1 ///////////////////////////////////////////////////////////////////////////////////////////////
2 // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
3 // Copyright (C) 2001-2026 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.metrics;
21
22 import java.util.regex.Pattern;
23
24 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
25
26 /**
27 * <div>
28 * Checks the number of other types a given class/record/interface/enum/annotation
29 * relies on. Also, the square of this has been shown to indicate the amount
30 * of maintenance required in functional programs (on a file basis) at least.
31 * </div>
32 *
33 * <p>
34 * This check processes files in the following way:
35 * </p>
36 * <ol>
37 * <li>
38 * Iterates over all tokens that might contain type reference.
39 * </li>
40 * <li>
41 * If a class was imported with direct import (i.e. {@code import java.math.BigDecimal}),
42 * or the class was referenced with the package name (i.e. {@code java.math.BigDecimal value})
43 * and the package was added to the {@code excludedPackages} parameter,
44 * the class does not increase complexity.
45 * </li>
46 * <li>
47 * If a class name was added to the {@code excludedClasses} parameter,
48 * the class does not increase complexity.
49 * </li>
50 * </ol>
51 *
52 * @since 3.4
53 */
54 public final class ClassFanOutComplexityCheck extends AbstractClassCouplingCheck {
55
56 /**
57 * A key is pointing to the warning message text in "messages.properties"
58 * file.
59 */
60 public static final String MSG_KEY = "classFanOutComplexity";
61
62 /** Default value of max value. */
63 private static final int DEFAULT_MAX = 20;
64
65 /** Creates new instance of this check. */
66 public ClassFanOutComplexityCheck() {
67 super(DEFAULT_MAX);
68 }
69
70 @Override
71 public int[] getRequiredTokens() {
72 return new int[] {
73 TokenTypes.PACKAGE_DEF,
74 TokenTypes.IMPORT,
75 TokenTypes.CLASS_DEF,
76 TokenTypes.EXTENDS_CLAUSE,
77 TokenTypes.IMPLEMENTS_CLAUSE,
78 TokenTypes.ANNOTATION,
79 TokenTypes.INTERFACE_DEF,
80 TokenTypes.ENUM_DEF,
81 TokenTypes.TYPE,
82 TokenTypes.LITERAL_NEW,
83 TokenTypes.LITERAL_THROWS,
84 TokenTypes.ANNOTATION_DEF,
85 TokenTypes.RECORD_DEF,
86 TokenTypes.COMPACT_COMPILATION_UNIT,
87 };
88 }
89
90 @Override
91 public int[] getAcceptableTokens() {
92 return getRequiredTokens();
93 }
94
95 @Override
96 protected String getLogMessageId() {
97 return MSG_KEY;
98 }
99
100 /**
101 * Setter to specify user-configured regular expressions to ignore classes.
102 *
103 * @param from array representing regular expressions of classes to ignore.
104 * @propertySince 7.7
105 */
106 @Override
107 public void setExcludeClassesRegexps(Pattern... from) {
108 super.setExcludeClassesRegexps(from);
109 }
110
111 /**
112 * Setter to specify user-configured class names to ignore.
113 *
114 * @param excludedClasses classes to ignore.
115 * @propertySince 5.7
116 */
117 @Override
118 public void setExcludedClasses(String... excludedClasses) {
119 super.setExcludedClasses(excludedClasses);
120 }
121
122 /**
123 * Setter to specify user-configured packages to ignore.
124 *
125 * @param excludedPackages packages to ignore.
126 * @throws IllegalArgumentException if there are invalid identifiers among the packages.
127 * @propertySince 7.7
128 */
129 @Override
130 public void setExcludedPackages(String... excludedPackages) {
131 super.setExcludedPackages(excludedPackages);
132 }
133
134 }