001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2025 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;
024
025/**
026 * <div>
027 * Checks that {@code catch} parameter names conform to a specified pattern.
028 * </div>
029 *
030 * <p>
031 * Default pattern has the following characteristic:
032 * </p>
033 * <ul>
034 * <li>allows names beginning with two lowercase letters followed by at least one uppercase or
035 * lowercase letter</li>
036 * <li>allows {@code e} abbreviation (suitable for exceptions end errors)</li>
037 * <li>allows {@code ex} abbreviation (suitable for exceptions)</li>
038 * <li>allows {@code t} abbreviation (suitable for throwables)</li>
039 * <li>allows {@code _} for unnamed catch parameters</li>
040 * <li>prohibits numbered abbreviations like {@code e1} or {@code t2}</li>
041 * <li>prohibits one letter prefixes like {@code pException}</li>
042 * <li>prohibits two letter abbreviations like {@code ie} or {@code ee}</li>
043 * <li>prohibits any other characters than letters</li>
044 * </ul>
045 *
046 * @since 6.14
047 */
048public class CatchParameterNameCheck extends AbstractNameCheck {
049
050    /**
051     * Creates a new {@code CatchParameterNameCheck} instance.
052     */
053    public CatchParameterNameCheck() {
054        super("^(e|t|ex|[a-z][a-z][a-zA-Z]+|_)$");
055    }
056
057    @Override
058    public int[] getDefaultTokens() {
059        return getRequiredTokens();
060    }
061
062    @Override
063    public int[] getAcceptableTokens() {
064        return getRequiredTokens();
065    }
066
067    @Override
068    public int[] getRequiredTokens() {
069        return new int[] {TokenTypes.PARAMETER_DEF};
070    }
071
072    @Override
073    protected boolean mustCheckName(DetailAST ast) {
074        return ast.getParent().getType() == TokenTypes.LITERAL_CATCH;
075    }
076
077}