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Diffstat (limited to '')
-rw-r--r-- | sca-java-2.x/tags/2.0-M5-RC2/modules/contribution/src/main/java/org/apache/tuscany/sca/contribution/resolver/DefaultModelResolverExtensionPoint.java | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/sca-java-2.x/tags/2.0-M5-RC2/modules/contribution/src/main/java/org/apache/tuscany/sca/contribution/resolver/DefaultModelResolverExtensionPoint.java b/sca-java-2.x/tags/2.0-M5-RC2/modules/contribution/src/main/java/org/apache/tuscany/sca/contribution/resolver/DefaultModelResolverExtensionPoint.java new file mode 100644 index 0000000000..a1eb85edca --- /dev/null +++ b/sca-java-2.x/tags/2.0-M5-RC2/modules/contribution/src/main/java/org/apache/tuscany/sca/contribution/resolver/DefaultModelResolverExtensionPoint.java @@ -0,0 +1,131 @@ +/* + * 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.contribution.resolver; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Collection; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.StringTokenizer; + +import org.apache.tuscany.sca.core.ExtensionPointRegistry; +import org.apache.tuscany.sca.extensibility.ServiceDeclaration; + + +/** + * The default implementation of a model resolver extension point. + * + * @version $Rev$ $Date$ + */ +public class DefaultModelResolverExtensionPoint implements ModelResolverExtensionPoint { + + private final Map<Class<?>, Class<? extends ModelResolver>> resolvers = new HashMap<Class<?>, Class<? extends ModelResolver>>(); + private Map<String, ServiceDeclaration> loadedResolvers; + private ExtensionPointRegistry registry; + + /** + * Constructs a new DefaultModelResolverExtensionPoint. + */ + public DefaultModelResolverExtensionPoint(ExtensionPointRegistry registry) { + this.registry = registry; + } + + public void addResolver(Class<?> modelType, Class<? extends ModelResolver> resolver) { + resolvers.put(modelType, resolver); + } + + public void removeResolver(Class<?> modelType) { + resolvers.remove(modelType); + } + + @SuppressWarnings("unchecked") + public Class<? extends ModelResolver> getResolver(Class<?> modelType) { + loadModelResolvers(); + + Class<?>[] classes = modelType.getInterfaces(); + for (Class<?> c : classes) { + Class<? extends ModelResolver> resolver = resolvers.get(c); + if (resolver == null) { + ServiceDeclaration resolverClass = loadedResolvers.get(c.getName()); + if (resolverClass != null) { + try { + return (Class<? extends ModelResolver>)resolverClass.loadClass(); + } catch (ClassNotFoundException e) { + throw new IllegalArgumentException(e); + } + } + } else { + return resolver; + } + } + + Class<? extends ModelResolver > resolver = resolvers.get(modelType); + if (resolver == null) { + ServiceDeclaration resolverClass = loadedResolvers.get(modelType.getName()); + if (resolverClass != null) { + try { + return (Class<? extends ModelResolver>)resolverClass.loadClass(); + } catch (ClassNotFoundException e) { + throw new IllegalArgumentException(e); + } + } + } + return resolver; + } + + /** + * Dynamically load model resolvers declared under META-INF/services + */ + private synchronized void loadModelResolvers() { + if (loadedResolvers != null) + return; + loadedResolvers = new HashMap<String, ServiceDeclaration>(); + + // Get the model resolver service declarations + Collection<ServiceDeclaration> modelResolverDeclarations; + try { + modelResolverDeclarations = registry.getServiceDiscovery().getServiceDeclarations(ModelResolver.class, true); + } catch (IOException e) { + throw new IllegalStateException(e); + } + + List<ServiceDeclaration> list = new ArrayList<ServiceDeclaration>(modelResolverDeclarations); + + // Load model resolvers, add entries from lower ranking to higher ranking so that higher ranking ones override + // the map + for (int i = list.size() - 1; i >= 0; i--) { + ServiceDeclaration modelResolverDeclaration = list.get(i); + Map<String, String> attributes = modelResolverDeclaration.getAttributes(); + String model = attributes.get("model"); + // The model can be a list of interfaces so that one model resolver can be used + // to resolve different types of models + if (model != null) { + StringTokenizer tokenizer = new StringTokenizer(model); + while (tokenizer.hasMoreTokens()) { + String key = tokenizer.nextToken(); + loadedResolvers.put(key, modelResolverDeclaration); + } + + } + } + } + +} |