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