001//////////////////////////////////////////////////////////////////////////////// 002// checkstyle: Checks Java source code for adherence to a set of rules. 003// Copyright (C) 2001-2014 Oliver Burn 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//////////////////////////////////////////////////////////////////////////////// 019package com.puppycrawl.tools.checkstyle.checks.metrics; 020 021import java.math.BigInteger; 022 023import com.puppycrawl.tools.checkstyle.api.DetailAST; 024import com.puppycrawl.tools.checkstyle.api.TokenTypes; 025 026/** 027 * Checks the npath complexity against a specified limit (default = 200). 028 * The npath metric computes the number of possible execution paths 029 * through a function. Similar to the cyclomatic complexity but also 030 * takes into account the nesting of conditional statements and 031 * multi-part boolean expressions. 032 * 033 * @author <a href="mailto:simon@redhillconsulting.com.au">Simon Harris</a> 034 * @author o_sukhodolsky 035 * TODO: For every or: _value += (_orCount * (nestedValue - 1)); 036 * TODO: For every and: ??? 037 */ 038public final class NPathComplexityCheck extends AbstractComplexityCheck 039{ 040 /** Default allowed complexity. */ 041 private static final int DEFAULT_MAX = 200; 042 043 /** Creates new instance of the check. */ 044 public NPathComplexityCheck() 045 { 046 super(DEFAULT_MAX); 047 } 048 049 @Override 050 public int[] getDefaultTokens() 051 { 052 return new int[] { 053 TokenTypes.CTOR_DEF, 054 TokenTypes.METHOD_DEF, 055 TokenTypes.STATIC_INIT, 056 TokenTypes.INSTANCE_INIT, 057 TokenTypes.LITERAL_WHILE, 058 TokenTypes.LITERAL_DO, 059 TokenTypes.LITERAL_FOR, 060 TokenTypes.LITERAL_IF, 061 TokenTypes.LITERAL_ELSE, 062 TokenTypes.LITERAL_SWITCH, 063 TokenTypes.LITERAL_CASE, 064 TokenTypes.LITERAL_TRY, 065 TokenTypes.LITERAL_CATCH, 066 TokenTypes.QUESTION, 067 }; 068 } 069 070 @Override 071 public void visitToken(DetailAST ast) 072 { 073 switch (ast.getType()) { 074 case TokenTypes.LITERAL_WHILE: 075 case TokenTypes.LITERAL_DO: 076 case TokenTypes.LITERAL_FOR: 077 case TokenTypes.LITERAL_IF: 078 case TokenTypes.QUESTION: 079 case TokenTypes.LITERAL_TRY: 080 case TokenTypes.LITERAL_SWITCH: 081 visitMultiplyingConditional(); 082 break; 083 case TokenTypes.LITERAL_ELSE: 084 case TokenTypes.LITERAL_CATCH: 085 case TokenTypes.LITERAL_CASE: 086 visitAddingConditional(); 087 break; 088 default: 089 super.visitToken(ast); 090 } 091 } 092 093 @Override 094 public void leaveToken(DetailAST ast) 095 { 096 switch (ast.getType()) { 097 case TokenTypes.LITERAL_WHILE: 098 case TokenTypes.LITERAL_DO: 099 case TokenTypes.LITERAL_FOR: 100 case TokenTypes.LITERAL_IF: 101 case TokenTypes.QUESTION: 102 case TokenTypes.LITERAL_TRY: 103 case TokenTypes.LITERAL_SWITCH: 104 leaveMultiplyingConditional(); 105 break; 106 case TokenTypes.LITERAL_ELSE: 107 case TokenTypes.LITERAL_CATCH: 108 case TokenTypes.LITERAL_CASE: 109 leaveAddingConditional(); 110 break; 111 default: 112 super.leaveToken(ast); 113 } 114 } 115 116 @Override 117 protected String getMessageID() 118 { 119 return "npathComplexity"; 120 } 121 122 /** Visits else, catch or case. */ 123 private void visitAddingConditional() 124 { 125 pushValue(); 126 } 127 128 /** Leaves else, catch or case. */ 129 private void leaveAddingConditional() 130 { 131 setCurrentValue( 132 getCurrentValue().subtract(BigInteger.ONE).add(popValue())); 133 } 134 135 /** Visits while, do, for, if, try, ? (in ?::) or switch. */ 136 private void visitMultiplyingConditional() 137 { 138 pushValue(); 139 } 140 141 /** Leaves while, do, for, if, try, ? (in ?::) or switch. */ 142 private void leaveMultiplyingConditional() 143 { 144 setCurrentValue( 145 getCurrentValue().add(BigInteger.ONE).multiply(popValue())); 146 } 147}