/*
* 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.tuscany.sca.contribution.java.impl;
import java.io.IOException;
import java.lang.ref.WeakReference;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.tuscany.sca.contribution.Contribution;
import org.apache.tuscany.sca.contribution.Import;
import org.apache.tuscany.sca.contribution.java.JavaImport;
import org.apache.tuscany.sca.contribution.processor.ProcessorContext;
import org.apache.tuscany.sca.contribution.resolver.ClassReference;
import org.apache.tuscany.sca.contribution.resolver.DefaultDelegatingModelResolver;
import org.apache.tuscany.sca.contribution.resolver.ModelResolver;
import org.apache.tuscany.sca.core.FactoryExtensionPoint;
import org.apache.tuscany.sca.extensibility.ServiceDiscovery;
/**
* A Model Resolver for ClassReferences.
*
* @version $Rev: 986740 $ $Date: 2010-08-18 16:28:56 +0100 (Wed, 18 Aug 2010) $
*/
public class ClassLoaderModelResolver extends URLClassLoader implements ModelResolver {
private WeakReference<Contribution> contribution;
private ProcessorContext context;
private Map<String, ModelResolver> importResolvers = new HashMap<String, ModelResolver>();
// a space to pass back the contribution that was used to resolve
// a class via an import
private Contribution contributionContainingClass;
private static ClassLoader parentClassLoader(Contribution contribution) {
if (contribution.getClassLoader() != null) {
return contribution.getClassLoader();
}
ClassLoader parentClassLoader = ServiceDiscovery.getInstance().getContextClassLoader();
return parentClassLoader;
}
private static URL[] getContributionURLs(final Contribution contribution) throws IOException {
if (contribution.getClassLoader() != null) {
// Do not include the contribution url
return new URL[0];
}
List<URL> urls = new ArrayList<URL>();
urls.add(new URL(contribution.getLocation()));
urls.addAll(ContributionHelper.getNestedJarUrls(contribution));
return urls.toArray(new URL[urls.size()]);
}
public ClassLoaderModelResolver(final Contribution contribution, FactoryExtensionPoint modelFactories) throws IOException {
super(getContributionURLs(contribution), parentClassLoader(contribution));
this.contribution = new WeakReference<Contribution>(contribution);
// Index Java import resolvers by package name
Map<String, List<ModelResolver>> resolverMap = new HashMap<String, List<ModelResolver>>();
for (Import import_: this.contribution.get().getImports()) {
if (import_ instanceof JavaImport) {
JavaImport javaImport = (JavaImport)import_;
List<ModelResolver> resolvers = resolverMap.get(javaImport.getPackage());
if (resolvers == null) {
resolvers = new ArrayList<ModelResolver>();
resolverMap.put(javaImport.getPackage(), resolvers);
}
resolvers.add(javaImport.getModelResolver());
}
}
// Create a delegating model resolver for each imported package
for (Map.Entry<String, List<ModelResolver>> entry: resolverMap.entrySet()) {
importResolvers.put(entry.getKey(), new DefaultDelegatingModelResolver(entry.getValue()));
}
}
public void addModel(Object resolved, ProcessorContext context) {
throw new IllegalStateException();
}
public Object removeModel(Object resolved, ProcessorContext context) {
throw new IllegalStateException();
}
public <T> T resolveModel(Class<T> modelClass, T unresolved, ProcessorContext context) {
if (!(unresolved instanceof ClassReference)) {
return unresolved;
}
try {
this.context = context;
contributionContainingClass = contribution.get();
// Load the class and return a class reference for it
String className = ((ClassReference)unresolved).getClassName();
Class<?> clazz = Class.forName(className, false, this);
ClassReference classReference = new ClassReference(clazz);
classReference.setContributionContainingClass(contributionContainingClass);
contributionContainingClass = null;
return modelClass.cast(classReference);
} catch (ClassNotFoundException e) {
return unresolved;
}
}
@Override
public URL findResource(String name) {
//TODO delegate to the Java import resolvers
URL url = super.findResource(name);
return url;
}
@Override
public Enumeration<URL> findResources(String name) throws IOException {
//TODO delegate to the Java import resolvers
//Enumeration<URL> importedResources;
Enumeration<URL> resources = super.findResources(name);
List<URL> allResources = new ArrayList<URL>();
//for (; importedResources.hasMoreElements(); ) {
// allResources.add(importedResources.nextElement());
//}
for (; resources.hasMoreElements(); ) {
allResources.add(resources.nextElement());
}
return Collections.enumeration(allResources);
}
@Override
protected Class<?> findClass(String name) throws ClassNotFoundException {
// Extract the package name
int d = name.lastIndexOf('.');
String packageName;
if (d != -1) {
packageName = name.substring(0, d);
} else {
packageName = null;
}
// First try to load the class using the Java import resolvers
ModelResolver importResolver = importResolvers.get(packageName);
if (importResolver != null) {
ClassReference classReference = importResolver.resolveModel(ClassReference.class, new ClassReference(name), context);
if (!classReference.isUnresolved()) {
contributionContainingClass = classReference.getContributionContainingClass();
return classReference.getJavaClass();
}
}
// Next, try to load the class from the current contribution
Class<?> clazz = super.findClass(name);
return clazz;
}
}