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;
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 * <ul>
046 * <li>
047 * Property {@code format} - Sets the pattern to match valid identifiers.
048 * Type is {@code java.util.regex.Pattern}.
049 * Default value is {@code "^(e|t|ex|[a-z][a-z][a-zA-Z]+|_)$"}.
050 * </li>
051 * </ul>
052 *
053 * <p>
054 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
055 * </p>
056 *
057 * <p>
058 * Violation Message Keys:
059 * </p>
060 * <ul>
061 * <li>
062 * {@code name.invalidPattern}
063 * </li>
064 * </ul>
065 *
066 * @since 6.14
067 */
068public class CatchParameterNameCheck extends AbstractNameCheck {
069
070    /**
071     * Creates a new {@code CatchParameterNameCheck} instance.
072     */
073    public CatchParameterNameCheck() {
074        super("^(e|t|ex|[a-z][a-z][a-zA-Z]+|_)$");
075    }
076
077    @Override
078    public int[] getDefaultTokens() {
079        return getRequiredTokens();
080    }
081
082    @Override
083    public int[] getAcceptableTokens() {
084        return getRequiredTokens();
085    }
086
087    @Override
088    public int[] getRequiredTokens() {
089        return new int[] {TokenTypes.PARAMETER_DEF};
090    }
091
092    @Override
093    protected boolean mustCheckName(DetailAST ast) {
094        return ast.getParent().getType() == TokenTypes.LITERAL_CATCH;
095    }
096
097}