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1   ///////////////////////////////////////////////////////////////////////////////////////////////
2   // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
3   // Copyright (C) 2001-2024 the original author or authors.
4   //
5   // This library is free software; you can redistribute it and/or
6   // modify it under the terms of the GNU Lesser General Public
7   // License as published by the Free Software Foundation; either
8   // version 2.1 of the License, or (at your option) any later version.
9   //
10  // This library is distributed in the hope that it will be useful,
11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  // Lesser General Public License for more details.
14  //
15  // You should have received a copy of the GNU Lesser General Public
16  // License along with this library; if not, write to the Free Software
17  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  ///////////////////////////////////////////////////////////////////////////////////////////////
19  
20  package com.puppycrawl.tools.checkstyle.checks.naming;
21  
22  import com.puppycrawl.tools.checkstyle.api.DetailAST;
23  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
24  
25  /**
26   * <p>
27   * Checks that {@code catch} parameter names conform to a specified pattern.
28   * </p>
29   * <p>
30   * Default pattern has the following characteristic:
31   * </p>
32   * <ul>
33   * <li>allows names beginning with two lowercase letters followed by at least one uppercase or
34   * lowercase letter</li>
35   * <li>allows {@code e} abbreviation (suitable for exceptions end errors)</li>
36   * <li>allows {@code ex} abbreviation (suitable for exceptions)</li>
37   * <li>allows {@code t} abbreviation (suitable for throwables)</li>
38   * <li>prohibits numbered abbreviations like {@code e1} or {@code t2}</li>
39   * <li>prohibits one letter prefixes like {@code pException}</li>
40   * <li>prohibits two letter abbreviations like {@code ie} or {@code ee}</li>
41   * <li>prohibits any other characters than letters</li>
42   * </ul>
43   * <ul>
44   * <li>
45   * Property {@code format} - Sets the pattern to match valid identifiers.
46   * Type is {@code java.util.regex.Pattern}.
47   * Default value is {@code "^(e|t|ex|[a-z][a-z][a-zA-Z]+)$"}.
48   * </li>
49   * </ul>
50   * <p>
51   * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
52   * </p>
53   * <p>
54   * Violation Message Keys:
55   * </p>
56   * <ul>
57   * <li>
58   * {@code name.invalidPattern}
59   * </li>
60   * </ul>
61   *
62   * @since 6.14
63   */
64  public class CatchParameterNameCheck extends AbstractNameCheck {
65  
66      /**
67       * Creates a new {@code CatchParameterNameCheck} instance.
68       */
69      public CatchParameterNameCheck() {
70          super("^(e|t|ex|[a-z][a-z][a-zA-Z]+)$");
71      }
72  
73      @Override
74      public int[] getDefaultTokens() {
75          return getRequiredTokens();
76      }
77  
78      @Override
79      public int[] getAcceptableTokens() {
80          return getRequiredTokens();
81      }
82  
83      @Override
84      public int[] getRequiredTokens() {
85          return new int[] {TokenTypes.PARAMETER_DEF};
86      }
87  
88      @Override
89      protected boolean mustCheckName(DetailAST ast) {
90          return ast.getParent().getType() == TokenTypes.LITERAL_CATCH;
91      }
92  
93  }