diff options
author | lresende <lresende@13f79535-47bb-0310-9956-ffa450edef68> | 2009-11-11 23:21:32 +0000 |
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committer | lresende <lresende@13f79535-47bb-0310-9956-ffa450edef68> | 2009-11-11 23:21:32 +0000 |
commit | 5b8a1832fcb2586965fff1ac2225399c8959f9c4 (patch) | |
tree | c83afeeb73cb5493bb91e3e41161e8708e3b18c1 /sca-java-2.x/tags/2.0-M1/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java | |
parent | 9f79c8a050ff86907695027893e56080988c09d8 (diff) |
Moving 2.x tags
git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@835148 13f79535-47bb-0310-9956-ffa450edef68
Diffstat (limited to 'sca-java-2.x/tags/2.0-M1/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java')
-rw-r--r-- | sca-java-2.x/tags/2.0-M1/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/sca-java-2.x/tags/2.0-M1/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java b/sca-java-2.x/tags/2.0-M1/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java new file mode 100644 index 0000000000..12979723b1 --- /dev/null +++ b/sca-java-2.x/tags/2.0-M1/modules/extensibility/src/main/java/org/apache/tuscany/sca/core/DefaultExtensionPointRegistry.java @@ -0,0 +1,186 @@ +/* + * 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.ServiceDeclaration; +import org.apache.tuscany.sca.extensibility.ServiceDiscovery; + +/** + * 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>(); + + /** + * Constructs a new registry. + */ + public DefaultExtensionPointRegistry() { + } + + /** + * 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 + * + * @throws IllegalArgumentException if extensionPoint is null + */ + public void addExtensionPoint(Object extensionPoint) { + if (extensionPoint == null) { + throw new IllegalArgumentException("Cannot register null as an ExtensionPoint"); + } + + Set<Class<?>> interfaces = getAllInterfaces(extensionPoint.getClass()); + for (Class<?> i : interfaces) { + extensionPoints.put(i, extensionPoint); + } + } + + 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 extension point by the interface that it implements + * + * @param extensionPointType The lookup key (extension point interface) + * @return The instance of the extension point + * + * @throws IllegalArgumentException if extensionPointType is null + */ + public <T> T getExtensionPoint(Class<T> extensionPointType) { + if (extensionPointType == null) { + throw new IllegalArgumentException("Cannot lookup ExtensionPoint of type null"); + } + + Object extensionPoint = extensionPoints.get(extensionPointType); + if (extensionPoint == null) { + + // Dynamically load an extension point class declared under META-INF/services + try { + ServiceDeclaration extensionPointDeclaration = ServiceDiscovery.getInstance().getFirstServiceDeclaration(extensionPointType.getName()); + if (extensionPointDeclaration != null) { + Class<?> extensionPointClass = extensionPointDeclaration.loadClass(); + + // Construct the extension point + Constructor<?>[] constructors = extensionPointClass.getConstructors(); + Constructor<?> constructor = getConstructor(constructors, new Class<?>[] {ExtensionPointRegistry.class}); + if (constructor != null) { + extensionPoint = constructor.newInstance(this); + } else { + constructor = getConstructor(constructors, new Class<?>[] {}); + if (constructor != null) { + extensionPoint = constructor.newInstance(); + } else { + throw new IllegalArgumentException( + "No valid constructor is found for " + extensionPointClass); + } + } + + // 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 + * + * @throws IllegalArgumentException if extensionPoint is null + */ + public void removeExtensionPoint(Object extensionPoint) { + if (extensionPoint == null) { + throw new IllegalArgumentException("Cannot remove null as an 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) { + 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); + } + } + +} |