org.quartz.classloading.CascadingClassLoadHelper Maven / Gradle / Ivy
/**
* Copyright 2001-2009 Terracotta, Inc.
* Copyright 2015 Xeiam LLC.
*
* 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 org.quartz.classloading;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.xeiam.sundial.Job;
/**
* A ClassLoadHelper uses all of the ClassLoadHelper types that are found in this package in its attempts to load a class,
* when one scheme is found to work, it is promoted to the scheme that will be used first the next time a class is loaded (in order to improve
* performance).
*
* This approach is used because of the wide variance in class loader behavior between the various environments in which Quartz runs (e.g. disparate
* application servers, stand-alone, mobile devices, etc.). Because of this disparity, Quartz ran into difficulty with a one class-load style fits-all
* design. Thus, this class loader finds the approach that works, then 'remembers' it.
*
*
* @see org.quartz.classloading.ClassLoadHelper
* @see org.quartz.classloading.LoadingLoaderClassLoadHelper
* @see org.quartz.classloading.SimpleClassLoadHelper
* @see org.quartz.classloading.ThreadContextClassLoadHelper
* @see org.quartz.classloading.InitThreadContextClassLoadHelper
* @author jhouse
* @author pl47ypus
*/
public class CascadingClassLoadHelper implements ClassLoadHelper {
/*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Data members.
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
private final Logger logger = LoggerFactory.getLogger(CascadingClassLoadHelper.class);
private LinkedList loadHelpers;
private ClassLoadHelper bestCandidate;
/*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Interface.
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
/**
* Called to give the ClassLoadHelper a chance to initialize itself, including the opportunity to "steal" the class loader off of the calling
* thread, which is the thread that is initializing Quartz.
*/
@Override
public void initialize() {
loadHelpers = new LinkedList();
loadHelpers.add(new LoadingLoaderClassLoadHelper());
loadHelpers.add(new SimpleClassLoadHelper());
loadHelpers.add(new ThreadContextClassLoadHelper());
loadHelpers.add(new InitThreadContextClassLoadHelper());
for (ClassLoadHelper loadHelper : loadHelpers) {
loadHelper.initialize();
}
}
/**
* Return the class with the given name.
*/
@Override
public Class loadClass(String name) throws ClassNotFoundException {
if (bestCandidate != null) {
try {
return bestCandidate.loadClass(name);
} catch (Throwable t) {
bestCandidate = null;
}
}
Throwable throwable = null;
Class clazz = null;
ClassLoadHelper loadHelper = null;
Iterator iter = loadHelpers.iterator();
while (iter.hasNext()) {
loadHelper = iter.next();
try {
clazz = loadHelper.loadClass(name);
break;
} catch (Throwable t) {
throwable = t;
}
}
if (clazz == null) {
if (throwable instanceof ClassNotFoundException) {
throw (ClassNotFoundException) throwable;
} else {
throw new ClassNotFoundException(String.format("Unable to load class %s by any known loaders.", name), throwable);
}
}
bestCandidate = loadHelper;
return clazz;
}
/**
* Finds a resource with a given name. This method returns null if no resource with this name is found.
*
* @param name name of the desired resource
* @return a java.net.URL object
*/
@Override
public URL getResource(String name) {
URL result = null;
if (bestCandidate != null) {
result = bestCandidate.getResource(name);
if (result == null) {
bestCandidate = null;
}
}
ClassLoadHelper loadHelper = null;
Iterator iter = loadHelpers.iterator();
while (iter.hasNext()) {
loadHelper = iter.next();
result = loadHelper.getResource(name);
if (result != null) {
break;
}
}
bestCandidate = loadHelper;
return result;
}
/**
* Finds a resource with a given name. This method returns null if no resource with this name is found.
*
* @param name name of the desired resource
* @return a java.io.InputStream object
*/
@Override
public InputStream getResourceAsStream(String name) {
InputStream result = null;
if (bestCandidate != null) {
result = bestCandidate.getResourceAsStream(name);
if (result == null) {
bestCandidate = null;
}
}
ClassLoadHelper loadHelper = null;
Iterator iter = loadHelpers.iterator();
while (iter.hasNext()) {
loadHelper = iter.next();
result = loadHelper.getResourceAsStream(name);
if (result != null) {
break;
}
}
bestCandidate = loadHelper;
return result;
}
/**
* Given a package name, search the classpath for all classes that extend sundial.job
*
* @param pkgname
* @return
*/
public Set> getJobClasses(String pkgname) {
Set> classes = new HashSet>();
String relPath = pkgname.replace('.', '/');
// Get a File object for the package
URL resource = getResource(relPath);
if (resource == null) {
throw new RuntimeException("Unexpected problem: No resource for " + relPath);
}
logger.info("Package: '" + pkgname + "' becomes Resource: '" + resource.toString() + "'");
resource.getPath();
if (resource.toString().startsWith("jar:")) {
processJarfile(resource, pkgname, classes);
} else {
processDirectory(new File(resource.getPath()), pkgname, classes);
}
return classes;
}
private void processDirectory(File directory, String pkgname, Set> classes) {
logger.debug("Reading Directory '" + directory + "'");
// Get the list of the files contained in the package
String[] files = directory.list();
for (int i = 0; i < files.length; i++) {
String fileName = files[i];
String className = null;
// we are only interested in .class files
if (fileName.endsWith(".class")) {
// removes the .class extension
className = pkgname + '.' + fileName.substring(0, fileName.length() - 6);
}
logger.debug("FileName '" + fileName + "' => class '" + className + "'");
if (className != null) {
filterJobClassWithExceptionCatch(className, classes);
}
File subdir = new File(directory, fileName);
if (subdir.isDirectory()) {
processDirectory(subdir, pkgname + '.' + fileName, classes);
}
}
}
private void processJarfile(URL resource, String pkgname, Set> classes) {
String relPath = pkgname.replace('.', '/');
String resPath = resource.getPath();
String jarPath = resPath.replaceFirst("[.]jar[!].*", ".jar").replaceFirst("file:", "");
logger.debug("Reading JAR file: '" + jarPath + "'");
JarFile jarFile;
try {
jarFile = new JarFile(jarPath);
} catch (IOException e) {
throw new RuntimeException("Unexpected IOException reading JAR File '" + jarPath + "'", e);
}
Enumeration entries = jarFile.entries();
while (entries.hasMoreElements()) {
JarEntry entry = entries.nextElement();
String entryName = entry.getName();
String className = null;
if (entryName.endsWith(".class") && entryName.startsWith(relPath) && entryName.length() > (relPath.length() + "/".length())) {
className = entryName.replace('/', '.').replace('\\', '.').replace(".class", "");
}
logger.debug("JarEntry '" + entryName + "' => class '" + className + "'");
if (className != null) {
filterJobClassWithExceptionCatch(className, classes);
}
}
}
private void filterJobClassWithExceptionCatch(String className, Set> classes) {
try {
Class clazz = loadClass(className);
if (clazz.getSuperclass().getName().equals("com.xeiam.sundial.Job")) {
classes.add(clazz);
}
} catch (ClassNotFoundException e) {
throw new RuntimeException("Unexpected ClassNotFoundException loading class '" + className + "'");
}
}
/**
* Enable sharing of the "best" class-loader with 3rd party.
*
* @return the class-loader user be the helper.
*/
@Override
public ClassLoader getClassLoader() {
return (this.bestCandidate == null) ? Thread.currentThread().getContextClassLoader() : this.bestCandidate.getClassLoader();
}
}
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