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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.sizes;
21  
22  import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
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   * <div>
29   * Checks for the number of types declared at the <i>outer</i> (or <i>root</i>) level in a file.
30   * </div>
31   *
32   * <p>
33   * Rationale: It is considered good practice to only define one outer type per file.
34   * </p>
35   * <ul>
36   * <li>
37   * Property {@code max} - Specify the maximum number of outer types allowed.
38   * Type is {@code int}.
39   * Default value is {@code 1}.
40   * </li>
41   * </ul>
42   *
43   * <p>
44   * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
45   * </p>
46   *
47   * <p>
48   * Violation Message Keys:
49   * </p>
50   * <ul>
51   * <li>
52   * {@code maxOuterTypes}
53   * </li>
54   * </ul>
55   *
56   * @since 5.0
57   */
58  @FileStatefulCheck
59  public class OuterTypeNumberCheck extends AbstractCheck {
60  
61      /**
62       * A key is pointing to the warning message text in "messages.properties"
63       * file.
64       */
65      public static final String MSG_KEY = "maxOuterTypes";
66  
67      /** Specify the maximum number of outer types allowed. */
68      private int max = 1;
69      /** Tracks the current depth in types. */
70      private int currentDepth;
71      /** Tracks the number of outer types found. */
72      private int outerNum;
73  
74      @Override
75      public int[] getDefaultTokens() {
76          return getRequiredTokens();
77      }
78  
79      @Override
80      public int[] getAcceptableTokens() {
81          return getRequiredTokens();
82      }
83  
84      @Override
85      public int[] getRequiredTokens() {
86          return new int[] {
87              TokenTypes.CLASS_DEF,
88              TokenTypes.INTERFACE_DEF,
89              TokenTypes.ENUM_DEF,
90              TokenTypes.ANNOTATION_DEF,
91              TokenTypes.RECORD_DEF,
92          };
93      }
94  
95      @Override
96      public void beginTree(DetailAST ast) {
97          currentDepth = 0;
98          outerNum = 0;
99      }
100 
101     @Override
102     public void finishTree(DetailAST ast) {
103         if (max < outerNum) {
104             log(ast, MSG_KEY, outerNum, max);
105         }
106     }
107 
108     @Override
109     public void visitToken(DetailAST ast) {
110         if (currentDepth == 0) {
111             outerNum++;
112         }
113         currentDepth++;
114     }
115 
116     @Override
117     public void leaveToken(DetailAST ast) {
118         currentDepth--;
119     }
120 
121     /**
122      * Setter to specify the maximum number of outer types allowed.
123      *
124      * @param max the new number.
125      * @since 5.0
126      */
127     public void setMax(int max) {
128         this.max = max;
129     }
130 
131 }