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; 021 022import java.io.BufferedInputStream; 023import java.io.IOException; 024import java.io.InputStream; 025import java.net.URL; 026import java.util.ArrayDeque; 027import java.util.Collections; 028import java.util.Deque; 029import java.util.Enumeration; 030import java.util.HashMap; 031import java.util.Iterator; 032import java.util.LinkedHashSet; 033import java.util.Map; 034import java.util.Set; 035 036import javax.xml.parsers.ParserConfigurationException; 037 038import org.xml.sax.Attributes; 039import org.xml.sax.InputSource; 040import org.xml.sax.SAXException; 041 042import com.puppycrawl.tools.checkstyle.api.CheckstyleException; 043 044/** 045 * Loads a list of package names from a package name XML file. 046 */ 047public final class PackageNamesLoader 048 extends XmlLoader { 049 050 /** The public ID for the configuration dtd. */ 051 private static final String DTD_PUBLIC_ID = 052 "-//Puppy Crawl//DTD Package Names 1.0//EN"; 053 054 /** The new public ID for the configuration dtd. */ 055 private static final String DTD_PUBLIC_CS_ID = 056 "-//Checkstyle//DTD Package Names Configuration 1.0//EN"; 057 058 /** The resource for the configuration dtd. */ 059 private static final String DTD_RESOURCE_NAME = 060 "com/puppycrawl/tools/checkstyle/packages_1_0.dtd"; 061 062 /** 063 * Name of default checkstyle package names resource file. 064 * The file must be in the classpath. 065 */ 066 private static final String CHECKSTYLE_PACKAGES = 067 "checkstyle_packages.xml"; 068 069 /** Qualified name for element 'package'. */ 070 private static final String PACKAGE_ELEMENT_NAME = "package"; 071 072 /** The temporary stack of package name parts. */ 073 private final Deque<String> packageStack = new ArrayDeque<>(); 074 075 /** The fully qualified package names. */ 076 private final Set<String> packageNames = new LinkedHashSet<>(); 077 078 /** 079 * Creates a new {@code PackageNamesLoader} instance. 080 * 081 * @throws ParserConfigurationException if an error occurs 082 * @throws SAXException if an error occurs 083 */ 084 private PackageNamesLoader() 085 throws ParserConfigurationException, SAXException { 086 super(createIdToResourceNameMap()); 087 } 088 089 @Override 090 public void startElement(String uri, 091 String localName, 092 String qName, 093 Attributes attributes) { 094 if (PACKAGE_ELEMENT_NAME.equals(qName)) { 095 // push package name, name is mandatory attribute with not empty value by DTD 096 final String name = attributes.getValue("name"); 097 packageStack.push(name); 098 } 099 } 100 101 /** 102 * Creates a full package name from the package names on the stack. 103 * 104 * @return the full name of the current package. 105 */ 106 private String getPackageName() { 107 final StringBuilder buf = new StringBuilder(256); 108 final Iterator<String> iterator = packageStack.descendingIterator(); 109 while (iterator.hasNext()) { 110 final String subPackage = iterator.next(); 111 buf.append(subPackage); 112 if (!subPackage.endsWith(".") && iterator.hasNext()) { 113 buf.append('.'); 114 } 115 } 116 return buf.toString(); 117 } 118 119 @Override 120 public void endElement(String uri, 121 String localName, 122 String qName) { 123 if (PACKAGE_ELEMENT_NAME.equals(qName)) { 124 packageNames.add(getPackageName()); 125 packageStack.pop(); 126 } 127 } 128 129 /** 130 * Returns the set of package names, compiled from all 131 * checkstyle_packages.xml files found on the given class loaders 132 * classpath. 133 * 134 * @param classLoader the class loader for loading the 135 * checkstyle_packages.xml files. 136 * @return the set of package names. 137 * @throws CheckstyleException if an error occurs. 138 */ 139 public static Set<String> getPackageNames(ClassLoader classLoader) 140 throws CheckstyleException { 141 final Set<String> result; 142 try { 143 // create the loader outside the loop to prevent PackageObjectFactory 144 // being created anew for each file 145 final PackageNamesLoader namesLoader = new PackageNamesLoader(); 146 147 final Enumeration<URL> packageFiles = classLoader.getResources(CHECKSTYLE_PACKAGES); 148 149 while (packageFiles.hasMoreElements()) { 150 processFile(packageFiles.nextElement(), namesLoader); 151 } 152 153 result = namesLoader.packageNames; 154 } 155 catch (IOException ex) { 156 throw new CheckstyleException("unable to get package file resources", ex); 157 } 158 catch (ParserConfigurationException | SAXException ex) { 159 throw new CheckstyleException("unable to open one of package files", ex); 160 } 161 162 return Collections.unmodifiableSet(result); 163 } 164 165 /** 166 * Reads the file provided and parses it with package names loader. 167 * 168 * @param packageFile file from package 169 * @param namesLoader package names loader 170 * @throws SAXException if an error while parsing occurs 171 * @throws CheckstyleException if unable to open file 172 */ 173 private static void processFile(URL packageFile, PackageNamesLoader namesLoader) 174 throws SAXException, CheckstyleException { 175 try (InputStream stream = new BufferedInputStream(packageFile.openStream())) { 176 final InputSource source = new InputSource(stream); 177 namesLoader.parseInputSource(source); 178 } 179 catch (IOException ex) { 180 throw new CheckstyleException("unable to open " + packageFile, ex); 181 } 182 } 183 184 /** 185 * Creates mapping between local resources and dtd ids. 186 * 187 * @return map between local resources and dtd ids. 188 */ 189 private static Map<String, String> createIdToResourceNameMap() { 190 final Map<String, String> map = new HashMap<>(); 191 map.put(DTD_PUBLIC_ID, DTD_RESOURCE_NAME); 192 map.put(DTD_PUBLIC_CS_ID, DTD_RESOURCE_NAME); 193 return map; 194 } 195 196}