| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with 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 |
| * |
| * 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 org.apache.hadoop.util; |
| |
| import java.io.File; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.net.MalformedURLException; |
| import java.net.URL; |
| import java.net.URLClassLoader; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.List; |
| import java.util.Properties; |
| |
| import org.apache.hadoop.classification.InterfaceAudience.Public; |
| import org.apache.hadoop.classification.InterfaceStability.Unstable; |
| import org.apache.hadoop.fs.FileUtil; |
| import org.apache.hadoop.fs.Path; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * A {@link URLClassLoader} for application isolation. Classes from the |
| * application JARs are loaded in preference to the parent loader. |
| */ |
| @Public |
| @Unstable |
| public class ApplicationClassLoader extends URLClassLoader { |
| /** |
| * Default value of the system classes if the user did not override them. |
| * JDK classes, hadoop classes and resources, and some select third-party |
| * classes are considered system classes, and are not loaded by the |
| * application classloader. |
| */ |
| public static final String SYSTEM_CLASSES_DEFAULT; |
| |
| private static final String PROPERTIES_FILE = |
| "org.apache.hadoop.application-classloader.properties"; |
| private static final String SYSTEM_CLASSES_DEFAULT_KEY = |
| "system.classes.default"; |
| |
| private static final Logger LOG = |
| LoggerFactory.getLogger(ApplicationClassLoader.class.getName()); |
| |
| static { |
| try (InputStream is = ApplicationClassLoader.class.getClassLoader() |
| .getResourceAsStream(PROPERTIES_FILE);) { |
| if (is == null) { |
| throw new ExceptionInInitializerError("properties file " + |
| PROPERTIES_FILE + " is not found"); |
| } |
| Properties props = new Properties(); |
| props.load(is); |
| // get the system classes default |
| String systemClassesDefault = |
| props.getProperty(SYSTEM_CLASSES_DEFAULT_KEY); |
| if (systemClassesDefault == null) { |
| throw new ExceptionInInitializerError("property " + |
| SYSTEM_CLASSES_DEFAULT_KEY + " is not found"); |
| } |
| SYSTEM_CLASSES_DEFAULT = systemClassesDefault; |
| } catch (IOException e) { |
| throw new ExceptionInInitializerError(e); |
| } |
| } |
| |
| private final ClassLoader parent; |
| private final List<String> systemClasses; |
| |
| public ApplicationClassLoader(URL[] urls, ClassLoader parent, |
| List<String> systemClasses) { |
| super(urls, parent); |
| this.parent = parent; |
| if (parent == null) { |
| throw new IllegalArgumentException("No parent classloader!"); |
| } |
| // if the caller-specified system classes are null or empty, use the default |
| this.systemClasses = (systemClasses == null || systemClasses.isEmpty()) ? |
| Arrays.asList(StringUtils.getTrimmedStrings(SYSTEM_CLASSES_DEFAULT)) : |
| systemClasses; |
| LOG.info("classpath: " + Arrays.toString(urls)); |
| LOG.info("system classes: " + this.systemClasses); |
| } |
| |
| public ApplicationClassLoader(String classpath, ClassLoader parent, |
| List<String> systemClasses) throws MalformedURLException { |
| this(constructUrlsFromClasspath(classpath), parent, systemClasses); |
| } |
| |
| static URL[] constructUrlsFromClasspath(String classpath) |
| throws MalformedURLException { |
| List<URL> urls = new ArrayList<URL>(); |
| for (String element : classpath.split(File.pathSeparator)) { |
| if (element.endsWith("/*")) { |
| List<Path> jars = FileUtil.getJarsInDirectory(element); |
| if (!jars.isEmpty()) { |
| for (Path jar: jars) { |
| urls.add(jar.toUri().toURL()); |
| } |
| } |
| } else { |
| File file = new File(element); |
| if (file.exists()) { |
| urls.add(new File(element).toURI().toURL()); |
| } |
| } |
| } |
| return urls.toArray(new URL[urls.size()]); |
| } |
| |
| @Override |
| public URL getResource(String name) { |
| URL url = null; |
| |
| if (!isSystemClass(name, systemClasses)) { |
| url= findResource(name); |
| if (url == null && name.startsWith("/")) { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("Remove leading / off " + name); |
| } |
| url= findResource(name.substring(1)); |
| } |
| } |
| |
| if (url == null) { |
| url= parent.getResource(name); |
| } |
| |
| if (url != null) { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("getResource("+name+")=" + url); |
| } |
| } |
| |
| return url; |
| } |
| |
| @Override |
| public Class<?> loadClass(String name) throws ClassNotFoundException { |
| return this.loadClass(name, false); |
| } |
| |
| @Override |
| protected synchronized Class<?> loadClass(String name, boolean resolve) |
| throws ClassNotFoundException { |
| |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("Loading class: " + name); |
| } |
| |
| Class<?> c = findLoadedClass(name); |
| ClassNotFoundException ex = null; |
| |
| if (c == null && !isSystemClass(name, systemClasses)) { |
| // Try to load class from this classloader's URLs. Note that this is like |
| // the servlet spec, not the usual Java 2 behaviour where we ask the |
| // parent to attempt to load first. |
| try { |
| c = findClass(name); |
| if (LOG.isDebugEnabled() && c != null) { |
| LOG.debug("Loaded class: " + name + " "); |
| } |
| } catch (ClassNotFoundException e) { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug(e.toString()); |
| } |
| ex = e; |
| } |
| } |
| |
| if (c == null) { // try parent |
| c = parent.loadClass(name); |
| if (LOG.isDebugEnabled() && c != null) { |
| LOG.debug("Loaded class from parent: " + name + " "); |
| } |
| } |
| |
| if (c == null) { |
| throw ex != null ? ex : new ClassNotFoundException(name); |
| } |
| |
| if (resolve) { |
| resolveClass(c); |
| } |
| |
| return c; |
| } |
| |
| /** |
| * Checks if a class should be included as a system class. |
| * |
| * A class is a system class if and only if it matches one of the positive |
| * patterns and none of the negative ones. |
| * |
| * @param name the class name to check |
| * @param systemClasses a list of system class configurations. |
| * @return true if the class is a system class |
| */ |
| public static boolean isSystemClass(String name, List<String> systemClasses) { |
| boolean result = false; |
| if (systemClasses != null) { |
| String canonicalName = name.replace('/', '.'); |
| while (canonicalName.startsWith(".")) { |
| canonicalName=canonicalName.substring(1); |
| } |
| for (String c : systemClasses) { |
| boolean shouldInclude = true; |
| if (c.startsWith("-")) { |
| c = c.substring(1); |
| shouldInclude = false; |
| } |
| if (canonicalName.startsWith(c)) { |
| if ( c.endsWith(".") // package |
| || canonicalName.length() == c.length() // class |
| || canonicalName.length() > c.length() // nested |
| && canonicalName.charAt(c.length()) == '$' ) { |
| if (shouldInclude) { |
| result = true; |
| } else { |
| return false; |
| } |
| } |
| } |
| } |
| } |
| return result; |
| } |
| } |