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