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Diffstat (limited to 'sca-java-1.x/tags/1.6/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java')
-rw-r--r-- | sca-java-1.x/tags/1.6/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/sca-java-1.x/tags/1.6/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java b/sca-java-1.x/tags/1.6/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java new file mode 100644 index 0000000000..6f7c83c8d9 --- /dev/null +++ b/sca-java-1.x/tags/1.6/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultUtilityExtensionPoint.java @@ -0,0 +1,184 @@ +/* + * 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.Map; +import java.util.Set; + +import org.apache.tuscany.sca.extensibility.ServiceDiscovery; + +/** + * Default implementation of an extension point to hold Tuscany utility utilities. + * + * @version $Rev$ $Date$ + */ +public class DefaultUtilityExtensionPoint implements UtilityExtensionPoint { + private Map<Class<?>, Object> utilities = new HashMap<Class<?>, Object>(); + + private ExtensionPointRegistry extensionPoints; + + /** + * Constructs a new extension point. + */ + public DefaultUtilityExtensionPoint(ExtensionPointRegistry extensionPoints) { + this.extensionPoints = 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) { + if (utility == null) { + throw new IllegalArgumentException("Cannot register null as a Service"); + } + + Set<Class<?>> interfaces = getAllInterfaces(utility.getClass()); + for (Class<?> i : interfaces) { + utilities.put(i, utility); + } + } + + private Constructor<?> getConstructor(Constructor<?>[] constructors, Class<?>[] paramTypes) { + for (Constructor<?> c : constructors) { + Class<?>[] types = c.getParameterTypes(); + if (c.getParameterTypes().length == paramTypes.length) { + boolean found = true; + for (int i = 0; i < types.length; i++) { + if (types[i] != paramTypes[i]) { + found = false; + break; + } + } + if (found) { + return c; + } + } + } + return null; + } + + /** + * 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) { + if (utilityType == null) { + throw new IllegalArgumentException("Cannot lookup Service of type null"); + } + + Object utility = utilities.get(utilityType); + if (utility == null) { + + // Dynamically load a utility class declared under META-INF/utilities + try { + Class<?> utilityClass = + ServiceDiscovery.getInstance().loadFirstServiceClass(utilityType); + if (utilityClass != null) { + // Construct the utility + Constructor<?>[] constructors = utilityClass.getConstructors(); + Constructor<?> constructor = getConstructor(constructors, new Class<?>[] {ExtensionPointRegistry.class}); + if (constructor != null) { + utility = constructor.newInstance(extensionPoints); + } else { + constructor = getConstructor(constructors, new Class<?>[] {}); + if (constructor != null) { + utility = constructor.newInstance(); + } else { + throw new IllegalArgumentException( + "No valid constructor is found for " + utilityClass); + } + } + + // Cache the loaded utility + addUtility(utility); + } + } 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 utilityType.cast(utility); + } + + /** + * 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"); + } + + Set<Class<?>> interfaces = getAllInterfaces(utility.getClass()); + for (Class<?> i : interfaces) { + utilities.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) { + 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); + } + } + +} |