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 * Licensed to the Apache Software Foundation (ASF) under one or more
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 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
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 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
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package com.sun.org.apache.bcel.internal.util;

import java.io.Closeable;
import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.net.URL;
import java.net.URLClassLoader;
import java.nio.file.DirectoryStream;
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

Wraps a Java 9 JEP 220 modular runtime image. Requires the JRT NIO file system.
Since:6.3
/** * Wraps a Java 9 JEP 220 modular runtime image. Requires the JRT NIO file system. * * @since 6.3 */
public class ModularRuntimeImage implements Closeable { static final String MODULES_PATH = File.separator + "modules"; static final String PACKAGES_PATH = File.separator + "packages"; private final URLClassLoader classLoader; private final FileSystem fileSystem;
Constructs a default instance.
Throws:
  • IOException – an I/O error occurs accessing the file system
/** * Constructs a default instance. * * @throws IOException * an I/O error occurs accessing the file system */
public ModularRuntimeImage() throws IOException { this(null, FileSystems.getFileSystem(URI.create("jrt:/"))); }
Constructs an instance using the JRT file system implementation from a specific Java Home.
Params:
  • javaHome – Path to a Java 9 or greater home.
Throws:
  • IOException – an I/O error occurs accessing the file system
/** * Constructs an instance using the JRT file system implementation from a specific Java Home. * * @param javaHome * Path to a Java 9 or greater home. * * @throws IOException * an I/O error occurs accessing the file system */
public ModularRuntimeImage(final String javaHome) throws IOException { final Map<String, ?> emptyMap = Collections.emptyMap(); final Path jrePath = Paths.get(javaHome); final Path jrtFsPath = jrePath.resolve("lib").resolve("jrt-fs.jar"); this.classLoader = new URLClassLoader(new URL[] {jrtFsPath.toUri().toURL() }); this.fileSystem = FileSystems.newFileSystem(URI.create("jrt:/"), emptyMap, classLoader); } private ModularRuntimeImage(final URLClassLoader cl, final FileSystem fs) { this.classLoader = cl; this.fileSystem = fs; } @Override public void close() throws IOException { if (classLoader != null) { classLoader.close(); } if (fileSystem != null) { fileSystem.close(); } }
Lists all entries in the given directory.
Params:
  • dirPath – directory path.
Throws:
  • IOException – an I/O error occurs accessing the file system
Returns:a list of dir entries if an I/O error occurs
/** * Lists all entries in the given directory. * * @param dirPath * directory path. * @return a list of dir entries if an I/O error occurs * @throws IOException * an I/O error occurs accessing the file system */
public List<Path> list(final Path dirPath) throws IOException { final List<Path> list = new ArrayList<>(); try (DirectoryStream<Path> ds = Files.newDirectoryStream(dirPath)) { final Iterator<Path> iterator = ds.iterator(); while (iterator.hasNext()) { list.add(iterator.next()); } } return list; }
Lists all entries in the given directory.
Params:
  • dirName – directory path.
Throws:
  • IOException – an I/O error occurs accessing the file system
Returns:a list of dir entries if an I/O error occurs
/** * Lists all entries in the given directory. * * @param dirName * directory path. * @return a list of dir entries if an I/O error occurs * @throws IOException * an I/O error occurs accessing the file system */
public List<Path> list(final String dirName) throws IOException { return list(fileSystem.getPath(dirName)); }
Lists all modules.
Throws:
  • IOException – an I/O error occurs accessing the file system
Returns:a list of modules
/** * Lists all modules. * * @return a list of modules * @throws IOException * an I/O error occurs accessing the file system */
public List<Path> modules() throws IOException { return list(MODULES_PATH); }
Lists all packages.
Throws:
  • IOException – an I/O error occurs accessing the file system
Returns:a list of modules
/** * Lists all packages. * * @return a list of modules * @throws IOException * an I/O error occurs accessing the file system */
public List<Path> packages() throws IOException { return list(PACKAGES_PATH); } public FileSystem getFileSystem() { return fileSystem; } }