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 * Measures the number of distinct classes that are instantiated
27 * within the given class or record. This type of coupling is not caused by inheritance or
28 * the object-oriented paradigm. Generally speaking, any data type with other
29 * data types as members or local variable that is an instantiation (object)
30 * of another class has data abstraction coupling (DAC). The higher the DAC,
31 * the more complex the structure of the class.
32 * </p>
33 * <p>
34 * This check processes files in the following way:
35 * </p>
36 * <ol>
37 * <li>
38 * Iterates over the list of tokens (defined below) and counts all mentioned classes.
39 * <ul>
40 * <li>
41 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#IMPORT">
42 * PACKAGE_DEF</a>
43 * </li>
44 * <li>
45 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#IMPORT">
46 * IMPORT</a>
47 * </li>
48 * <li>
49 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CLASS_DEF">
50 * CLASS_DEF</a>
51 * </li>
52 * <li>
53 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INTERFACE_DEF">
54 * INTERFACE_DEF</a>
55 * </li>
56 * <li>
57 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_DEF">
58 * ENUM_DEF</a>
59 * </li>
60 * <li>
61 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LITERAL_NEW">
62 * LITERAL_NEW</a>
63 * </li>
64 * <li>
65 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_DEF">
66 * RECORD_DEF</a>
67 * </li>
68 * </ul>
69 * </li>
70 * <li>
71 * If a class was imported with direct import (i.e. {@code import java.math.BigDecimal}),
72 * or the class was referenced with the package name (i.e. {@code java.math.BigDecimal value})
73 * and the package was added to the {@code excludedPackages} parameter, the class
74 * does not increase complexity.
75 * </li>
76 * <li>
77 * If a class name was added to the {@code excludedClasses} parameter,
78 * the class does not increase complexity.
79 * </li>
80 * </ol>
81 * <ul>
82 * <li>
83 * Property {@code excludeClassesRegexps} - Specify user-configured regular
84 * expressions to ignore classes.
85 * Type is {@code java.util.regex.Pattern[]}.
86 * Default value is {@code ^$}.
87 * </li>
88 * <li>
89 * Property {@code excludedClasses} - Specify user-configured class names to ignore.
90 * Type is {@code java.lang.String[]}.
91 * Default value is {@code ArrayIndexOutOfBoundsException, ArrayList, Boolean, Byte,
92 * Character, Class, Collection, Deprecated, Deque, Double, DoubleStream, EnumSet, Exception,
93 * Float, FunctionalInterface, HashMap, HashSet, IllegalArgumentException, IllegalStateException,
94 * IndexOutOfBoundsException, IntStream, Integer, LinkedHashMap, LinkedHashSet, LinkedList, List,
95 * Long, LongStream, Map, NullPointerException, Object, Optional, OptionalDouble, OptionalInt,
96 * OptionalLong, Override, Queue, RuntimeException, SafeVarargs, SecurityException, Set, Short,
97 * SortedMap, SortedSet, Stream, String, StringBuffer, StringBuilder, SuppressWarnings, Throwable,
98 * TreeMap, TreeSet, UnsupportedOperationException, Void, boolean, byte, char, double,
99 * float, int, long, short, var, void}.
100 * </li>
101 * <li>
102 * Property {@code excludedPackages} - Specify user-configured packages to ignore.
103 * Type is {@code java.lang.String[]}.
104 * Default value is {@code ""}.
105 * </li>
106 * <li>
107 * Property {@code max} - Specify the maximum threshold allowed.
108 * Type is {@code int}.
109 * Default value is {@code 7}.
110 * </li>
111 * </ul>
112 * <p>
113 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
114 * </p>
115 * <p>
116 * Violation Message Keys:
117 * </p>
118 * <ul>
119 * <li>
120 * {@code classDataAbstractionCoupling}
121 * </li>
122 * </ul>
123 *
124 * @since 3.4
125 *
126 */
127 public final class ClassDataAbstractionCouplingCheck
128 extends AbstractClassCouplingCheck {
129
130 /**
131 * A key is pointing to the warning message text in "messages.properties"
132 * file.
133 */
134 public static final String MSG_KEY = "classDataAbstractionCoupling";
135
136 /** Default allowed complexity. */
137 private static final int DEFAULT_MAX = 7;
138
139 /** Creates bew instance of the check. */
140 public ClassDataAbstractionCouplingCheck() {
141 super(DEFAULT_MAX);
142 }
143
144 @Override
145 public int[] getRequiredTokens() {
146 return new int[] {
147 TokenTypes.PACKAGE_DEF,
148 TokenTypes.IMPORT,
149 TokenTypes.CLASS_DEF,
150 TokenTypes.INTERFACE_DEF,
151 TokenTypes.ENUM_DEF,
152 TokenTypes.LITERAL_NEW,
153 TokenTypes.RECORD_DEF,
154 };
155 }
156
157 @Override
158 public int[] getAcceptableTokens() {
159 return getRequiredTokens();
160 }
161
162 @Override
163 protected String getLogMessageId() {
164 return MSG_KEY;
165 }
166
167 }