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Diffstat (limited to '')
-rw-r--r-- | sca-java-2.x/tags/2.0-Beta1-RC2/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/sca-java-2.x/tags/2.0-Beta1-RC2/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java b/sca-java-2.x/tags/2.0-Beta1-RC2/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java new file mode 100644 index 0000000000..40e4635d77 --- /dev/null +++ b/sca-java-2.x/tags/2.0-Beta1-RC2/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java @@ -0,0 +1,219 @@ +/* + * 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 static org.apache.tuscany.sca.extensibility.ServiceHelper.newInstance; + +import java.lang.reflect.Modifier; +import java.util.HashSet; +import java.util.IdentityHashMap; +import java.util.Iterator; +import java.util.Map; +import java.util.Set; +import java.util.concurrent.ConcurrentHashMap; + +import org.apache.tuscany.sca.extensibility.ServiceDeclaration; + +/** + * Default implementation of an extension point to hold Tuscany utility utilities. + * + * @version $Rev$ $Date$ + */ +public class DefaultUtilityExtensionPoint implements UtilityExtensionPoint { + private Map<Object, Object> utilities = new ConcurrentHashMap<Object, Object>(); + + private ExtensionPointRegistry registry; + /** + * Constructs a new extension point. + */ + public DefaultUtilityExtensionPoint(ExtensionPointRegistry extensionPoints) { + this.registry = extensionPoints; + } + + /** + * Add a utility to the extension point. This default implementation + * stores utilities against the interfaces that they implement. + * + * @param utility The instance of the utility + * + * @throws IllegalArgumentException if utility is null + */ + public void addUtility(Object utility) { + addUtility(null, utility); + } + + public void addUtility(Object key, Object utility) { + if (utility == null) { + throw new IllegalArgumentException("Cannot register null as a Service"); + } + + if (utility instanceof LifeCycleListener) { + ((LifeCycleListener)utility).start(); + } + + if (key == null) { + Class<?> cls = utility.getClass(); + Set<Class<?>> interfaces = getAllInterfaces(cls); + for (Class<?> i : interfaces) { + utilities.put(i, utility); + } + if (interfaces.isEmpty() || isConcreteClass(cls)) { + utilities.put(cls, utility); + } + } else { + utilities.put(key, utility); + } + } + + /** + * Get the utility by the interface that it implements + * + * @param utilityType The lookup key (utility interface) + * @return The instance of the utility + * + * @throws IllegalArgumentException if utilityType is null + */ + public <T> T getUtility(Class<T> utilityType) { + return getUtility(utilityType, null); + } + + /** + * Remove a utility based on the interface that it implements + * + * @param utility The utility to remove + * + * @throws IllegalArgumentException if utility is null + */ + public void removeUtility(Object utility) { + if (utility == null) { + throw new IllegalArgumentException("Cannot remove null as a Service"); + } + + if(utility instanceof LifeCycleListener) { + ((LifeCycleListener) utility).stop(); + } + + for (Iterator<Map.Entry<Object, Object>> i = utilities.entrySet().iterator(); i.hasNext();) { + Map.Entry<Object, Object> entry = i.next(); + if (entry.getValue() == utility) { + i.remove(); + } + } + } + + /** + * 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); + implemented.remove(LifeCycleListener.class); + return implemented; + } + + private static void getAllInterfaces(Class<?> clazz, Set<Class<?>> implemented) { + Class<?>[] interfaces = clazz.getInterfaces(); + for (Class<?> interfaze : interfaces) { + 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); + } + } + + public <T> T getUtility(Class<T> utilityType, Object key) { + if (utilityType == null) { + throw new IllegalArgumentException("Cannot lookup Service of type null"); + } + + if (key == null) { + key = utilityType; + } + + Object utility = utilities.get(key); + + if (utility == null) { + + // Dynamically load a utility class declared under META-INF/services/"utilityType" + try { + ServiceDeclaration utilityDeclaration = + registry.getServiceDiscovery().getServiceDeclaration(utilityType.getName()); + Class<?> utilityClass = null; + if (utilityDeclaration != null) { + utilityClass = utilityDeclaration.loadClass(); + } else if (isConcreteClass(utilityType)) { + utilityClass = utilityType; + key = utilityType; + } + if (utilityClass != null) { + // Construct the utility + if (utilityDeclaration != null) { + utility = newInstance(registry, utilityDeclaration); + } else { + try { + utility = newInstance(utilityClass, ExtensionPointRegistry.class, registry); + } catch (NoSuchMethodException e) { + utility = newInstance(utilityClass); + } + } + // Cache the loaded utility + if (key == utilityType) { + addUtility(utility); + } else { + addUtility(key, utility); + } + } + } catch (Throwable e) { + throw new IllegalArgumentException(e); + } + } + return utilityType.cast(utility); + } + + private boolean isConcreteClass(Class<?> utilityType) { + int modifiers = utilityType.getModifiers(); + return !utilityType.isInterface() && Modifier.isPublic(modifiers) && !Modifier.isAbstract(modifiers); + } + + public void start() { + // NOOP + } + + public synchronized void stop() { + // Get a unique map as an extension point may exist in the map by different keys + Map<LifeCycleListener, LifeCycleListener> map = new IdentityHashMap<LifeCycleListener, LifeCycleListener>(); + for (Object util : utilities.values()) { + if (util instanceof LifeCycleListener) { + LifeCycleListener listener = (LifeCycleListener)util; + map.put(listener, listener); + } + } + for (LifeCycleListener listener : map.values()) { + listener.stop(); + } + utilities.clear(); + } + +} |