ParameterNameCheck.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 java.util.Arrays;
import java.util.Optional;

import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
import com.puppycrawl.tools.checkstyle.utils.CheckUtil;

/**
 * <p>
 * Checks that method parameter names conform to a specified pattern.
 * By using {@code accessModifiers} property it is possible
 * to specify different formats for methods at different visibility levels.
 * </p>
 * <p>
 * To validate {@code catch} parameters please use
 * <a href="https://checkstyle.org/checks/naming/catchparametername.html#CatchParameterName">
 * CatchParameterName</a>.
 * </p>
 * <p>
 * To validate lambda parameters please use
 * <a href="https://checkstyle.org/checks/naming/lambdaparametername.html#LambdaParameterName">
 * LambdaParameterName</a>.
 * </p>
 * <ul>
 * <li>
 * Property {@code accessModifiers} - Access modifiers of methods where parameters are
 * checked.
 * Type is {@code com.puppycrawl.tools.checkstyle.checks.naming.AccessModifierOption[]}.
 * Default value is {@code public, protected, package, private}.
 * </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>
 * <li>
 * Property {@code ignoreOverridden} - Allows to skip methods with Override annotation from
 * validation.
 * Type is {@code boolean}.
 * Default value is {@code false}.
 * </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 ParameterNameCheck extends AbstractNameCheck {

    /**
     * Allows to skip methods with Override annotation from validation.
     */
    private boolean ignoreOverridden;

    /** Access modifiers of methods where parameters are checked. */
    private AccessModifierOption[] accessModifiers = {
        AccessModifierOption.PUBLIC,
        AccessModifierOption.PROTECTED,
        AccessModifierOption.PACKAGE,
        AccessModifierOption.PRIVATE,
    };

    /**
     * Creates a new {@code ParameterNameCheck} instance.
     */
    public ParameterNameCheck() {
        super("^[a-z][a-zA-Z0-9]*$");
    }

    /**
     * Setter to allows to skip methods with Override annotation from validation.
     *
     * @param ignoreOverridden Flag for skipping methods with Override annotation.
     * @since 6.12.1
     */
    public void setIgnoreOverridden(boolean ignoreOverridden) {
        this.ignoreOverridden = ignoreOverridden;
    }

    /**
     * Setter to access modifiers of methods where parameters are checked.
     *
     * @param accessModifiers access modifiers of methods which should be checked.
     * @since 7.5
     */
    public void setAccessModifiers(AccessModifierOption... accessModifiers) {
        this.accessModifiers =
            Arrays.copyOf(accessModifiers, accessModifiers.length);
    }

    @Override
    public int[] getDefaultTokens() {
        return getRequiredTokens();
    }

    @Override
    public int[] getAcceptableTokens() {
        return getRequiredTokens();
    }

    @Override
    public int[] getRequiredTokens() {
        return new int[] {TokenTypes.PARAMETER_DEF};
    }

    @Override
    protected boolean mustCheckName(DetailAST ast) {
        boolean checkName = true;
        final DetailAST parent = ast.getParent();
        if (ignoreOverridden && isOverriddenMethod(ast)
                || parent.getType() == TokenTypes.LITERAL_CATCH
                || parent.getParent().getType() == TokenTypes.LAMBDA
                || CheckUtil.isReceiverParameter(ast)
                || !matchAccessModifiers(
                        CheckUtil.getAccessModifierFromModifiersToken(parent.getParent()))) {
            checkName = false;
        }
        return checkName;
    }

    /**
     * Checks whether a method has the correct access modifier to be checked.
     *
     * @param accessModifier the access modifier of the method.
     * @return whether the method matches the expected access modifier.
     */
    private boolean matchAccessModifiers(final AccessModifierOption accessModifier) {
        return Arrays.stream(accessModifiers)
                .anyMatch(modifier -> modifier == accessModifier);
    }

    /**
     * Checks whether a method is annotated with Override annotation.
     *
     * @param ast method parameter definition token.
     * @return true if a method is annotated with Override annotation.
     */
    private static boolean isOverriddenMethod(DetailAST ast) {
        boolean overridden = false;

        final DetailAST parent = ast.getParent().getParent();
        final Optional<DetailAST> annotation =
            Optional.ofNullable(parent.getFirstChild().getFirstChild());

        if (annotation.isPresent()) {
            final Optional<DetailAST> overrideToken =
                Optional.ofNullable(annotation.orElseThrow().findFirstToken(TokenTypes.IDENT));
            if (overrideToken.isPresent()
                && "Override".equals(overrideToken.orElseThrow().getText())) {
                overridden = true;
            }
        }
        return overridden;
    }

}