001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 * 017 */ 018package org.apache.bcel.util; 019 020import java.io.Closeable; 021import java.io.File; 022import java.io.IOException; 023import java.net.URI; 024import java.net.URL; 025import java.net.URLClassLoader; 026import java.nio.file.DirectoryStream; 027import java.nio.file.FileSystem; 028import java.nio.file.FileSystems; 029import java.nio.file.Files; 030import java.nio.file.Path; 031import java.nio.file.Paths; 032import java.util.ArrayList; 033import java.util.Collections; 034import java.util.Iterator; 035import java.util.List; 036import java.util.Map; 037 038/** 039 * Wraps a Java 9 JEP 220 modular runtime image. Requires the JRT NIO file system. 040 * 041 * @since 6.3 042 */ 043public class ModularRuntimeImage implements Closeable { 044 045 static final String MODULES_PATH = File.separator + "modules"; 046 static final String PACKAGES_PATH = File.separator + "packages"; 047 048 private final URLClassLoader classLoader; 049 private final FileSystem fileSystem; 050 051 /** 052 * Constructs a default instance. 053 * 054 * @throws IOException 055 * an I/O error occurs accessing the file system 056 */ 057 public ModularRuntimeImage() throws IOException { 058 this(null, FileSystems.getFileSystem(URI.create("jrt:/"))); 059 } 060 061 /** 062 * Constructs an instance using the JRT file system implementation from a specific Java Home. 063 * 064 * @param javaHome 065 * Path to a Java 9 or greater home. 066 * 067 * @throws IOException 068 * an I/O error occurs accessing the file system 069 */ 070 public ModularRuntimeImage(final String javaHome) throws IOException { 071 final Map<String, ?> emptyMap = Collections.emptyMap(); 072 final Path jrePath = Paths.get(javaHome); 073 final Path jrtFsPath = jrePath.resolve("lib").resolve("jrt-fs.jar"); 074 this.classLoader = new URLClassLoader(new URL[] {jrtFsPath.toUri().toURL() }); 075 this.fileSystem = FileSystems.newFileSystem(URI.create("jrt:/"), emptyMap, classLoader); 076 } 077 078 private ModularRuntimeImage(final URLClassLoader cl, final FileSystem fs) { 079 this.classLoader = cl; 080 this.fileSystem = fs; 081 } 082 083 @Override 084 public void close() throws IOException { 085 if (classLoader != null) { 086 classLoader.close(); 087 } 088 if (fileSystem != null) { 089 fileSystem.close(); 090 } 091 } 092 093 /** 094 * Lists all entries in the given directory. 095 * 096 * @param dirPath 097 * directory path. 098 * @return a list of dir entries if an I/O error occurs 099 * @throws IOException 100 * an I/O error occurs accessing the file system 101 */ 102 public List<Path> list(final Path dirPath) throws IOException { 103 final List<Path> list = new ArrayList<>(); 104 try (DirectoryStream<Path> ds = Files.newDirectoryStream(dirPath)) { 105 final Iterator<Path> iterator = ds.iterator(); 106 while (iterator.hasNext()) { 107 list.add(iterator.next()); 108 } 109 } 110 return list; 111 } 112 113 /** 114 * Lists all entries in the given directory. 115 * 116 * @param dirName 117 * directory path. 118 * @return a list of dir entries if an I/O error occurs 119 * @throws IOException 120 * an I/O error occurs accessing the file system 121 */ 122 public List<Path> list(final String dirName) throws IOException { 123 return list(fileSystem.getPath(dirName)); 124 } 125 126 /** 127 * Lists all modules. 128 * 129 * @return a list of modules 130 * @throws IOException 131 * an I/O error occurs accessing the file system 132 */ 133 public List<Path> modules() throws IOException { 134 return list(MODULES_PATH); 135 } 136 137 /** 138 * Lists all packages. 139 * 140 * @return a list of modules 141 * @throws IOException 142 * an I/O error occurs accessing the file system 143 */ 144 public List<Path> packages() throws IOException { 145 return list(PACKAGES_PATH); 146 } 147 148 public FileSystem getFileSystem() { 149 return fileSystem; 150 } 151 152}