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/*
* 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.lang.ref.WeakReference;
import java.lang.reflect.Constructor;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.HashMap;
import java.util.Map;
import org.apache.tuscany.sca.contribution.Contribution;
import org.apache.tuscany.sca.contribution.java.ContributionClassLoaderProvider;
import org.apache.tuscany.sca.contribution.java.ContributionClassloaderProviderExtensionPoint;
import org.apache.tuscany.sca.contribution.java.DefaultContributionClassLoaderProvider;
import org.apache.tuscany.sca.contribution.resolver.ClassReference;
import org.apache.tuscany.sca.contribution.resolver.ModelResolver;
import org.apache.tuscany.sca.core.ExtensionPointRegistry;
import org.apache.tuscany.sca.core.UtilityExtensionPoint;
import org.apache.tuscany.sca.extensibility.ServiceDiscovery;
/**
* A Model Resolver for ClassReferences.
*
* @version $Rev: 557916 $ $Date: 2007-07-20 01:04:40 -0700 (Fri, 20 Jul 2007) $
*/
public class ClassReferenceModelResolver implements ModelResolver {
private final ExtensionPointRegistry registry;
private final Contribution contribution;
private WeakReference<ClassLoader> classLoader;
private Map<String, ClassReference> map = new HashMap<String, ClassReference>();
private ModelResolver osgiResolver;
public ClassReferenceModelResolver(final Contribution contribution, ExtensionPointRegistry registry) {
this.contribution = contribution;
this.registry = registry;
if (this.contribution != null) {
// Allow privileged access to get ClassLoader. Requires RuntimePermission in security policy.
// ClassLoader cl = contribution.getClassLoader();
ClassLoader cl = AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() {
public ClassLoader run() {
return contribution.getClassLoader();
}
});
if (cl == null) {
// Allow privileged access to get ClassLoader. Requires RuntimePermission in security policy.
//ClassLoader contextClassLoader = AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() {
// public ClassLoader run() {
// return Thread.currentThread().getContextClassLoader();
// }
//});
ClassLoader contextClassLoader = ServiceDiscovery.getInstance().getServiceDiscoverer().getClass().getClassLoader();
ContributionClassLoaderProvider provider = null;
try {
ContributionClassloaderProviderExtensionPoint providers =
registry.getExtensionPoint(ContributionClassloaderProviderExtensionPoint.class);
provider = providers.getProvider(contribution.getType());
} catch (Throwable e) {
// Ignore errors
}
if (provider == null) {
provider = new DefaultContributionClassLoaderProvider();
}
cl = provider.getClassLoader(contribution, contextClassLoader);
contribution.setClassLoader(cl);
}
this.classLoader = new WeakReference<ClassLoader>(cl);
} else {
// This path should be used only for unit testing.
// Allow privileged access to get ClassLoader. Requires RuntimePermission in security policy.
// this.classLoader = new WeakReference<ClassLoader>(this.getClass().getClassLoader());
ClassLoader cl = AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() {
public ClassLoader run() {
return this.getClass().getClassLoader();
}
});
this.classLoader = new WeakReference<ClassLoader>( cl );
}
try {
Class<?> osgiResolverClass =
Class.forName("org.apache.tuscany.sca.contribution.osgi.impl.OSGiClassReferenceModelResolver");
if (osgiResolverClass != null) {
Constructor constructor =
osgiResolverClass.getConstructor(Contribution.class, ExtensionPointRegistry.class);
this.osgiResolver = (ModelResolver)constructor.newInstance(contribution, registry);
}
} catch (Throwable e) {
// Ignore error, non-OSGi classloading is used in this case
}
}
public void addModel(Object resolved) {
ClassReference clazz = (ClassReference)resolved;
map.put(clazz.getClassName(), clazz);
}
public Object removeModel(Object resolved) {
return map.remove(((ClassReference)resolved).getClassName());
}
public <T> T resolveModel(Class<T> modelClass, T unresolved) {
if (!(unresolved instanceof ClassReference)) {
return unresolved;
}
Object resolved = map.get(((ClassReference)unresolved).getClassName());
if (resolved != null) {
return modelClass.cast(resolved);
}
//Load a class on demand
Class clazz = null;
if (osgiResolver != null) {
resolved = osgiResolver.resolveModel(modelClass, unresolved);
clazz = ((ClassReference)resolved).getJavaClass();
}
if (clazz == null) {
try {
// Search contribution ClassLoader (which has visibility of classes in the contribution
// as well as explicitly imported packages from other contributions)
clazz = Class.forName(((ClassReference)unresolved).getClassName(), true, classLoader.get());
} catch (ClassNotFoundException e) {
} catch (NoClassDefFoundError e) {
}
}
if (clazz != null) {
//if we load the class
// Store a new ClassReference wrapping the loaded class
ClassReference classReference = new ClassReference(clazz);
map.put(clazz.getName(), classReference);
// Return the resolved ClassReference
return modelClass.cast(classReference);
} else {
return unresolved;
}
}
/***************
* Helper methods
***************/
private String getPackageName(ClassReference clazz) {
int pos = clazz.getClassName().lastIndexOf(".");
return clazz.getClassName().substring(0, pos);
}
}
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