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Diffstat (limited to 'sca-java-1.x/branches/sca-java-0.99/modules/core-spi/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java')
-rw-r--r-- | sca-java-1.x/branches/sca-java-0.99/modules/core-spi/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/sca-java-1.x/branches/sca-java-0.99/modules/core-spi/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java b/sca-java-1.x/branches/sca-java-0.99/modules/core-spi/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java new file mode 100644 index 0000000000..aafa23b7f5 --- /dev/null +++ b/sca-java-1.x/branches/sca-java-0.99/modules/core-spi/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java @@ -0,0 +1,152 @@ +/* + * 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); + } + } + +} |