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1   ////////////////////////////////////////////////////////////////////////////////
2   // checkstyle: Checks Java source code for adherence to a set of rules.
3   // Copyright (C) 2001-2018 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 class type parameter names conform to a format specified
28   * by the format property.  The format is a
29   * {@link java.util.regex.Pattern regular expression} and defaults to
30   * <strong>^[A-Z]$</strong>.
31   * </p>
32   * <p>
33   * An example of how to configure the check is:
34   * </p>
35   * <pre>
36   * &lt;module name="ClassTypeParameterName"/&gt;
37   * </pre>
38   * <p>
39   * An example of how to configure the check for names that are only a single
40   * letter is
41   * </p>
42   * <pre>
43   * &lt;module name="ClassTypeParameterName"&gt;
44   *    &lt;property name="format" value="^[a-zA-Z]$"/&gt;
45   * &lt;/module&gt;
46   * </pre>
47   *
48   * @author Travis Schneeberger
49   */
50  public class ClassTypeParameterNameCheck
51      extends AbstractNameCheck {
52  
53      /** Creates a new {@code ClassTypeParameterNameCheck} instance. */
54      public ClassTypeParameterNameCheck() {
55          super("^[A-Z]$");
56      }
57  
58      @Override
59      public int[] getDefaultTokens() {
60          return getRequiredTokens();
61      }
62  
63      @Override
64      public final int[] getAcceptableTokens() {
65          return getRequiredTokens();
66      }
67  
68      @Override
69      public int[] getRequiredTokens() {
70          return new int[] {
71              TokenTypes.TYPE_PARAMETER,
72          };
73      }
74  
75      @Override
76      protected final boolean mustCheckName(DetailAST ast) {
77          final DetailAST location =
78              ast.getParent().getParent();
79          return location.getType() == TokenTypes.CLASS_DEF;
80      }
81  
82  }