001/////////////////////////////////////////////////////////////////////////////////////////////// 002// checkstyle: Checks Java source code and other text files for adherence to a set of rules. 003// Copyright (C) 2001-2023 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.coding; 021 022import com.puppycrawl.tools.checkstyle.FileStatefulCheck; 023import com.puppycrawl.tools.checkstyle.api.AbstractCheck; 024import com.puppycrawl.tools.checkstyle.api.DetailAST; 025import com.puppycrawl.tools.checkstyle.api.TokenTypes; 026 027/** 028 * <p> 029 * Restricts nested {@code for} blocks to a specified depth. 030 * </p> 031 * <ul> 032 * <li> 033 * Property {@code max} - Specify maximum allowed nesting depth. 034 * Type is {@code int}. 035 * Default value is {@code 1}. 036 * </li> 037 * </ul> 038 * <p> 039 * To configure the check: 040 * </p> 041 * <pre> 042 * <module name="NestedForDepth"/> 043 * </pre> 044 * <p>Example:</p> 045 * <pre> 046 * for(int i=0; i<10; i++) { 047 * for(int j=0; j<i; j++) { 048 * for(int k=0; k<j; k++) { // violation, max allowed nested loop number is 1 049 * } 050 * } 051 * } 052 * 053 * for(int i=0; i<10; i++) { 054 * for(int j=0; j<i; j++) { // ok 055 * } 056 * } 057 * </pre> 058 * <p> 059 * To configure the check to allow nesting depth 2: 060 * </p> 061 * <pre> 062 * <module name="NestedForDepth"> 063 * <property name="max" value="2"/> 064 * </module> 065 * </pre> 066 * <p>Example:</p> 067 * <pre> 068 * for(int i=0; i<10; i++) { 069 * for(int j=0; j<i; j++) { 070 * for(int k=0; k<j; k++) { 071 * for(int l=0; l<k; l++) { // violation, max allowed nested loop number is 2 072 * } 073 * } 074 * } 075 * } 076 * 077 * for(int i=0; i<10; i++) { 078 * for(int j=0; j<i; j++) { 079 * for(int k=0; k<j; k++) { // ok 080 * } 081 * } 082 * } 083 * </pre> 084 * <p> 085 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker} 086 * </p> 087 * <p> 088 * Violation Message Keys: 089 * </p> 090 * <ul> 091 * <li> 092 * {@code nested.for.depth} 093 * </li> 094 * </ul> 095 * 096 * @since 5.3 097 */ 098@FileStatefulCheck 099public final class NestedForDepthCheck extends AbstractCheck { 100 101 /** 102 * A key is pointing to the warning message text in "messages.properties" 103 * file. 104 */ 105 public static final String MSG_KEY = "nested.for.depth"; 106 107 /** Specify maximum allowed nesting depth. */ 108 private int max = 1; 109 /** Current nesting depth. */ 110 private int depth; 111 112 /** 113 * Setter to specify maximum allowed nesting depth. 114 * 115 * @param max maximum allowed nesting depth. 116 */ 117 public void setMax(int max) { 118 this.max = max; 119 } 120 121 @Override 122 public int[] getDefaultTokens() { 123 return getRequiredTokens(); 124 } 125 126 @Override 127 public int[] getAcceptableTokens() { 128 return getRequiredTokens(); 129 } 130 131 @Override 132 public int[] getRequiredTokens() { 133 return new int[] {TokenTypes.LITERAL_FOR}; 134 } 135 136 @Override 137 public void beginTree(DetailAST rootAST) { 138 depth = 0; 139 } 140 141 @Override 142 public void visitToken(DetailAST ast) { 143 if (depth > max) { 144 log(ast, MSG_KEY, depth, max); 145 } 146 ++depth; 147 } 148 149 @Override 150 public void leaveToken(DetailAST ast) { 151 --depth; 152 } 153 154}