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.metrics;
21
22 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
23
24 /**
25 * <div>
26 * Checks the number of other types a given class/record/interface/enum/annotation
27 * relies on. Also, the square of this has been shown to indicate the amount
28 * of maintenance required in functional programs (on a file basis) at least.
29 * </div>
30 *
31 * <p>
32 * This check processes files in the following way:
33 * </p>
34 * <ol>
35 * <li>
36 * Iterates over all tokens that might contain type reference.
37 * </li>
38 * <li>
39 * If a class was imported with direct import (i.e. {@code import java.math.BigDecimal}),
40 * or the class was referenced with the package name (i.e. {@code java.math.BigDecimal value})
41 * and the package was added to the {@code excludedPackages} parameter,
42 * the class does not increase complexity.
43 * </li>
44 * <li>
45 * If a class name was added to the {@code excludedClasses} parameter,
46 * the class does not increase complexity.
47 * </li>
48 * </ol>
49 * <ul>
50 * <li>
51 * Property {@code excludeClassesRegexps} - Specify user-configured regular
52 * expressions to ignore classes.
53 * Type is {@code java.util.regex.Pattern[]}.
54 * Default value is {@code ^$}.
55 * </li>
56 * <li>
57 * Property {@code excludedClasses} - Specify user-configured class names to ignore.
58 * Type is {@code java.lang.String[]}.
59 * Default value is {@code ArrayIndexOutOfBoundsException, ArrayList, Boolean, Byte,
60 * Character, Class, Collection, Deprecated, Deque, Double, DoubleStream, EnumSet, Exception,
61 * Float, FunctionalInterface, HashMap, HashSet, IllegalArgumentException, IllegalStateException,
62 * IndexOutOfBoundsException, IntStream, Integer, LinkedHashMap, LinkedHashSet, LinkedList, List,
63 * Long, LongStream, Map, NullPointerException, Object, Optional, OptionalDouble, OptionalInt,
64 * OptionalLong, Override, Queue, RuntimeException, SafeVarargs, SecurityException, Set, Short,
65 * SortedMap, SortedSet, Stream, String, StringBuffer, StringBuilder, SuppressWarnings, Throwable,
66 * TreeMap, TreeSet, UnsupportedOperationException, Void, boolean, byte, char, double,
67 * float, int, long, short, var, void}.
68 * </li>
69 * <li>
70 * Property {@code excludedPackages} - Specify user-configured packages to ignore.
71 * Type is {@code java.lang.String[]}.
72 * Default value is {@code ""}.
73 * </li>
74 * <li>
75 * Property {@code max} - Specify the maximum threshold allowed.
76 * Type is {@code int}.
77 * Default value is {@code 20}.
78 * </li>
79 * </ul>
80 *
81 * <p>
82 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
83 * </p>
84 *
85 * <p>
86 * Violation Message Keys:
87 * </p>
88 * <ul>
89 * <li>
90 * {@code classFanOutComplexity}
91 * </li>
92 * </ul>
93 *
94 * @since 3.4
95 */
96 public final class ClassFanOutComplexityCheck extends AbstractClassCouplingCheck {
97
98 /**
99 * A key is pointing to the warning message text in "messages.properties"
100 * file.
101 */
102 public static final String MSG_KEY = "classFanOutComplexity";
103
104 /** Default value of max value. */
105 private static final int DEFAULT_MAX = 20;
106
107 /** Creates new instance of this check. */
108 public ClassFanOutComplexityCheck() {
109 super(DEFAULT_MAX);
110 }
111
112 @Override
113 public int[] getRequiredTokens() {
114 return new int[] {
115 TokenTypes.PACKAGE_DEF,
116 TokenTypes.IMPORT,
117 TokenTypes.CLASS_DEF,
118 TokenTypes.EXTENDS_CLAUSE,
119 TokenTypes.IMPLEMENTS_CLAUSE,
120 TokenTypes.ANNOTATION,
121 TokenTypes.INTERFACE_DEF,
122 TokenTypes.ENUM_DEF,
123 TokenTypes.TYPE,
124 TokenTypes.LITERAL_NEW,
125 TokenTypes.LITERAL_THROWS,
126 TokenTypes.ANNOTATION_DEF,
127 TokenTypes.RECORD_DEF,
128 };
129 }
130
131 @Override
132 public int[] getAcceptableTokens() {
133 return getRequiredTokens();
134 }
135
136 @Override
137 protected String getLogMessageId() {
138 return MSG_KEY;
139 }
140
141 }