0-9]*|_)$"}.
* </li>
* </ul>
* <p>
* Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
* </p>
* <p>
* Violation Message Keys:
* </p>
* <ul>
* <li>
* {@code name.invalidPattern}
* </li>
* </ul>
*
* @since 3.0
*/
public class LocalVariableNameCheck
extends AbstractNameCheck {
/**
* Allow one character variable name in
* <a href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/for.html">
* initialization expressions</a>
* in FOR loop if one char variable name is prohibited by {@code format} regexp.
*/
private boolean allowOneCharVarInForLoop;
/** Creates a new {@code LocalVariableNameCheck} instance. */
public LocalVariableNameCheck() {
super("^([a-z][a-zA-Z0-9]*|_)$");
}
/**
* Setter to allow one character variable name in
* <a href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/for.html">
* initialization expressions</a>
* in FOR loop if one char variable name is prohibited by {@code format} regexp.
*
* @param allow Flag for allowing or not one character name in FOR loop.
* @since 5.8
*/
public final void setAllowOneCharVarInForLoop(boolean allow) {
allowOneCharVarInForLoop = allow;
}
@Override
public int[] getDefaultTokens() {
return getRequiredTokens();
}
@Override
public int[] getAcceptableTokens() {
return getRequiredTokens();
}
@Override
public int[] getRequiredTokens() {
return new int[] {
TokenTypes.VARIABLE_DEF,
};
}
@Override
protected final boolean mustCheckName(DetailAST ast) {
final boolean result;
if (allowOneCharVarInForLoop && isForLoopVariable(ast)) {
final String variableName = ast.findFirstToken(TokenTypes.IDENT).getText();
result = variableName.length() != 1;
}
else {
final DetailAST modifiersAST = ast.findFirstToken(TokenTypes.MODIFIERS);
final boolean isFinal = modifiersAST.findFirstToken(TokenTypes.FINAL) != null;
result = !isFinal && ScopeUtil.isLocalVariableDef(ast);
}
return result;
}
/**
* Checks if a variable is the loop's one.
*
* @param variableDef variable definition.
* @return true if a variable is the loop's one.
*/
private static boolean isForLoopVariable(DetailAST variableDef) {
final int parentType = variableDef.getParent().getType();
return parentType == TokenTypes.FOR_INIT
|| parentType == TokenTypes.FOR_EACH_CLAUSE;
}
}