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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.core;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.tuscany.sca.contribution.ModelFactoryExtensionPoint;
import org.apache.tuscany.sca.contribution.util.ServiceConfigurationUtil;
/**
* Default implementation of a registry to hold all the Tuscany core extension
* points. As the point of contact for all extension artifacts this registry
* allows loaded extensions to find all other parts of the system and register
* themselves appropriately.
*
* @version $Rev$ $Date$
*/
public class DefaultExtensionPointRegistry implements ExtensionPointRegistry {
private Map<Class<?>, Object> extensionPoints = new HashMap<Class<?>, Object>();
/**
* Add an extension point to the registry. This default implementation
* stores extensions against the interfaces that they implement.
*
* @param extensionPoint The instance of the extension point
*/
public void addExtensionPoint(Object extensionPoint) {
Set<Class> interfaces = getAllInterfaces(extensionPoint.getClass());
for (Class i : interfaces) {
extensionPoints.put(i, extensionPoint);
}
}
/**
* Get the extension point by the interface that it implements
*
* @param extensionPointType The lookup key (extension point interface)
* @return The instance of the extension point
*/
public <T> T getExtensionPoint(Class<T> extensionPointType) {
Object extensionPoint = extensionPoints.get(extensionPointType);
if (extensionPoint == null) {
// Dynamically load an extension point class declared under META-INF/services
ClassLoader classLoader = extensionPointType.getClassLoader();
try {
List<String> classNames = ServiceConfigurationUtil.getServiceClassNames(classLoader, extensionPointType.getName());
if (!classNames.isEmpty()) {
Class<?> extensionPointClass = Class.forName(classNames.iterator().next(), true, classLoader);
// Construct the extension point
try {
Constructor constructor = extensionPointClass.getConstructor();
extensionPoint = constructor.newInstance();
} catch (NoSuchMethodException e) {
try {
Constructor constructor = extensionPointClass.getConstructor(ModelFactoryExtensionPoint.class);
extensionPoint = constructor.newInstance(getExtensionPoint(ModelFactoryExtensionPoint.class));
} catch (NoSuchMethodException e2) {
try {
Constructor constructor = extensionPointClass.getConstructor(ExtensionPointRegistry.class);
extensionPoint = constructor.newInstance(this);
} catch (NoSuchMethodException e3) {
throw new IllegalArgumentException(e3);
}
}
}
// Cache the loaded extension point
addExtensionPoint(extensionPoint);
}
} catch (InvocationTargetException e) {
throw new IllegalArgumentException(e);
} catch (IOException e) {
throw new IllegalArgumentException(e);
} catch (ClassNotFoundException e) {
throw new IllegalArgumentException(e);
} catch (InstantiationException e) {
throw new IllegalArgumentException(e);
} catch (IllegalAccessException e) {
throw new IllegalArgumentException(e);
}
}
return extensionPointType.cast(extensionPoint);
}
/**
* Remove an extension point based on the interface that it implements
*
* @param extensionPoint The extension point to remove
*/
public void removeExtensionPoint(Object extensionPoint) {
Set<Class> interfaces = getAllInterfaces(extensionPoint.getClass());
for (Class i : interfaces) {
extensionPoints.remove(i);
}
}
/**
* Returns the set of interfaces implemented by the given class and its
* ancestors or a blank set if none
*/
private static Set<Class> getAllInterfaces(Class clazz) {
Set<Class> implemented = new HashSet<Class>();
getAllInterfaces(clazz, implemented);
return implemented;
}
private static void getAllInterfaces(Class clazz, Set<Class> implemented) {
Class[] interfaces = clazz.getInterfaces();
for (Class interfaze : interfaces) {
String name = interfaze.getName();
if (name.startsWith("java.") || name.startsWith("javax.")) {
continue;
}
if (Modifier.isPublic(interfaze.getModifiers())) {
implemented.add(interfaze);
}
}
Class<?> superClass = clazz.getSuperclass();
// Object has no superclass so check for null
if (superClass != null && !superClass.equals(Object.class)) {
getAllInterfaces(superClass, implemented);
}
}
}
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