001//////////////////////////////////////////////////////////////////////////////// 002// checkstyle: Checks Java source code for adherence to a set of rules. 003// Copyright (C) 2001-2015 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.design; 021 022import java.util.Map; 023import java.util.SortedMap; 024import java.util.TreeMap; 025 026import org.apache.commons.lang3.ArrayUtils; 027 028import com.puppycrawl.tools.checkstyle.api.Check; 029import com.puppycrawl.tools.checkstyle.api.DetailAST; 030import com.puppycrawl.tools.checkstyle.api.TokenTypes; 031 032/** 033 * Checks that each top-level class, interface 034 * or enum resides in a source file of its own. 035 * <p> 036 * Official description of a 'top-level' term:<a 037 * href="http://docs.oracle.com/javase/specs/jls/se8/html/jls-7.html#jls-7.6"> 038 * 7.6. Top Level Type Declarations</a>. If file doesn't contains 039 * public class, enum or interface, top-level type is the first type in file. 040 * </p> 041 * <p> 042 * An example of code with violations: 043 * </p> 044 * <pre>{@code 045 * public class Foo{ 046 * //methods 047 * } 048 * 049 * class Foo2{ 050 * //methods 051 * } 052 * }</pre> 053 * <p> 054 * An example of code without top-level public type: 055 * </p> 056 * <pre>{@code 057 * class Foo{ //top-level class 058 * //methods 059 * } 060 * 061 * class Foo2{ 062 * //methods 063 * } 064 * }</pre> 065 * <p> 066 * An example of check's configuration: 067 * </p> 068 * <pre> 069 * <module name="OneTopLevelClass"/> 070 * </pre> 071 * 072 * <p> 073 * An example of code without violations: 074 * </p> 075 * <pre>{@code 076 * public class Foo{ 077 * //methods 078 * } 079 * }</pre> 080 * 081 * <p> ATTENTION: This Check does not support customization of validated tokens, 082 * so do not use the "tokens" property. 083 * </p> 084 * 085 * @author maxvetrenko 086 */ 087public class OneTopLevelClassCheck extends Check { 088 089 /** 090 * A key is pointing to the warning message text in "messages.properties" 091 * file. 092 */ 093 public static final String MSG_KEY = "one.top.level.class"; 094 095 /** 096 * True if a java source file contains a type 097 * with a public access level modifier. 098 */ 099 private boolean publicTypeFound; 100 101 /** Mapping between type names and line numbers of the type declarations.*/ 102 private final SortedMap<Integer, String> lineNumberTypeMap = new TreeMap<>(); 103 104 @Override 105 public int[] getDefaultTokens() { 106 return getAcceptableTokens(); 107 } 108 109 // ZERO tokens as Check do Traverse of Tree himself, he does not need to subscribed to Tokens 110 @Override 111 public int[] getAcceptableTokens() { 112 return ArrayUtils.EMPTY_INT_ARRAY; 113 } 114 115 @Override 116 public int[] getRequiredTokens() { 117 return getAcceptableTokens(); 118 } 119 120 @Override 121 public void beginTree(DetailAST rootAST) { 122 publicTypeFound = false; 123 lineNumberTypeMap.clear(); 124 125 DetailAST currentNode = rootAST; 126 while (currentNode != null) { 127 if (currentNode.getType() == TokenTypes.CLASS_DEF 128 || currentNode.getType() == TokenTypes.ENUM_DEF 129 || currentNode.getType() == TokenTypes.INTERFACE_DEF) { 130 if (isPublic(currentNode)) { 131 publicTypeFound = true; 132 } 133 else { 134 final String typeName = currentNode 135 .findFirstToken(TokenTypes.IDENT).getText(); 136 lineNumberTypeMap.put(currentNode.getLineNo(), typeName); 137 } 138 } 139 currentNode = currentNode.getNextSibling(); 140 } 141 } 142 143 @Override 144 public void finishTree(DetailAST rootAST) { 145 if (!lineNumberTypeMap.isEmpty()) { 146 if (!publicTypeFound) { 147 // skip first top-level type. 148 lineNumberTypeMap.remove(lineNumberTypeMap.firstKey()); 149 } 150 151 for (Map.Entry<Integer, String> entry 152 : lineNumberTypeMap.entrySet()) { 153 log(entry.getKey(), MSG_KEY, entry.getValue()); 154 } 155 } 156 } 157 158 /** 159 * Checks if a type is public. 160 * @param typeDef type definition node. 161 * @return true if a type has a public access level modifier. 162 */ 163 private static boolean isPublic(DetailAST typeDef) { 164 final DetailAST modifiers = 165 typeDef.findFirstToken(TokenTypes.MODIFIERS); 166 return modifiers.findFirstToken(TokenTypes.LITERAL_PUBLIC) != null; 167 } 168}