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 * Checks the number of other types a given class/record/interface/enum/annotation 027 * relies on. Also, the square of this has been shown to indicate the amount 028 * of maintenance required in functional programs (on a file basis) at least. 029 * </p> 030 * <p> 031 * This check processes files in the following way: 032 * </p> 033 * <ol> 034 * <li> 035 * Iterates over all tokens that might contain type reference. 036 * </li> 037 * <li> 038 * If a class was imported with direct import (i.e. {@code import java.math.BigDecimal}), 039 * or the class was referenced with the package name (i.e. {@code java.math.BigDecimal value}) 040 * and the package was added to the {@code excludedPackages} parameter, 041 * the class does not increase complexity. 042 * </li> 043 * <li> 044 * If a class name was added to the {@code excludedClasses} parameter, 045 * the class does not increase complexity. 046 * </li> 047 * </ol> 048 * <ul> 049 * <li> 050 * Property {@code excludeClassesRegexps} - Specify user-configured regular 051 * expressions to ignore classes. 052 * Type is {@code java.util.regex.Pattern[]}. 053 * Default value is {@code ^$}. 054 * </li> 055 * <li> 056 * Property {@code excludedClasses} - Specify user-configured class names to ignore. 057 * Type is {@code java.lang.String[]}. 058 * Default value is {@code ArrayIndexOutOfBoundsException, ArrayList, Boolean, Byte, 059 * Character, Class, Collection, Deprecated, Deque, Double, DoubleStream, EnumSet, Exception, 060 * Float, FunctionalInterface, HashMap, HashSet, IllegalArgumentException, IllegalStateException, 061 * IndexOutOfBoundsException, IntStream, Integer, LinkedHashMap, LinkedHashSet, LinkedList, List, 062 * Long, LongStream, Map, NullPointerException, Object, Optional, OptionalDouble, OptionalInt, 063 * OptionalLong, Override, Queue, RuntimeException, SafeVarargs, SecurityException, Set, Short, 064 * SortedMap, SortedSet, Stream, String, StringBuffer, StringBuilder, SuppressWarnings, Throwable, 065 * TreeMap, TreeSet, UnsupportedOperationException, Void, boolean, byte, char, double, 066 * float, int, long, short, var, void}. 067 * </li> 068 * <li> 069 * Property {@code excludedPackages} - Specify user-configured packages to ignore. 070 * Type is {@code java.lang.String[]}. 071 * Default value is {@code ""}. 072 * </li> 073 * <li> 074 * Property {@code max} - Specify the maximum threshold allowed. 075 * Type is {@code int}. 076 * Default value is {@code 20}. 077 * </li> 078 * </ul> 079 * <p> 080 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker} 081 * </p> 082 * <p> 083 * Violation Message Keys: 084 * </p> 085 * <ul> 086 * <li> 087 * {@code classFanOutComplexity} 088 * </li> 089 * </ul> 090 * 091 * @since 3.4 092 */ 093public final class ClassFanOutComplexityCheck extends AbstractClassCouplingCheck { 094 095 /** 096 * A key is pointing to the warning message text in "messages.properties" 097 * file. 098 */ 099 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}