/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2010, Red Hat Inc. or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Inc.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.boot.registry.classloading.internal;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.ServiceLoader;
import org.hibernate.boot.registry.classloading.spi.ClassLoaderService;
import org.hibernate.boot.registry.classloading.spi.ClassLoadingException;
import org.hibernate.cfg.AvailableSettings;
import org.hibernate.internal.CoreLogging;
import org.hibernate.internal.util.ClassLoaderHelper;
import org.jboss.logging.Logger;
/**
* Standard implementation of the service for interacting with class loaders
*
* @author Steve Ebersole
*/
public class ClassLoaderServiceImpl implements ClassLoaderService {
private static final Logger log = CoreLogging.logger( ClassLoaderServiceImpl.class );
private final Map<Class, ServiceLoader> serviceLoaders = new HashMap<Class, ServiceLoader>();
private AggregatedClassLoader aggregatedClassLoader;
/**
* Constructs a ClassLoaderServiceImpl with standard set-up
*/
public ClassLoaderServiceImpl() {
this( ClassLoaderServiceImpl.class.getClassLoader() );
}
/**
* Constructs a ClassLoaderServiceImpl with the given ClassLoader
*
* @param classLoader The ClassLoader to use
*/
public ClassLoaderServiceImpl(ClassLoader classLoader) {
this( Collections.singletonList( classLoader ) );
}
/**
* Constructs a ClassLoaderServiceImpl with the given ClassLoader instances
*
* @param providedClassLoaders The ClassLoader instances to use
*/
public ClassLoaderServiceImpl(Collection<ClassLoader> providedClassLoaders) {
final LinkedHashSet<ClassLoader> orderedClassLoaderSet = new LinkedHashSet<ClassLoader>();
// first, add all provided class loaders, if any
if ( providedClassLoaders != null ) {
for ( ClassLoader classLoader : providedClassLoaders ) {
if ( classLoader != null ) {
orderedClassLoaderSet.add( classLoader );
}
}
}
// normalize adding known class-loaders...
// then the Hibernate class loader
orderedClassLoaderSet.add( ClassLoaderServiceImpl.class.getClassLoader() );
// then the TCCL, if one...
final ClassLoader tccl = locateTCCL();
if ( tccl != null ) {
orderedClassLoaderSet.add( tccl );
}
// finally the system classloader
final ClassLoader sysClassLoader = locateSystemClassLoader();
if ( sysClassLoader != null ) {
orderedClassLoaderSet.add( sysClassLoader );
}
// now build the aggregated class loader...
this.aggregatedClassLoader = new AggregatedClassLoader( orderedClassLoaderSet );
}
/**
* No longer used/supported!
*
* @param configValues The config values
*
* @return The built service
*
* @deprecated No longer used/supported!
*/
@Deprecated
@SuppressWarnings({"UnusedDeclaration", "unchecked", "deprecation"})
public static ClassLoaderServiceImpl fromConfigSettings(Map configValues) {
final List<ClassLoader> providedClassLoaders = new ArrayList<ClassLoader>();
final Collection<ClassLoader> classLoaders = (Collection<ClassLoader>) configValues.get( AvailableSettings.CLASSLOADERS );
if ( classLoaders != null ) {
for ( ClassLoader classLoader : classLoaders ) {
providedClassLoaders.add( classLoader );
}
}
addIfSet( providedClassLoaders, AvailableSettings.APP_CLASSLOADER, configValues );
addIfSet( providedClassLoaders, AvailableSettings.RESOURCES_CLASSLOADER, configValues );
addIfSet( providedClassLoaders, AvailableSettings.HIBERNATE_CLASSLOADER, configValues );
addIfSet( providedClassLoaders, AvailableSettings.ENVIRONMENT_CLASSLOADER, configValues );
if ( providedClassLoaders.isEmpty() ) {
log.debugf( "Incoming config yielded no classloaders; adding standard SE ones" );
final ClassLoader tccl = locateTCCL();
if ( tccl != null ) {
providedClassLoaders.add( tccl );
}
providedClassLoaders.add( ClassLoaderServiceImpl.class.getClassLoader() );
}
return new ClassLoaderServiceImpl( providedClassLoaders );
}
private static void addIfSet(List<ClassLoader> providedClassLoaders, String name, Map configVales) {
final ClassLoader providedClassLoader = (ClassLoader) configVales.get( name );
if ( providedClassLoader != null ) {
providedClassLoaders.add( providedClassLoader );
}
}
private static ClassLoader locateSystemClassLoader() {
try {
return ClassLoader.getSystemClassLoader();
}
catch (Exception e) {
return null;
}
}
private static ClassLoader locateTCCL() {
try {
return ClassLoaderHelper.getContextClassLoader();
}
catch (Exception e) {
return null;
}
}
private static class AggregatedClassLoader extends ClassLoader {
private ClassLoader[] individualClassLoaders;
private AggregatedClassLoader(final LinkedHashSet<ClassLoader> orderedClassLoaderSet) {
super( null );
individualClassLoaders = orderedClassLoaderSet.toArray( new ClassLoader[orderedClassLoaderSet.size()] );
}
@Override
public Enumeration<URL> getResources(String name) throws IOException {
final HashSet<URL> resourceUrls = new HashSet<URL>();
for ( ClassLoader classLoader : individualClassLoaders ) {
final Enumeration<URL> urls = classLoader.getResources( name );
while ( urls.hasMoreElements() ) {
resourceUrls.add( urls.nextElement() );
}
}
return new Enumeration<URL>() {
final Iterator<URL> resourceUrlIterator = resourceUrls.iterator();
@Override
public boolean hasMoreElements() {
return resourceUrlIterator.hasNext();
}
@Override
public URL nextElement() {
return resourceUrlIterator.next();
}
};
}
@Override
protected URL findResource(String name) {
for ( ClassLoader classLoader : individualClassLoaders ) {
final URL resource = classLoader.getResource( name );
if ( resource != null ) {
return resource;
}
}
return super.findResource( name );
}
@Override
protected Class<?> findClass(String name) throws ClassNotFoundException {
for ( ClassLoader classLoader : individualClassLoaders ) {
try {
return classLoader.loadClass( name );
}
catch (Exception ignore) {
}
}
throw new ClassNotFoundException( "Could not load requested class : " + name );
}
public void destroy() {
individualClassLoaders = null;
}
}
@Override
@SuppressWarnings({"unchecked"})
public <T> Class<T> classForName(String className) {
try {
return (Class<T>) Class.forName( className, true, aggregatedClassLoader );
}
catch (Exception e) {
throw new ClassLoadingException( "Unable to load class [" + className + "]", e );
}
}
@Override
public URL locateResource(String name) {
// first we try name as a URL
try {
return new URL( name );
}
catch (Exception ignore) {
}
try {
return aggregatedClassLoader.getResource( name );
}
catch (Exception ignore) {
}
return null;
}
@Override
public InputStream locateResourceStream(String name) {
// first we try name as a URL
try {
log.tracef( "trying via [new URL(\"%s\")]", name );
return new URL( name ).openStream();
}
catch (Exception ignore) {
}
try {
log.tracef( "trying via [ClassLoader.getResourceAsStream(\"%s\")]", name );
final InputStream stream = aggregatedClassLoader.getResourceAsStream( name );
if ( stream != null ) {
return stream;
}
}
catch (Exception ignore) {
}
final String stripped = name.startsWith( "/" ) ? name.substring( 1 ) : null;
if ( stripped != null ) {
try {
log.tracef( "trying via [new URL(\"%s\")]", stripped );
return new URL( stripped ).openStream();
}
catch (Exception ignore) {
}
try {
log.tracef( "trying via [ClassLoader.getResourceAsStream(\"%s\")]", stripped );
final InputStream stream = aggregatedClassLoader.getResourceAsStream( stripped );
if ( stream != null ) {
return stream;
}
}
catch (Exception ignore) {
}
}
return null;
}
@Override
public List<URL> locateResources(String name) {
final ArrayList<URL> urls = new ArrayList<URL>();
try {
final Enumeration<URL> urlEnumeration = aggregatedClassLoader.getResources( name );
if ( urlEnumeration != null && urlEnumeration.hasMoreElements() ) {
while ( urlEnumeration.hasMoreElements() ) {
urls.add( urlEnumeration.nextElement() );
}
}
}
catch (Exception ignore) {
}
return urls;
}
@Override
@SuppressWarnings("unchecked")
public <S> LinkedHashSet<S> loadJavaServices(Class<S> serviceContract) {
ServiceLoader<S> serviceLoader;
if ( serviceLoaders.containsKey( serviceContract ) ) {
serviceLoader = serviceLoaders.get( serviceContract );
}
else {
serviceLoader = ServiceLoader.load( serviceContract, aggregatedClassLoader );
serviceLoaders.put( serviceContract, serviceLoader );
}
final LinkedHashSet<S> services = new LinkedHashSet<S>();
for ( S service : serviceLoader ) {
services.add( service );
}
return services;
}
@Override
public void stop() {
for ( ServiceLoader serviceLoader : serviceLoaders.values() ) {
serviceLoader.reload(); // clear service loader providers
}
serviceLoaders.clear();
if ( aggregatedClassLoader != null ) {
aggregatedClassLoader.destroy();
aggregatedClassLoader = null;
}
}
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// completely temporary !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
/**
* Hack around continued (temporary) need to sometimes set the TCCL for code we call that expects it.
*
* @param <T> The result type
*/
public static interface Work<T> {
/**
* The work to be performed with the TCCL set
*
* @return The result of the work
*/
public T perform();
}
/**
* Perform some discrete work with with the TCCL set to our aggregated ClassLoader
*
* @param work The discrete work to be done
* @param <T> The type of the work result
*
* @return The work result.
*/
public <T> T withTccl(Work<T> work) {
final ClassLoader tccl = Thread.currentThread().getContextClassLoader();
boolean set = false;
try {
Thread.currentThread().setContextClassLoader( aggregatedClassLoader );
set = true;
}
catch (Exception ignore) {
}
try {
return work.perform();
}
finally {
if ( set ) {
Thread.currentThread().setContextClassLoader( tccl );
}
}
}
}