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 * <p> 026 * Measures the number of instantiations of other classes 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 * </p> 033 * <p> 034 * This check processes files in the following way: 035 * </p> 036 * <ol> 037 * <li> 038 * Iterates over the list of tokens (defined below) and counts all mentioned classes. 039 * <ul> 040 * <li> 041 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#IMPORT"> 042 * PACKAGE_DEF</a> 043 * </li> 044 * <li> 045 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#IMPORT"> 046 * IMPORT</a> 047 * </li> 048 * <li> 049 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CLASS_DEF"> 050 * CLASS_DEF</a> 051 * </li> 052 * <li> 053 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INTERFACE_DEF"> 054 * INTERFACE_DEF</a> 055 * </li> 056 * <li> 057 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_DEF"> 058 * ENUM_DEF</a> 059 * </li> 060 * <li> 061 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LITERAL_NEW"> 062 * LITERAL_NEW</a> 063 * </li> 064 * <li> 065 * <a href="https://checkstyle.org/apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RECORD_DEF"> 066 * RECORD_DEF</a> 067 * </li> 068 * </ul> 069 * </li> 070 * <li> 071 * If a class was imported with direct import (i.e. {@code import java.math.BigDecimal}), 072 * or the class was referenced with the package name (i.e. {@code java.math.BigDecimal value}) 073 * and the package was added to the {@code excludedPackages} parameter, the class 074 * does not increase complexity. 075 * </li> 076 * <li> 077 * If a class name was added to the {@code excludedClasses} parameter, 078 * the class does not increase complexity. 079 * </li> 080 * </ol> 081 * <ul> 082 * <li> 083 * Property {@code excludeClassesRegexps} - Specify user-configured regular 084 * expressions to ignore classes. 085 * Type is {@code java.util.regex.Pattern[]}. 086 * Default value is {@code ^$}. 087 * </li> 088 * <li> 089 * Property {@code excludedClasses} - Specify user-configured class names to ignore. 090 * Type is {@code java.lang.String[]}. 091 * Default value is {@code ArrayIndexOutOfBoundsException, ArrayList, Boolean, Byte, 092 * Character, Class, Collection, Deprecated, Deque, Double, DoubleStream, EnumSet, Exception, 093 * Float, FunctionalInterface, HashMap, HashSet, IllegalArgumentException, IllegalStateException, 094 * IndexOutOfBoundsException, IntStream, Integer, LinkedHashMap, LinkedHashSet, LinkedList, List, 095 * Long, LongStream, Map, NullPointerException, Object, Optional, OptionalDouble, OptionalInt, 096 * OptionalLong, Override, Queue, RuntimeException, SafeVarargs, SecurityException, Set, Short, 097 * SortedMap, SortedSet, Stream, String, StringBuffer, StringBuilder, SuppressWarnings, Throwable, 098 * TreeMap, TreeSet, UnsupportedOperationException, Void, boolean, byte, char, double, 099 * 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 */ 127public 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}