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Diffstat (limited to 'sandbox/ant/sca/branches/2.0-M2/modules/workspace/src/main/java/org/apache/tuscany/sca/workspace/builder/DefaultContributionBuilderExtensionPoint.java')
-rw-r--r-- | sandbox/ant/sca/branches/2.0-M2/modules/workspace/src/main/java/org/apache/tuscany/sca/workspace/builder/DefaultContributionBuilderExtensionPoint.java | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/sandbox/ant/sca/branches/2.0-M2/modules/workspace/src/main/java/org/apache/tuscany/sca/workspace/builder/DefaultContributionBuilderExtensionPoint.java b/sandbox/ant/sca/branches/2.0-M2/modules/workspace/src/main/java/org/apache/tuscany/sca/workspace/builder/DefaultContributionBuilderExtensionPoint.java new file mode 100644 index 0000000000..8ce6f53f20 --- /dev/null +++ b/sandbox/ant/sca/branches/2.0-M2/modules/workspace/src/main/java/org/apache/tuscany/sca/workspace/builder/DefaultContributionBuilderExtensionPoint.java @@ -0,0 +1,138 @@ +/* + * 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.workspace.builder; + +import java.lang.reflect.Constructor; +import java.util.HashMap; +import java.util.Map; +import java.util.Set; + +import org.apache.tuscany.sca.contribution.Contribution; +import org.apache.tuscany.sca.core.ExtensionPointRegistry; +import org.apache.tuscany.sca.core.FactoryExtensionPoint; +import org.apache.tuscany.sca.extensibility.ServiceDeclaration; +import org.apache.tuscany.sca.extensibility.ServiceDiscovery; +import org.apache.tuscany.sca.monitor.Monitor; +import org.apache.tuscany.sca.workspace.Workspace; + +/** + * Default implementation of a provider factory extension point. + * + * @version $Rev$ $Date$ + */ +public class DefaultContributionBuilderExtensionPoint implements ContributionBuilderExtensionPoint { + + private ExtensionPointRegistry registry; + private final Map<String, ContributionBuilder> builders = new HashMap<String, ContributionBuilder>(); + private boolean loaded; + + public DefaultContributionBuilderExtensionPoint(ExtensionPointRegistry registry) { + this.registry = registry; + } + + public void addContributionBuilder(ContributionBuilder builder) { + builders.put(builder.getID(), builder); + } + + public void removeContributionBuilder(ContributionBuilder builder) { + builders.remove(builder.getID()); + } + + public ContributionBuilder getContributionBuilder(String id) { + loadBuilders(); + return builders.get(id); + } + + /** + * Load builders declared under META-INF/services. + */ + private synchronized void loadBuilders() { + if (loaded) + return; + + FactoryExtensionPoint factories = registry.getExtensionPoint(FactoryExtensionPoint.class); + + // Get the provider factory service declarations + Set<ServiceDeclaration> builderDeclarations; + ServiceDiscovery serviceDiscovery = ServiceDiscovery.getInstance(); + try { + builderDeclarations = serviceDiscovery.getServiceDeclarations(ContributionBuilder.class.getName()); + } catch (Exception e) { + throw new IllegalStateException(e); + } + + for (ServiceDeclaration builderDeclaration : builderDeclarations) { + Map<String, String> attributes = builderDeclaration.getAttributes(); + String id = attributes.get("id"); + + ContributionBuilder builder = new LazyContributionBuilder(id, builderDeclaration, this, factories); + builders.put(id, builder); + } + } + + /** + * A wrapper around a contribution builder allowing lazy + * loading and initialization of implementation providers. + */ + private static class LazyContributionBuilder implements ContributionBuilder { + + private FactoryExtensionPoint factories; + private String id; + private ServiceDeclaration builderDeclaration; + private ContributionBuilder builder; + private ContributionBuilderExtensionPoint builders; + + private LazyContributionBuilder(String id, ServiceDeclaration factoryDeclaration, + ContributionBuilderExtensionPoint builders, FactoryExtensionPoint factories) { + this.id = id; + this.builderDeclaration = factoryDeclaration; + this.builders = builders; + this.factories = factories; + } + + public String getID() { + return id; + } + + public void build(Contribution contribution, Workspace workspace, Monitor monitor) throws ContributionBuilderException { + getBuilder().build(contribution, workspace, monitor); + } + + private ContributionBuilder getBuilder() { + if (builder == null) { + try { + Class<ContributionBuilder> builderClass = (Class<ContributionBuilder>)builderDeclaration.loadClass(); + try { + Constructor<ContributionBuilder> constructor = builderClass.getConstructor(FactoryExtensionPoint.class); + builder = constructor.newInstance(factories); + } catch (NoSuchMethodException e) { + Constructor<ContributionBuilder> constructor = builderClass.getConstructor(ContributionBuilderExtensionPoint.class, FactoryExtensionPoint.class); + builder = constructor.newInstance(builders, factories); + } + } catch (Exception e) { + throw new IllegalStateException(e); + } + } + return builder; + } + + } + +} |