001/////////////////////////////////////////////////////////////////////////////////////////////// 002// checkstyle: Checks Java source code and other text files for adherence to a set of rules. 003// Copyright (C) 2001-2024 the original author or authors. 004// 005// This library is free software; you can redistribute it and/or 006// modify it under the terms of the GNU Lesser General Public 007// License as published by the Free Software Foundation; either 008// version 2.1 of the License, or (at your option) any later version. 009// 010// This library is distributed in the hope that it will be useful, 011// but WITHOUT ANY WARRANTY; without even the implied warranty of 012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 013// Lesser General Public License for more details. 014// 015// You should have received a copy of the GNU Lesser General Public 016// License along with this library; if not, write to the Free Software 017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 018/////////////////////////////////////////////////////////////////////////////////////////////// 019 020package com.puppycrawl.tools.checkstyle.checks.metrics; 021 022import com.puppycrawl.tools.checkstyle.api.TokenTypes; 023 024/** 025 * <div> 026 * Measures the number of distinct classes that are instantiated 027 * within the given class or record. This type of coupling is not caused by inheritance or 028 * the object-oriented paradigm. Generally speaking, any data type with other 029 * data types as members or local variable that is an instantiation (object) 030 * of another class has data abstraction coupling (DAC). The higher the DAC, 031 * the more complex the structure of the class. 032 * </div> 033 * 034 * <p> 035 * This check processes files in the following way: 036 * </p> 037 * <ol> 038 * <li> 039 * Iterates over the list of tokens (defined below) and counts all mentioned classes. 040 * <ul> 041 * <li> 042 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#IMPORT"> 043 * PACKAGE_DEF</a> 044 * </li> 045 * <li> 046 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#IMPORT"> 047 * IMPORT</a> 048 * </li> 049 * <li> 050 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CLASS_DEF"> 051 * CLASS_DEF</a> 052 * </li> 053 * <li> 054 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INTERFACE_DEF"> 055 * INTERFACE_DEF</a> 056 * </li> 057 * <li> 058 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_DEF"> 059 * ENUM_DEF</a> 060 * </li> 061 * <li> 062 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LITERAL_NEW"> 063 * LITERAL_NEW</a> 064 * </li> 065 * <li> 066 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_DEF"> 067 * RECORD_DEF</a> 068 * </li> 069 * </ul> 070 * </li> 071 * <li> 072 * If a class was imported with direct import (i.e. {@code import java.math.BigDecimal}), 073 * or the class was referenced with the package name (i.e. {@code java.math.BigDecimal value}) 074 * and the package was added to the {@code excludedPackages} parameter, the class 075 * does not increase complexity. 076 * </li> 077 * <li> 078 * If a class name was added to the {@code excludedClasses} parameter, 079 * the class does not increase complexity. 080 * </li> 081 * </ol> 082 * <ul> 083 * <li> 084 * Property {@code excludeClassesRegexps} - Specify user-configured regular 085 * expressions to ignore classes. 086 * Type is {@code java.util.regex.Pattern[]}. 087 * Default value is {@code ^$}. 088 * </li> 089 * <li> 090 * Property {@code excludedClasses} - Specify user-configured class names to ignore. 091 * Type is {@code java.lang.String[]}. 092 * Default value is {@code ArrayIndexOutOfBoundsException, ArrayList, Boolean, Byte, 093 * Character, Class, Collection, Deprecated, Deque, Double, DoubleStream, EnumSet, Exception, 094 * Float, FunctionalInterface, HashMap, HashSet, IllegalArgumentException, IllegalStateException, 095 * IndexOutOfBoundsException, IntStream, Integer, LinkedHashMap, LinkedHashSet, LinkedList, List, 096 * Long, LongStream, Map, NullPointerException, Object, Optional, OptionalDouble, OptionalInt, 097 * OptionalLong, Override, Queue, RuntimeException, SafeVarargs, SecurityException, Set, Short, 098 * SortedMap, SortedSet, Stream, String, StringBuffer, StringBuilder, SuppressWarnings, Throwable, 099 * TreeMap, TreeSet, UnsupportedOperationException, Void, boolean, byte, char, double, 100 * float, int, long, short, var, void}. 101 * </li> 102 * <li> 103 * Property {@code excludedPackages} - Specify user-configured packages to ignore. 104 * Type is {@code java.lang.String[]}. 105 * Default value is {@code ""}. 106 * </li> 107 * <li> 108 * Property {@code max} - Specify the maximum threshold allowed. 109 * Type is {@code int}. 110 * Default value is {@code 7}. 111 * </li> 112 * </ul> 113 * 114 * <p> 115 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker} 116 * </p> 117 * 118 * <p> 119 * Violation Message Keys: 120 * </p> 121 * <ul> 122 * <li> 123 * {@code classDataAbstractionCoupling} 124 * </li> 125 * </ul> 126 * 127 * @since 3.4 128 * 129 */ 130public final class ClassDataAbstractionCouplingCheck 131 extends AbstractClassCouplingCheck { 132 133 /** 134 * A key is pointing to the warning message text in "messages.properties" 135 * file. 136 */ 137 public static final String MSG_KEY = "classDataAbstractionCoupling"; 138 139 /** Default allowed complexity. */ 140 private static final int DEFAULT_MAX = 7; 141 142 /** Creates bew instance of the check. */ 143 public ClassDataAbstractionCouplingCheck() { 144 super(DEFAULT_MAX); 145 } 146 147 @Override 148 public int[] getRequiredTokens() { 149 return new int[] { 150 TokenTypes.PACKAGE_DEF, 151 TokenTypes.IMPORT, 152 TokenTypes.CLASS_DEF, 153 TokenTypes.INTERFACE_DEF, 154 TokenTypes.ENUM_DEF, 155 TokenTypes.LITERAL_NEW, 156 TokenTypes.RECORD_DEF, 157 }; 158 } 159 160 @Override 161 public int[] getAcceptableTokens() { 162 return getRequiredTokens(); 163 } 164 165 @Override 166 protected String getLogMessageId() { 167 return MSG_KEY; 168 } 169 170}