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Fibers, Channels and Actors for the JVM
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/*
* Quasar: lightweight threads and actors for the JVM.
* Copyright (c) 2013-2018, Parallel Universe Software Co. All rights reserved.
*
* This program and the accompanying materials are dual-licensed under
* either the terms of the Eclipse Public License v1.0 as published by
* the Eclipse Foundation
*
* or (per the licensee's choosing)
*
* under the terms of the GNU Lesser General Public License version 3.0
* as published by the Free Software Foundation.
*/
/*
* Based on Guava's com.google.common.reflect.ClassPath
*/
/*
* Copyright (c) 2012 The Guava Authors
*
* Licensed 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
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package co.paralleluniverse.common.reflection;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLClassLoader;
import java.net.URLConnection;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Set;
import java.util.jar.Attributes;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.Manifest;
/**
*
* @author pron
*/
public final class ClassLoaderUtil {
public interface Visitor {
void visit(String resource, URL url, ClassLoader cl) throws IOException;
}
private static final String CLASS_FILE_NAME_EXTENSION = ".class";
public static boolean isClassFile(String resourceName) {
return resourceName.endsWith(CLASS_FILE_NAME_EXTENSION) && !resourceName.endsWith("module-info.class");
}
public static String classToResource(String className) {
if (className == null)
return null;
return className.replace('.', '/') + CLASS_FILE_NAME_EXTENSION;
}
public static String classToResource(Class clazz) {
if (clazz == null)
return null;
return classToResource(clazz.getName());
}
public static String classToSlashed(String className) {
if (className == null)
return null;
return className.replace('.', '/');
}
public static String classToSlashed(Class clazz) {
if (clazz == null)
return null;
return classToSlashed(clazz.getName());
}
public static String resourceToClass(String resourceName) {
if (resourceName == null)
return null;
return resourceToSlashed(resourceName).replace('/', '.');
}
public static String resourceToSlashed(String resourceName) {
if (resourceName == null)
return null;
if (!resourceName.endsWith(CLASS_FILE_NAME_EXTENSION))
throw new IllegalArgumentException("Resource " + resourceName + " is not a class file");
return resourceName.substring(0, resourceName.length() - CLASS_FILE_NAME_EXTENSION.length());
}
public static void accept(URLClassLoader ucl, Visitor visitor) throws IOException {
accept(ucl, ucl.getURLs(), visitor);
}
public static void accept(ClassLoader cl, URL[] urls, Visitor visitor) throws IOException {
try {
final Set scannedUris = new HashSet<>();
for (URL entry : urls) {
URI uri = entry.toURI();
if (uri.getScheme().equals("file") && scannedUris.add(uri))
scanFrom(new File(uri), cl, scannedUris, visitor);
}
} catch (URISyntaxException e) {
throw new RuntimeException(e);
}
}
private static void scan(URI uri, ClassLoader classloader, Set scannedUris, Visitor visitor) throws IOException {
if (uri.getScheme().equals("file") && scannedUris.add(uri))
scanFrom(new File(uri), classloader, scannedUris, visitor);
}
private static void scanFrom(File file, ClassLoader classloader, Set scannedUris, Visitor visitor) throws IOException {
if (!file.exists())
return;
if (file.isDirectory())
scanDirectory(file, classloader, visitor);
else
scanJar(file, classloader, scannedUris, visitor);
}
private static void scanDirectory(File directory, ClassLoader classloader, Visitor visitor) throws IOException {
scanDirectory(directory, classloader, "", new HashSet(), visitor);
}
private static void scanDirectory(File directory, ClassLoader classloader, String packagePrefix, Set ancestors, Visitor visitor) throws IOException {
File canonical = directory.getCanonicalFile();
if (ancestors.contains(canonical)) {
// A cycle in the filesystem, for example due to a symbolic link.
return;
}
File[] files = directory.listFiles();
if (files == null) {
// logger.warning("Cannot read directory " + directory);
// IO error, just skip the directory
return;
}
Set newAncestors = new HashSet<>();
newAncestors.addAll(ancestors);
newAncestors.add(canonical);
for (File f : files) {
String name = f.getName();
if (f.isDirectory()) {
scanDirectory(f, classloader, packagePrefix + name + "/", newAncestors, visitor);
} else {
String resourceName = packagePrefix + name;
if (!resourceName.equals(JarFile.MANIFEST_NAME))
visitor.visit(resourceName, f.toURI().toURL(), classloader);
}
}
}
private static void scanJar(File file, ClassLoader classloader, Set scannedUris, Visitor visitor) throws IOException {
JarFile jarFile;
try {
jarFile = new JarFile(file);
} catch (IOException e) {
// Not a jar file
return;
}
try {
for (URI uri : getClassPathFromManifest(file, jarFile.getManifest()))
scan(uri, classloader, scannedUris, visitor);
for (Enumeration entries = jarFile.entries(); entries.hasMoreElements();) {
JarEntry entry = entries.nextElement();
if (entry.isDirectory() || entry.getName().equals(JarFile.MANIFEST_NAME))
continue;
try {
visitor.visit(entry.getName(), new URL("jar:file:" + file.getCanonicalPath() + "!/" + entry.getName()), classloader);
} catch (IOException e) {
throw new IOException("Exception thrown during scanning of jar file " + file + " entry " + entry, e);
} catch (RuntimeException e) {
throw new RuntimeException("Exception thrown during scanning of jar file " + file + " entry " + entry, e);
}
}
} finally {
try {
jarFile.close();
} catch (IOException ignored) {
}
}
}
public static URL getResource(ClassLoader cl, String resource) {
return cl != null ? cl.getResource(resource) : ClassLoader.getSystemResource(resource);
}
public static Enumeration getResources(ClassLoader cl, String resources) throws IOException {
return cl != null ? cl.getResources(resources) : ClassLoader.getSystemResources(resources);
}
public static InputStream getResourceAsStream(ClassLoader cl, String resource) throws IOException {
URL url = getResource(cl, resource);
if (url == null)
return null;
URLConnection uc = url.openConnection();
uc.setUseCaches(false);
return uc.getInputStream();
}
/**
* Returns the class path URIs specified by the {@code Class-Path} manifest attribute, according
* to
* JAR File Specification. If {@code manifest} is null, it means the jar file has no
* manifest, and an empty set will be returned.
*/
private static Set getClassPathFromManifest(File jarFile, Manifest manifest) {
if (manifest == null)
return new HashSet<>();
HashSet s = new HashSet<>();
String classpathAttribute = manifest.getMainAttributes().getValue(Attributes.Name.CLASS_PATH.toString());
if (classpathAttribute != null) {
for (String path : classpathAttribute.split("\\s")) {
if (path != null && path.trim().length() > 0) {
URI uri;
try {
uri = getClassPathEntry(jarFile, path.trim());
} catch (URISyntaxException e) {
// Ignore bad entry
// logger.warning("Invalid Class-Path entry: " + path);
continue;
}
s.add(uri);
}
}
}
return s;
}
/**
* Returns the absolute uri of the Class-Path entry value as specified in
*
* JAR File Specification. Even though the specification only talks about relative urls,
* absolute urls are actually supported too (for example, in Maven surefire plugin).
*/
private static URI getClassPathEntry(File jarFile, String path) throws URISyntaxException {
URI uri = new URI(path);
if (uri.isAbsolute())
return uri;
else
return new File(jarFile.getParentFile(), path.replace('/', File.separatorChar)).toURI();
}
private ClassLoaderUtil() {
}
}