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1   ////////////////////////////////////////////////////////////////////////////////
2   // checkstyle: Checks Java source code for adherence to a set of rules.
3   // Copyright (C) 2001-2017 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.coding;
21  
22  import com.puppycrawl.tools.checkstyle.StatelessCheck;
23  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
24  import com.puppycrawl.tools.checkstyle.api.DetailAST;
25  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
26  
27  /**
28   * Checks that no method having zero parameters is defined
29   * using the name <em>finalize</em>.
30   *
31   * @author fqian@google.com (Feng Qian)
32   * @author smckay@google.com (Steve McKay)
33   * @author lkuehne
34   */
35  @StatelessCheck
36  public class NoFinalizerCheck extends AbstractCheck {
37  
38      /**
39       * A key is pointing to the warning message text in "messages.properties"
40       * file.
41       */
42      public static final String MSG_KEY = "avoid.finalizer.method";
43  
44      @Override
45      public int[] getDefaultTokens() {
46          return getAcceptableTokens();
47      }
48  
49      @Override
50      public int[] getAcceptableTokens() {
51          return new int[] {TokenTypes.METHOD_DEF};
52      }
53  
54      @Override
55      public int[] getRequiredTokens() {
56          return getAcceptableTokens();
57      }
58  
59      @Override
60      public void visitToken(DetailAST aAST) {
61          final DetailAST mid = aAST.findFirstToken(TokenTypes.IDENT);
62          final String name = mid.getText();
63  
64          if ("finalize".equals(name)) {
65  
66              final DetailAST params = aAST.findFirstToken(TokenTypes.PARAMETERS);
67              final boolean hasEmptyParamList =
68                  params.findFirstToken(TokenTypes.PARAMETER_DEF) == null;
69  
70              if (hasEmptyParamList) {
71                  log(aAST.getLineNo(), MSG_KEY);
72              }
73          }
74      }
75  }