/**
* 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 backtype.storm.utils;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import sun.misc.CompoundEnumeration;
public class WorkerClassLoader extends URLClassLoader {
private static final Logger LOG = LoggerFactory.getLogger(WorkerClassLoader.class);
private ClassLoader defaultClassLoader;
private ClassLoader JDKClassLoader;
private boolean isDebug;
protected static WorkerClassLoader instance;
protected static boolean enable;
protected static Map<Thread, ClassLoader> threadContextCache;
protected WorkerClassLoader(URL[] urls, ClassLoader defaultClassLoader, ClassLoader JDKClassLoader, boolean isDebug) {
super(urls, JDKClassLoader);
this.defaultClassLoader = defaultClassLoader;
this.JDKClassLoader = JDKClassLoader;
this.isDebug = isDebug;
}
// for all log go through logback when enable classloader
protected boolean isLogByDefault(String name) {
return name.startsWith("org.apache.log4j") || name.startsWith("org.slf4j");
}
protected boolean isLoadByDefault(String name) {
return name.startsWith("backtype.storm") || name.startsWith("com.alibaba.jstorm") || isLogByDefault(name);
}
@Override
public Class<?> loadClass(String name) throws ClassNotFoundException {
Class<?> result = null;
try {
result = this.findLoadedClass(name);
if (result != null) {
return result;
}
try {
result = JDKClassLoader.loadClass(name);
if (result != null)
return result;
} catch (Exception ignored) {
}
try {
if (!isLoadByDefault(name)) {
result = findClass(name);
if (result != null) {
return result;
}
}
} catch (Exception ignored) {
}
result = defaultClassLoader.loadClass(name);
return result;
} finally {
if (result != null) {
ClassLoader resultClassLoader = result.getClassLoader();
LOG.info("Successfully load class " + name + " by " + resultClassLoader + ",threadContextLoader:"
+ Thread.currentThread().getContextClassLoader());
} else {
LOG.warn("Failed to load class " + name + ",threadContextLoader:" + Thread.currentThread().getContextClassLoader());
}
if (isDebug) {
LOG.info(Utils.printStack());
}
}
}
public static WorkerClassLoader mkInstance(URL[] urls, ClassLoader DefaultClassLoader, ClassLoader JDKClassLoader,
boolean enable, boolean isDebug) {
WorkerClassLoader.enable = enable;
if (!enable) {
LOG.info("Don't enable UserDefine ClassLoader");
return null;
}
synchronized (WorkerClassLoader.class) {
if (instance == null) {
instance = new WorkerClassLoader(urls, DefaultClassLoader, JDKClassLoader, isDebug);
threadContextCache = new ConcurrentHashMap<>();
}
}
LOG.info("Successfully created classloader " + mk_list(urls));
return instance;
}
public static WorkerClassLoader getInstance() {
return instance;
}
public static boolean isEnable() {
return enable;
}
public static void switchThreadContext() {
if (!enable) {
return;
}
Thread thread = Thread.currentThread();
ClassLoader oldClassLoader = thread.getContextClassLoader();
threadContextCache.put(thread, oldClassLoader);
thread.setContextClassLoader(instance);
}
public static void restoreThreadContext() {
if (!enable) {
return;
}
Thread thread = Thread.currentThread();
ClassLoader oldClassLoader = threadContextCache.get(thread);
if (oldClassLoader != null) {
thread.setContextClassLoader(oldClassLoader);
} else {
LOG.info("No context classloader of " + thread.getName());
}
}
private static <V> List<V> mk_list(V... args) {
ArrayList<V> rtn = new ArrayList<V>();
for (V o : args) {
rtn.add(o);
}
return rtn;
}
public Enumeration<URL> getResources(String name) throws IOException {
Enumeration<URL>[] tmp = (Enumeration<URL>[]) new Enumeration<?>[2];
tmp[0] = super.getResources(name);
tmp[1] = defaultClassLoader.getResources(name);
return new CompoundEnumeration<>(tmp);
}
public InputStream getResourceAsStream(String name) {
InputStream is = super.getResourceAsStream(name);
if (is == null) {
is = defaultClassLoader.getResourceAsStream(name);
}
return is;
}
}